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All mentioned professional receivers were operated and tested using standard SWL antennas. Unfortunately, professional antennas were not available.

 

AEG E800/2

AEG/Telefunken E1800/3

Enablia TitanSDR Hagenuk RX 1001 M Icom IC-R9500 Lowe HF-235
Racal RA1792 Racal RA3712 Reuter RDR54 Reuter RDR55D RFT EKD 500 SRT CR91
Telefunken E1501 Telefunken E1700 Ten-Tec RX340 Watkins Johnson HF-1000    

 

Icom IC-R9500

The wideband receiver ICOM IC-R9500 is the direct follow -up model of the IC-R9000 which at its time was the benchmark of a broad band receiver. No other radio combined shortwave with the upper frequency bands with such high a reception quality. The IC-R9500 was introduced to the market in 2007 and is still (2015) being produced.

If you have a closer look at the IC-R9500 the trained eye will notice the excellent manufacturing quality. The radio comes in an elegant grey-white color.  The blue lines  on  the front (made of aluminum) gives the appearance of the IC-9500 a special touch and reminds you of the receivers made by Rohde & Schwarz. The feel of the control buttons is simply phenomenal. Everything is in its place. The big and heavy VFO has a flywheel effect which I had never encountered on a radio before.  Additionally, you can activate the latching function, if you want to hop from channel to channel.

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If you open the case to have a look at the inner parts you will be surprised at how heavy this receiver is.  You will hold 20Kg of concentrated reception technology in your hands. Most of the weight comes from the case and the cover. After unscrewing approximately 30 screws, the radio is open and you will see scrupulously separated and shielded boards. The case is made of thick aluminum cast and absolutely torsion-free.  The boards are all shielded by a thick sheet covering. The integrated power supply is even shielded twice.  The mechanical construction is completely satisfying and on a professional level. It is clear that such a radio produces heat. In order to minimize the heat load, the IC-R9500 has a cooling fan on the back. It is activated when a certain level of heat is exceeded.  Unfortunately though, the fan is very loud; to be exact: it produces quite a lot of noise; even if  you have your headphones on you will hear the fan. For a top class receiver, this is an absolute no go. I took care of the fan and replaced it by a 'silent fan' The result can be viewed under the link "Icom IC-R-9500 Fan Modification"

The IC-R9500 in Action Full HD Video

 

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The IC-R9500 is a very flexible receiver.

The front of the IC-R9500 is full of control knobs and push buttons. You really have to get a general overview before you can start. With all these controls, you cannot do without the manual. But with some technical knowledge, you can operate the radio very well. To start with: Almost every function of the IC-R9500 can be user-defined. The IC-R9500 has all those important features, which a DXer or a SWL needs on his hunt for weak and rare stations.

- a big 7" color display with a resolution of 800x400 pixels
- all important modes
- a great number of DSP band width filters
- double passband tuning
- user-defined and adjustable AGC
- automatic notch filter
- 2 manual notch filters with selectable blanking level and width
-big VFO with selectable flywheel effect and multiple levels of rotational resistance
-10 VFOs
- pre-programmed tuning steps and one selectable tuning step
- highly effective noise reduction
- highly effective bass and treble control
- 2 noise blankers with selectable blanking level and width
- built-in speech recorder
- a good-sounding built-in loudspeaker
- multi-functional spectrum scope with a max. width of 1000MHz
- built-in FSK-decoder with direct output on the 7" display.
 
 
The most important technical parameters
 
Double-DSP with 32bit each (one DSP for the receiver, the other for the spectrum)
-Frequency range:  5Khz - 3335 MHz continuous
-Modes: AM, AMS, USB, LSB, CW, FSK, FM, WFM, P25(optional)
DSP-bandwiths:
AM: 200Hz - 10 KHz in 200 Hz steps selectable
SSB, CW: 50 Hz - 500 Hz in 50 Hz steps selectable (soft & sharp)
                  600 Hz - 3600 Hz in 100 Hz steps
FSK: 50 Hz - 500 Hz in 50 Hz steps selectable    
                      600Hz - 2700 Hz in 100 Hz selectable
FM:  7KHz, 15KHz, 50KHz fixed
WFM: 180 KHz fixed band width
5 roofing filters: 240, 50, 15, 6, 3 KHz (pre-filters)
Excellent large signal immunity on Shortwave with +40dBm IP 3
Dynamic range up to 109 dB
Memories: 1220 alphanumeric
Signal strength indication in: S-values, dBµ dBµ [EMF], dBm

Connectors on the rear panel

1. External speaker jack
2. DC output jack (15,0 V)
3. ACC jack
4. DC output jack (13,8V), selectable via the [ANT] switch (for active antennas)
5. Reference frequency in and output jack
6. speech synthesizer output
7. NF-output for external recording
8. remote control jack for external recording
9. Detector output
10. Video input jack
11. Video output jack
12. spare jack (de-activated)
13. IF-output (10,7 MHz)
14. Power connector (13,5 - 15 V DC)
15. Fuses
16. Power socket
17. Main switch
18. DATA input jack
19. CI-V-remote control jack
20. RS232CV- jack
21. Connector for external monitor
22. Antenna jack 2
23. Ethernet jack
24. Antenna jack 1/ shortwave antenna jack 3
25. S/P-DIF output
26. USB jack (for USB flash drive and keyboard
27. Shortwave antenna jack 2
28. Shortwave antenna jack 1
29. Ground connector

Working with the IC-R9500

You will not become familiar with such a radio right away. It will take some time to get to know all its functions. I worked with it for a couple of months practically on a daily basis and compared it to other receivers, mainly the Watkins Johnson HF-1000. But the Perseus SDR and the NDR 525/535 were used for comparisons as well.  The IC-R9500 beats any other receiver as far as the 'feel' of it and the workmanship are concerned.

I need not  say much about the receptions qualities of the IC-R9500. All in all, they are absolute top class! Large signal immunity is not much of a topic. With a IP3 +40dB, it can handle very large and effective antennas. In some other areas, though, the IC-R9500 has to shed feathers. In the AM-synchronous mode, the HF-1000 and the Perseus with HDSDR software are better. Although the IC-9500 has a synchronous detector with selectable sidebands, the suppression of the sidebands of the synchronous detector leaves something to be desired. The other side band is not very well suppressed. This became clear, when the IC-9500 was compared to the Perseus with HDSDR software. Also, the stability of the synchronous detector is not beyond all doubt because it often loses synchronization. In this regard, I was reminded of the Ten-Tec RX-340. Additionally, the noise blanker loses its effectivity in this mode. The interferences caused by a nearby pasture fence became noticeable as soon as AMS was activated. They could not be heard with the HF-1000 in AMS. Nonetheless, the synchronous detector of the IC-9500 eliminates the typical crackling of AM.

The sensitivity of the IC-9500 is acceptable on longwave and medium wave, but can be enhanced by the low-noise pre-amplifiers and then the IC-9500 is on par with the HF-1000. On shortwave, it can handle any situation and because of its exemplary features and its effective signal processing capabilities, it produces in most cases a better signal than the HF-1000. None of these capabilities is superfluous or works badly. The two configurable noise blankers, which because of near by pasture fences are very important for me, were effective and suppressed the interferences without a trace. Another strong feature of the IC-R9500 is the treble and bass control, which work highly effective. The sound can be adjusted to the receiving conditions. It sounds more natural and more analogue than the one of the HF-1000. The audio amplifier is perfectly designed and produces no inherent noise.  

Should reception conditions be not so good, the IC-9500 puts an adjustable noise filter at your disposal, which "de-noises" the signal as long as you don't open it too wide. Then it starts to make bubbling sounds (artifacts). Both of the manual notch filters can be adjusted and customized. There are three filter widths which can get rid of whistling sounds very effectively.

The double passband tuning (Twin-PTB) makes it possible to shift the pass band of the band width filter on both sides. This way, interferences within the pass band can be eliminated. With the Twin-PBT you can also reduce the band width if you push both buttons in opposite directions. Additionally, the band width can be changed in steps of 200 Hz in AM and 100 Hz in SSB. Unfortunately though, the way of changing the band width is a little inconvenient. First, you have to access the band width menu by pressing the key, then you press the "BW"-key and keep it pressed and only then can you adjust the band width with the big VFO. It would have been better to make this operation easier with the installation of one button or switch for just this purpose.  A good example of a good solution is the band width adjustment of the JRC NRD 545 DSP, where you can program three fixed band widths and select them by repeatedly  pressing the appropriate key. Although the IC-R9500 has sharp DSP-filters, it also features so called "roofing filters". Before the signal reaches the DSP filters, it is passed through a selectable roofing filter which enhances selectivity.

In difficult receiving conditions, the AGC is a decisive factor. Ideally, it should be possible to switch it off completely or should be adjustable. The IC-9500 sports this feature in an impressive manner. The AGC can be programmed separately (SLOW, MID, FAST)  for AM and SSB.  You can also bypass these settings by using the turning knob. When things become difficult, you can turn off the AGC and carefully  use the RF-Gain. Unfortunately, the RF-Gain influences the signal strength indicator which is atypical of a professional receiver.

A Dxer can almost not do without the built-in digital speech recorder. It has two modes. A short recording can take up to 30 Sec. You activate this function by pressing the "Rec" button temporarily. This is very handy, if, e.g.,  you didn't understand the station identification. A long recording is started by pressing the "Rec" button a littler longer. It can be as long as you wish until the memory is full. The internal "CF-Card" memory has a capacity of 121 MB. You can also insert a USB flash drive which can't be bigger than 2 GB. The recording quality can be adjusted as well to make better use of the memories.

