Tuesday, 24 December 2013

Review of Realistic DX394 Short Wave Receiver by RadioShack

DX-394 with Radio Shack Speaker 21-549A



Close-up of the superb display on the DX-394




This is a review of the Realistic DX394 Receiver by RadioShack. It is, in my humble opinion, a very much under-valued radio and I want to tell you why, having tried AOR 7030's, The Yaesu FRG100, The Lowe HF150, and numerous portable radios, my all-time number one favourite is the DX394!

The first thing I should explain is that, as far as I am aware, there are one or two, perhaps three, slightly different versions of this radio. I have serial number C006779 and on the back panel there is a small sticker with the letter "B" on it, identifying it as a "B" version model. The first DX394 I owned was an "A" model and years later when I purchased the "B" model I now own, there were a number of big differences immediately apparent. The first, and as a utility listener this was HUGELY important to me, was that the upgraded model didn't need to be offset by de-tuning the "fine tune" control. Let me explain: On the "A" model, if you wanted to tune to 8867 KHz, you would enter 8867 and then have to de-tune to approx 8866.8 KHz to be spot on. I also noted some frequencies needed more or less of an offset than others. This was fine when the frequency was active with plenty of traffic to enable the fine-tuning required, but seriously problematic for sitting on silent frequencies for hours waiting for that elusive call from far away. I missed some great stuff because of this short-coming, and I often woke up to a tape recording of aircraft over the South Pacific region calling Nadi or Auckland or Pascua Island only to discover I had forgotten to de-tune, and had 45 minutes of garbled rubbish. Very annoying! This does not happen with the "B" version. 8867 KHz is spot on 8867 KHz and I have never once had to de-tune a single frequency to correctly resolve a signal.

The second difference was in the sound quality. On both sideband but especially on AM, the audio quality was far superior. It seems to my ears (forgive me as I am not aware of the technical differences between the various models) that the "B" version uses better quality filters. I wouldn't want to go back to an "A" version. Just thought I'd mention this before I start telling you more about the radio as it is important.

I do not know of ANY short wave radio receiver with so many timers! There are 5, yes FIVE, separate timers on the DX-394. Many times have I set up a few minutes of recording on WWV Fort Collins at 18 minutes past each hour for the propagation report. For example: at 0217, 0317, 0417 and 0517 for 2 minutes each time. Just think of the number of late-night DX your could try to identify on the hour!

Another thing I love about this radio and that sets it apart from others I have tried is the excellent medium wave performance. It hears weak MW signals far better than my Yaesu FRG-100 or my portables. I have made a small, passive, medium wave loop covering 540khz to 2500khz and feed it directly into the 50ohm input of the DX-394. It is a terrific combination. If you are interested in medium wave broadcast or maritime MW utility listening, the DX-394 would be an excellent choice.

However, the NDB beacon band is not so good. In fact it is appallingly bad. Do not buy the DX-394 if you are an NDB beacon DXer. It is just totally deaf on this band. Even with a high quality RF Systems DX-10 amplified vertical antenna outside, it hears nothing at all.

The audio quality is OK. Fine for utility listening, but only adequate for broadcast listening. Years ago I had read that the Radio Shack speakers were very good and to consider them in preference to the costly Yaesu and Icom optional speakers. Well last month I was lucky enough to come across one at my local radio club equipment sale. And so for only £3 I bought one. In my opinion it is simply made for the DX-394. I hadn't realized before connecting the speaker, but afterwards it was evident that what I didn't like about the DX-394 audio was the fact it was somewhat muffled. It lack clarity and sharpness and isn't all that pleasant to listen to for any length of time. And during fading there is quite a lot of hiss evident. But through the Radio Shack speaker, the audio is beautiful. I prefer it to my Yaesu FRG100 and Icom 703 both of which I would rate highly for audio in their own right. When there is QSB on the signal, the signal deterioration is far less marked on the Radio Shack speaker, and I find I can listen for hours through this speaker, when on the DX-394 alone I would long ago have switched off. Gone is that muffled, almost processed characteristic. It has nice bass tones, but not too much so. And the higher, treble tones are much more soothing on the ear. As you can see, I can't recommend the combination of DX-394 and Radio Shack speaker highly enough.

The DX-394 also has another really cool feature: it will tune below 150khz all the way down to VLF and ELF. This is nicely demonstrated on this nicely demonstrated You Tube video
This means you can hear time signals, submarine communications, beacons and all sorts of other interesting utility stations. On his You Tube video Steven is using only a long wire and getting acceptable results. I was lucky enough to already own the RF Systems DX-10 antenna, which hears all the way down on VLF, and I can hear a plethora of stations down here. Just to re-cap: the button sequence to open your DX-394 up for VLF and ELF is:

LIMIT
PGM
1
FRQ
ENT

I have tried, somewhat half-heartedly, to listen for some natural radio sounds, but have so far had no luck.

