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SDR - Software Defined Radio


CiaoRadio H101 CommRadio CR-1 ELAD FDM-DUOr ELAD FDM-S1 ELAD FDM-S2
Enablia TitanSDR Expert E. ColibriDDC SDR ColibriNANO Microtelecom FM+ Icom IC-R8600 KiwiSDR
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Profi- Receivers

AEG E800/2

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Racal RA1792 Racal RA3712 Reuter RDR54 Reuter RDR55D RFT EKD 500 SRT CR91
Telefunken E1501 Telefunken E1700 Ten-Tec RX340 Watkins Johnson HF-1000 Cubic CDR-3250  


Portable World Band Receivers

Degen DE1105 Degen DE1106 Eton E5 Eton / Lextronix E1 Grundig Yacht Boy 80 Grundig G6 Aviator
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Tecsun PL-600 Tecsun PL-880 Tecsun S-8800e      


Receiver Kit

Junior 1 from Stampfl          

RadioJet 1102S

Even before its introduction to the market shortly before Christmas 2011, there were wild speculations, debates and even fights. Nobody knew exactly, what sort of radio would appear on the market. Due to faulty parts, production and shipping were delayed and additionally, there was a shortness of supply which gave even more reasons for speculations. All in all, it was an unsuccessful start for the RadioJet 1102. In the mean time, the receivers have been shipped and speculations ended. Bonito was friendly enough to put a RadioJet at my disposal for testing Thank you vey much! What sort of radio is the RadioJet? Well, it is no normal SDR. It is an analogue receiver with a soundcard in the same case. The signals are digitized and sent to the PC. With  an extensive software the signal can then be decoded, analyzed before it is sent to the loudspeaker. There is some getting  used to it because of the enormous capabilities of the software. During this learning curve, the manual will become a good friend of yours because you will get to know functions which you didn't know before. Reception range is from 40 KHz to 30MHz in AM, SSB, CW, FM, WFM and DRM.  There is also room for external frequency converters to enhance the reception range.  By the way, DRM works without external software. The software has functions which are unrivalled in its class. An interesting new function is the RX/DX channel. This function makes it possible to enhance sensitivity and decrease noise at the same time. Of course, this results in a slight loss of large signal immunity but it makes listening to weak signal possible. This feature only works in a quiet environment. Another handy feature: The selected station is shown in the spectrum next to the signal peak and appears on a world map with the borderline of day/night being shown. Another unique feature is the 'filter manipulator'. You can create your own bandwidths and save them. Its is also possible to draw any number of notch filters within these band width filters. The steepness of the filters can be adjusted as well. The spectrum scope can have the form of a waterfall and even 3D with many possibilities of adjusting the scope. Then there are the software window and the extensive frequency bank which can be edited, of course. I will do without a further list of other functions and possibilities. That would be far beyond the scope of this short presentation. Please, consult the manual on Bonito's website. Everything is described  there in detail with pictures of the functions.

The most important question: How is reception?

At the time of writing (March 28, 2012), I am comparing the RadioJet with the Perseus SDR and have been able to  gather a few hours of experience with the RadioJet. This is absolutely vital because the RadioJet is very demanding regarding its software. After adjusting everything the way it is supposed to be,  both radios are alike as far as the rendering of the signals is concerned. There were no problems with strong signals,  not even with the DX-channel. As regards sensitivity, both radios are on par. Contrary to the technical data,  the Perseus is a tiny bit more sensitive and has a little less noise. This article is meant to be short presentation of the RadioJet 1102. On the page " reception samples", you can hear audio samples of both radios. As a preliminary result you can say that the RadioJet is a top class receiver with an extraordinary software. With a current price of 600 € it is not cheap but worth it.

Please note: Just with other SDRs, the software of the RadioJet requires extensive programming.  Naturally, there are still minor bugs which are gotten rid of by Bonito. The software will be continuously improved.

posted 24.04.2012


RadioJet in Action (HD Video)


RadioJet 1102S >> News

Since the first test many changes and improvements of the RadioJet software have been made. So much has been done that mentioning everything would be too much of a good thing. But I would like to mention some improvements, nonetheless. It has always been a point of critique that the frequency spectrum of the RadioJet is only 24 KHz wide. Now, the software makes it possible to incorporate a second SDR with a large broadband spectrum. This way, you can make use of the RadioJet as an 'audio receiver' and the signal of the second SDR is shown on the broadband spectrum. This broadband spectrum can be adjusted, too. If you already own a RadioJet you can buy ,e.g., the FiFi-SDR resulting in an enlarged broad band width of up to 192 KHz. Other SSDRs are supported as well, e.g., the Perseus. You then will have a 1600 KHz wide- spectrum. Please, consult the Bonito project page for further details. The new noise blanker and the new selection of the modes should also be mentioned. The reception quality was also improved and is now on par with the Perseus and even better in case of weak stations.

Below are a few HD videos showing the RadioJet in Action. The best  open in YouTube for HD.




Reuter RDR50B

It took some time for the RDR50B, which had been promised to me, to find its way into my home. The reasons were supply bottlenecks of electronic parts and a lack of available test units. However, Mr. Reuter kept his promise. Now the RDR50B with an additional FM-module has been on my table for three weeks. The RDR50B functions almost exactly like its bigger brother, the RDR54. The RDR54 is built in a modular concept; it has only one big main board on which you can attach the FM- and the transmitter modules. The biggest difference to the RDR54 is its large touch screen. Every function can be controlled with a touch of your finger, almost like an iPad! Luckily, the radio has a sensitive VFO made of stainless steel for frequency selection. The special feature of all of the Reuter-radios is their mechanical work, no plastic parts were used. The case is made of milled aluminum and anodized in black. In this respect, the Reuter radios are in their own league. Absolute top quality!
If you are familiar with RDRs, the operation of the RDR50B is easy. Compared with the RDR54, everything can now be controlled faster because of the touch screen. The click area is a little too small at times. You have to aim very accurately to get at some functions. But that is all a matter of getting used to it. After some hours, everything went smoothly.
The RDR50B has the following modes and options for reception improvements:
-SYNC automatic detection of the carrier with selectable sidebands (like AM-synchronous)*
-EUSB - for signals starting at 0 Hz*
-SBCW-automatic switching of the side bands at 10 MHz
-IFIQ direct readout of the received signals on an intermediate frequency
-BAIQ direct readout of the received signals in a base band
-63 memories, which save all the parameters of the frequency. Unfortunately, the memories are not alphanumeric for the time being because of technical reasons.
-The bandwidth filters can be adjusted in 40 Hz steps from 10 Hz - 10 KHz and in 80 Hz steps from 10 KHz - 20 KHz.
-Band pass tuning (IF shift)
-manual notch filter
-noise blanker
-DNR (Digital Noise Reduction)
Thus, the RDR50B is ready for almost every situation.
Regarding the most important criteria, such as low noise, intelligibility, selectivity and large signal immunity, the RDR50B is top class! Compared to my other radios, the RDR50B was almost always just as good. It especially showed its strength when trying to receive weak stations. With such low noise, it was almost always better than the other receivers. But where there is light, there is also shadow. Because of its special way of working, the RDR50B sounds a little tinny in its modulation. It sounds digital and artificial. But these are the only weak points of the radio.
Just like the RDR54, the RDR50B is a SDR (Software Defined Radio) and depends on a PC. Except when downloading software updates.
The built in FM- module is in its own class. It has a sound and selectivity, which are unrivalled in its class. I will put audio comparisons on the internet, which can be found here….
As to the scope of the functions of the RDR50B, I refer to the webpage of the manufacturer, Reuter Electronics. That would be beyond the scope of this article.
If you are looking for high quality manufacturing and low noise reception, the RDR50B could be the right radio for you.
*For the special modes, please consult the manual of the RDR50B.


The RDR50B in Action (HD Video) First on FM, then on SW.





RFSpace Cloud-IQ

Almost still hot from the factory, the Cloud-IQ by RFSpace is on my table. Not directly, however, because it was  the WIMO company from Germany which  put the receiver at my disposal for the first tests in Europe. After a few e-mails with Ekki (DF4OR),  the section manager for receivers, I was sent the brand-new Cloud-IQ.

Just like its preceding model, the SDR-IQ, the Cloud IQ is an inconspicuously small box with a red rim. It barely weighs 300g and its size is 101mmx122mmx30mm (width x depth x height) and is made of anodized aluminum. Included are:  a 5V external power adapter with an adapter for Europe, a two-meter long RJ 45 Ethernet cable and a power cable with a barrel connector on a USB plug for a direct connection to the PC. There is a CD with the software as well. Unfortunately, so far RFSpace has not realized that switching power supplies can cause noise on long-, medium-, and shortwave.It would have been nice, if a SMA/BNC adapter was included because the Cloud-IQ has SMA- connectors. Among amateur radio operators and SWLs, the SMA norm is not very common. You will have to buy an adapter beforehand, if you want to use the receiver right away.


Blockdiagram from Cloud-IQ

The most prominent features:
Sampling rate: 122.88 MHz 0 9Khz - 56 MHz (direct sampling)
-- 14 bit A/D converter
-- Frequency range; 9KHz - 56 MHz
-- Modes: AM, SAM, LSB, USB, WUSB, CW-L, CW-U, NFM, WFM (modes depend on software. The ones mentioned here are from SpectraVue)
-- Selectable attenuators: 0/-10/-20/-30dB
-- 2MHz switchable  high pass filter
-- 60MHz low pass filter
- -Broadband spectrum 56 MHz wide (with demodulation up to 10MHz)
-- TXCO, temperature compensated oscillator
-- 2 SMA antenna connectors
-- RF45 LAN- connector for connecting the PC or net work
-- built-in remote server
-- 5V operating voltage
-- RS232 connector for controlling external devices
-- solid, black case made of anodized aluminum.

The Cloud-IQ has its name not without a reason. It can be operated in two different ways: Either in the "Local-Mode" or in the "Cloud-Mode":

"Local mode" means that the receiver is directly connected to a local network or directly to the PC. This operating mode offers reception with all functions, full band width and full resolution of the spectrum.