The IC-R9500 sports 10 VFOs, which is very helpful if you want to compare the signal strength of different stations transmitting on different frequencies. Of course, each VFO remembers the data which were used on a particular frequency.

With 14 fixed tuning steps and a programmable step width between 0.1 KHz - 999.9kHz, you will almost always find the best step width. I say "almost" because the channel spacing of 8.33 kHz used in aviation in missing. You may program your own steps but only in 100 Hz intervals. If you want to scan aeronautical radio in 8.33 kHz steps, you are out of luck, you will also be outside the desired frequency.        

The IC-R9500 has a search function which scans 40 channels/Sec in the memory mode. It also has intricate search mechanisms which leave nothing to be desired.

Of course, the center piece of the IV-9500 has to be mentioned: the big 7" display. Without this information center, the operation of such a complex receiver would become difficult. On the display, the spectrum and the modes are shown simultaneously. The width of the spectrum goes from 5 kHz - 10 MHz in the audible range. Beyond that, the width is up to 1000 Mhz. A special function is the built-in FSK decoder, which decodes the signals right away.  The default Baud- and Shift rates are atypical, though, because they are exclusively used in ham radio. Nonetheless, professional services, e.g., the German Weather Service (DWD),  can  be decoded without any problems. Decoded Synop is not possible. Unfortunately, this spectrum is not real time like with any good SDR, but it is "wobbled". At a high resolution, the wobbling is slowed down, which in return slows the speed of the spectrum. That is unfortunate, because the usability of the spectrum is somewhat diminished. More would have definitely been possible. When the IC-9500 was developed, SDR technology had already been available. This is a big flaw, but still the spectrum can be used for an overview.  The filter menu can also be shown with the Twin-PBT. The functions are displayed with symbols. The memory management and the scan functions are shown very well.

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Reception above 30 MHz is very good, there were no large signal problems. The 6m-band could be received with my antennas without any problems. Here, the IC-R9500 proved to be a very sensitive receiver. FM reception in WFM was a bit disappointing because WFM has only a filter width of 180 kHz.  An additional width of 110 kHz or 80 kHz would not have been out of place and the IC-R9500 would  have been a good DX receiver for FM.  The scanning function was very useful for the air bands. The air band can be scanned in a few seconds when scanning at a medium speed. Nothing can be criticized  in this respect, except that the 8.33 KHz step is missing and that the scan always stops in the middle of the frequency. The 2m and 70cm-band was without any problems. The frequency range of the IC-R9500 is up to 3335 MHz.  To evaluate the receiver in the highest frequencies,  you would need special antennas and expert knowledge, which I don't have; so I had to stop the test with the 70cm band.

Conclusion

The ICOM IC-R9500 is an outstanding receiver with an incredible number of functions and adjustments.  It is the receiver with the best features that has ever been on my table. It is built very sturdy and of excellent quality. Reception with this radio is top class and is on par with any other receiver. Although it has so many features, some aspects leave something to be desired. The loud fan was the thing that annoyed the most, but luckily that could be remedied. The spectrum did not make the best impression; it does not work real time, which is really too bad because it diminishes its usability. The third flaw is the lack of an additional, narrower filter for WFM. This makes the radio a little less useful for FM- DXing. Above 30Mhz, reception is flawless. The scanning capabilities leave nothing to be desired. Too bad, though, that an 8.33 kHz step for the air band is lacking. The synchronous detector did not make the best impression, either, but is useful, nonetheless.

 The IC-R9500 is the epitome of a top class receiver.

Download: >Flyer  >Specifications

Audiocomparisons between the IC-R9500 and the HF-1000 you find here.

postet 16.08.2015

 

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Enablia TitanSDR

The small company Enablia was founded in 2009 and is run by four HF- and software engineers. It is located in Rome.  Some really important SDRs come from Italy and so it's not surprising that this country is at the forefront of developing SDR receivers.

Enablia, which so far has been not known among radio enthusiasts, presents a SDR  receiver which is mainly for professional users, e.g., the military or monitoring services.  But it comes at a price range which makes this receiver also interesting for ham radio operators or shortwave listeners. 

Upon my request, Giovanni de Maio, who is the chief engineer of Enablia, sent me the TitanSDR with the pro software for tests and comparison.

The most important features:
-- Multi- channel receiver with max. four wide band channels from 312.5KHz to 2.187500MHz
-- Eight narrowband channels in the standard version and 40 narrowband channels in the Pro-version.
-- Frequency range: 9KHz - 40MHz
-- Modes: AM, LSB, USB, CW, FSK, FM, eLSB, eUSB, DRM
-- Band width: continuous from 200Hz to 20KHz (depending on the mode)
-- Tuning steps with the arrow key: 1Hz, 10Hz, 100Hz, 200Hz, 500Hz, 1KHz, 2KHz, 5KHz, 9Khz, 10KHz
-- 16 manually selectable band passes (preselectors)
-- Very good large signal characteristics up to IP3+ 37dBm
-- AGC: Fast, Slow, manual
-- Panorama spectrum: wide band- and narrowband spectrum and waterfall
-- scalable spectrums
-- recording of wide and narrowband channels
-- timer-controlled recording of the frequency band with various configurations
-- 6V transformer power supply included

The Hardware

The Titan SDR comes in a massive high-quality aluminum casing. It is black and looks  very sophisticated with its laser-cut labeling.  The dimensions are 243mmx52mmx145mm (WxHxD) and weighs 1.5. Kg.  Most connectors are on the back of the receiver. Here you will find the BNC antenna connector, a SMA IF-jack, a 6V DC jack,  the on/off switch, and a USB 2 connector.  On the underside there is a small fan for cooling. Luckily, a transformer 6V power supply is included. That is not  the normal case these days because in most instances the receivers come with a switching power supply.

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Blockdiagramm

First, the signal passes through a four-level selectable attenuator and then comes to a manually selectable preselector with 16 band passes. After passing an anti-aliasing filter (low-pass filter), the signal reaches the RF/IF switch. Here, e.g., the  IF-signal of an additional  receiver  can be fed into the Titan SDR via the SMA jack.  After amplification and filtering, the signal reaches the 16Bit A/D converter.  Here, the analogue signal is digitalized. Then the signal passes an FPGA, where the frequency is selected and the sampling rate is reduced, this results in a higher dynamic range.  Finally, the signal is sent to the computer via the USB 2 port.


The Software

The fast installation is without any problems. When using Windows 8 or higher, you should first deactivate the driver signature because otherwise the installation will not work correctly.

The TitanSDR is in a league of its own.  The software is not directly made for scanning frequencies as is the case with conventional receivers for ham radio operators or hobby listeners.  The Titan SDR is a multi-channel receiver with its main task to send teleprinter signals of any kind to be processed by a decoder.  The Pro- version works with the decoder programs Krypto 500 and Hoka Code300.   Additionally,  the monitoring of bands and their analysis are possible.

As  seen in the diagram, the data can be sent via VAC (Virtual Audio Cable) to any decoding program that works with  VAC. This is also possible via a local network (LAN).
 
Furthermore, the wide and narrowband channels  (Pro-Version) can be recorded and stored for later analysis (Rec & Replay). The standard software comes only with four wideband channels and eight narrowband channels.  Remote control of the receiver is also possible.
 
 
The following combinations of wideband channels are possible:
1 x 2.1875000 khz
1 x 1.875000 khz
1 x 1.562500 khz & 1 x 312.500 khz
1 x 1.250000 khz & 1 x 625.000 khz
1 x 1.250000 khz & 1 x 312.500 khz
2 x 937.500 khz
1 x 937.500 khz & 1 x 625.000 khz
1 x 937.500 khz & 2 x 312.5000 khz
2 x 625.000 khz & 1 x 312.500 khz
1 x 625.000 khz & 1 x 1.250000 khz
1 x 625.000 khz & 1 x 937.500 khz
1 x 625.000 khz & 2 x 312.500 khz
4 x 312.500 khz

First of all I focused on the basic task of the Titan SDR: The decoding of diverse signals on multiple channels. Because I do not own Krypto 500 etc, I had to be contented with freeware programs which can work using a VAC (Virtual Audio Cable). I installed the great DSC  decoding program YaDD and connected it to the Titan SDR via VAC.  First you put the wideband channels into the panoramic spectrum. Then you add the narrowband channels, which are the transmitting frequencies, e.g., 8414.5 KHz in FSK mode with a band width of 1KHz. After configuration of four channels, you can start.  You let the program  run in the background because signals are not being transmitted continuously.  After some time you will find some transmissions on the four frequencies and you can analyze them.  I used the same procedure with the Navtex-decoder "Yand" and "Zorns Lemma".  Without any problems, I could monitor and decode the Navtex- channels on 490 KHz and 518 KHz and the RTTY Signal of the DWD (German Weather Service) on 7646 KHz. During the night, several transmissions were received that could be analyzed later on. The settings can be stored and recalled for the next session. You can store as many 'sessions' as you like.

You can also make timer-controlled frequency recordings.  You just program the time of recording, frequency, mode and band width.  Several timers can be activated.  Afterwards, you can listen to the recordings with the integrated player. To do this, you need the USB-dongle which is supplied.  Only when this dongle is attached and recognized by the software,  will you be able to listen to the files.

