HFU HF Underground
Technical Topics => Equipment => Topic started by: syfr on April 24, 2021, 2042 UTC
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Just ordered one of these , given the good reviews it's been getting. I got the one with the internal speaker(ette) though this may or may not turn out to be the choice I end up with
Pretty impressive little box, looks like:
https://www.eham.net/reviews/view-product?id=14803
Anyone have one? Easy online transaction directly from Alex, received email conformation within minutes of the order.
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Mine should be coming in any day...I also got the version with the built in speaker and reduced battery size. From everything I've read & seen, this little receiver should be impressive - we'll see.
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You are both going to enjoy the BELKA DX. I have had mine for about 6 months and for the money it is a fantastic little receiver. It is super sensitive. Even with the 1/2 battery, it will run for a very long time. I have the non-speaker version and have not charged mine since November and use it fairly regularly.
The only negative I have is that reception starts at 1.5 MHz. Most of us who own this radio wished it went down to at least 500 kHz to cover the entire AM band. Even if it tuned to 0 kHz with reduced specification that would be fine by me.
Anyway, I have taken mine on walks, just slip it in your pocket, although the antenna gets a little tricky and I have had on bike rides etc ... Sometime I just stop on the trail for 10 minutes and do a little DXing. I have used it with a rubber ducky antenna and that works pretty good as well. It also receives the strong pirate station just by sitting in the house with the telescopic antenna. I have had limited success with the audio cord plugged into the sound system of the Jeep. The receiver requires an external antenna.
You will find that the display can cause some digital hash under certain conditions but that is not a problem. I use the display timer which turns off the backlight after a preset amount of time.
The receiver does not come with any instructions so be sure to download the PDF from the web site. Enjoy.
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This radio seems getting great reviews for its high performance.
Pity it doesn't cover MW and LW bands.
With ever keep diminishing number of TX stations on SW bands, and persisting poor SW band condition,
MW and LW are very important DXing bands now.
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Sadly, I doubt many longwave broadcasters will be around a few years from now. Several have already shut down.
The cost to maintain the transmitters and antenna arrays can be quite prohibitive, even compared to mediumwave and shortwave broadcasters. Imagine ongoing replacement tubes for a 500KW station, less long the electricity costs. o.0
Taking it to an even further extreme, Medi 1 runs (or ran?) 1600KW into three 1250' tower antennas. That is likely why it often is the first or loudest longwave broadcaster I can dig out of the noise when DX actually allows LW BCB reception here.
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We still have many LW signals coming up with very nice signals and contents every night here.
Not sure on the longevity on the LW stations, but it is still RXed by many BCLs in Europe.
I am sure that MW will be always active and busy as long as human civilisation in existence on Earth :)
The big power transmitters might be going off Air time to time, but there are always plenty of LPAM
community radios scattered around everywhere.
And MW transmissions from China, North Korea, South Korea, Mongolia, Japan and will always be active as long as the civilisation exists I am sure.
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Shipping delays on my Belka because of components shortages.
Patience is a virtue I've hear them say...
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Alex updated shipping and I'm looking forward to the end of the month!
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I love this radio - it runs circles around my Tecsun's. I've done a few experiments using both the whip vs my on-the-ground antennas (MMD dipole & longwire w/MLB) and although there is a difference in signal strength, as long as you're away from noise, the whip can easily hear what the other two can. I was listening to WTF last night in bed rockin out to Queen's 'Fat Bottom Girls' - this past May was in Seattle and enjoyed arm chair copy of North Korea's English service on both 11710 & 9435 also with just the whip & earbuds.
The quality of the sync detector is the closest I've found to my HF-150 on a portable, but without the selectable sidebands and low frequency rumble; paired up with a Bose Soundlink, it is killer! The sideband audio is also excellent; very similar to my Ten Tec.
I should clarify that I ran the two external antennas through a MFJ 16010 tuner since it's input is designed for the high impedance whip. Also, I'm getting around 10 -12hrs per charge which is fine for my use.
If I had any gripes, I would rather have a dedicated line out than the I/Q, but that's just me.