In the "Cloud-Mode", the radio can be operated remotely at a different location without a computer. It only has to be connected to a router. In order to make the data transfer more stable, the amount of data is reduced in this mode, which means that the band width and the resolution are smaller. RFSpace offers a client-software at no extra charge which is available for three operating systems: Windows, OSX and Android. You can run Android on an Android-pad or on an Android smartphone.

On the included CD is the program SpectraVue which supports all functions in the "Local Mode". The three remote client-applications for Windows, OSX and Android are also on this CD. Additionally, you will find the configuration program for the remote operation of the Cloud-IQ. Last but not least there are the manuals for all these programs.

Program Installation

First, you should install the configuration software "Cloud Setup" for the Cloud-IQ. There were no problems installing it on Windows 8.1 and Windows 10. A small hint: Install all programs as "Administrator" which will avoid problems that might occur with the administrator rights. After that you connect the Cloud-IQ to the power supply, to the PC or to the router. Then you start the configuration software and look for the Cloud-IQ with "Find SDRs". Normally, it will be found at once. With a double click on the selected SDR, you reach the configuration page for the Cloud-IQ. There you select the IQ-mode for local operation and you close the window with "OK". If you want to use a router, you may  have to modify the port forwarding to activate port 50000. In the configuration window, you can also make other settings. In case you want to make your SDR accessible for the public, you can enter a time limit.

If you want to limit access to a group of people, you will have to choose a password. The settings of the IP-addresses are important, of course. All SDRs, which are available online, are listed on the web page "RFSpace SDR's on the Web."

The control program “SpectraVue” is easily installed as well. Because it is compatible with all RFSpace SDRs, you have to select the Cloud-IQ after starting the program. After that, SpectraVue has to find the Cloud-IQ, so you click the button ‘Find’ in the network setup. Now you can start at last. The installation took approx. 10 minutes including the configuration of the router and the Cloud-IQ. Not every router has to be configured, though. With my present router “Netgear WNDR3700” the port forwarding had be configured.

At first glance, the SpectraVue software looks Spartan. Many features are adjusted in the menus. Unfortunately, there is no frequency input mask. You can only select the frequency via the keypad by putting the mouse arrow above the frequency display. This is a little  unusual. The frequency can be changed with the mouse wheel by putting the mouse arrow in the spectrum. You can adjust the tuning steps in the menu. You can either tune continuously or only in the visible spectrum which is activated by clicking the button “Center Frequency-Ins.” The most important controls, such as mode selection, band width selection  etc are in the lower right corner in the program window, which is a little small, though. The menu for the selection of the AGC, noise blanker etc. can be accessed by clicking the “Set up” button. The most important parameters for the spectrum can be selected on the left side of the program window. With the function “Auto Scale” you  adjust the spectrum, the waterfall and the levels. Under the frequency display is the zoom function “Span” for the spectrum. With this function you can zoom in and out in selectable steps. SpectraVue offers 20 memories which can be selected with the button “Memory Channels” next to the span indicator. These can be edited in many ways. There are other selections for the pan adapter function, recordings and other spectrum settings. It would be beyond the scope of this article to discuss all of these.

Unfortunately, SpectraVue does not have some functions which a SDR program of the latest generation should have. SWLs will miss the inclusion of frequency lists like Eibi or Aoki. There is no notch filter, noise suppression, passband tuning and no DRM mode. In AM-synchronous mode, you cannot select the side bands separately, either. Another program, which works with the Cloud-IQ perfectly, is CuteSDR. SDR-Radio and HDSDR will be compatible soon. (September 2015).



Reception with the Cloud-IQ and SpectraVue

With a click on “Start” or on the F12 button, you start the Cloud-IQ. The first impression is always the most important one. And it was good! But let’s start at the beginning. The reference radio was the Perseus SDR. This radio also has a 14bit ADC (Analogue/Digital Converter) Both radios were operated with the supplied software. As reception antenna I used the NTi ML200, which renders the strongest signals. But I also used the NTi MegActiv and the Fenu-CrossLoop/RLA4B antennas.

Let's start at 23.4 KHz where the German Navy station DH038 transmits. Both radios had the same signal strength.  Unfortunately, this frequency range is interfered by a robotic lawn mower as can be seen in the spectrum. Antenna: ML200  

At 147.3Khz where the DWD (German Weather Service) transmits, there are practically no differences between the two receivers as far as signal strength is concerned. Antenna: ML200

In order for you to be able to make your own judgment, I recorded some reception comparisons and commented upon them. There might be differences, of course, between your and my auditory impression.

The recordings have two sections:

Sec. 0 - 10 > Cloud-IQ
Sec. 10 - 20 > Perseus
As always I recommend the use of headphones.

After DLF (Deutschlandfunk) has discontinued the use of 153 KHz, the Rumanian station Antena Satelor can be received well. As you can hear in the audio sample, the robotic lawn mower is audible and disturbs the signal. It has to be mentioned that the noiseblanker of the Perseus filters out the interference a lot better. On the other hand, the signal from the Cloud-IQ is a little better. Redeption was in AM-synchronous and 9KHz band width. Antenna: NTi MegActiv.


Europe 1 on 183 KHz renders a S9+30dB signal on both receivers. Of course, differences are small. The Cloud-IQ has a  slighter brighter and less distorted signal than the Perseus. Recdeption in AM-synchronous and 9KHz bandwidth. Antenna: NTi MegActiv.


DLF (Deutschlandfunk) on 549 KHz. Here the Cloud-IQ has clearly the upper band with a clean signal. The Perseus is noticeably less clear with local interferences. Both SDRs had their noise blankers on. The music in the background comes from UR1 from Ukraine. Reception in AM-synchronous and 9 KHz band width. Antenna: NTiMegActiv.


Laser Hot Hits on 4025 KHz. In my opinion, you can see here the weaknesses of both receivers. The noiseblanker of the Cloud-IQ badly filters out the local interferences and sometimes not at all. There is a high level of background noise in the Perseus. The crackling of the Cloud-IQ  disturbs the signal to a higher degree, though. Reception in AMS and 7 KHz bandwidth. Antenna: ML200


Radio Rebelde from Cuba on 5025 KHz. The first station I listen to in the morning before work. A real wake up call with salsa music! A little distorted today on both receivers. Receptiion in AMS and 10KHz band width. Antenna: ML200


RAF Volmet, the Royal Air Force with weather reports on 5450 KHz. Both receives render almost identical signals. Reception in USB and 2.8 KHz band width. Antenna: ML 200


A short stop on 6070 KHz with the program of the DARC. The signal is relatively strong but al little distorted from both radios. They sound fairly similar. With both radios you will notice the bane of the shortwave, namely PLC (Power line Connection). Reception in AM-synchronous and 12 KHz band width. Antenna: ML200


The 40m ham radio band: Here the signal of the Cloud-IQ is more pleasant. It has less background noise than the signal rendered by the Perseus. Reception in LSB and 3KHz bandwidth. Antenna: ML200


A short visit at the fishermen who often chatter on 8250KHz. The Cloud-IQ has a low noise signal which is disturbed, however, by some kind of crackling noise. The Perseus does not have this noise, but there is some hiss to be noticed. Reception in USB and 3 KHz band width. Antenna: ML200


Radio Revival on 9405 KHz in USB. A pirate station from Sweden. Both SDR sound very similar, with a crackling sound in the background in the case of the Cloud-IQ. With the Perseus, there is a slight hiss in the background. Reception in USB and 3.3.KHz band width. Antenna: ML200


A narrow signal for some change! On 10355 KHz, there is a channel marker of the Israeli navy. Both SDRs render the signal equally well. Reception in CW and 100 Hz band width. Antenna: ML200


On 11580 KHz Brother Stair from Florida/USA can be heard. At the time of reception, there was a very weak signal and a challenge for both receivers. The Cloud-IQ renders the signal a little better because there is less background noise. Reception in AMS and 6.7KHz band width. Antenna: Fenu-CrossLoop/RLA4B


Manila/Philippines on 12120 KHz. Identical rendering of the signals. Reception in AMS and 7.2 KHz band width. Antenna: Fenu-CrossLoop/RLA4B


Here again something from fishing! On a 13343 KHz you can hear a Portuguese fisherman, who is talking to another vessel about his catch. Generally, the Perseus seems to have more of a background hiss in SSB. Reception in USB and 2.8. KHz band width. Antenna: ML200


On 13955 a pirate station in an undetermined mode. Best in LSB. No difference in reception. Reception in LSB and 2.8 KHz band width. Antenna: NTi MegActiv


HamRadio in the 20m-band on 14275 KHZ. The Cloud-IQ had a clear edge. Reception in USB and width. Antenna: NTiMegActiv


The time signal from Canada on 14670 KHZ. The signal was very weak and had to be amplified a bit with the recording program in order to hear something at all. The Cloud-IQ seemed to be bit more sensitive. Reception in USB and 2.8KHz band width. Antenna: NTiMegActiv


Sound of Hope from Taiwan on 15800 KHz. A little more noise with the Cloud-IQ. Reception in AMS and 7.2KHz band width. Antenna:ML200


Radio France International on 17615KHz with a weak signal. Both SDRs with identical reception. Reception in AMS and 7.2 KHZ band width. Antenna: Fenu-CrossLoop/RLA4B


16m-band ham radio. Intelligibility of both signals identical. More background noise with the Perseus. Reception in USB and 2.8KHz bandwidth. Antenna. ML200


World Harvest Radio on 21600 KHz. Practically identical audio. Reception in AMS and 7.2KHz band width. Antenna: ML200.



Reception in the 6m-band with relatively poor conditions. The signal of the CW-beacon HB9SIX from Säntis (CH) can be heard well, but weak. Reception in CW and 300Hz bandwidth. Antenna: ML200.


Remote operation with the Windows Remote-Client

A really fantastic option and one which comes at no extra charge is RFSpace's Remote Client for Windows, OSX and Android. A remote client is a software, which allows the remote operation of a SDR via the internet or the local network. You don't have to be present at your PC anymore to listen to shortwave programs. You can do it leisurely from your sofa in the living room.