This multi-channel recording can be interesting for DX'ers and wave hunters. You can record the wide and narrowband channels.  You can analyze the recordings later on and scan them in any mode and band width to find rare stations.  But also 40 individual frequencies within these four wideband channels can be monitored.

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Reception

Of course, with the Titan SDR you can also listen to the radio. Beside the usual modes, the Titan SDR also offers an unusual, but interesting mode: "eSSB"., or "extended SSB".  This mode offers an  extension of the frequency response in SSB (LSB/USB). In the eSSB-mode,  you can listen to AM-stations with 6KHz band width or even more.  Of course, you can listen to 'normal' SSB as well. With eSSB, AM-stations lose their  typical fading and sound much better.

During the first hours of operation I noticed something unusual: the very noisy fan of the Titan SDR!  Although I was only working with headphones, the small ventilator could be heard.  There is a reason for this ventilator:  The radio becomes rather hot.

As already mentioned, the software is not directly made for scanning frequencies. It does not offer (yet) the comfort of continuous scanning with a concurrent preselector.  That means that scanning is only possible within the wide band channels.  When you  reach the end of the wide band, the wideband shifts on by half. It can be expected, however, that this function will be extended with the next software update.

If you want to scan frequencies in a somewhat wider range, you choose the wide band with 2.187500 KHz. This band width can be put into the panoramic spectrum only once. After setting the wideband channel, a narrowband channel is added into it and you will hear the audio immediately.  Clicking on a number in the frequency display activates the frequency tuning with the mouse wheel with the numbers turning to yellow.  But there are also small arrow keys  to the left of the display . If you click on an arrow and stay there, the frequency changes continuously.  By default, the preselector is deactivated.  If you are using high performance  antennas, it is advisable to activate the preselector to suppress  outband disturbances. Unfortunately, the preselector  does not run automatically alongside and has to be controlled manually.

My tests showed that the Titan SDR has an excellent reception behavior. The audio is clear and understandable.  For comparisons, I used the tried and tested Perseus SDR. In a direct comparison in AM, the Titan SDR has a better intelligibility.  In the case of distorted and fading signals, you select  the Perseus'  SAM mode. The Titan SDR does not have this feature , but it does have the eSSB  mode. With this mode activated, the intelligibility is enhanced and surpasses the one of the Perseus.  The advantage is that you can toggle between eLSB and eUSB  to avoid sideband disturbances. But if the station is not exactly tuned, you have to retune.  With the AM-Synchronous mode of the Perseus, this is not necessary because it is done automatically.  The excellent intelligibility can even be optimized by switching off the AGC and controlling it manually (MGC). The reception of SSB is beyond any criticism and clearer and more intelligible than the one of the comparative radio. The sensitivity of both receivers is practically identical.

But there was one flaw with the Titan SDR, however. When using the wide band mode with the preselector deactivated, there were  spurious FM signals.  With the preselector activated, these signals disappeared right away.  Active antennas with their strong signals such as the Dressler ARA-30 caused the Titan SDR to overload. With the activated preselector this was no problem and it shows how important a preselection is.

For comparisons, I mainly used the Fenu-CrossLoop/RLA4B. This renders a fairly strong signal with a good SNR.  But I also used the Mini-Whip and the new NTi Mega-Active.  With these antennas, the Titan SDR functioned without any problems.

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Conclusion

The Titan SDR is built solidly and shows very good reception performance, although the software was not primarily developed for speech signals.  For the reception of these signals,  the software lacks important tools for signal enhancement and further optimization.  A noiseblanker, auto-notch, manual notch,  noise suppression, AM-synchronous etc are desirable features.  Let's hope that Enablia will deliver these things additionally.

Enablia deserves a special thank for including a transformer power supply which is not the rule these days and very welcome!

Posted on 09.04.2015

 

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Hagenuk RX 1001 M

The Hagenuk RX 1001 M is a receiver which was built for military- and marine communication. It is most certainly still in operation on some ocean vessels and probably in some coast guard stations. Typical as other professional receivers is the RX 1001 M built very solid. In comparison with hobby receivers does it look like a tank, certainly from the point of weight and size. The receiver only weights almost 17 kg and with the housing it puts almost 30 kg on the scale. This is understandable because it is built for daily operation under professional conditions for many years.

My RX 1001 M was a so-called “depot receiver”, a backup receiver and was never taken in operation. It looks as new even when it was built in 1992. 

The Hagenuk RX 1001 M has a tunable frequency range from 10 kHz – 30 Mhz for the operating modes AM, USB, LSB, CW and RTTY. Tuning steps are 10 Hz and 100 Hz.

It has 99 memory channels which can be scanned with various search modes. Each channel can be individually programmed, for example “Scan by Time”. This means that each memory channel can be activated for a defined time period starting from a set time. This is a great feature for unmanned frequency surveillance stations.

The receiver has a very good large-signal behavior of IP3 +26dbm, although only from 1 Mhz upwards. The Hagenuk is easy to operate. It is not as with other receivers which have for each function a button. No, a code has to be entered via the keypad when for example the mode has to be changed. When AM mode is required has the code “11” to be entered. For LSB has the code “13” to be entered, each function has a code. These codes are clearly marked on the front side of the RX 1001 M. The active function is marked with a LED. The massive main tuning knob is first class, which is magnetisch rasted. Just beautiful to turn the main tuning knob. This is also the case for the BFO knob. The receiver has a build-in loudspeaker which does not sound that bad and can be switched off by a switch on the front panel. All other functions and switches are self-explaining on the front panel.

 

How about the reception !

 

First its strengths: very good reception in SSB, very good large-signal behavior and a very good sound. From about 500 kHz upwards is the RX 1001 M very good. Below can, certainly in the evening hours, large-signal noises be heard. Apparently is no low- pass filter installed for operation below 1 Mhz. Only when the optional pre-selector is installed, is a low-pass filter installed. This pre-selector is hard to get ! As previously mentioned is SSB its real strength. The reception is almost noise-free and very understandable. For DXing in SSB mode is this definitely a top-notch receiver.  With a good audio filter, such as example the Dierking ED 88 NF, can disturbing noises be cut out because the receiver has no notch-filter and band-pass tuning. In AM mode is the sound also very well but a light clear noise can be heard which is disturbing with weak signals. But there for helps the SSB mode or an audio filter.

 

Final statement : a top receiver especially in SSB, just pure fun !

 

Why a professional receiver ?

 

It is not just the reception quality that makes such a receiver interesting. A Drake R8B, which I also have, or a JRC NRD 525G, are definitely not that much inferior to a professional receiver. Yes, even in certain situations has a professional receiver to underdo.

 

It is more the fascination having a professional receiver in his shack. Just its size and weight are crazy. The original packaging is so stable that it can withstand an earthquake. The manuals with all its schematics and service manuals are a 10 cm thick binder. On top of that is an extra binder just for spare parts. Of course is also a quality certificate of the quality control included.

 

It is just pure fun listening to the shortwaves with such a receiver.

 

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Lowe HF-235

The Lowe HF-235 is not that well-known as the HF-225 or the HF-150. Also is it hard to find. It is a professional receiver. Although the electronic internals are almost identical to these in the HF-225.

The installed filters of 2.2 kHz, 4 kHz, 7 kHz and 10 kHz are equal to those in the HF-225. In the 19 inch version are a build-in keypad, a loudspeaker, a RS-232 board (optional) and the power supply. Also optional is the synchronous detector board (build-in) and a TXCO (high stable main quartz) board. All functions are equal as on the HF-225 with the exception that the HF-235 has an adjustable IF-Gain and on on-off switch for the AGC instead of the tone controls.

How does the HF-235 sound:

One can be said from the start: better and less noise. The HF-235 is in comparison to the Perseus SDR an old receiver. The Perseus is superior what concerns reception quality, audio and noise. The HF-235 has a nice fine noise which allows listening with headphones for hours to stations without getting tired. I compared it also to the AOR 7030. The sensitivity is very good. The HF-235 is without doubt on the same level as the Perseus SDR and AOR 7030. The HF-235 and AOR 7030 are very similar, but the HF-235 sounds better. From the HF-235 is said that it does not withstand very well active antennas. The HF-235 withstands the ALA1530+ without problems.

In the night hours could some interference be heard on the 60 m band. When switched to a 20 m long-wire do they disappear. This indicates that the HF-235 prefers passive antennas. The synchronous detector cannot be compared with the one in the AOR 7030. The synchronous detector in the AOR 7030 is definitely better. In some conditions can the synchronous detector of the HF-225 still improve the reception.

Shortwave listeners like to have PBT (Pass-Band Tuning) and notch-filter. But the HF-235 does not have these. Here we find again the Lowe-philosophy: good reception, few buttons. Even when the bandwidth filters do not have a high quality does it still makes fun tuning through the shortwave bands. Final comment : its audio is very nice to the ears.

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RACAL RA1792

The Racal RA1792 is a professional shortwave receiver which was used in military and marine services. It was built in the 80’s.

My RA1792 came from the coastguard in Scheveningen, Holland, but was luckily not used for daily service. It was used as a reference receiver for the radio technicians and was there for rarely in operation.

Even though some small parts had to be replaced, such as the display. This is the weak point of the RA1792 as they tend to leak over time.