Something else I love about the DX-394 is how easily it lends itself to quickly entering and then swapping between a number of frequencies. If you knew for instance that RAI Radio Uno in Italy were on 657, 900 and 1575khz and you wanted to quickly jump to and fro between these frequencies to see the best one, or to spot when the changeover to RAI's regional programming had occurred, this is all the key presses that would be required:

FRQ 657 ENT PGM 1 ENT
FRQ 900 ENT PGM 2 ENT
FRQ 1575 ENT PGM 3 ENT

then all you would need to do to quickly jump between them is to enter their respective memory channel number. So simply pressing 2 will take you straight to 900khz, another single press of the number 3 will take you to 1575khz etc etc I have used this facility numerous times to help identify different stations or to check for new frequencies of the same station. It has been invaluable. I know you can do this on all radios. But it is the ease with which the DX-394 lends itself to this task with so few key presses that I so appreciate.  

I hope I have covered everything you might have wanted to know, and I hope this review has been helpful. As always, if you want to contact me please do so via comments and I will reply that way too.

73 and as I have finished this on 24th December: Merry Christmas 

Saturday, 26 October 2013

First log of Turkish Civil Defence ALE Network

I made up a QRG file this morning of all the Turkish Civil Defence frequencies and at 0536UTC got my first catch, a sounding from the Turkish province of Karabuk on the Black Sea Coast. The ALE address was 3781, the 78 identifying the province.

I like this network as there is a way of identifying the station heard. Many ALE nets do not have such a system and when you receive the ALE addresses you have no way of knowing where the station was. SONATRACH, the Algerian Oil & Gas network are like this. It would be so cool to be able to identify which oilfield or pumping station you are receiving, but sadly I have found nothing online to suggest this is possible.

Wednesday, 23 October 2013

Israeli Air Force Boeing 707 Appears on ALE

This Boeing 707 serial #272 (a "vc" variant of the Boeing 707 - whatever that means. I can't find an explanation on the net except that it is somehow modified) appeared on my PC-ALE screen this morning at 06:57UTC on 9057khz. This is such a cool way of hearing aircraft. The other evening I was sitting down relaxing, listening to Rachmaninov's vespers whilst the PC was doing all the hard work of scanning lots of white noise in search of some interesting catches for me!

I like ALE so much I am hoping to get a second laptop running on my Icom 703  - the idea being to scan another range of freqs I might otherwise not scan due to their inactivity and thus increase my chances of a nice catch for the log book.

By the way, the aircraft ID appeared as M72.

73 Adam M6RDP

Wednesday, 16 October 2013

Israeli Air Force Active on HF ALE Network


Last night between 1634 and 1733UTC I heard a number of cals on the Israeli Air Force HF ALE netwrok frequency 9219 khz. They were 3 Israeli Air Force C130H/KC130Hs K35, K22 and K45  (serial numbers #435 ,#522 and #545). Also got a call from TSM, though I can not find any address info on the net for it.

Since starting ALE decoding I have heard some great traffic I would never otherwise have heard on voice channels: USCG Jayhawk Helicopters, HC144s and Bombardier Q400s, RAF AWACS E3s, Air Force Bases across Northern Algeria, and now these terrific catches from the Israeli Air Force.

It is a really exciting mode, still very active and with plenty to offer the utility listener and aircraft/military enthusiast.


Saturday, 5 October 2013

Yaeus FRG100 and PC-ALE

video
I just wanted to show you this video of G4ZLP Electronics' superb Yaesu CT62 Digimaster CAT interface set-up to scan the 50 Algerian Air Force ALE frequencies using PC-ALE at the 5 channels/sec scan speed. To scan HF freqs like this is, in itself, awesome. But that it actually stops on receipt of ALE signals and remains on channel to decode them is unbelievable.

The Algerian Military have divided up the countro into 6 military regions (RM):

ale address CM1 - First military region of BLIDA
ale address CM2 - Second military region of ORAN
ale address CM3 - Third military region of BECHAR
ale address CM4 - Fourth military region of OURGLA
ale address CM5 - Fifth military region of CONSTANTINE
ale address CM6 - Sixth military region of TAMANRASSET

ale address COF - Commandement de Forces Aeriennes, Cheraga, Algiers
ale address CNC - can't find this one but would hazard a guess at Centre National de Communications. It is at Algerian Air Force HQ at Cheraga, Algiers

HMG - Hammaguir Air Base (SW of Bechar) notable for its role in French Rocket Launches in the 1960s and 1970s. A close up view of Google Maps  shows the debris of decaying rocket towers in the desert sand.