During this test, I used the Windows- and the Androids clients. Unfortunately, I did not have OSX at my disposal. The Windows Remote RemoteSDRClient can just as easily be installed as SpectraVue. You start the client with a double click on the appropriate icon. It will try to access the internet with the Windows firewall warning that access is blocked. Of course, you have to allow access, otherwise the client will not work.  The next step is clicking on "Find SDRs" in the upper left corner. A window will open where you can see which RFSpace-SDRs are available worldwide. You choose one by double clicking the appropriate entry. Then you push "Start" and you should hear something.

In order to avoid interruptions, the amount of data was reduced and so there is a limited spectrum and resolution, which makes sense. Data transfer via the internet or WLan can be interrupted, no matter how advanced the technology has become in the mean time.

All important modes are available, such as selectable band widths up to 7.8 KHz depending on the mode. With the Windows client, interesting opportunities are available which SpectraVue does not have, e.g., a built-in decoder which shows the decoded signals. You select the decoder by choosing the "DIG" mode. The spectrum can be adjusted between 1 KHZ and 10 MHz with constant demodulation of the signal.

To receive acceptable audio, you should set the "AGC Threshold" back to approx. -80dB. resulting in less hiss. I recommend to reduce "RF-Gain" to -10dB; then there will be less "ADC Clipping". It all depends on the connected antenna, of course.

And because it's free, here is the link for the download:


Remote operation with the Android-Client

The Remote-Client for Android is outstanding. Listening to shortwave from your own sofa in really good quality! It works very similar to the Windows-Client, but comes without the PSK-Decoder. You can adjust the frequency by swiping on the screen. By swiping on the waterfall you can change the frequency in 500Hz steps in AM. Swiping on the spectrum will change the frequency slowly also in 500 Hz steps, which makes fine-tuning easy. IN SSB, the steps are 100 Hz. In the upper right corner, there are two arrows for frequency selection.  If you want to change the frequency in MHz-steps, you touch the MHz digit in the frequency display, which turns red.  Then you simply touch one of the arrow buttons for frequency tuning in MHz- steps. With "Auto" button you can adjust the level of the spectrum. In the menu you can select band width, mode and other features.

I could tell you much more,  but it's best for you to try it yourself. It is free, after all.

Here you can download the Remote-Client for Android. SDRAnywhere



The RFSpace Cloud-IQ really surprised me and positively at that. After intensive tests and comparisons, I couldn't notice any clipping effects when SpectraVue was used, despite the fact that the radio has no pre-selection. The clipping indicator often lit up but there were no overdrive effects. When the clipping indicator lit up, in most cases it was because of the near-by pasture fences which are not more than 20m away from the antennas. That makes for strong electrical impulses. In the evenings with the reception levels rising, the clipping indicator lit up at times, especially on the lower frequencies. But that was only the case when I used the NTi ML200 antenna. Because of its size, this antenna renders big signals which are too much for the ADC of the Cloud-IQ, but even then there were no overdrive effects. Although the Cloud-IQ has only a high- and low pass filter, it can tolerate a high signal level. As far as reception quality is concerned, the receiver is on par with the Perseus.

The program SpectraVue requires some getting used to, maybe more than other programs. But once you have checked out all functions and understood them, SpectraVue turns out to be a really good control program. With the correct configuration, SpectraVue renders a good and intelligible sound and is well suited for DXing. But there are some important features missing which a modern SDR program should have. The noise blanker could be improved, because the interferences from the pasture fence were only partially filtered out.

The Remote-Clients worked very well. Especially the Android Client is fantastic and I liked it very much. But you have to make some compromises regarding the functions, but that is really of no consequence. Just give it a try.

The RFSpaceCloud-IQ is a welcome addition to the SDR market.  In the same price range as the Perseus SDR,  it renders absolutely the same signals and with the Remote Clients access to RFSpace-SDRs worldwide.

Many thanks to the WIMO company for putting the Cloud-IQ at my disposal 

Cloud-IQ product page:

WiMo home page:

posted 4.09.2015





During the past few years, the trend has been more and more toward software defined radios (SDR). Why is that? Well, in our computerized age, more and more jobs are done with the help of a PC. So it stands to reason to have hobby-related applications done by a PC as well. As far as listening to the radio is concerned, there are some advantages which we cannot do without any more.  Almost all functions, which in the past were done by hardware, are done now with computer software. You don't need hardware radios for an excellent reception of shortwave.  But still these have their right to exist because not every listener likes sitting in front of the computer all the time and would like to have a few buttons to turn.

That is the reason why I had the SDR-IQ by RFSpace sent to me from the USA.  A small nice box, solidly built, is now on my table. There isn't much to connect. A USB-cable, the antenna and that is all. The power is supplied by the USB port. The installation is without any problems. The SDR-IQ comes with a CD which contains the program "SpectraVue", which is an easy to handle program which fulfills almost all wishes of the listeners. If you want to have more functions and settings, you can use the great program "SDR Radio", which is free of charge. There you have an almost unlimited number of functions and settings. This program is a piece of joy for the listener with a good knowledge of PCs. If that is too much after all, you can try the excellent program "HDSDR", which runs on the SDR-IQ, too.

How is reception with the small SDR IQ?

I compared it to the Perseus SDR and other hardware radios. Because reception depends very much on the software, the sound of the programs is different. I liked the sound of "SDR Radio" the best. You can adjust the sound with an equalizer. But it's not perfect. When setting the frequency, the spectrum  lags behind. HDSDR can handle that a lot better and makes the tuning of the frequency really smooth. I didn't like SpectraVue that much. Tuning the frequency  cannot be done without  some jerking. But all programs are almost noise-free and make good reception possible.  The large signal immunity of the SDR-IQ is rather good with IP3+15dBm. There were hardly any overdrive effects with my antennas: 35m long wire and Fenu-Loop/HDLA3. In this respect, the Perseus is a lot better. Sensitivity is not as good as for the other radios, but is good enough for DXing. All in all, a great receiver with the possibility of using other control programs. The right radio for the SDR beginner. Not too expensive and good value.

Control programs:
SDR Radio





Ten-Tec RX-350

The Rx-350 is relatively rare in Europe. The radio comes from the USA and has not been in production since ca. 2004. The big black box is a so called SDR-receiver. That means that some functions are software-based, e.g.,  the band width filters. If you open the radio, you wonder how it all works. There is only a motherboard with some parts on it.  Well, let's close the box again and let's see what the radio is capable of. Reception is from 100 KHz - 30 MHz in the modes AM, AMS, LSB, USB, CW, RTTY and FM. It has 34 DSP band width filters, 1024 alphanumeric  memories,  a spectrum display up to 2.4. MHz ( not in real time, though), auto notch, BPT (band pass tuning) etc…. so it's well-equipped. It even has a 12 KHz IF-output and so you can decode DRM with your PC.  But there is no keyboard for entering the frequencies. Instead, there is a keyboard/VFO control unit available which can be attached at the rear panel.

In view of the scant interior of the radio, I was eager to test the receiver. I compared it to the Drake R8B and the Reuter RDR50B. This receiver is very similar to the RX-350 because it is completely digital. For an antenna I used a tried and tested 35m- long wire. I was surprised to find out that the RX-350 is a very low-noise radio on AM and has a pleasant audio.  Thinking of the JRC NRD545DSP, the RX-350 is a real treat for your ears.  But there is more to come! Seldom have I heard such a clean SSB signal from a shortwave receiver. It is practically noise-free.  Sensitivity on shortwave is very good as well. On the other hand, the RX-350 has shortcomings on long wave and medium wave. It is rather insensitive and AM synchronous is not very stable, it loses the synchronisation  relatively fast.  Large signal immunity was mostly good,  except a few overloads above 10 MHz.

A rather strange thing is the display of the band width filters. If you select 6 KHz in AM, you end up at ca. 12 KHz. In order to use 6 KHz, you have to select 3 KHz.  That is very unique! It seems as if the band width of a sideband is shown. This strange feature was kept in several firmware updates. In SSB, the display of the band width is normal.

The quality of the case is typically American: inexpensive! If you knock on the case, there is a clattering noise and it sounds hollow.

But apart from that, the Ten Tec RXC-350 is a good shortwave receiver with an impressive SSB audio. Many thanks to an anonymous hobbyist  for putting this radio at my disposal.

posted 03.09.2012



Winradio G31DDC Excalibur

What does "Excalibur" mean? It is about the sword, that the sorcerer Merlin rammed into a rock and anyone who could pull it out again had a right to the throne. According to the legend, it was Artus, who pulled the sword out and became king.

But in this context it is an entirely different story. It is about an excellent software defined radio, in short: an SDR. The Excalibur can only be operated with a PC or a powerful notebook. It is a so-called black box like the Perseus SDR and the SDR IQ.  The frequency range is from  0 - 50MHz. The whole frequency spectrum can be displayed in the lower part of the software. You can also select 30 MHz. The upper left display shows a selectable frequency range, called "DDC Band Width", which can be between 50 KHz and 2000KHz. To the right of it, there is the demodulator window.   It changes the width depending on the selected DDC band width.  In the demodulator window you can process the signal. All these windows can be displayed as waterfall or spectrum, except the demodulation window itself.  The Excalibur has all modes: AM, AMS (with selectable sidebands), LSB, USB, CW, FM, DRM, FSK UDM (user definable mode).  The Eibi-list, the HFCC frequency lists and user definable memories are also included. There is a variable notch filter and an audio high- and low pass filter. By the way, the Excalibur has three independent receivers (software) which are freely programmable. In short, almost every feature can be user-defined, which is good on the one hand, but on the other, there is much more to do which is not really easy for the casual  short waver listener. The Perseus SDR is more user-friendly because not so many features are user-definable. But if you are patient and take your time to become familiar with the Excalibur,  you won't be disappointed.

But now back to the receiving qualities. What does  Artus' sword sound like?  To start with: Top class!!

Compared to the Perseus SDR, the Excalibur proved to be more sensitive. Especially in the upper frequencies, e.g., Radio Ex. de Espania on 21610 KHz, the Excalibur is clearly superior to the Perseus.  The sound is excellent, too. Thanks to the audio high-/low pass filters and other selectable features, you can get the best possible audio quality.  But there are disadvantages as well: The large signal immunity is not as good as the Perseus'.  Below the long wave range, strong overloads from shortwave are noticeable.  Also, the noise blanker could be improved a lot. Because I live in the country,  near some pasture fences, "NB" would be very important to me. Unfortunately, the Excalibur cannot filter out the noise from the electric fences, whereas the Perseus can achieve that completely and the noise is eliminated. In conclusion, you may say that the Excalibur has great potential.  If the software is improved, the receiver will be top notch.  Analogue radios cannot compete with this flexibility.