The RA1792 has the common operating modes such as AM, USB, LSB, CW and FM. The bandwidth filters for AM are crystal filter with bandwidths of 16 kHz, 6kHz, 3.2 kHz, 1 kHz and 0.3 kHz. For USB is a Collins filter with 2.7 kHz and for LSB is a crystal filter of 2.7 kHz installed. As with many other professional receivers has the RA1792 no tools for noise elimination. Only in SSB can a band-pass tuning be activated.

But there for is the selectivity of the crystal filter and Collins filter prime quality. The selectivity is as good as receivers with DSP technology. Even the 6 kHz filter for AM is just a dream !

The receiver has 100 memories which can also store the operating mode and AGC.

One can ask why having a 14 kg heavy receiver on his desk. Very simple. First there is the audio quality which is great, even in AM or SSB mode. No other receiver which I had so far in my shack could come close to the audio quality and the sensitivity of the RA1792. Weak signals were still very understandable. Of course at some point has the RA1792 its limits as other receivers have band-pass tuning, notch-filter, noise blanker etc. which give them some advantages.

When no disturbing signals are present is the Racal definitely superior. The large-signal behavior is very good, which is normal for such a receiver. On my antennas (Fenu-Loop/HDLA3 & 35 m longwire, both 8 m above ground) could no clipping be observed.     

 

Fact :

A great receiver! Easy to operate and receiving quality is of top level. Something for purists.

Someone who wants to acquire such a receiver should be aware that these receivers have some years. With other words, the probability for defects cannot be ignored. There for is it absolute important to know where you acquire the receiver. Very often is the condition described as heaven on earth but you get a receiver with defects. 


Repairing such a receiver can be quiet expensive. Some good advise : acquire only from reliable sources and test the receiver first !

 

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Racal RA3712

The Racal RA3712 is a relatively hard to come by professional receiver. It was widely used by the Royal Navy, but certainly found several further areas of use. Unfortunately there is little specific documentation available describing the RA3712 fields of application. The RA3712 is a dual HF receiver. This means that two independent receiver modules are mounted in the chassis. Switching between the receivers is done via keypad command.

Here the most important facts and figures:
Frequency range RX1: 500khz - 30Mhz
Frequency range RX2: 10khz - 40Mhz
100 memories with scan functions
Tuning rate:
Slow > 1Hz
Medium > 50Hz
Fast > 1Khz
Variable > 1Hz > depending on the turning rate of the tuning knob with flywheel effect.
Pass band tuning
Modes: AM, USB, LSB, CW, FM, FSK & ISB (optional)
Filter bandwidths: 0.3 - 1.8 - 2.7 - 12khz (roofing filter) LSB only 2.7Khz
AGC: slow, medium, fast & manual. Additionally, the gain control auto / manual can be combined. A special AGC setting is reserved for the "Link11" military radio link.
Various BITE functions (self test)
Modular construction
Very good strong signal performance

Like many professional RX, the RA3712 were custom fitted. This means the receiver will only in very few cases be equipped with appropriate filter bandwidths for SWL use. The AM filter of this specific unit is 12 kHz wide. Much too wide for reasonable AM reception. This leaves only the 2.7khz and the 1.8khz filters. So AM stations can only be heard reasonably by switching to SSB mode.
I've been comparing the RA3712 with the legendary AEG/Telefunken E1800/3. The RA3712 has installed more suitable SSB filters for our needs compared to the E1800/3. But this has to do only with the width of the filters, not their selectivity. The E1800/3 uses mechanical filters that are incredibly sharp! The RA3712 uses quartz filters of comparable selectivity. Both receivers perform almost on the same level. The RA3712 audio is quite similar with a treble-dominated tendency. A clear benefit of the RA3712 is its pass band tuning! Signals can be "edited" for better intelligibility which is not possible with the E1800/3. Unfortunately, the pass band tuning is a bit complicated to use. First select PBT in the menu, then select the filter, and only then you can use PBT. Although the RA3712 has a flexible AGC, it can best be used in manual gain control. So noise can be handled elegantly. In terms of reception the RA3712 plays in the top league. In a low noise RF environment, the RA3712 is a wonderful shortwave receiver. Like the E1800/3, the Racal RA3712 is a top receiver.
Also for the RA3712 applies: Be careful when buying! Some of these receivers have been in continuous use for years and can suddenly cause problems. Repairs can be costly. Additionally, such receivers are not primarily intended for SWL use.

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The Racal RA3712 in Action (HD Video)

 

 

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Reuter RDR54

It took some long thinking whether I should acquire a Reuter RDR54 certainly as the receiver is not well-known in the SWL scene. Nobody could provide a comparison with other receivers. In the Internet were mainly technical data available but no test reports. There for it is hard to decide whether to get such an expensive receiver. But when I get, as a radio-freak, offered a RDR54 it is hard to withstand.

Now I have the receiver and am ready for some receiving comparisons.

What kind of receiver is the RDR54 ?

 

The RDR54 is a European! More precisely, it is manufactured in Germany by Reuter Elektronik. The manufacturer was unknown in the SWL scene. Originally was the RDR54 designed as a measurement receiver and was quiet hard to operate. There for wrote Burkhard Reuter, the designer and name-giving of the receiver, a new operating software which made the RDR54 easier to operate for the SWL. The RDR54 is a receiver of the newest generation. It is a “SDR”, a Software Defined Radio which requires no PC.

 There for is the RDR54 independent of a PC for regular operation. Only for software updating is a connection to a PC required. But the RDR54 cannot be compared with the common SDR’s because it operates with the newly designed discrete frequency principal. The common SDR’s operate with the time discrete principal. For an in-depth explanation please consult the manufacturer.

The housing looks like an industrial measurement equipment. It looks cold but elegant at the same time.

 

The workmanship of the housing is just top-notch ! The entire housing is made out of aluminum. The only cheap component is the main tuning-knob, which just does not fit with the RDR54 … But improvement is on its way. Recently is a magnetic raster VFO-knob available made out of stainless steel. In the middle, which cannot be overseen, is the beautiful and large display. The resolution is very good and gives information about most functions. All is good readable, even the small prints.  

 

The display can show waterfall spectra, curve spectra or line spectra. The visible frequency range is about 164 kHz. The spectra can be zoomed in.

On the left side of the display are the audio functions. The wobbling volume knob has an additional function. When the volume knob is pushed and held can the volume be changed. The build-in loudspeaker is not that big but gives sufficient audio quality for shortwave listening, but is lacking a bit of bass.

 

For further details on the functions of the RDR54 I refer to the manufacturer website of Reuter Elektronik, because this would otherwise be too much on this site.

How is the receiving quality ?

The receiver operates 100% digital. It gives almost a noise-free and clean audio. The band-noise is pleasant and allows listening with headphones for hours.

But it has on some signals a bit of typical metal-audio, as can be heard on receivers with DSP technology. But this relates to the operating principal of the RDR54. For an in-depth explanation please contact Burkhard Reuter. But after some time listening is this no longer noticeable as the audio is very clear.

 

It is there for really a joy DXing with headphones. The loud raster main tuning knob and the “Auto” operating mode are bit disappointing. The “Auto” mode is a kind of AM-synchronous mode. When tuning fast through the bands is the audio quality not as with common analog receivers. The “Auto” mode tries to synchronize immediately  each signal in the band-pass range, which gives an unfamiliar sound. But Burkhard Reuter has put this issue immediately on the list of should be corrected with the next software release. The sensitivity is definitely better than the Perseus. But at very weak signals is the Perseus a bit better understandable. But this is all software defined. The Reuter RDR54 exists since 2009 and there is still much room for improvement in the software. The Perseus required also some time until it was at today’s level.


The large-signal behavior is quiet at a high level : above 44 dBm. Some very long antennas can be connected to this receiver. Not surprisingly were no large-signal disturbances monitored.

The RDR54 can convince with its concept (SDR without PC) and his very sensitivity.

When the manufacturer optimizes the software can the RDR54 soon play in the top league of shortwave receivers.

***In the meantime is the software version V302 released. The user interface has been simplified, new operating modes have been added and the receiving quality has definitely been improved. Details can be found in the latest Operating manual of the RDR54.

  
A top-receiver with some not so-common user interface.

Because the mechanical tuning encoder was quiet loud I have installed a magnetic raster tuning encoder along with the knob made out of stainless steel. Now it is a joy to tune through the bands. No more mechanical noise. The heavy stainless steel knob has a nice flywheel-effect, but not too heavy. Additionally has a matching audio volume knob been installed, free of charge. Reuter Elektronik made the modifications within a working day. That is real service !

 

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The RDR54 in action (HD Video)

 

The FM-module

 

The RDR54 is a modular built receiver. This way can new modules, such as the FM-module, easily be installed. With the 100% software digitalization can new functions be integrated to expand the functionality of the receiver. Burkhard Reuter was so kind to lend me the FM-module for some weeks for test purposes.

This FM-module offers the FM frequency range of 87.5 – 108 Mhz, tunable between mono and stereo. Additionally is the 2-meter radio amateur band (144 – 148 MHz) included, just in receiving mode.

For the FM mode are 4 filter bandwidths available : 

 

50khz S & HQ
80khz S & HQ
120khz S & HQ
240khz S & HQ

S = Steep (sharp)
HQ = High Quality (HiFi)

 

For detailed information I refer to the website of Reuter Elektronik.

How does the FM-module sound?

Just first-class!