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I'm really glad to hear your positive response . I hope Alex can keep his design out of the hands of the Chinese IP pirates for a while at least.
I've got a lot of radios, but this one I'm really looking forward to. 12 hours is fine with that battery pack. I'd much rather have a small radio with no UI "bling" than a big fancy brick with battery eating waterfalls, etc.
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I got mine yesterday ..... without question, it's the best portable I've ever used. It's also capable of holding its own with a lot of the desktops I've used. Yes, there's the issue of it needing to be adjacent some metal (or body) to supply a ground plane, but that's always going to be an issue with portables.
40Meter CW during a contest at night, is perhaps the best test of dynamic range handling that there is , and the Belka did fine there. I could EASILY operate this as a ham receiver during a contest, it's that good. Oh, and this with just about 16" of the telescoping antenna extended.
I'm still learning how to use it as there's no manual with it, but it's pretty intuitive so far.
No BCB reception if that's important, but perhaps that contributes to its overall performance.
This thing is one of the performance bargains that's currently on the marketplace, and is the ideal portable SW rx. It's chargeable via the USB port too, so that solar panel you have can top it off in the field.
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Good to hear that you are pleased with the receiver. I continue to enjoy mine and it is taking its first road trip to the 49th parallel this week. I will be bringing a dipole and and my YouLoop along. The YouLoop works very well with this receiver. As for a "ground plane" a small piece of wire as a counterpoise works well. I sometime just alligator clip the ground part of the SMA connector from the YouLoop to the BNC on the telescopic whip and that makes a wold of difference as well.
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syfr, I forgot to mention, the Belka manual is on the website: http://belrig.by/belka-DX (http://belrig.by/belka-DX)
Switch to the English language, click on Belka-DX Receiver without speaker and scroll down to the bottom of the page. There you will find the link to the User Manual Belka-DX.
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Thanks very much for the info, I'll go snag a copy. It's really a nice UI.... even with just 4 buttons and the encoder/button it's pretty natural to move around.
I keep loading strange frequencies into memory by accident however, instead of fetching them, but that's my mistake!
Now to try some mobile....
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Yes, there are actually some nice "hidden" options that you would never guess by pressing some "2 key" combinations. I also highly recommend that you turn on the backlight timer. You will notice that when the backlight is on and you place the palm of your hand over the display that the receiver is so sensitive that it picks up the noise from the display. There are also a few other conditions where this can happen as well. This will not be an issue when the backlight is off. As soon as you use the encoder dial or push one of the buttons it will come on again.
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I echo the views of others on the Belka DX -- the addition of a speaker and battery back available
from Mobimax (https://swling.com/blog/2021/03/a-new-belka-dx-dsp-speaker-from-mobimax/)
makes all the difference. Whereas before you had to have a mini to mini out to a speaker, plus
the antenna, now the Belka is the ultimate portable. I recently was able to use the Belka DX on
the beach (see attached photo). Its small size makes it perfect for setting on a carrying bag and
the apparent excellent sensitivity with a whip makes it the ideal beach radio. There is a bit of signal
loss when not holding it in the hand, but nothing as serious as the Tecsun PL36xxxx series which suffer
from major signal loss if the receiver is not handheld. Now, if as I expect, Alex modifies the Belka to
tune down to MW while not jeopardizing any of its current excellence, future models will be even better.
I think that if Alex were to come out with a slightly larger Belka that provides the superb features of
the Malachit series, then we're really talking about some fun.
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Belka has a SYNC mode? News to me . . . .where and how is it activated? Or do you mean ECSS with SSB?
UPDATE: Ah, I see it now, AM2 is described as "pseudo-sync" Not sure that can be compared to HF-150 and others...
I love this radio - it runs circles around my Tecsun's. I've done a few experiments using both the whip vs my on-the-ground antennas (MMD dipole & longwire w/MLB) and although there is a difference in signal strength, as long as you're away from noise, the whip can easily hear what the other two can. I was listening to WTF last night in bed rockin out to Queen's 'Fat Bottom Girls' - this past May was in Seattle and enjoyed arm chair copy of North Korea's English service on both 11710 & 9435 also with just the whip & earbuds.