Yaesu FRG-8800

During the 1990s, the FRG-8800 was the most favorite receiver of the shortwave listeners and was widely used.  It was a short wave receiver, which did not cost too much and offered good reception. Like many other receivers in this league, theFRG-8800 does not tolerate large antennas.  You should not use more than a 10m long wire. Active antennas should also be only used with caution.  The active antenna FRA-7700 could be attached without any problems, because it has a pre-selection feature.  The audio and the tone control work rather well. You can also add a VHF converter, which makes listening to 118 MHz - 174 MHz possible.  The FRG-8800 can also be used as portable radio because it has a battery case.  I am sure that the FRG 8800 is still in many a shack and serves its purpose. Way back then, it was a bestseller.




Yaesu FRG-100

The FRG-100 is a very good shortwave receiver, which is not built any more. That is really too bad because it has a very good large signal immunity, indeed, it is one of the very few hobby receivers which can handle long wires without much overdrive. The radio has 50 memories which store the modes and the filter widths.  Unfortunately, FM is only available as an option, which is not too bad, really. One thing which is missing, though, is a frequency input keyboard. Changing frequencies with Up/Down buttons is a little cumbersome.  But you get used to it.

How is reception?

By and large it is very good! The receiver can handle large antennas. Using a 20m long wire antenna and a vertical modified 5.5m long CB-antenna, there were no overload effects. Well done!! But just like other receivers,  the FRG-100 is not perfect, either. The AGC is too slow. In case of thunderstorms, the S-meter deflects because of the electrical impulses.  During the time the S-meter goes back to indicate the actual field strength, the receiver is mute. The same effect occurs when you scan the bands fast. There is a small and easy-to-build modification to make the AGC faster. The sound is not really impressive. It reminds you of the NRD 525/535. There is small modification for this problem as well. With these modifications installed, the FRG-100 will convince you.



Yaesu VR-5000

To start with, the operation of the Yaesu VR-500 is complicated. The frequency range is from 100Khz - 2600MHz, so the radio is not only for shortwave reception. It is solidly built, nice-looking an sounds good. The radio has many functions, I don't know how many. I didn't have the receiver for long. It should be mentioned that although being a scanner, the VR-5000 works rather well on shortwave, provided you use a preselector or an antenna which mustn't be too long. Otherwise, there will be overload effects right away.





Portable World Band Receivers

Degen DE1105

I imported this Degen DE1105 directly from China because it is not available in Europe. It is unbelievable what you get for a ridiculously small amount of60 $ or 75 CHF incl. shipping. This little radio is in a league of its own: 118x73x23 (HxLxW) and 1000 non-volatile memories divided into 10 pages. Modes are: FM (70-108 MHz), shortwave (5800KZ - 26100 KHz) and medium wave (522-1620KHz). It is even possible to listen to programs in stereo with selectable bass boost. It has one timer and three fully programmable alarm clocks. You can store the time, any frequency and the volume of the alarm clock. Reception with a 50cm long telescopic antenna is surprisingly good. Reception on shortwave is also very good because of the rather good selectivity of the radio. Listening to music on FM is a real joy especially with a good stereo earplug which is included. You will notice that there are no annoying noises when tuning the radio with the thumb wheel or the +/- button. Brilliant!! The DE1105 also has an integrated charger and a complete keyboard, a thermometer in °C etc, etc…. The workmanship is top quality. The front of the DE1105 is made of titanium colored brushed aluminum.

Scope of delivery: DE1105, protective bag made of flannel, 2 NiMh-batteries, carger and power supply stereo ear plug.

In sum, a totally fully-fledged world receiver which has no competitor in this price class.




Degen DE1106

The Degen DE1106! There had been rumors about this radio for a long time and now it is here. The dimensions are the same as  for the Eton E5 and the electronics are the same, too, except that the DE 1106 has some new features. The most important addition for the shortwave listener is without doubt the synchronous detector. Because the De1106 can also receive FM, a "RDS" function is included as well as air band reception. The radio has also a "Line in" jack to connect it to an iPod which makes it possible to us the Degen 1106 as an amplifier. All other features are the same as for the E5. The radio looks noble and well-manufactured but it does not a have a rubber surface as the E5.  The radio's interesting features are the synchronous detector and the "RDS" (Radio Data System) which works in the FM function. If the synchronous detector is switched on, the sidebands are freely selectable and so you can eliminate noise and disturbances from neighboring channels. This function works very well. Even when listening to weak stations,  the synchronous detector locks in place and remains locked in most cases. The "RDS" function shows the following information: station, title/artist, date, scroll text. But, of course, the station has to transmit this information.

Receiving range: 150 KHz - 30 MHz; 76 - 108 MHz; 118 - 137 MHz.

Modes: AM, synchronous AM with selectable side bands, USB, LSB, WFM (UKW)

Two selectable band widths

700 alpha-numeric non -volatile memories etc.

How is reception ?

The first thing to notice the almost non-audible noise on free frequencies.  You might think that the radio is defective or insensitive.  But this is not so! I have never seen or listened to a radio which has so little internal noise. I contacted the dealer and he assured me that the radio was  working fine. When I wrote this report, I  briefly compared the DE1106 with the Sangean ATS-909. Of course, the ATZS-909 is in a different league which should not be forgotten. Because the Degen radios have a good reputation, a comparison seemed natural.

Well, let's compare reception!

Basically, the DE1106 receives signals just as well as the ATS-909. The are differences in the upper frequency range, though.  From ca. 17 MHz and up, the ATS-909 is more sensitive.  Below 17 MHz, both receivers have the same sensitivity.  Reception on long wave  is not very good and the DE1106 is almost deaf. Also, medium wave reception is not really adequate . But the built-in ferrite antenna  has a good directional effect.

The band width filters of the DE1106 are more effective than the ones of the AT-909. In the narrow position, the sound is still pleasant and not muffled.

What is really good about the DE1106, is its synchronous detector. It locks into place in case of relatively weak stations and remains locked. Very well done!!  SSB works just as well as with the ATS-909.  Tuning  is easy and the intelligibility is good.  As is the case with these radios, large signal immunity is not very good and 900 KHz  above and below the selected frequency, there are image frequencies but admittedly , the transmitter has to be fairly strong to cause this effect.  Outdoor antennas can only be used with a preselector. The ATS-909 has a better large signal immunity.

FM works pretty well. The RDS sensitivity is the same as the one of the ATS-909. The airbands work fairly well near an airport. However, there is no scanning function for the airbands…

By and large a nice and interesting receiver with a synchronous detector that make makes up for the radio's small weaknesses.

The DE1106 is identical in construction to the Eton/Grundig G3

Soon, I will make comparison tests with several portable receivers.

This test can be found here.




Eton / Lextronix E1

Usually I only test radios, which I personally own. But because I do not always have access to every receiver,  I decided to review radios  which are on loan to me as well. Again a warm "Thank you" to an anonymous hobbyist.

Although the Eton E1 is not in production anymore, it is still in high demand because it is the best portable radio since the manufacture of the Sony ICF-SW77. Looking at the Eton 1 and holding it in your hands, the knowledgeable SWL might even think that it was produced in China. Wrong! It was made in India. The American company R.L. Drake had a role in the development of the E 1. Just like some other radios by Degen, the E 1 has a rubber surface.  Technically,  the receiver is quite good. For the first time, Pass Band Tuning (PBT) was put into a portable receiver. A well- functioning synchronous detector, which offers selectable sidebands including double sideband, is rare among portable radios.  There are lots of memories: 1700 memories, 500 of which are alphanumeric.  The others are linked to a special "Country Data Bank", i.e., you can allocate frequencies to specific countries.  That makes sense and thanks to a large display is easy to do. As a fully fledged world receiver,  the E1 sports FM, LW, MW and of course the entire shortwave range with the usual modes AM, AMS, LSB, USB. Interestingly, the E 1 does not have a ferrite antenna for LW and MW! All frequencies are received with a telescopic antenna; instead the E1 has an amplifier, which can be switched on, if necessary. Of course, the E1 has a jack for external antennas, which is non-standard, though. 


…is convincing! There were no overloads using the telescopic antenna. I compared the E 1 to the Sony ICF-2001D.  The audio comparisons can be found here.

Sensitivity is very good. The synchronous detector locks in on the signal, even if it is weak.  Thanks to the very narrow tuning steps of 10 Hz, reception of amateur radio and SSB is outstanding.  Tuning causes no noise, either. Super! Because of the three band width filters of 2.3 KHz, 4.0 KHz and 7.0 KHz you are well-equipped for every situation.  The filters are high quality, in thin plate encapsulated ceramic filters made by Murata. No effort was spared here.

The sound of the rather large loudspeakers is pleasant. With the bass- and treble control you can adjust the sound to your liking. The E 1 gives you a real treat! A portable radio with almost all technical subtleties. The large, clear and back-lit display makes easy operation possible. What's lacking is a RDS function for FM and PC-programmable memories. A negative point is the fact that the battery holders are badly or even not all padded. If you move the radio, the batteries are rattling in the battery tray. You can hear that very noticeably.

But still a great radio, which deserves much praise.