 

I connected the RDR54 to a FM antenna, mounted on the roof of the house, and to the cable-network connection. The cable-network connection gives often a stronger signal. Although a clipping signal could not be monitored. Also connected to the roof-mounted antenna, unfortunately not rotatable, performed the RDR54 flawless. The digital filters are extreme steep and can isolate easily adjacent transmitter. Is the transmitter signal undisturbed can be switched to 240 kHz-HQ and FM can almost be heard in HiFi quality. What fails is the nowadays common RDS-decoder. According Burkhard Reuter will this feature be implemented in the next software release.


The 2 meter band could not be thoroughly tested because of lacking a proper antenna and very weak signals.

 

Fact :

All in all is the FM-module very recommendable, surely the receiving performance. The price tag gives you a cold wake-up call. For the FM-module have 350 Euros be put on the table.

 

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Reuter RDR55D

The Reuter company is a household name among shortwave listeners and beyond  and is well known for its high-quality products. Above all, the receivers of the RDR-series were the benchmark as regards workmanship and receiving quality.   The receiver technology is digital as with all other SDRs, but signal processing is different.  Most SDRs, e.g.,  Perseus SDR or ELAD FDM-S2  operate  time-based. The receivers of the RDR series on the other hand make use of frequency-based signal processing. Information about frequency-based signal processing can be found in Dipl.-Ing.  Ralph Menn's lecture in paragraph 2.1.

Zeit- und Frequenzbasis des Signals
 
Modularbauweise des RDR55D

Now I have the latest receiver RDR55D with the software version V500 in front of me.  There is a little story behind it.  The combination of the RDR 54, which has measure instrument qualities and its smaller brother RDR 50, which has a big and user-friendly touch screen is the result of many a customer's request.  This shows how this company respects  customers' wishes and ideas.

Like the RDR54, the RDR55D is modular-structured. By adding further modules on the  rear panel, the radio can be enlarged. It can also be made into a fully-fledged ham radio QRP rig. The case is made of milled and anodized aluminum, the tuning knob is made of high-grade steel.  The RDR55D can be expanded with various modules and thus customized according to the user's whishes.

This RDR55D has the following modules built in:

RAD18EF (preselector, pre-amplifier, attenuator, 4x16bit ADC and FM module)
RDA31B (High-End Stereo Audio-DAC with High Power headphone amplifier)
RDR35B (GPS and WLAN module)
RPS25G (high-quality power supply)
 
Ratings
Frequency range with module RAD18EF:
1KHz-30MHz (separate antenna jack ANT1)
50MHZ-71MHz (separate antenna jack ANT2)
87,5MHZ-108MHZ (separate antenna jack ANT3
136MHz-154MHz (separate antenna jack ANT4)
Band width filters: 10Hz-20KHz, freely selectable in 40 Hz steps
Modes frequency-based: Sync-DSB-LSB-USB-EUSB-SBCW-CW
Modes time-based: AME-FMN-FMW-USBQ-LSBQ-DIGI-DBSQ
Tuning steps: freely selectable from 0.5Hz-999.999.5KHz
199 memories
Passband tuning
Notchfilter
Noiseblanker
AGC:  rise and decay freely selectable
GPS module for frequency calibration
WLAN connection for cable-free firmware update and screenshot functions
Built-in preselection
very good large signal immunity
7" (178mm) WVGA-color display and touch screen
Ham radio upgrades  via modules are available
 
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Operation.

Except for the On/Off switch, the tuning knob made of high-quality steel is the only mechanical element for operating the radio. Practically all parameters are controlled by this knob.  The selection of the functions is done by using the touch screen, e.g., if you want to tune the band width filter, you touch the band width indicator with your finger and then select the bandwidth with the tuning knob.  Then you touch the next function or the action can be set in such a way that the active function goes back automatically to the frequency indicator. The length of time on the active function is also user settable. Except for the adjustments in the menu, all functions can be controlled in this manner.

The eye catcher, of course, is the spectrum in real time.  That means, whatever you see, and you can listen to without any time delay.  The spectrum has a max. Range of 164 KHZ and can be zoomed to 1.6 KHz.  A waterfall diagram is also possible. Basically operation of this radio is foolproof, but you have to get used to the very small touch field and if you have small fingers, you are at an advantage, but you can also use a plastic pen for the PDAs.

For frequency calibration, you have a GPS receiver at your disposal, which comes with the RDR35B module.  If you connect a standard GPS antenna, some satellites will be received after a few minutes.  With the help of these satellites, the internal oscillator will be calibrated exactly to 1 Hz. If you select the GPS function, the following data are shown:

-- Number of satellites which can be received
-- Satellite identification
-- Signal/noise ratio of the satellite signal
-- Correction of the internal oscillator
-- Geographical length and latitude of present position
-- height above sea level.
-- current time (UTC)
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Via the WLAN, which is also contained in the RDR35B module, a wireless connection to a PC is possible.  At the moment, this connection is used for firmware updates and screenshots and for sending them to the PC.  Soon it will be possible to operate the RDR55D with suitable software via this interface.  The advantage of the WLAN connection is that you don't need any cables anymore.  It is a well known fact that a PC can cause heavy interferences in the long wave, medium wave and shortwave range.  Of course, the RDR35B module also has a standard USB2.0 interface.  There is also a S/PDIF interface for digital audio signals.

The RDA31B module offers a high-end 24bit headphones amplifier. The audio signal can also be sent to a stereo system via a cinch plug.  This module only processes the time-based modes AM-E, FM, FM-W, DSB/SSB-Q and DIGI.  The audio quality of FM-signals via this module is of outstanding quality.

In the RAD18E module, the signals from the antenna pass through the preselector before they are passed on to the 4x16bit ADCs. Here, the filtered analogue signals are digitalized and redirected for demodulation.  When using this module, only the antennas have to be connected to the correct jack.  

Reception

I had my first experiences with time-based operation in 2011 with the RDR54. Later, there was the RDR50. Ever since, due to the development of ADCs (Analogue Digital Converter)  and FPGAs ( Field Programmable Gate Array) big improvements of reception have become possible.  The earlier RDR models, which had already been low-noise, were further improved.  The RD55D is the receiver with the least noise that I could ever review.  If you work with this radio for a longer period of time and then use a standard receiver, you will be surprised at the amount of noise that these radios have.

Well, I compared the RDR55D with the ICOM-R9500 over some weeks. For antennas, I used the Fenu-CrossLoop/RLA4B and the NTi ML200 with the 8m loop.

The sensitivity of the RDR55D is linear from the lowest to the highest frequency. Signals on VLF, LW and MW were received best and most pleasant.  AM-signals are best received in the "Synch" mode, where the signals are automatically got rid of noise and fading. In addition, some local interferences were filtered out , e.g., PLC-interference from  the neighborhood.  On shortwave, the differences were smaller.  The IC-R9500 was able to render some signals better which was due to its complete setup. Getting rid of interferences worked better with the IC-R9500.  When listening became difficult, the RDR has its surround function, which works very well even in case of weak stations.  SSB reception worked very well, as was expected.  Because of the sharp filters of the RDR55D, the IC-R9500 was at a disadvantage on the ham radio bands. You will only notice the extreme selectivity when you slowly reduce the bandwidth.  You will already notice a reduction of 40 Hz.

Because of the frequency-based operation of the RDR55D, the audio is somewhat "tinny" But you won't notice that after some time and you get used to it. But you do notice the lack of intelligibility of weak signals.  In these instances, the IC-R95090 was mostly better, but there was more noise.

If you operate the RDR55D in a noise-free environment, you can use the time-based mode "AM-E" when listening to an AM station.  This mode simulates an envelope detector and the audio sounds as if it is coming from a radio with tubes, warm and full. Unfortunately, this mode has only a few fixed bandwidths. All other functions, e.g., band pass tuning, notch filter etc. are not available in this mode. That is really too bad and a lot of potential is not made use of. All time-based modes suffer from this lack of functions.

A real treat is the reception of FM signals. Here, the RDR55D operates time-based, i.e. in the usual way. Because of the high-quality parts of this module, reception becomes a high-end experience.  Reception in stereo and mono is possible, of course.  To even enhance this experience,  the stereo width is user selectable. RDS is included as well.  FM-DXers are well taken care of. The FM- module is designed for highest sensitivity and predestined for DX.  For difficult situations, the RDR55D has a special attenuator, which can attenuate the signals up to 48dB in 1dB steps.

Currently, the following band widths are available for FM:
--38 KHz S
--50 KHz S
--60 KHz HQ
--80 KHz HQ
--120KHz S
--120 KHz HQ
--300 KHz HQ
"S" means "sharp" > steep filtering slope
"HQ" stands for "High Quality" > round, less steep filtering slope. Sounds more pleasant, fuller.

To start with, FM reception of the RDR55D surpasses the IC-R9500 by far regarding sound, selectivity, sensitivity and functionality.

Large signal handling of the FM module is beyond criticism. Reception via a cable network was without any problems.  Here, the RDR55D gets really going and can show its FM qualities.  The audio quality with a 300 KHz HQ filter was simply superb.  Noise, which is often noticeable with such wide filters, could not be detected when using the cable network. However, signals had to be attenuated by -20dB, because the ADCs suffered from overload.  But that is really not too bad considering such high sensitivity.

