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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    

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




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 !



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.







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--
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.


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






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.





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





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






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:

unit price
Price in DM

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.

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

Written at 21.04.2014



The E1800/3 in Action (HD-Video)




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





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



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.





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
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.

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


HD Video from HF-1000