The Belka (-DSP/-DX/-v3) appreciation thread

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Andrew (grayhat)
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Re: The Belka (-DSP/-DX/-v3) appreciation thread

Post by Andrew (grayhat) »

13dka wrote: Sun Jul 30, 2023 11:34 pm There were no thunderstorms announced,I couldn't see or hear any lightning (in the radio) but apparently the air was full of surplus electrons or something, causing static buildup on the whip, which then got shunted to my finger, then to the roof metal (or everything vice versa, not a physicist). 10 minutes later the first lightning discharges could be seen in some distance, there was definitely electricity in the air!
Not sure it's the case "up there", but here we had such issues due to the Sahara sand carried by high winds, not sure the sand did its way so far north, but if so then it may explain the issue you experienced ... maybe you should consider carrying a run of strap and a stake to connect your car to ground :D ?
13dka
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Re: The Belka (-DSP/-DX/-v3) appreciation thread

Post by 13dka »

Ah yeah I know that super fine brown Sahara dust, I have it on my car every early summer but that's not it. Apparently high electric charges under rain clouds long before they reach the thunderstorm charge levels are known, for example I found kite surfers reporting that they got shocks when they ended up in deteriorating weather in summer. Static electricity buildup on antennas is a thing too of course but I didn't expect that to happen on a short whip.

I forgot to mention that after I started getting zapped by the Belka and saw the arcing between the whip and the car roof (seems you need 3kV to get 1mm of arc!) I also touched the car roof to see what is charged and it wasn't the car. It seems the jury is still out on that but maybe you remember the anti static ribbons many cars had attached to the exhaust pipes under their cars in the 70s, apparently they are useless:
"In the 1980s, English trading standards officers prosecuted a company for selling anti-static strips because they simply do not work as described: car tires are 10 million times more effective at transmitting static charges to Earth (New Scientist, 4 July 1985, p.63)"
Apparently very curved surfaces like an antenna rod are particularly prone to pick up static charges out of thin air and the potential slowly increased over time when the center of the cloud came closer, which explains why it slowly escalated from nothing, via "my finger discharging it only creating a pop in the reception" and "pre-plasma discharge via the roof" (which is probably what you hear in the video) to "me getting zapped and visible arcing between whip and roof". Yikes!

According to Google such static buildup can destroy radio frontends and there are some videos demonstrating pretty gross high voltage arcing out of PL plugs on YouTube*. Basically all known to me but like I said, I didn't deem that possible with a puny little whip! Now that I googled that a bit more I know that is a thing on mobile rigs too. Anyway, I just checked the Belka carefully (good to have 2 of them for comparison!) and it didn't take any damage from that. Phew! :)

* Here's one:
13dka
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Belka - whip vs. SULA vs IC-705

Post by 13dka »

I figured this would fit best here, even though it could also fit in "Utility" or the "SULA" thread(s):

Last Monday I took the chance to compare the Belka and its whip with the IC-705 and the SULA (and also the whip against the SULA on the Belka alone), with some results that could be considered stunning or a little bit sobering, depending on the angle you look at it. There is also some quite some wiggle room for interpretation.

First off - the example videos demonstrate that there is incredibly little difference between the 2 rigs, or between the 2 incredibly different antennas on the Belka. This could be taken as yet another testimony for the almost inexplicable performance of that tiny radio with the whip, and it sure is. It could also be held against the SULA if one skips some considerations, but then again - being as good as the whip on the Belka isn't exactly a bad result either. I should also add that I didn't use the LANA HF+ preamp this time, I also wanted to test a super cheap + simple (single transistor) +20dB LNA for 10 bucks off Amazon, which worked fine but the noise figure may be worse - and with results so close in such a low-noise enviroment, even just 2dB more transistor noise could've made a noticable difference.

Then it should be noted that the examples do not showcase what the SULA is good for because the channels were clean. I briefly compared the reception while 17m was still haunted by the second OTH radar on the band - there's one pretty strong at the high edge of the band, and a second one that's almost the same level as the background noise but covering the entire band (so likely not audible in most regions in Europe with an ever so slightly higher noise level). This is where the SULA clearly wins of course - the attenuation on the backside of the beam is sufficient for much worse interference. Also, I felt the super power of the SULA later on 20m, when pretty good signals from South America and the US East Coast made finding the very few and only medium good signals from VK and JA that night pretty hard - turning the SULA a bit more to the east got rid of most and the VK/JA signals were easy to detect.