Conclusion

Reviewing the RDR55D was not a difficult task, i.e., absolute top class receiver! Starting with the workmanship and the material of the case up to the reception quality on long-, medium- and shortwave and FM, the RDR55D was without serious flaws.   However, there were two aspects, which I did not like: The lack of intelligibility in case of frequency-based weak signals on shortwave and the unsatisfactory function of the noise blanker and the noise reduction.  These small shortcomings can probably be corrected by a correction of the software.  Except for this, the RDR55 is a dream of a receiver.  Unfortunately, this luxury receiver with the qualities of a measuring tool costs ca. 5000€ in this setup.

posted at 5.11.2015

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RFT EKD 500

It is big; it is heavy and built like a tank. We are talking about the EKD 500. This radio was built by "Funkwerke Köpenick" near Berlin around 1986. At that time, there still was the DDR, the German Democratic Republic. At Funkwerke Köpenick, receivers were built which are still in use and which many shortwave listeners rave about. The EKD 500, just like its predecessor EKD 300, was widely used by radio services, mainly by the military. It certainly played a big role during the Cold War. However, the EKD 500 was also used by marine radio services and other civil agencies.

The most important features:
Frequency range: 14KHz - 30MHz
Tuning steps: 10Hz - 9999KHz (freely selectable)
Locking rotary knob
Modes: AM, ECSS Synch, USB, LSB, CW, FAX
Band Filter Width: 0.15-0.4--0.75.1.75.3.1-6.0-3KHz-(USB)-3KHz-(LSB)
Sensitivity:  150KHz-30MHz AM  5microvolt --SSB   1.5microvolt
AGC: short - long manual control for all modes
99 memories
remote control
scanning function
Tracking preselection
Excellent large signal rejection
Very good frequency stability
Modular design in cassette style
Extremely stable construction
Weight: 25Kg
table-top receiver  with own case

In contrast to its predecessor, the EKD 500 could be remotely controlled with a computer. It was designed this way. It had, however, a disadvantage: A normal frequency selection like with the EKD 300 was not possible anymore. The EKD 500 only had an inconspicuous small rotary knob which stopped with quite some noise. Additionally, there were signal drop-outs caused by noise. After manual tuning for ten minutes,  your hands were hurting. A real grind. This could only be remedied by two easy modifications. The scanning mechanism could easily be removed and in order to get rid of the noise drop-outs during the tuning, a resistor had to be replaced by another one on the control unit. That is rather easy to do, if you have some knowledge of electronics. However, only the 10 Hz and 100Hz tuning steps are without noise drop-outs. They are still noticeable when using tuning steps about 1KHz, but not as extreme anymore. I made these modifications myself and also installed a bigger tuning knob. Now the EKD 500 was ready for reception.

First, I had to learn how to operate the EKD 500. I did this based on the notes which were  pasted on the front part of the radio. If, e.g., you want to change the mode or the filter widths etc., you have to enter something like a code. If you want to change to AM, you have to press the button 'MOD', followed by a '2'. If you want to change the width to 3.1 KHz, you have to press 'B' and then a '5'. For AGC -short, you press 'GC'  followed by a '1'.  With 'SEL' you can enable and disable the preselection. After a short while it was easy to do.

During the few weeks  that I had the EKD 500, I compared it with all receivers which were at my disposal at that time.

Starting from Long wave to the 10m-band, the EKD showed very good signal quality with steady sensitivity and little noise. The manual gain control (MGC) turned out to be the best choice. The automatic gain control (AGC)  could not convince me. The decay time way too short.  The noise during the speech pauses increased considerably. 

Comparisons with common semiprofessional receivers, e.g., AOR AR7030, JRC NRD-525 etc showed how good the speech intelligibilty of the EKD 500 is. It proved to be better most of the time. The audio is nothing for audiophiles, stresses the pitch and has practically no bass. The intelligibility is also enhanced by the excellent mechanical  and highly selective  filters. A big help is also the very stable synchronic detector which synchronizes the signals in the ECSS- mode and optimizes the suppression of the noise and the crackling. Even the sidebands are selectable. But there are also negative aspects which should be mentioned.

The EKD 500 is a professional receiver which was developed for large antennas.  These antennas offer so much signal strength that the sensitivity of the receiver was a minor problem. When we connected such a receiver to one of the antennas mostly used by SWLs, e.g., a 20m long wire or a ALA1530+, we were not surprised when the EKD 500 became more and more deaf under a certain signal strength.  This happened because hobby antennas simply do not have enough strength.  This is the EKD's 500 weakest point.

Just like many other professional receivers, the EKD 500 does not offer any help for optimizing the signal. You will look in vain for noise blankers, notch filters or passband tuning.

The EKD has been in use for a considerable time.  Although these receivers are built extremely robust and seem as if they would work for ever, you should think twice if such a boat anchor with its considerable weight on you desk is the right radio for you. Unfortunately, even the EKD 500 will break down and can cause huge repair bills. Only the  shipping a 25Kg radio is not exactly cheap.  There are still enough spare parts available. Some technician are specialized for these receivers and can help if problems occur.

In the pictures, you can also see the additional EZ 100. This is a preselector and has a demodulator for RTTY.  It is of no use for the SWLs.

Conclusions:

A huge and heavy shortwave receiver Made in Germany. It offers very good reception with suitable (large) antennas. It is excellent as far as speech intelligibility is concerned. In any case,  SWLs should modify the tuning knob

A big "Thank you" to Reinhold Schuttkowski for loaning me his EKD 500.

Written at  08.11.2014

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SRT CR91

The SRT CR91, or in full "Standart Radio and Telephone",  is a professional 19" receiver made in Sweden.  The CR 91 was built, however, with Telefunken technology.  Some circuits and especially the bandwidth filter with 200 kHz IF point to this fact. This model was built between 1982 and 1992. It was mainly used in Scandinavia at embassies and listening posts for monitoring radio communication. However, some radios made their way to other countries and also to Switzerland. SRT even used to have an office in Switzerland.

Here are the most important features:
Frequency range: 10 kHz-30MHz
Tuning Steps:   1Hz - 10Hz - 100Hz
Tuning speeds:
Slow: 2.5 kHz/turn        MED: 25 kHz/turn             Fast: 250 kHz/turn
Rotary knob with flywheel effect
Bandwidth filters: 0.3 - 0.6 - 1.5 - 6.8 3(USB) - 3kHz(LSB)
AGC: Short - Med - Long - and manual control for all modes
100 Memories
Remotely controllable
Excellent large signal rejection
Very good frequency stability
Weight: 12Kg
19" rack-mounting unit

As is often the case with such radios, it had to be repaired before the test. The colleague, who loaned me the CR91, had forgotten to test the unit before he gave it to me. Therefore, it happened what was bound to happen. The CR91 could not be switched on. Therefore, I had to use my contacts to specialists to find someone, who could bring back the CR 91 to life.  After only two weeks I could finally switch the CR 91 on.

After some time of familiarization, the CR 91 could be operated easily and speedily.  However, I had to use the manual because some functions were not immediately obvious.

The reception was really good when the radio was connected to normal SWL antennas.  Because of its excellent 200 kHz IF Telefunken filters , which offer an excellent selectivity, the CR 91 is a good receiver for SSB as well as AM.  DSP radios were not more selective. The CR 91  was on par with modern SDR-radios, up to a point! If you had to suppress a secondary carrier, its options were very limited. There are no noise blankers or other features.  The CR91 cannot offer the flexibility,  which is expected today.  What I noticed negatively,  was the extremely fast start of the flywheel effect.  Practically, I could only work with 1Hz tuning steps. Unfortunately, I could not find out,  if this effect could be switched off.  The socket for the headphones was not  typical, either. It is a DIN 5 - pole jack with 240°. Fortunately, I found such a plug at the Hamradio 2014 to build an adapter.

Basically, it is a good receiver in "Telefunken quality", so to speak.

A radio for specialists. Not practical for short wave listeners.

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Telefunken E1501

The Telefunken 19 inch professional receiver, model E1501, is the most advanced version of the E1500 model. The latter is a sized-down version without ISB, antenna diversity and tuning aid / display for RTTY. The 1501 can be expanded with various modules, the most valuable expansion is the pre-selector-module.This module is installed in my receiver.

 

The most important features :
Frequency range : 10 kHz – 30 Mhz
Tuning steps :
With lever switch ↑ 300kHz/s
With lever switch ↑↑ 3MHz/s
Tuning knob with flywheel-effect
Operating modes : AM, USB, LSB, CW, RTTY & ISB (Optional)
Filter bandwidths : 0.1 – 0.3 – 0.6 – 7.0 – 14 - +3(USB) - - 3 kHz (LSB)
AGC : for AM> fast, SSB> slow & fast and manual control for all modes
Very good large-signal behavior

The E1501 was used in the coastguard and military for communication surveillance and communication intelligence. It could be adapted to particular requirements because of its modular design. The E1501 was widely used because of its excellent performance. It was also used by the Swiss governmental agencies and military. Once in a while are these receivers offered at Ebay or sold privately. I would like to recommend, better advice, to test these receivers prior making an offer to the seller. Quiet often are these receivers offered with defects. The excellent features of the E1501 start with the mechanical design of the receiver and continue with the electronics and finally with its receiving performance. These receivers were built to last forever, without failing. I got mine from a skilled owner who maintained it properly, mechanically and electronically. I only replaced the tuning knobs as they had become a bit yellow. The E1501 is for the classist. Its ideal location is QRM-free because it has no features such as a notch-filter, pass-band tuning etc. Only a noise reduction has been built in which limits the high-frequency audio peaks and there for makes the reception at bit quieter. That was it. What also could be seen as a noise aid are the mechanical bandwidth filters which are very steep and give an excellent sound quality. Someone who cannot miss a notch-filter etc. can install an external audio filter. I used an old Dierking GD 82 NF which could once in a while improve the reception from some disturbances.