Friday, 4 October 2013

Monitoring the Algerian Air Force ALE Network

It has taken a long time to get the software and hardware set-up correctly, but after a lot of help from Sam on the UDXF Yahoo Group and a lot of patience on my behalf, I am now successfully monitoring a whole host of interesting military HF networks using ALE. Although the software is easy enough to download (PC-ALE & MultiPSK) and I have used it before for single channel monitoring, getting it hooked up to my Yaesu FRG100 and then successfully scanning was a little trickier. I think the different versions of PC-ALE work better with some radios than others. Finally, the new Beta test version v1.08 was installed and it works like a dream, stopping on active channels even at the fast scan rate of 5 channels per second. Previous versions would scan but not stop properly. I still find MultiPSK a lot more sensitive to weak signals, but it is really not so well set up to monitoring large numbers of frequencies (The Algerian AF have over 50!) for SWLers like myself. Here are some of my latest decodes from the last few days:

[19:17:20][FRQ 11156000][TO ][CM3            ][TIS][CNC            ][AL0] BER 20 SN 05
[19:17:18][FRQ 11156000][TO ][CNC            ][TIS][CM3            ][AL0] BER 20 SN 04
[19:17:16][FRQ 11156000][TO ][CM3            ][TIS][CNC            ][AL0] BER 21 SN 04

[19:24:07][FRQ 11114000][TO ][COF            ][TIS][CM2            ][AL0] BER 30 SN 07

[06:23:41][FRQ 13377000][TO ][CM3 CLR        ][TIS][CNC            ][AL0] BER 18 SN 04

CM3 3rd Regional Command Centre Bechar AFB
CNC Algerian Air Force HQ, Cheraga
COF Algerian Air Force HQ, Cheraga
CM2 2nd Regional Command Centre, Oran AFB

Interestingly, I have hooked up MultiPSK with DX Labs free "Commander" software using the setting for the Yaesu FT757. I nned to disable the "continuous interrogation" button, and then it all works fine.

In addition to the Algerian Air Force, I have had decodes from the Brazilian Navy in Fortaleza contacting its vessels in the South Atlantic; the USAF air bases and AWACS aircraft; the UK AWACS aircraft on the UK DHFCS network; FEMA The Federal Emergency Management Agency in the USA; The Civil Air Patrol in the USA; .... there is so much to hear and what's more, you can leave the set-up decoding while you walk the dog or prepare dinner and come back to interesting transmissions on the screen!

I have also experimented with Sorcerer multimode decoder and although more sensitive than PC-ALE it won't hook up to my radio and in fact the facilities for scanning and radio hook up seem far too limited to be of much practical help.

Anyway, just wanted to update the blog with these latest ALE musings. Next project is to build a broadband HF loop for the back garden. The commercial offering are way out of my financial league for the moment and I suffer a lot of local QRM from a house full of youngsters next door! My single-freq tuned loops out in the garden offer total noise elimination, but being tuned devices are quite useless for scanning multiple frequencies. I have seen a design by Des (M0AYF) and with the help of an Mo friend in the radio club here in Torquay, I hope to build it myself.

73 for now. Adam

Wednesday, 24 July 2013

Tecsun PL660 Review

I have been using my Tecsun PL660 for a little over 6 months now, and thought a few comments might help others who are thinking of buying this radio make up their mind. I initially owned a Sony SW7600GR, but I kept tiring of having a totally useless battery meter and no signal meter. So I sold my Sony (good riddance!) and was soon the proud owner of the Tecsun PL660.

The review I based my purchase on was that in The World Radio and TV Handbook, as I was impressed by the highly favourable review of the synchronous detector, a feature I find invaluable when programmelistening on shortwave. The sync on the Sony was terrific, but I didn't like the fiddly side switch nor the way the display didn't differentiate between whether the sync detector mode selected was Upper or Lower sideband. I also felt the audio was a bit "flat" on the Sony. The Tecsun synchronous detector is also terrific: it locks onto the weakest of signals and even if the signal meter falls back to zero the sync stays locked. What I especially like is the way the display boldly shows whether Upper or Lower sideband is selected when in sync mode. The audio is also very much more to my liking: it sounds to me as though the audio bandwidth might be wider. Even when the "narrow" bandwidth is selected the audio sounds more wholesome and rounded. That of the 7600GR was more like the Icom R75 - neither sounding very nice to my ears. I use the synchronous detector not only to knock out an interfering sideband but also to smooth out distortion during fades. In both respects the sync on the Tecsun PL660 functions seamlessly.

