Articles from and for hams
• 4 receivers in a SWL Shack
Added at 2016-04-05 15:43:03
4 receivers compared by usage, for SWL ICOM R75, NRD 535, AR7030, RADIOJET 1102S
In a SWL SHACK,
Comparison of 4 receivers
The number of facilities to receive shortwaves is quite large, and all are sold to be the “best”. I have thought useful to compare materials in their use in the shack by a neophyte SWL; going beyond the features in the brochures to talk about the feeling everyday. This article does not pretend to do "scientific" test of the 4 receivers. Skills and special equipment are needed and some specialized laboratories already do it.
The 4 receivers cover thirty years of electronics manufacturing; 4 different brands with their technology, their specificities. Over such period, technologies and fashions have evolved. One of the questions was: "Does the efficiency has taken advantage of them?".
-> NRD-535 from Japan Radio Company.
A reference of the 90s! it received 5 star WRTH (which publishes annually the almanac “World all stations and TV Broadcast”). Of conventional construction with an electronic card per function and discrete and analog filters.
Station receiver, with 10 kg, he ceased to be produced in 1996, and its value
second hand is growing due to its reputation.
-> AR7030 from AOR
designed by the engineer who developed the LOEWE range, famous also for reception. It uses special ergonomics, hybrid of software menus and conventional controls. Quite small, it is easily transportable, due its building that already uses SMT but keeps the analog filters.
-> IC-R75 ICOM
modern device, classical format and renowned. It is the only tested that is still in production. It uses CMS, combines analog and DSP filter ( option present on the device under test). Its ergonomic design is intuitive and is also
use controls and menus.
-> 1102S RADIOJET Bonito,
the only of the comparison of that is produced in Europe!
Latest developments in technology, its performances are stunning on the data sheet. The originals are many tools (spectrograph, digital filters, IF and AF recorders, decoder, list of broadcast stations, ...). It brings together all the SMD receiving electronics in a small box that can fit in a pocket. The commands and tools are assigned to a software (highly evolved) that runs on the PC which is connected the SDR. The power of the PC also brings graphics, memory, recordings etc ...
Why these 4 Rigs ?
In the beginning, and it was he who led me to be SWL, I acquired the RADIOJET based on its announced characteristics:
sensitivity of "secret services", adaptable to all cases with filters, graphics tools, a “Star Wars equipment” what ! ... Later I heard about the 50 MHz and at the same time I was struggling to exploit the SDR. A good opportunity to ICOM R75 made me cracking and returning to a conventional ergonomics. And 2!
time passes, I take pleasure and improvement of my skill with these 2 receivers and the virus grew. Kenwood R5000 joined the others for its VHF potential and HF reputation. With it, a sound comfort is discovered. A NRD525 lying on Ebay at a correct price (rare) joined the group. The latter two were sold and replaced respectively by an AOR 7030 and by NRD535, I really enjoyed the 525 and 535 is given as even better. The problem with NRD is that the rating still rising.
In use, the RADIOJET and R75 have always posed problems with settings and sound quality visited. Kenwood reassured me about the fact that we could get some nice plays without fighting against the controls. validated by the AOR, the NRD 525 & 535. Maybe I did not understand the manipulation of digital filters???
Now in THE SHACK!
The 4 receivers are placed side by side, but arranged so as not to disturb each other (eg the display of the ND535 disrupted the RADIOJET). The antenna is a 25m randomwire oriented E-O with 9/1 balun and own ground. The passage from a receiver to the other is done by conventional antenna switch.
All the tests were performed in one evening for constant conditions, there was a fairly present QRM which after all, was not too bad for comparison. The tests were made in SSB or AM, preliminary tests had shown that the results in digital modes (PSK31, JT65, ..) relied more on the decoder performance PC that really the receiver.
The tests increased from the lowest frequency detected this evening (Europe 1-163 kHZ) to the highest (Foreign Broadcast =15,545 MHz).
the highest frequencies, up to 30 Mhz, were deserted by voice, at least for my installation.
The procedure was:
1. emission is detected from the spectrograph SDR: with the usual one "sees" almost inaudible signals.