Eton E5

For some time now there have been reports and opinions about a Chinese radio factory called "Degen".  The Degen Company not only designs and builds radios for its own brand but also for others. One of these brands is Eton. The Eton E5 was supposed to come onto the market as Degen DE1106 but so far I have not been able to find one on the internet.  Only "Lextronic" and Eton sell the E 5. Because of the predominantly positive reviews of other E5 owners, I became curious and ordered an E5 at Nevada Radio in England. After only four days, the radio arrived. Included were the E5, a multi-lingual instruction booklet (German included), a protective pouch, stereo ear phones,  a cable antenna and a power supply, which unfortunately does not fit into Swiss outlets, so an adapter is necessary. The rechargeable batteries are not included, although it says so in the manual.   Finally then, I held the E5 in my hands.  First impressions: Very well manufactured, it lies snugly in your hands. The case has a sort of rubber surface which results into a good grip. I was a little surprised by the size of the radio: "so small"! From the ads and pictures on the internet it had appeared a little bigger, something like the Sony ICF-SW7600GR. The E5 has two options. Either from 76-108 MHz or from 87,5 - 108 MHz in FM. The range for long wave, medium wave and shortwave is from 150 - 30 000 KHz in AM and SSB. A new feature in this price class is the two selectable shortwave band widths. Some thing that is unusual for such a small radio: it has 700 memories divided into 100 pages each of which can be tagged with four letters.  This can be compared to the memory management of the Sony ICF-SW55, only that the E5 has five times as many memories.  The E5 has four timers, each of which can be programmed individually. It is very nice that the keyboard is standard. The keys have a very pleasant feel which results in comfortable operation. I especially liked the tuning with the VFO on the right side of the E5. When scanning the bands, there is no signal loss or noise between the 1 KHz steps.  You almost have an "analogue feeling".  The VFO also seems to have a flywheel effect. The faster you tune, the faster the frequency changes. Now, let's take a listen! Because I have had the E5 only for three days, this is merely a short comparison to the Panasonic RF-B65.  What you will notice immediately is the radio's good sound.  Stronger stations on shortwave or FM sound almost room-filling. I have never experienced that with such a small receiver.  In case the selected station is interfered by a neighboring channel, you have the band width selection at your disposal, which is very effective.  I was amazed at the reception of a Greek pirate station in the X-Band on 1645 KHz without any other help. The Panasonic RF-B65 had to give up and the station could be guessed at best.  SSB reception can be compared to the RF-B65. Weak signals could be tuned with the BFO and were understandable.  But where there is light, there is also shadow. Large signal immunity, which is very important for me, was not what I had been hoping for. Below the 49m band, you could clearly hear stations from this band.  In this respect, the RF-B65 excelled, there were no image frequencies, not a single one.  The SW 55 caused considerably more image frequencies.  I have to say that in this regard the E5 is better than the SW55.  Conclusion: A good companion on shortwave and FM at a unbeatable price. A serious competitor for the Sony ICF-SW7600GR!!.



Grundig G6 Aviator

Basically, the Grundig G6 Aviator is not a real Grundig.   The basic components carry the "Eton" label. The radio is probably built by Degen just like so many other radios made in China. And that was why I had the small receiver sent from the USA.  Although it carries the CE-label, it is not available in Europe and it is going to stay this way. The most interesting version is the so called "Buzz Aldrin Edition" which is the smallest radio with SSB and the air bands.  The radio covers the frequency range from 150 KHz - 30 MHz, the FM band in two varieties (76 MHz or 87.5 MHz - 108 MHz) and the air band from 117 MHz - 137 MHz.   The G6 has 700 alphanumeric memories just like the Eton (Grundig) E 5.  The G 6 has the same functions as the E5 except that the E5 has a selectable band width filter.  The G6 is the first receiver built in China of this size which can do without a clarifier for SSB reception.  SSB is tuned with a jog dial (main tuning wheel). In the "slow" position, there are approx. 10 Hz steps and an absolutely analog tuning feeling with no tuning noises.

How is reception?

I compared the "Aviator" to the Eton E 5.  By and large, reception was the same, which is remarkable for such a small radio. Also, sensitivity is about the same, with the G6 not quite as good in the long wave and medium wave range. The G6 has an extremely directional ferrite antenna so you can blank out interferences very efficiently. The bandwidth of the E 5 is much wider.  FM reception is on the same level as the E5. For stereo reception you have to use the headphones. Unfortunately, reception of the air bands is very bad. It's more like an extra to play around with. Sensitivity is not very high, either.  Also the scanning function does not work properly in this range, which is really too bad.

As is the case with almost all small world receivers, large signal immunity is not especially good. It is not advisable to connect an external antenna. This will result into overloads right away, at least in Europe. 

The radio has practically no tuning noises and only a very low internal hum. Great!!

Dimensions. : L x W x D: 124mm x 75 x 28mm.




Grundig Yacht Boy 80

I bought this Yacht Boy 80 at Media Markt. Reception in the European bands is rather good, but only in FM. SSB does not work satisfactorily because you cannot tune the frequencies adequately and the stations sound rather distorted. The Sony ICF-SW 7600 GR is much better in this respect; it even sports a fully fledged synchronous detector.  Tuning with the YB 80 works very well, though. With the VFO wheel, you can scan the bands without any noise.  If you want the signals to be stronger, simply connect the supplied wire with the antenna jack. But the YB 80 cannot handle the wire and flies off the handle!

Good audio quality, also on FM. SSB is useless.  If you do not demand too much of a radio, you may be happy with the YB 80, which costs 169 CHF.



Panasonic RF-B65

Every shortwave fan should be familiar with the RF-R65 because according to older tests it is the best portable world receiver. I could compare it to the Sony ICF-SW55. It can handle strong signals much better than the SW55. The SW55 produced some images from the 49m band between 5000 KHz and approx. 5500 KHz.  The B 65 shines in this respect….not a single image frequency.  This of course with its own telescopic antenna.  Regarding today’s reception conditions and in urban areas you should not ask for miracles from this portable receiver. You should leave the supplied wire antenna in its box because in most cases it will only produce overloads.  My motto is: "Less is more!". The B 65 does not shine with a lot of memories or other bells and whistles. The radio is simply good at what is expected of a good radio, i.e. good reception.  The RF-B65 is getting on in years, so, be careful when buying one!




Redsun RP300

The RP 300 was launched on the Chinese market at almost the same time as the Redsun RP2100.  What does the RP 300 offer? The first thing you'll notice is its tiny size. With W x H x D 120mm x 75mm x 25mm, the radio is really small. The antenna is a mere 45 cm long. But the radio does have the usual gimmicks, which modern Chinese receivers sport these days. It does not have DSP, though: The radio has 200 memories, an automatic scanning function without muting reception (!) and practically noiseless tuning. FM is from 70 MHz - 108 MHz (stereo with headphones), medium wave from 520 KHz - 1710 KHz, shortwave in two bands: SW 1>2300 KHz - 7500 KHz, SW 2>9200 KHz - 22000 KHz etc….


Prized at $30.00, you cannot expect miracles from this tiny radio. With some stations in the shortwave and medium wave range it was noticeable that the shielding of the electronics was not very effective. There were interfering noises, which were actually only present when you use the earphones. Large signal immunity is bad as could be expected.  Attempts to improve reception by extending the antenna failed because this resulted in overloads. But a direct comparison with the Aviator G6 by Grundig, which is about the same size,  showed that the Redsun RP300 is not really bad. It clearly beats the Grundig regarding sensitivity in the medium wave band.  Even the Tecsun PL-600 was not better on medium wave.  The RP300 is really good on medium wave. By and large, shortwave reception was on par with the Grundig G 6 Aviator. Selectivity is the same as the G 6.

FM reception of the RP 300 is adequate.  Sensitivity, noise, selectivity are not worse than the Aviator's.

Considering a sales prize of 33$ plus 10$ shipping, the Redsun RP 300 is an interesting receiver.  If you do not ask for the highest standards, you will be happy with the RP 300.  Good value for your money!



Redsun RP2100

I had this world receiver, the "Redsun RP2100", sent from China. Originally, this radio was built for the Chinese market, but now a version is also produced for the rest of the world and comes with English labeling, which, however, is not totally free of mistakes.  The receiver is offered in Europe under the name "Elta 3569". The RP 2100 is a world receiver, mainly for the listeners of broadcast stations.  It has FM from 87 MHz - 108 MHz, medium wave and shortwave 1'711 kHz - 30'000 kHz, divided into SW1, SW2 and SW3. There are ten memories for each of these segments, at total of 50 memories.  To be frank, I have never seen such a strange memory organization.  But the RP2100 has one special   feature, which at present is unique for a portable, cheap world receiver. It has got an IF-jack.  So you can connect the radio to a DRM, SSB-decoder, which is presently not available, however.  So far, this feature has not come with radios in this prize range.  It costs a mere 100.00 $ incl. shipping.  By the way, the RP2100 has also an alarm function, separate controls for bass and treble, 2 selectable band widths for medium wave and shortwave and RF-Gain. Everything else can be seen on the large display.  There is also a jack for an external antenna, but you need a TV-plug.  There is another unique feature: You can operate the RP2100 with two types of batteries.  The constructional quality is good and robust, it's better than the one of the Sony ICF-SW77, whose case makes a creaking noise.  The telescopic antenna is also of good quality, I will not comment on the antenna of the SW77. L

How is reception? Good to very good, indeed.  As far as sensitivity is concerned, it is not on the same level as the SW77, there is a little more noise.   Large signal immunity is nothing to write home about, either, in other words:  it is not especially good. I was under the impression that the upper frequency range was used as a sort of dump.  Starting at ca. 25 MHz and using the telescopic antenna, there were lots of image frequencies and signal mixes. Interestingly, this did almost not occur in the 41m and 49m bands.  But there are positive points as well:  The RP 2100 has super audio quality, whereas the audio of the SW77 is somewhat dull and muffled. The audio reminded me of the times when you listened to medium wave stations with a tube radio. That is how the RP2100 almost sounds.  A really full and great audio!  It is a lot fun to scan the medium wave frequencies   because there are almost no tuning noises. In comparison, the SW77 gets on your nerves in this respect. If you select a narrower bandwidth, noise is reduced, but the audio does not become dull.

FM works very well, also, even in stereo with headphones or line-out.  The RP2100 is a little more selective and sounds better.

If you just want to listen to the radio without having to spend a large amount of money, the RP2100 is a good choice.




Sangean ATS-909X

The Sangean ATS-909X is the direct successor to the well-known ATS-909W. Compared to this model, some features were changed, especially as far as reception of FM stations is concerned, which has been digitized. You will notice this because of the very good selectivity and the superb audio.  RDS, which was also possible with the old 909W, seems to react a little faster with the new 909X. And even the internal clock is synchronized with RDS.