The WRTH 2012 review of the PL660 stated that the airband feature was poorly implemented and was highly negative. Whilst the addition of the airband wasn't a purchase decision, I do find myself using it from time to time, especially when sat in the garden as an aircraft flies overhead and I want to identify it: I switch over from SW to airband and tune into my local airport radar frequency. Admittedly there is no squelch, but if you were serious about an airband radio you would probably have another handheld set anyway. But I find it a lovely addition and would miss it if I didn't have it. If I tune to London Ctl on, say, 126.075, then even strong signals will not splatter across a large bandwidth: 126.050 and 126.100 are both silent. This makes it a joy to use on this now very crowded band. I have just returned from a holiday to Cornwall, and whilst there we went to the Classic Air Force Aerohub at Newquay Airport. I hadn't brought my Maycom AR108 or my Yaesu VX3, but I had brought along the PL660 and so I decided to give it a more thorough workout. Boy oh boy what a joy this radio was! Admittedly it was a bit bulky, but what I generally tend to do is set myself up at a little corner of the airfield with my radios, thermos, packed lunch and cameras and so it didn't matter that it was a bit on the large side. I tuned into the tower frequency (I find you have to detune by about 3 khz so 134.375mhz needs to be reset to 134.372mhz) and it was immediately clear that this radio was going to be a lot of fun to use. The audio is loud and punchy, and so unlike these little handheld radios that often need to be held up to your ear, I could leave the PL660 standing on the grass in front of me and not only myself but anyone sat planespotting alongside me could hear perfectly well. Being able to "share" the radio in this way made it much more enjoyable. The batteries (1000mah NiMHs) lasted all holiday, including several hours of nonstop use at the airport - bearing in mind this radio has no squelch I think this is a tremendous feat. I almost forgot to say that, unlike my AR108 and VX3, the PL660 has direct button frequency entry. Normally, when I am at an airport, I just stay tuned to the tower on one radio and approach on another. But sometimes I want to follow an aircraft to its en-route frequency and to do this on the 108 and VX3 can be time-consuming enough to miss the call on the new frequency. So having the facility to just punch in any frequency immediately on the PL660 is a feature I wouldn't be without. Now I wouldn't consider a trip to the airport without this little gem in my rucksack. 

Another feature which I couldn't live without if I were to lose this radio is the open squelch scanning I enjoy on USB. You just enter, say, 6733, 8992, 9016 and 11175 into the memory and then scan. The radio slowly scans these frequencies, listening to each one for 5 seconds. I often activate it when washing up, cooking the roast or sitting in the summerhouse on a wet afternoon, and I've lost count of the number of interesting flights I've caught this way. It's priceless if you are at all into utility band DXing.

I am an avid NDB Beacon enthusiast and here the Sony 7600GR was quite significantly better. On its own internal bar antenna the Tecsun is very much quieter. But I always use an external homemade loop for LF beacons and when this is sat nearby performance is very much improved and as similar to my Sony as I can remember. I always pack the loop and my Tecsun when I go away for a few days holiday to see what new beacons I might catch, and I rather thought this might not be possible when I sold the Sony.

MW performance is also very good. Again it is quieter and a lot less lively than the Sony when using the internal rod antenna. But couple it up to a loop and it is superb. I actually recently treated myself to the Tecsun AN200 MW Loop as it is so much more attractive than my ugly homebrew loops, and even given the small size of this loop, performance is terrific when sat next to the Tecsun 660.

I only use FM for Radio Three and Four and quick scans of local stations when I am on my hols, so am not really qualified to comment to this band, but it sounds great and works well, and that's good enough for me!

For portable listening a good battery meter is essential. Forget the 7600GR. Its meter is completely useless. That of the Tecsun, in contrast, is simply superb: you can select whether you are using NiMH or Alkaline batteries, and after days and days of regular use (in my case about an hour each day, perhaps a little less, and with 2000 or 3000mAH MiMHs fitted)  the battery icon then imperceptibly slowly drops first one bar then another. When there is only an hour or so of battery life remaining the icon shows only one bar, then only an outline, then a flashing outline. You will never run out of power unexpectedly at the most inconvenient times with this lovely feature. 

I am a huge fan of Tecsun: I have the PL310 in my bedroom, and use the PL660 everywhere else. If my 660 were to go wrong I would buy it over again and again, something definitely not true of the Sony 7600GR which I was glad to be rid of.

I hope this helps if you are considering purchasing this fine little radio.


Please feel free to leave any questions in the comments and I will do my best to help. 

73 Adam (M6RDP)