2. the frequency is displayed on the 4 receivers
3. Listening to everyone seeking to get the maximum, using all possibilities (Notch, passband, IF Shift,integrated amplifiers, attenuator ....)
its results reported in the table below. One can notice rather quickly:
that age is not a handicap
the number of functions is not always an advantage
the best features do not always lead to the pole...
performance and capabilities very above the rest, on the paper, must necessarily be connected to a PC. At the ^resent time, on an old Celeron 2Gb ram and the software never saturated the CPU. the band's visualization tools allows to find the QSO, to filter theoretically perfectly, but it does not always spell the understandability signal or give a pleasant to listen to sound. And the number of possibilities complicates the manipulation that is "full mouse". The sound is still a little metalic, handling tainted he suffered by the signal processing software.
Its small size makes it a unbeatable mobile receiver for travel, functionalities are really interesting for the one who masters their handling.
inherently simpler from the facade is ultra easy to use. It quickly provides a usable signal. Intuitive, essential functions only and a well designed electronics, it is also the one that best supports the strong signals without saturating ( Broadcasts stations Or hyper-kilowated OM) which seems to prove that it is planned for these stations. Its limit is the lack of adaptive Notch filter types, to clean the noise, which is still quite present when the QRM is there. (the further version 7030+ will have it later). Finally, it is the smallest stand-alone, portable and with 3 options of antennas connection.
yet only product. He climbs up the frequency band of 50 MHz, this is the only lot. It enjoys an excellent reputation, can be equipped with a DSP (digital signal processing on audio) .The DSP provides adaptive NR and automatic Notch, but has a relative effectiveness which is not always successful in purifying the signal. Sometimes it adds unpleasant rattling. In use, the interface is pretty intuitive, mixing commands by buttons and menus. PBT is effective and allows the IF Shift and / or Notch. The speaker is (very) small and gives an aggressive sound.. This receiver is small in size, lightweight. Stand exists for mobile use and is provided for a supply 12-14V.
the oldest that was already discontinued when others did not yet exist ...
A solid and reliable construction, ergonomic with a conventional front panel controls, good sensitivity, a decent sized speaker have earned it a
reference in its time. Very sensitive, it extracts the signals and, once found the right filter, gives it in a pleasant way. some signals are not completely cleaned but it does rarely less than others.
From "station" format, it is heavy, almost 10 kg, and its construction in several cards should not be too exposed to shocks, especially as more than 20 years.
If I had to do a ranking:
1) NRD535 for its ease of use and ability to dig out the QRM to a usable signal.
2) AR7030, for its simplicity, portability and the fact that extract good sound quickly, even if it remains noisy.
3) RADIOJET for its small size and its very extensive features. the Utramobile / laptop as long as you have a PC.
4) ICOM R75, it does the job and covers a wide frequency range. But remains recessed relative to the other, with a nasal sound and a DSP that does not keep its promises.
About digital filters, the SDR and ICOM have them, the possibilities are extensive and allow adaptive filtering that others do not with analog filters. By cons they give dry sound and sometimes add snap under whistles. Listening is less pleasant.
Receivers Advantages / Disadvantages
+ Top technology, visual and many new features over the others on this point
- Complicated, metallic sound, emphasizing the sometimes painful mouse driving
+ Great value at the present time
- Sound, and imperfect signal cleaning, I have not hooked
+ Simple and effective
- Ideal companion if he would had the notch: noise is present
+ Grandpa is resisting, effective sensitivity and cleaning
- He'll be accusing her age, eventually “transportable”
Now it is only a personal opinion: a geek will certainly get the most of performance and possibilities of SDR.
The NRD show its age, will one day reach its MTBF despite a robust construction. ICOM can cover up to 6m remaining mobile and has a good filter possibilities (DSP).
The AOR is easy, fast and gives a correct listening, general purpose. It is the only one to pass the VLF.
The ideal then?
* RADIOJET Sensitivity,
* The RADIOJET tools
* Lower band of the AOR
* High band of theICOM
* Ergonomics of the NRD,
* Portability of the AOR
But that is another story ....
The use I make today:
the NRD for audio DX,
AOR for digital modes,
the RADIOJET to visually search the signals, and sometimes try to purify more highly and mobile : always in the PC case.
The R75 will be sold, I expected to have written this article to bring the comparative ads.
receivers comparison for SWL