Nothing much seems to have changed regarding shortwave reception, which is rather good; when using the telescopic antenna, large signal immunity is acceptable, there were no overloads to be noticed.  One flaw with the ATS909X is its weak sensitivity this can be remedied by having an antenna amplifier installed by an expert like Henry Mohr or Jürgen Martens.  The disadvantage here is a slight loss of large signal immunity.  Reception on longwave and mediumwave is satisfactory. The Sony ICF-7600GR is clearly better on LW and MW.  SSB reception on the amateur radio bands works quite well.  The 40Hz increments on SSB have not changed, either.

Further improvements are: Tuning on LW, MW and SW is uninterrupted by noise. It is now a lot more pleasant to be able to scan the bands without these noise effects.  You will notice the new design of the 909X right away.  I think it's well-made. And the nice display, which can be illuminated, looks very good, too.  The 909X has 406 alphanumeric memories, the 909W had 306.  Switching the bandwidth in AM is not very effective which the case with the old 9089W was also.

Sangean failed to implement a small, but important detail with the 909X: Sangean economized on the tuning wheel, which has click positions.  This wheel has some tolerance, which is due to the cheap mechanics of the tuning wheel.  Because of this tolerance, a selected frequency is not kept exactly at some positions. If you turn the tuning knob within a certain position, the frequency changes by several steps. That is simply unacceptable. My receiver showed this flaw in three click positions.

If you buy the 909X hoping to get better reception on LW, MW and SW, you will probably be disappointed.  The radio is not better or worse than the 909W, except for FM reception.  Because of the digital reception, the 909X is clearly at an advantage.  The audio is generally better than the 909W's.

The 909X is a very nice radio which offers the same reception quality as the preceding model.

(Written March 9, 2012)



Sony ICF-SW55

The Sony ICF-SW55 is a very well-known and good world receiver with a lot of special features: 125 alphanumeric memories, timer, world clock, SSB etc. etc. Reception on SW is very good and SSB works very well, too.  But all too often there are image frequencies.  This seems to be a common flaw with the small receivers by Sony.  Often, there are stations to be heard around 910 kHz of the selected frequency and with some signal strength at that.  Except for this, the SW55 is a top receiver, which offers a lot of functions like no other radio.

A hint:  In central Europe with strong stations around, you should operate the SW 55 only with its telescopic antenna, which will result in clean reception. (Less is more!)



Sony ICF-2001D

Without really looking for it, I came across the Sony ICF-2001D.  After finding out, which the seller was, I simply had to buy it because I knew him as someone who really takes care of his equipment.  I do not really have to write much about the ICF-2001D because it is known as simply the best portable world receiver which has been built so far.  Because the ICF-2001 is getting on in years (it was manufactured in the 1980s), a test of the radio is highly advisable before buying it.  Over the years, the electrical parameters change which leads to bad reception or even to defects.  But luckily, my ICF-2001D works very well. It once was serviced at Jürgen Martens' shop and he installed a high quality narrow 2.4 kHz bandwidth filter, a Murata CFJ455K5.

The ICF-2001D can really fill its owner with enthusiasm: Very good reception on all bands without any large signal problems.  The synchronous detector with its selectable side bands is a highly effective tool for unsteady frequencies. SSB works very well, too.  Receiving marine radio without the air bands on shortwave is no problem at all.  I connected the ICF-2001D to my Wellbrook ALA1530+ antenna and compared the results with my table top receivers.  Whatever I could hear with these receivers, I could also listen to with the ICF-2001D. To my astonishment, the ICF-2001D produced very few overloads.  You can use really highly effective antennas with this receiver.  But don't overdo it! It is a portable radio after all and is mainly designed for its telescopic antenna and not for too highly effective external antennas.  The ICF-Sw77 is absolutely suitable for DXing, but everybody knows that already.  Experiments with external antennas are really worthwhile.

In conclusion, it can be said the Sony ICF-2001D is still a superb receiver.  Not without reason, the synchronous detector is very popular.  The ICF-2001D is easy to operate and is solidly built.  When you see this radio in a nice and operational state, you should get it.



Sony ICF-SW77

The Sony ICF-SW77 was the last large world receiver built by Sony, which is really too bad. As the direct successor of the Sony ICF-2001D, the SW77 had to face many comparative tests. Sometimes, the SW77 was better, sometimes the 2001D. The SW77's range is from 150kHz to 30'000 kHz in AM, AM synchronous and SSB. There is also FM from 87,5 MHz to 108 MHz, in stereo when using headphones. When tuning shortwave frequencies manually, step widths from 1kHz to 50Hz are available. The radio has 162 alphanumeric memories. On the side, there is a jack for external antennas and a line-out.  Of course, there is a timer, alarm clock, and other features.  The constructional quality is acceptable. In this respect, its small brother, the SW55, is better. The case is not really stable.  There is a noticeable creaky noise. The telescopic antenna is not very stable, either.  If it is collapsed, it is easy to bend it. The SW 77 has so many buttons and controls, that it is almost impossible to operate the radio without consulting the manual, i.e., very complicated.  Now, what about the main thing? How is reception?  All in all, it is very good.  I compared the SW77 to the Redsun RP2100, which has about the same size.  Pricewise, they are worlds apart.  The SW 77 costs eight times as much as the RP2100.  The SW77 is a little more sensitive than the RP2100. There is less noise. What you will notice right away, is the tinny sound of the SW77 compared to the RP2100. The tone controls are not really effective.  In this respect, the RP2100 with its fuller audio is far better. The SW77 has two selectable bandwidths, just like the RP2100. Unfortunately, the filters of the SW77 are not designed ideally. They are selective, but the sound is muffled.  Here, the RP2100 is better, too.  On densely used bands, the wide filter of the RP2100 lets pass through whistling sounds caused by interferences, but the smaller filter is really superb. If activated, the interferences disappear, but the audio does not change.   The SW77’s narrow filter is very muffled and almost not usable for AM-reception. On the other hand, the large signal immunity of the SW77 is very good when using the telescopic antenna.  Across the whole shortwave band, I could not detect any large signal effects, which occurred with the RP2100, also during daytime reception. For a manual scan of the bands, the SW77 is not really suited. Why? Simply because of its annoying tuning noises. Further down, you will find an audio/video sample.  The receiver is suitable for DXing, but the noise and the interruptions when tuning the radio make scanning a real test of nerves. I cannot understand why Sony did not take care of this problem with this otherwise good radio.  When the SW77 became available, noise-free tuning was technically feasible. The "cheap" receiver Redsun RP2100 offers a far more pleasant tuning without almost any noise.

But in conclusion, the SW 77 is a very good world band receiver with many features, and not least because of its synchronous detector, it is a super receiver.




Sony CRF-1

This is one of the best shortwave receivers ever built by Sony, but it was not widely in use, which is probably due to its price.  When it reached the markets, it was about 3000 CHF.  This elaborately built receiver was mainly sold in Switzerland and the Netherlands.  In Germany, it was not officially approved by the authorities.  The case is completely made of aluminum pressure die-casting and guarantees high stability and shielding.  Only the upper lid and the front are made of plastic.  Although the CRF-1 was designed as portable receiver, probably only a few people used it as such, because it weighs 6.5 Kg!.  The radio receives 10 kHz - 30 MHz continuously in AM, USB, LSB and CW. Unfortunately, operation is complex and difficult. The whole frequency range is divided in 100 kHz segments.  When you have reached the end of the segment of a frequency range,  you have to go back,  pull out the tuning knob and have to select the next 100 kHz segment. Then you can continue fine tuning.  Compared with the tuning of the current radio generation, this is very tiresome. The Drake R7 has a similar tuning method.  But that is not all! If you want to tune the receiver exactly to the desired frequency, you also have to tune the preselector.  But luckily, this can be bypassed.

For a couple of days, I compared the CRF-1 with my other radios, which of course are more modern.  When tuned correctly, the CRF-1 was on par with the other radios. It is obvious that you cannot think in clear-cut terms when making these comparisons.   The CRF-1 has very wide AM filters and thus produces whistling noises caused by interference on busy bands. Also the narrow 4.4 kHz AM filter could not always guarantee sharp selectivity. For SSB, the results were better because of a 2.0 kHz band width. Sensitivity was as good as for the other receivers. Despite correct tuning, the CRF-1 produced overloads in the evening hours when connected to a 35m long wire antenna. But these flaws can be overlooked.  If you want to go "station hunting" you need the necessary time and some patience, anyway. Otherwise, you will not enjoy your CRF-1.

It is a wonderful radio, but not quite on par with modern receivers,; especially when DXing, you have to make compromises.

Please notice:  if you buy such a radio, the seller should guarantee you perfect functioning. Seldom, these receiver s have defective electrolytic condensators or need alignment, all which can result in a big repair bill.

Best thanks to Franz for making the CRF-1 available.

posted 02.12.2013




Sony ICF-SW07

The Sony ICF-SW07 is a small world receiver deluxe which has everything. As a successor to the SW100E it also has a synchronous detector built in. As small and exquisite the radio is, it is good as well. Reception is superb, especially with the supplied active loop antenna.  If you are inside and reception is becoming weak, you simply get out the loop and reception is back! The SW07 has a lot of alphanumeric memories, so you have a good overview of your stations. Compared to the YB80, the SW07 is at least a notch above the Yacht Boy by Grundig, except for the audio. Of course, the radio has 100Hz tuning in SSB.

A portable receiver of the luxury category, highly recommendable; but it comes at a price!


Sony ICF-SW7600GR

The only thing you can write about this radio, which is probably known by all shortwave fans,  is that it is a very good portable receiver which is on par with the SW07 as far as reception is concerned.  The most important differences are: SSB tuning with BFO (Clarifier), because there are only 1kHz steps available. There are no alphanumeric memories. Tuning is a little slow and because of its size, the audio is better than the SW07's. Not too many image frequencies. Convincing price/performance ratio!