How is the 17 kg heavy receiver? I compared it with other amateur- and professional receivers. When there are few HF-disturbances is the E1501 an excellent receiver. It is a real hardcore dx-machine, even when the bandwidth filters are poorly selected for voice understandability. The E1501 can beat almost 80 % of the amateur receivers in receiving performance. The sensitivity, the (very) clear sound and the super large-signal behavior puts the E1501 in the front league. When operating it with manual AGC performs the E1501 even better and comes close to the performances of the recently tested Ten-Tec RX-340.  It is there for hard to decide its favorite receiver as the differences are minimal, not least because such receivers have a magical attraction.

A receiver without any bells and whistles but with an excellent reception quality!

Written at 13 Nov. 2012

 

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Telefunken E1700

The Telefunken E1700 is the direct successor of the E1500 series. The technical data are very close to those of the E1501. Only the large-signal behavior has been improved. The 30 memory locations are really new, in which frequency, operating mode and filter bandwidth can be stored. The memory function is located on the top left side of the front panel. It are the black lever switches. Its operation is easy. Select with the lever switches the memory, push the small below lever switch together with the lever right of main tuning knob down and the memory is stored. To recall the memory is the lever switch below the memory unit pushed down.

 

There are almost no differences in receiving performance between the E1700 and E1501. I listened for hours during many nights for situations where I could hear some differences, but I could not find any. The only difference is that the E1700 is a bit more sensitive for electrical disturbances. Electric fences and electrical clicks can be heard better with the E1700. There for there are no audio samples comparing with the E1501. The differences are, as already earlier mentioned, just nil.

What makes the E1700 so attractive? The hobby world is quite crazy for this receiver. Appealing is that this receiver is very seldom. It is almost impossible to get an E1700. Most of them are sold privately … when they are available.

 

The E1700 is an excellent receiver. As with the E1501 you can hear the grass growing, assuming the proper antenna is connected to the E1700 and most important a QRM- quiet location.

 

Written at 24 Dec. 2012

 

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AEG Telefunken E1800/3

The E1800/3 is one oft the most sought-after professional receivers. According to tests performed in the 1990s it was  judged the best receiver in the world. No wonder then that it was sold at enormously high prices.   It was not unusual for people top pay  more than 10000 € for a used E1800/3 on the secondhand market. The original price of the E1800/3, which is shown here, was 52835 DM.

Here is a detailed line up  based on the original price list:

Type
unit price
quantity
Price in DM
E1800/3
40200
1
40200
TD1710/2
4560
1
4560
AD1710
2680
1
2680
BT1800
1450
1
1450
SER1810
2245
1
2245
Filter
850
2
1700
 
 
 
 
 
 
Total
52835

After the E1800, the E1800/3 is the successor of the tried and tested E1501 and E1700 receivers. Some components  taken from the E1501 and E1700 were used for the E1800/3. These components, however, were  optimized again and again.

Like its preceding models, the E1800/3 was used mostly by the military in their listening posts as well as at marine radio stations. Many of these receivers were also used at automated listening posts where a computer-based system monitored the frequencies. These receivers were partly   taken out of service and replaced by software defined radios (SDR). That is why some of these receivers are available on the second hand market almost brand new, because they were never touched.

Here are the important specifications:
Frequency range: 10kHz - 30MHz
Tuning step sizes:
the tuning speed depends on the selected band width
Position 'Slow':  1/2 turn  results in a frequency change corresponding to the selected IF-band width
Position 'Fast': 1/2 turn results in a frequency change of abt. 10x the selected IF-band width.
Smallest tuning step: 10Hz
Modes: AM, USB, LSB, CW, RTTY and FAX
Filter width: 0.1-0.3-0.6-1.5-3.0-10- +3kHz (USB) - 3kHz(LSB)  >>10kHz is the roofing filter
AGC: for all modes: fast - slow - and defeatable for manual control
100 memories with scan function and optional language squelch
Frequency scan with optional language squelch.
BITE Test (Self-testing function)
Excellent large signal rejection

Depending on its intended use, the receiver specifications may vary. The receiver which I tested was mainly used for CW, RTTY and SSB.

I tested the E1800/3 for about two weeks and formed an opinion about the then "best receiver in the world". In order to make a fair comparison, I borrowed a Racal RA3712 from a colleague of mine. This is a somewhat more modern and flexible radio than the E1800/3 but its performance is practically on par with  the E1800/3. Additionally, I used my own receivers for this test.

The E1800/3 really  is a top class receiver. But it was not better or worse than the RA3712. Both receivers had the same signal quality. I have to emphasize, however, that this was only possible with the manual  gain control activated because the AGC automatic is not optimized for SSB or broadcast. The AGC control sets in much too fast. As a result, the  first syllables at the beginning of a sentence are cut off because  of the AGC control.  A big disadvantage for such a receiver which is corroborated by other owners of the 1800/3!  Just like other professional receivers, the E1800/3 is flexible as rock! There are no controls to improve reception, e.g.,  noise blanker, band pass tuning, etc.  If a shortwave listeners want to operate  such a receiver, they have to have additional equipment. e.g. audio filters. If the receiver does not have the appropriate IF- filters, things can become very expensive and can result in an extensive search. Such IF-filters are practically non-existent, especially the 5 and 6kHz AM filters are nowhere to found.

The E1800/3 is a top-class receiver with an improved and simplified handling compared to its predecessors.  But unfortunately, it is not a suitable receiver for shortwave listeners.  Despite its excellent reception quality with the manual gain control active,  the E1800/3 is only partly usable because it is too inflexible. Compared to a modern receiver , e.g., the Reuter RDR50CV2 or the Perseus SDR, it becomes clear immediately what such a receiver is lacking: Flexibility!

Is such a receiver worth  buying? From a practical point of view, clearly NO! If you see things sentimentally and have the necessary wherewithal: definitely YES! It is a wonderful piece of equipment that puts a spell on you and which is lots of fun.

Under this link there  are technical data and further information about the E1800/3. >E1800/3< Thanks Reinhart.

Pro:
-A real legend
-Wonderful piece of equipment to rave about.
-Excellently manufactured. Top quality.
 
Con:
-Still very expensive, partly overpriced
-Inflexible
-Additional filters are  rarely available and expensive
-Repairs are difficult to carry out and can be extremely expensive

Written at 21.04.2014

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The E1800/3 in Action (HD-Video)

 

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AEG E800/2

Thanks to a fellow ham radio operator here's the first report on the AEG E800/2 on the internet. He gave me his E800/2 for testing for 2 weeks. At this point, many thanks to Paul, HB9MFD.

Virtually nothing is known about this professional receiver. According to my knowledge it was offered on Ebay only once. And that's it!

The E800/2 is based on the well known and sought after E1800 receiver series. So why an E800/2? For some simple monitoring tasks, such as e.g. the interception of voice communications, the E1800 was simply too expensive. Not every agency was ready to spend around 50'000DM for such a device in those days. Considering that a monitoring site was using several, perhaps dozens of these receivers, one can imagine the tremendous cost it must have caused. That was the reason why the E800/2 was developed. A slimmed-down version of the E1800, so to speak. The E800/2 cost around 32'000DM. It is not constructed in a modular fashion, so it weighs only about half of the E1800/3. It consists of only two large circuit boards, a linear power supply, and a control unit which is bolted to the front panel. This corresponds to the conventional construction of a amateur radio receiver. Also some electronic downgrades were performed which were not important for use. For example a slower synthesizer because the E800/2 was not used for direction finding. Also the number of control elements was reduced. The RF gain control and the BFO control have been omitted. The control of these functions is taken over by a "magnetic snap" VFO tuning knob.
All this could make you believe that the savings lead to a reduced reception performance. But far from it! The reception performance is nearly identical to the E1800/3! The large signal handling capability still had to be very good because the E800/2 was used in large transmitting /
receiving stations.

Here the key facts and figures:
Tuning range: 10kHz - 30MHz
Tuning steps:
Tuning rate depends on the selected bandwidth
Position slow: 1/2 turn corresponds to a change of frequency approximately equal to the set IF bandwidth
Position fast: 1/2 turn corresponds to a change of frequency approximately equal to 10x of the set IF bandwidth
Smallest tuning step: 10Hz
Modes: AM, USB, LSB, CW, RTTY & Fax
Bandwidth filters: 0.3 - 0.6 - 1.0 - 3.0 - 6.0 - 10 + 3 kHz (USB) -3 KHz (LSB) >> 10kHz is the roofing filter
AGC: for all modes, fast, slow & off for manual control
100 memories with scan function
Frequency scan
BITE test (self test function)
Very good large signal handling capability
Magnetic snap VFO t
uning knob

The E800/2 is very easy to use. Actually, almost the same as the E1800/3. Like its big brother, the E800/2 has no tools on board to fight noise. The reception quality is nearly the same as for the E1800/3 System. On usual SWL antennas the E800/2 works without any problems. Using  manual gain control will be of advantage. It will reduce noise and make listening more enjoyable. Used like that the E800/2 delivers great audio! One point should be mentioned here. The AGC of the E800/2 is more suitable for voice reception than the E1800/3! It is not as fast as the E1800/3.
All in all a great receiver! The E800/2 is more suitable for the SWL compared to the E1800/3. But only in one regard! The repairability! It is built like an amateur radio receiver and much easier to repair. Unfortunately, the problem is the availability of parts. Should the receiver fail, you will have similar problems as with theE1800/3.