The quality of the sync detector is the closest I've found to my HF-150 on a portable, but without the selectable sidebands and low frequency rumble; paired up with a Bose Soundlink, it is killer! The sideband audio is also excellent; very similar to my Ten Tec.
I should clarify that I ran the two external antennas through a MFJ 16010 tuner since it's input is designed for the high impedance whip. Also, I'm getting around 10 -12hrs per charge which is fine for my use.
If I had any gripes, I would rather have a dedicated line out than the I/Q, but that's just me.
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UPDATE: Ah, I see it now, AM2 is described as "pseudo-sync" Not sure that can be compared to HF-150 and others...
I am talking about the recovered audio quality with moderate to strong signals using Belka's version. Actually, the sensitivity of the DX makes for good copy of most AM signals using the AM2 mode.
13DKA's review of the DX has a good description of the “Pseudo”-Sync detector here (https://swling.com/blog/2020/09/state-of-the-art-spy-radio-a-comprehensive-review-of-the-belka-dsp-portable-shortwave-receiver/) and it's ability with weak signals here (https://swling.com/blog/2021/09/guest-post-a-synchronous-detector-crash-course/).
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Ultimate test: I am currently listening to Drunken DJ Radio 6950 USB 0138 UTC 05 JULY 2021 with the BELKA-DX and telescopic antenna while sitting in the basement from a location 500 miles North of Toronto, Ontario Canada. The receiver is working like a charm on this pirate broadcast.
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Yes, there are actually some nice "hidden" options that you would never guess by pressing some "2 key" combinations.
Are these outside of what's mentioned in the manual & if so, would you mind sharing?
A simple trick I've used to improve reception if I don't have a conductive surface and want to listen using the internal speaker is to plug my earphones into the I/Q socket instead.
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I am not aware of any undocumented "2 key" combinations. Only the ones mentioned in the manual.
For a counterpoise, technically, any piece of wire connected to the receiver ground (antenna, audio out or I/Q out) should work. Chances are that they are all common ground. My Sennheiser headphone has a 10 ft long cord so that in theory is a 10 ft long counterpoise.
A friend of mine just received his Belka today. I'll be looking forward to his feedback on the receiver.
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Jumping in a bit late here - I acquired a Belka DX a couple of months ago and have been extremely impressed with this little receiver. It has seen use with headphones and ear-buds and provides plenty of audio with either. For antennas, the whip is excellent if true portabity is needed, but the radio seems to work nicely with my external antennas.
I do a lot of monitoring for 22 m beacons, and put Belka to work, feeding the audio to a computer running Spectrum Lab. For this operation, it was a serious rival for any of the table-top receivers, and was excellent on this weak signal work.
For broadcast, the "pseudo-Sync" is very well implemented, and the recovered audio is very clear. It almost pains me to say it, but it's ability to "hang on" to a signal and maintain clarity perhaps exceeds the very good AMS of the Lowe HF-150 and HF-225
Before purchase, I had wondered if the minimalist controls could be difficult, but they are very easy to learn and use. It has a smooth and professional feel.
Count me very pleased to own this radio.
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Ed H -> Question, do you use the audio output or I/Q output of the Belka to Spectrum Lab? I have read that the bandwidth of the I/Q output can be up to 192 kHz. Obviously this would also require a sound card in the PC capable of a 192 kHz sample rate. The I/Q output does open options to interface to external SDR software or decoders such as CW Skimmer plus the ability to create a digital recording of the spectrum for later processing. You can see an example of the later at the London Shortwave blog page: https://blog.londonshortwave.com/ (https://blog.londonshortwave.com/)
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Thanks for the insight here SIGINT
So far, a quick test using just the headphone output - mimicking the same methods used with the conventional receivers. However, additional bandwidth would be a great benefit, particularly for monitoring 22m beacons. Since the whole band is only 14 kHz wide it could be monitored at once even with the basic audio facilities in the PC on my radio desk. I have yet to play with I/Q techniques, but plan to explore eventually.