Sony ICF-SW100S

As far as I know, the Sony ICF-SW100S is the smallest world receiver whose receive characteristics can be taken seriously. It offers the frequency ranges from 150 kHz - 30 MHz continuously in AM, AMS, USB and LSB. Additionally, there is FM from 76 MHz - 108 MHz the ICF-SW100 has 50 memories, which can be labeled with six characters each. Other functions, e.g., alarm clock, timer etc. are also built in.  Operation is straight forward and so you do not have to have the manual with you at all times.  It is really astonishing, what the Sony developers have all put in such a small case! It is a small receiver, which does not have to shy away from bigger radios as far as reception is concerned.  The strongest feature of the SW100 is the reception of shortwave stations in AM synchronous. This feature is really superb.  Who has not experienced the following situation: The selected station is interfered with by whistling noises because the neighboring station is so strong, that it affects the selected frequency.  When this happens, you activate the synchronous detector, select the sideband, which less interfered with and the annoying whistling is gone! Because the SW100 has also SSB, it is possible to listen to ham radio operators and aeronautical radio on shortwave.  On the other hand, the SW100 with its built in antenna is a little deaf, which is not necessarily a disadvantage. Thus the SW 100 does not suffer from overloads so easily as other world receivers.  If you want to listen to shortwave extensively, you connect the radio to a small wire coil or to the selective active antenna AN-100.  That is what I did. With this antenna, which is powered by the SW100, the radio gets attentive ears and you can do even DXing.  By pre-selecting three reception ranges, there is a preselection of frequency segments, which is good for suppressing large and strong signals, image frequencies etc.  All in all, a great receiver for your pocket, which is really fun and surprises you a lot. 




Tecsun PL-350

Since early 2005, the PL-350 has been available. But it was not sold in Europe and could only be bought in China, of course with Chinese labeling.  But for some time now, the PL-350 has also been available with English labeling.  I had the PL-350 flown in from Hongkong.  What sort of world receiver is the Tecsun PL-350? It is really small: 15x9x3cm (WxHxD) It has 550 non-volatile memories, which can be divided into three parts.  Frequency range:  MW: 522-1620 or 520 - 1710 kHz (9kHz or 10kHz  or 1kHz steps) and 1710 kHz - 30 MHz (1 kHz or 5 kHz steps), only in AM. FM from 76 - 108 MHz, with earphones also stereo. A n antenna attenuator with three positions, pitch control, alarm clock, timer etc. There are some unique features as well:  an antenna trimmer, which makes it possible to tune the frequency exactly. Because the PL-350 is only a single conversion receiver, naturally there are more image frequencies than in a double conversion radio.  But to overcome this problem, the PL-350 has something special built in: it has two switchable intermediate frequencies (455 kHz and 450kHz). If there are interferences on the selected frequency, you simply press the IF button in the lower right corner of the radio, and you will move the interfering frequency by +/- 10 kHz to the side and the desired frequency is clear.  That is really a great feature, which I had not seen before on any other world receiver. The radio also has a so called lighting timer, which means that between 7 p.m and 7 a.m the buttons or the VFO will automatically light up. Of course, you can select this feature for any other time.  Additionally, there is connector for an external antenna and a charger for NI-MH accus.  The scope of delivery is complete: accus, power supply (a travelling adapter is required), wire antenna, stereo earphones and a protective bag.  The constructional quality is very good.  How then is reception?  I compared the PL-350 with the Eton E5. What you can get with the E5, you can also receive with the PL-350. On MW, the E5 is definitively superior.  It simply receives the stations better and more intelligibly.  On shortwave, the differences are not so big. The PL-350 sound a little tinny, which, of course, has to do with the size of the radio. It also hisses a little more than the E5.  But the PL-350 has the IF-shift function, which the E5 does not sport and which is a huge advantage.  As already mentioned, there are image frequencies between 6200 kHz  - 6700 kHz, which also occur in table top receivers.  If, e.g., you are listening to Mystery Radio on 6220 kHz, stations coming from the 41m band on 6220 kHz may be audible.  With the E5 there is no chance of avoiding interferences, but the PL-350 has got a trick up its sleeve! You press the IF-Shift button, and voila! you move the image frequency to the side by +/- 10 kHz and the channel becomes clear.  Tuning the PL-350 is the same as the E5's, there is almost an analogous feeling to it. If you like tuning with some noise (short interruptions when tuning), you can re-program. Great! In my opinion, the filter widths were selected well. Sometimes, there are whistling sounds caused by interferences on busy bands.  FM is also convincing: good selectivity, good and loud audio.  All in all, a fun radio especially for the price of ca. 90CHF or 60Euro incl. shipping.




Tecsun PL-600

In Europe, the PL-600 is only available at some dealers. You can have it sent by EBay from Chinese dealers; that is what I did. For ca. 70 US Dollars, you get a receiver which fulfills almost every desire of a radio listener.  The only thing that is missing is a synchronous detector for AM reception.  Everything else is fine.

Most prominent features:
Frequency range: 100kHz - 30MHz; 76-108MHz (stereo with earphones)
Modes: AM, SSB tuning via a clarifier (BFO), WFM for FM
Double conversion
1 kHz and 5kHz tuning steps for shortwave;  1kHz, 9kHz and 10kHz for medium wave
Three-step attenuator
2 selectable bandwidths: 6kHz and 3kHz
Connector for external antenna
600 non-volatile memories
Noise-free tuning
Good audio
Solidly built
Shipped with protective bag, accus, charger, earphones, cable-antenna

How is reception?

Just like all portable radios, the PL-600 suffers from the" strong signal virus".  In Europe,  you have to be careful  when operating the radio with an external antenna. Not every received signal is a" real" one!

Fortunately though, the PL-600 has more good than bad sides!

I compared this receiver to the Degen1106. By and large, both radios have the same sensitivity and almost the same selectivity. Early in the morning, I could receive Radio Rebelde on 5025 kHz with both radios with the same signal strength. As far as signal processing is concerned, the Degen DE1106 was more flexible and with its synchronous detector, this receiver could suppress a RTTY-signal in the lower sideband.  With the PL-600 you could understand the program, but the RTTY-signal could be heard well at the same time and interfered with the other signal. It was no use switching to SSB to receive the station in "ECSS", because the PL-600 is not suitable for this trick, the audio is not clean. What I really liked, is the noise-free tuning with the VFO button, which also has a smooth feel to it.   DXing with the PL-600 is limited and only possible, when there are no interfering stations nearby.  Around 4 a.m., I could even receive Radio Clube do Para from Brazil and with the telescopic antenna at that. But nonetheless, the PL-600 reached its limit, because the AM- signals in SSB were audible rather poorly. The DE1106 worked very well, on the other hand!

FM works very well: high selectivity and very good audio with the loudspeaker and even better with the headphones. For its prize, you really get a very good world receiver, which is also convincing in its constructional quality.






Tecsun PL-880

When it reached the markets, the PL-880 made a splash. A pocket receiver with several selectable DSP-bandwidths, DSP-demodulation, synchronous detector and some other interesting and hidden features.  All this resulted in a lot of interesting debates and food for thought in the internet forums.  Mainly,  people puzzled over the hidden and undocumented functions.  Because I cannot buy every receiver, I depend on friendly people, who put the PL-880 at my disposal. After some searching, I found someone.  Harald Denzel loaned me his PL-880 and a big thank you to him!

The PL-880 had predecessor models, which were very much talked about, e.g., PL-600, PL-660 and now the new PL-880. The preceding models were all analogue radios and were real assets to the market.  In the PL-880, digital signal processing is used. Demodulation and filter band widths are achieved with DSP.

Die wichtigsten Eckdaten:

Basic parameters:
-- Frequency coverage: 100kHz-30MHz and 64MHZ-108MHz, configurable
-- Modes of operation: AM, AM synchronous, LSB, USB and WFM for FM
-- Band widths for AM: 2.3kHz, 3.5kHz, 5.0kHz, 9kHz
-- Band widths for SSB: 0.5kHz, 1.2kHz, 2.3kHz, 3.0kHz, 4.0kHz
-- Band width for FM: ca. 200kHz
-- Tuning steps long-, medium-, shortwave: 10Hz, 50Hz, 5kHz, 9kHz, 10kHz (depends on the mode)
-- Tuning steps FM: 10kHz, 100kHz
-- Synchronous detector with selectable sidebands, but no DSB
-- Attenuator in three selectable steps: (Local - Normal - DX)
-- Memories: 3050, divided in 25 memory banks
-- 3.7V Li-ion Accu
-- USB connector
Scope of delivery:
-- PL-800
-- Protective bag (brown imitation leather)
-- 3.7V Li-ion Accumulator
-- USB charging cable

For the power supply of the PL-800, Tecsun came upon an unconventional solution.  The radio has only a mini USB connector which also charges the 3.7V Li-ion accumulator. Unfortunately, the accu does not have standard size and so you cannot use standard size batteries.  This is very disadvantageous when your accumulators run out of power and you have no opportunity of recharging them.   If you want to use the radio with an external power supply, you have a serious problem!  You can only connect the receiver to a PC or to 5V switching power supply.  And you can imagine the consequences!  Receiving long- medium- and shortwave does not get along very well with switching power supplies and computers because reception is heavily interfered with. If you want to listen to long-, medium-, and shortwave seriously, you can only operate the PL-880 with accumulators.

A signal strength indicator that shows the values in dBµ and dB is very unusual for radios in this price range. These values do not mean a thing to the normal radio listener.  Only with the help of tables and some special knowledge,  these values can be converted  into the usual S-meter values.  dBµ and dB is mainly used for professional receivers.

Here a small conversion table from dBµ* to S-values (dBµ is dBµV = voltage)*

dBμ              >>

-14 -8 -2 4 10 16 22 28 34 44 54 64 74 84 94

S-Wert        >>

1 2 3 4 5 6 7 8 9 9+10dB 9+20dB 9+30dB 9+40dB 9+50dB 9+60dB

The dB- value stands for the S/N, which equals the SNR = signal/noise ratio. The higher the value, the better the intelligibility. In theory, anyway.