My tip: professional receivers are for professionals
:-)

Written at 18.05.2014

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Ten-Tec RX340

The RX340 is a professional 19 inch DSP receiver, which is currently still being built. Since its initial appearance in 2000 were various modifications made to its software and hardware. Mine is manufactured in 2005.

 

Most important features :
Frequency range : 50 kHz – 30 MHz
Tuning steps: 1 Hz, 10 Hz, 100 Hz, 1 kHz, 5 kHz, 9 kHz, 10 kHz, 100 kHz, 1 MHz
(note that SWL-specific tuning steps were implemented)
Operating modes : AM, SAM, USB, LSB, ISB, CW, CW1, FM
DSP-filter bandwidth : 57
AGC : fast, medium, slow & programmable
Memory : 200
Very good large-signal behavior

The RX340 is, as with most professional receiver, hard to get. Although it is one of the few professional receiver that covers the requirements of the SWL. So is, thanks to the DSP, a notch-filter, pass-band tuning and a noise blanker available. The mechanical workmanship is good although a plastic adhesive film is put on the front which has the labeling for the various buttons. When comparing its front with a Telefunken or Racal is this a very cheap and sensitive front cover. But that was the only slip on the RX340. The RX340 can show off with its receiving quality. The receiver has such a large-signal behavior and quiet reception that it is hard not to fall for. But to use its full capabilities one has to operate the receiver with manual AGC so that it can show its reception performance.

I compared the receiver with the Reuter RDR50B, Telefunken E1501 & E1700. Its sensitivity is on the same level as the Telefunken receivers. But at very weak signals are the Telefunken ahead because of their clear sound. But there for do they have a stronger noise level! The RDR50B falls behind in this discipline. Very weak signals are not its strength. For the SWL is the synchronous detector (SAM) an important function. This allows a fading-free listening. But here goofed-up the RX340 big time!

The synchronous detector loses too quickly its synchronization when the signal gets a bit weaker. When the signal strength is above a specific level works the synchronous detector just fine. Absolutely clear reception. Noticeable is that the noise-blanker does not work in SAM mode. I suspect that the programming was not fully completely finished. Also hard to understand why the notch-filter is not available in AM mode. In SSB mode are all functions working. What also makes it a great receiver is the free-programmable AGC. The attack time, hang time and decay time can be individually set. This function is hard to find in other receivers. Working with the memory functions are easy and effective. The operating manual does not have first to be read.

Bottom line: the RX340 belongs in the top league! Its receiving quality is top-level. Possibly SDR receiver of the latest generation could be a bit better and more flexible. But these are no stand-alone receivers.

The RX340 is a wonderful receiver!

The RX340 Story below the pictures.

Written on 10 Nov. 2012

 

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For some who are interested in professional receivers may have noted the similarity between the Ten-Tec RX340 and the Watkins Johnson HF1000. This is no coincidence because both receivers had the same godfather. The godfather was a joint-development project of Ten-Tec & Watkins Johnson. What happened? The story goes back to 1991 when the NSA (National Security Agency) opened a project to develop the newest generation of receiver with a price tag below $10K.

 

At that time the market for governmental-military receivers was mainly dominated by Watkins Johnson, Racal and Cubic. And Ten-Tec wanted to join this group. So engineers from both companies worked together for a year to get the NSA specification below the $10K price tag. At the moment to present the NSA the newest generation receiver Watkins Johnson added a particular definition to the specification to their benefit and went their own way.

 

The newest specification stated that the equipment required a 20,000 hours MTBF (Mean Time Between Failure), which is commonly used for space electronics. Ten-Tec could not guarantee this at that time and was here with so-called pushed out of the business. This specification was absolutely no problem for Watkins Johnson as they already manufactured for years equipment according to military specifications. But Ten-Tec did not give up and built the RX330, a PC-controlled receiver, and went so their own way. The RX330 was a great success and was sold to many military agencies. The RX340 was the successor to the RX330, a DSP receiver with front user-interface. The RX340 is still being built and sold commercially.

 

 

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Watkins Johnson HF-1000

Watkins Johnson was an American manufacturer of professional communication technology. It produced communication equipment for the military and other agencies with special tasks. NASA and NSA were among its customers. The predecessor of the HF-1000, the WJ -8711, was built around 1991 based on a project award by the NSA.  Because other civil agencies also showed interest in the receiver , the HF-1000 was introduced to the market around 1994.

The Watkins Johnson HF-1000 is a DSP- short wave receiver constructed similar to the Ten-Tec RX340. Both radios show the same development.  Like many other professional radios, the HF 1000 can seldom be found on the market. Sometimes such receivers show up on E-bay and change owners at high prices.

Basic data:
Frequency range: 5KHz - 30 MHz
Tuning steps:  freely selectable
Modes: AM, SAM, USB, LSB, CW, ISB, FM
Filter Width: 58 digital filters (DSP) 56 Hz - 8KHz
AGC: Fast, Medium, Slow , Manual (decay rates are selectable)
100 Memories with Scan-function
BITE Test (Self-Test Function)
Good large signal immunity
Large Tuning Knob
19" construction
Weight: 6Kg

When a colleague of mine brought me the HF-100 I was rather excited. In the previous tests it said that this radio is addictive. Well, then let's try this drug. Around evening I started to operate the receiver. Obviously, I had to familiarize myself with it and turn the knobs a little bit. During the first half hour I noticed that the ventilators of the radio were humming quite loudly.  I put my hand on the receiver to check the temperature. The HF-1000 was not even lukewarm. I bent over the HF-1000 and looked for the ventilator but I did not find one.  To my surprise, I noticed  that the humming came from the loudspeaker of the receiver. I thought that perhaps the cable was not plugged in correctly and opened the radio. Wrong! Everything was plugged in the way it should be.  Due to the awkward design of the printed circuit board,  there was digital humming in the NF audio. The headphone output was also affected. There was quite a strong hum, even when the volume was not  raised. I contacted a specialist in the USA and he confirmed the audio problems of the first HF-1000s. Later models were said  to be without this problem. This humming could be suppressed with an equalizer. In the case of very weak stations and when you turned down the RF-Gain,  the humming was still audible in the background,  though.

That was the first damper, the next one was around the corner.

Now that the hum was not audible anymore,  something else was noticed: The miserable AGC! There was an awful scratching noise. This shortcoming could only be overcome by using the manual gain control. I thought to myself: "That can't be true! This is supposed to be the legendary HF-1000." And so I was looking for answers. And I found one really fast: This HF-1000 had the old firmware installed! From a specialist in the USA I got the latest firmware for the HF-1000. I then had itput onto two Eproms. Luckily, this only cost some research and shipping costs (48USD)

Finally, after two weeks I could start reception tests. The new firmware resulted in a considerably improved AGC and 4KHz bandwidth for SSB. Mainly, I compared the HF-1000 with the Reuter RDR50C2 and the JRC NRD 525 with the Kiwa-modification.

The HF-100 has a wonderfully broad audio output. It has a nice bass range and sounds very clear. The clarity is enormous. The radio sounds almost like the RDR50C2 but is a tiny bit better with very weak signals. Despite the Kiwa-Modification, the NRD 525 sounds a little bit muffled. The sensitivity of the HF-1000 is same as for the other two receivers. Except for the upper frequencies (11m - 10m),  the sensitivity decreases a little.  The other two receivers are somewhat better in this respect. The switchable pre-amplifier is  actually of no use, it only creates some noise. The lack of Passband Tuning (PBT) in the SSB mode was disappointing, it only works in CW. The noise blanker worked very well and filtered out the noise created by a nearby pasture fence. The notch filter is excellent, it  practically gets rid of any interference. One of the best notch filters that I have encountered with table top receivers. The reception of broadcasting stations in AM synchronous (SAM) was a delight.  The synchrone detector hardly ever lost synchronization and received weak stations in very good quality. Unfortunately, the sidebands cannot be switched to avoid interference.

The operation of the HF-1000 is rather simple. You only need the manual for seldom used features. One thing, though, gave me a headache: The mechanical quality of the HF-1000. It simply is bad! I have seldom encountered such a cheaply made tin can. Also the front is not worthy of a professional receiver.  It simply is a self- adhesive film . It comes off easily when conditions are adverse. In short:  They really saved on the mechanics.

It is not easy to judge this receiver which  I tested because it was one of the first ones to reach the market, subsequent models improved quite a bit. In this version, the radio does not offer its full scope of functions.  A few important functions were missing, e.g., Pass Band Tuning in SSB and the selectable side bands in SAM. Apart from that and the digital hum in the audio channels, this DSP-receiver offers a wonderful reception with excellent selectivity and intelligibility. It can be operated very easily and you can handle it right away. The mechanical quality is not good, however.  It simply is cheap.

Despite some shortcomings you can call the HF-1000 a top receiver.  Seldom have I heard such a clear and intelligable rendition of the signals.

Hints:
When buying a HF-1000 you should make sure that
--the preselector  is built in
--that the firmware is at least version 04.01.03
--the BITE-test is without flaws
--the audio is free of digital humming.
 
Written at 30.11.2014

 

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HD Video from HF-1000