Anyway, here are the short clips. At first the signal from VMC Charleville (AUS) an hour before the grayline peaked - pretty weak and quite ideal to show how little difference there was:



For comparison, here's what it sounded like an hour later:



Last, the experiment with the SULA on the Belka (0:00s-0:17s), then the whip (0:18-end):




Whatever you think about this strange comparison, the capability of that little radio to pull something out of a whip that rivals disproportionally more sophisticated and expensive radios and antennas is uncanny. If you remember, I sorted the raw sensitivity of the SULA somewhere in the range of expensive SMLs like the ML-200 I compared it with directly, that would mean the 400 bucks would not buy me "more stations" than the whip in a quiet environment, because if it's so close to the SULA, it would be just as close to the ML-200 and likely to a Wellbrook etc. loop. Another thing I learned is that the SULA (expectedly) works fine with the Belka as well, even though we probably get a few dB of losses through the impedance mismatch, and the SULA has not many dBs do spend for such shenanigans.
13dka
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Collection of misinformation on reddit about the Belka

Post by 13dka »

Reddit, the self-proclaimed "homepage of the internet" is known to be a pretty toxic place. Since it has some "subs" related to all of my hobbies, e.g. r/shortwave, r/amateurradio and r/hamradio I occasionally read the newest posts there anyway, but more for the entertaining cringe than for gaining valuable knowledge. A prime example is how the Belka is represented there by people who don't know what it really is, never mind having any hands-on experience with that radio. Here's an example post where someone was particularly asking for the smallest, but best performing SW portable for ultralight backpack traveling, the Belka was fitting his further descriptions to the i-dot and somebody (of course) suggested it. But then these guys showed up...


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The same odd point was made again today (as if the post-processing power would have anything to do with the deciding performance metrics of the frontend):

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Needless to say that the Airspy HF+ Discovery is a good SDR that may very well have what's needed to outperform the Belka (that comparison is on my to-do list), or at least be on par with it - if they're connected to a decent external antenna. But I'd be incredibly surprised if it could do that with the Belka's 74cm whip! The other guy continues to point out the other thing that's wrong with this comparison but then...

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Just to show that these guys were never even near a Belka, here's the same two in another post where someone asked about the Belka:

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There are plenty of reviews, videos and sound clips discussing and demonstrating literally every aspect of the radio, so a simple Google search and 15minutes of reading could've kept them from repeatedly putting their feet in their mouths - if they'd care about that.

And then there is one guy who actually owns a Belka but had bad luck with his headphone jack. Yes, that's bad and I can understand the anger but instead of letting Alex solve the problem...

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Well, that's at least some actual experience shared. Of course the traveling guy seemed to buy all that bold speculation disguised as advice and may have actually opted for a different radio. OK, he could have asked Google and do a little reading as well, instead he opted for asking on what might be the worst place for that question so my compassion is staying within limits.

Why do I even care? Of course I'm a die-hard Belka fanboi (but solely based on the performance and quality of the radio, not some odd ideology, brand fetishism or the like) and that this needless bad-mouthing is keeping people from enjoying that thing irks me. The good old "somebody's wrong on the internet" syndrome. What irks me more though is that reddit, with its pretty young demography is attracting actual newcomers on said "subs" more than any other platform, and its strange comment voting system is making the visibility of comments more based on timing than anything else, so noise usually swims up and the rare well-thought out response is prone to get washed down the threads. The same can be observed in the other subs I'm topically interested in and Wikipedia has a whole section in the article about that. It often helps watering down, dissolving or even inverting what used to be common knowledge, increasing the entropy, misleading uninitiated people...in short, and I guess you saw that coming by now, I don't like that platform very much. :mrgreen:
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Andrew (grayhat)
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Re: The Belka (-DSP/-DX/-v3) appreciation thread

Post by Andrew (grayhat) »

Late on this (have been on holidays :D) but I think that those folks are comparing apples and oranges and they just "shoot" stuff w/o even understanding what they're talking about; just consider that the Belka is a "self contained" unit, while a standard SDR needs a computer, let's add that an SDR, even good, somewhat "suffers" from the noise generated by the computer (and which may also be carried by the USB cable), and last but not least important, just try to connect the same whip used by the belka to an SDR and then let's see how the SDR performs with such an antenna :D
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