The constructional quality of the PL-800 is high. The controls are placed conveniently and allow for easy operation of the receiver. A novelty for a pocket receiver are the two tuning knobs.  One is for coarse tuning, the other, the smaller one,  is for fine tuning to at least 10Hz. Thus you can stop conveniently at the desired station without changing the tuning steps and then do the fine tuning.  A good solution!  Tuning on long-, medium-, and shortwave is without signal drop-outs  and provides an absolutely analogous feeling.  The PL-800 has an antenna connector for shortwave, but unfortunately, not for long- and medium wave. There is also a line- out and a stereo headphones connector.  As a fully-fledged world receiver, the PL-800 can also receive FM  in stereo with headphones.  When tuning the FM-band, you will notice signal drop-outs, which are kept to a limit, though.  Additionally, there are other functions like alarm clock, automatic memory function etc., which I will not discuss.

How does it play?

I tested the PL-880 for some weeks and examined it thoroughly. As reference I used the Sony ICF-SW7600GR.  The PL800's reception is rather noise-free and has a very good, almost bass-like audio. Crackling noises and hissing were less noticeable with the PL-800 than with the ICF-SW7600GR. I really was surprised at the good reception of long- and medium wave. So far, most radios made in China had been rather deaf in this range, but this cannot be said about the PL-880. Here, the Tecsun clearly beat the Sony. Sensitivity, noise and last but not least the DSP-selectivity helped the PL-880 to a very good reception.  But there is a downside, nonetheless.  The legendary synchronous detector of the PL-880 could not convince me.  Neither in the case of weak nor strong stations, could the synchronous detector improve reception.  The detector "bubbled" and lost synchronization rather quickly.  It was just useless. Maybe the detector will be improved with new firmware at a later date.  Anyway, the synchronous detector of the Sony was much better.

The good reception quality of the PL-880 could also be noticed on shortwave. The noise-free and pleasant reception was convincing and receiving stations with the built-in telescopic antenna was never subject to criticism. And there were no overloads, either. The Sony, on the other hand, showed some flaws in this respect.  Sometimes you could hear "ghost stations" below busy broadcast bands.

At the time of testing, I had the indoor antennas Reuter RLA3A and the Grahn GS5-SE/ML3 at hand and I took the opportunity to operate the Tecsun with these antennas.  The PL-880 worked very well with the Grahn antenna. Reception was improved considerably and there were no overloads.  It didn't go to well with the Reuter antenna, though.  The receiving level was better, but at the expense of the signal/noise ratio and there were overloads at times.

SSB-reception was good, but the Sony sounded clearly better. The audio of the Pl-880 has a scratchy sound which is due to a suboptimal AGC. And the audio was muffled, too.  But tuning with the two knobs was superb! When turning the small knob slowly, tuning was in 10Hz steps. When turning faster, the flywheel effect is activated and the steps are 50Hz.

There is no criticism as far as FM reception is concerned. Pleasant audio, excellent selectivity and good strong signal performance convinced me right away. Too bad though that there is only one band width.  With such a high-tech radio, RDS would have been good, too. The Sony was the loser in the FM reception category.  There were some overloads and it did not reach the audio quality of the Tecsun.


Hidden functions

Unfortunately, it was impossible to find out, why Tecsun is hiding the following functions or did not activate them.  Some functions are certainly useful; others do not seem to be fully developed. The hidden functions can be activated by pushing some of the buttons.  Presently, I know the following features:

With the radio switched on
(These functions were found on the internet)
Warning: When using the following functions, you do so at your own risk! Your radio may be damaged!
Synchronous detector:
--press the USB or LSB button for three seconds
Noise reduction while tuning:
--Press button "9" for three seconds and select the value with the rotary knob. Press button "9" again to save the setting.
Noise reduction during reception:
--Press button "6"for three seconds for switching on/off
Changing De-Emphasis for FM
--Press button "5" for three seconds and select either 50 or 75. 50µs is for Europe, 75µs for USA. This only works in the FM mode.
Frequency calibration for long- and shortwave
--Select a strong station and switch to USB or LSB. Then fine-tune with the small tuning knob until reaching Zero Beat.  Press the "Snooze" button for three seconds and wait for the correction in the display. Press "Snooze" again to save the value.
With the radio switched off
Display control, firmware number and date of manufacture
--For control of the display keep the button "AM BW" depressed. Release the button and press again for firmware number. Press once again for date of manufacture.
Line-out level
--Press button "7" for three seconds and select a value with the rotary knob. Press the button again to save the setting.
Activation of the display of seconds
--Press button "8"for three seconds and wait for the display to light up.
Shutdown threshold for weak batteries
--Press button "4"for three seconds and select the value with the rotary knob. My recommendation: 3.5V.
Operating time since last charging the accumulators
--Press button "VF/VM for three seconds
Sorting the memories
--Press button "M" for three seconds.


For its reasonable price and its DSP- technology, the Tecsun PL-880 is a superb pocket receiver.  It outshines almost all of its competing products. But SSB-reception and the synchronous detector were disappointing, the detector was unable to improve reception in any given situation, it even made it worse. In AM, the audio of the PL-880 is excellent and makes the synchronous detector superfluous.  FM reception is sophisticated.

The PL-880 still has some minor flaws, which can be remedied by later firmware updates. Whether this can be done via the USB connector, I do not know.

The hidden functions left me with some mixed impressions. Either you make them available without  many lengthy searches or you deactivate them…

A recommendable receiver!

posted at October 18, 2014




Empfänger Bausätze

Junior 1 von Stampfl

Heinz Stampfl (HB9KOC), who is well-known because of his hand-made precision Morse keys,  has also a heart for radio listeners. For some time now, Heinz has been tinkering with several receiver concepts, which he also shows on his web site. It is his aim to be able to offer these projects as assembly kits in the future.  But unfortunately, this is not as easy as it sounds. On the one hand, enough kits have to be produced for the project to be profitable, and on the other enough buyers have to be found as well. These days, when everything can be bought as "plug and play" such a projects bears a big financial risk.

Despite these risks, Heinz Stampfl now would like to offer a small kit: the Junior 1.

Description of the Junior 1 kit (by Heinz Stampfl)

The Junior1 one is a double conversion shortwave receiver, which can easily and quickly be assembled.  No alignments, no measuring equipment or special knowledge of high frequency technology are necessary. Junior 1 is meant to be a small project for the young and for the young-at-heart listeners, who are interested in radio technology.
The main part of the radio is an AM/FM-IC from the former DDR (East Germany), the A4100D, which was especially developed for battery-powered devices.  According to the data sheet, the A4100D has a particularly good signal/noise ratio for AM and FM and only requires little external wiring.
The tried and tested NE612 is used for the front end mixer and for the oscillator.  It is possible to connect a low-resistance dipole with a coil. Tests, which were run during the early evening hours, surprisingly showed no overloads when using a G5RV.  If you want to use the Junior 1 as a portable, 1.5m of Litz wire should be enough for the high-resistance antenna connector.
For cost-reasons, the 1. IF-filter comes as a ceramic resonator. Because of its high bandwidth, it does nothing for the near-selection of the radio and so no effort was spared for the 2. IF-filter. The conversion oscillator (10.245 MHz) is a monolithic and adjustment-free component. If you are fond of experiments, you can design you own favorite frequency range by altering the input circuit and the oscillator stage. A LED is used as a field strength indicator.  You can connect a µA-meter with a suitable series resistor.
In the original design, the input circuit and the oscillator are mainly for the 49m/41m band. A local oscillator makes SSB-reception in the 40m ham radio band possible. But let me make clear: Due to the high 1. IF-frequency and the varactor diode of the LO, SSB reception is a little adventuresome and nothing for experienced DXers.  But nonetheless, it is certainly exciting for someone who has never listened to ham radio operators.  
Power consumption and the supply voltage range is from 7.5V to 16V at approx. 70mA. A LM380 with a 4 Ohm loudspeaker makes for good reception.
In conclusion, the Junior 1 has a deliberately simple concept, but still is an effective receiver, which shows good audio, high selectivity, high sensitivity and at the same time good signal processing.
The case is made of blue anodized aluminum. The labeling is etched with laser. 



Heinz Stampfl was friendly enough and put a Junior 1 at my disposal for testing purposes.  The radio came assembled, though, because I did not have the time for putting it together.

As can be seen in the picture, the receiver has the serial number 001. It is the first radio which comes out in the open.

I had the Junior 1 on my table for over a month and used it at every opportunity.  I mainly used external antennas for the Junior 1. To make this possible, I added a BNC-connector. To test the potential of the kit, I wanted to avoid interferences in my house. On the front of the radio, you can plug in a piece of wire as an antenna with a banana plug. There is also a connector for grounding the radio. To avoid overloads, I used a switchable attenuator and because the Junior 1 is not made for highly effective antennas, I used a 10 - 20dB attenuation.  Interestingly, there were no overloads. There were hardly any "ghost stations" to be heard and only during the early evening hours and very weak at that. Because the radio is a simple do-it-yourself project, the Junior 1 needs a little warm-up time because the oscillator drifts a little. You can power the receiver with either a 9V battery or an external power supply with 7.5V to 16V.

Because the frequency is not shown, tuning is a little unusual. Starting with the rotary knob all the way to the left,  you have to turn it five times to reach the 40m ham radio band. Then you switch to SSB and scan slowly and carefully through the band with the big tuning knob until you hear a station.  After that fine tuning is done with the left -0+ knobs until you hear the station clearly. With a little practice and patience, it works rather well. The low noise and the bright and intelligible audio are surprising.  Selectivity is good enough to receive SSB signals in the 40m band.  If you tune further down, you will come to the 41m broadcast band.  Then you select AM again and can listen to programs.  Comparisons with other radios showed rather high sensitivity.  Very weak stations on a clear frequency could be listened to well and intelligibly. It is clear that the Junior 1 is no DX machine, but for such a small radio, reception is rather good.


Heinz Stampfl dared to start an interesting do-it-yourself project. For young beginners, who are interested in building a radio themselves, the Junior 1 is the ideal kit.  But also for experienced listeners, the kit is certainly interesting.  For assembling the radio, you need interest and some experience with a soldering iron. It remains to be hoped that the Junior 1 will become a success. Perhaps then a kit will appear on the market, which Heinz will proudly present on his web page. …

The Junior 1 kit is now available at "Stampfl Morsetasten" and costs CHF 72.-

Beginning in 2015, the Junior 1 will be available in the shop of the "Funkamateur" magazine.

The assembly instructions can be downloaded here.

posted November 22, 2014