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Ed, you are all set. Most modern PCs do 44.1 kHz and 48 kHz and if you are lucky, 96 kHz. Anything above that generally requires a higher end sound card. If you are running Windows, you will find those settings in the "playback devices" and "recording devices". Make sure you use a uniform setting across both recording and playback devices to avoid re-sampling. I use both Spectrum Lab and Spectran. Spectrum Lab has a steep learning curve (and in my opinion is one of the "gold standards") but you have given me an excuse to try it with the Belka.
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Great - thank you.
I may have to borrow the other laptop for this - the cheap laptop at the radio desk is running from a plug-in USB sound I/O that I now realise only has mono input.
Further, I'd like to explore going really mobile with Belka and a spectrum analyser to check out HiFERs from other locations. A brief test with the laptop and the Belka receiving with the whip resulted in 5&9 reports to the computer, traced to the screen. Second test was to try a small tuned loop. Care with the feed decoupled most of the QRM from the PC. I think this had promise, but for the test, conditions were just awful.
Ed
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Update from the Central Coast of Calif where I'm currently /6 for a few more days.
I'm near Santa Barbara, and just got in from listening to the Windy beacon on 4102 on the Belka....with the antenna fully collapsed to it's 6" length. Just blows me away.
I'm really impressed by this little guy!
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Great - thank you.
I may have to borrow the other laptop for this - the cheap laptop at the radio desk is running from a plug-in USB sound I/O that I now realise only has mono input.
Further, I'd like to explore going really mobile with Belka and a spectrum analyser to check out HiFERs from other locations. A brief test with the laptop and the Belka receiving with the whip resulted in 5&9 reports to the computer, traced to the screen. Second test was to try a small tuned loop. Care with the feed decoupled most of the QRM from the PC. I think this had promise, but for the test, conditions were just awful.
Ed
Hi Ed
Any further updates on these experiments? I'd enjoy some mobile hifer experiments. I'm going to see how the little rig works hooked to a hustler mobile in the car, but I'd like to try for some mobile Hifer QRSS receptions too.
Also...about those "hidden" two button options.........................................?
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I have had my Belka mobile driving around in the Jeep and plugged into the sound system. It definitely requires an external antenna. I do not believe that it would need anything special for an antenna. Any unloaded (no coils etc ...) mag mount should work well. I have also used my Belka with a rubber ducky without issue.
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BELKA-DX I/Q Output
I had the opportunity this past weekend to experiment with the I/Q output of the Belka. My quick tests revealed that is does work as expected.
Test #1 and screen shot #1 bellow is the Belka I/Q output connected to the PC's line input which is set to a 48 kHz sampling rate. As can be seen, Spectrum Lab can visualize a portion of the 40 metre CW band. Test #2 and screen shot #2 is CW Skimmer. Skimmer is decoding the Morse Code.
(http://www.milspec.ca/board/img/2021-08-01_204124.png)
(http://www.milspec.ca/board/img/2021-08-01_212224.png)
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tagging so I can find my way back to this thread.. thanks Syfr!
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Thanks Sig, for the info on the Belka and IQ output. That's a really nice looking grab. I'll have to give it a go also with some QRSS signals. I took the Belka mobile, and it hears the ignition noise in my truck pretty well! :-)
Hooked to a Hustler mobile whip I found that it would make a decent ham receiver for casual CW contacts on 40. There's really not enough audio to overcome background noise with the built in speaker but it works great with earbuds.
Will see how stable it is during some QRSS grabs
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I picked up a old Larsen / Motorola mag mount and a 32 inch unloaded antenna element on the weekend at the surplus store. I am going to test it for mobile operation. All I have to do is change the connector on the coax to a BNC.
I am good for audio. The Jeep's sound system has an external mini jack input so the Belka is loud and clear over 6 speakers. You can get a nice battery operated amplified speaker for the Belka. I use my HP portable speakers with mine.
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Interesting results, thanks for sharing. I've had no opportunity for testing (distracted by other projects) but will follow up. One requirement is a stereo mic or line input to the PC - I don't have anything to hand yet.