Saturday, March 13, 2021

Video: The Belka-DX micro-receiver on external antennas

Apologies for the lackluster editing. I chose content over form, hoping to provide a glimpse of what it's like to tune around the bands with this little radio hooked up to something other than the small whip antenna that comes with it.

The high bands, as we know, have been circling the drain for a while now - not much there that I could find - so this is an "AM broadcast band to 14 MHz" test on CW, SSB and AM.

The rest of the video's description is given in the opening 15 seconds. The lighting gets better (a relative term) 3 minutes in.


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9 comments:

John AE5X said...

If you're considering one of these radios, the following posting by Mersey Radar is IMO the equivalent of a Wiki - lots of info and useful links, all in one place:

https://tinyurl.com/72m5zspa

Dave New said...

Sounds like the Belka-DX is leaving the BFO on in Synchronous AM? That might explain the tones you heard when rocking the tuner on either side of zero-beat.

John AE5X said...

Here's an explanation (about 1/8th of the way down) on Thomas K4SWL's page:
https://tinyurl.com/4ztkyz3m

I haven't yet noticed any improvement using this mode but will continue comparing from time to time.

73,
John

Anonymous said...

Hi John, like I wrote in the review, you need to record 2 receivers (ideally the same model) simultaneously, one with syno on and the other one with regular AM in order to know if the sync helped in a particular fading phase. This is particularly true if the sync detector is so unobtrusive like the Belka's - most sync detectors I came across so far want to make sure you notice that they're on, either by malfunctioning or by switching filters. :) The Belka's pseudo-sync just sits there, sounding exactly the same as regular AM and waiting for that particular moment when selective fading tries to notch out just the carrier, leaving a lot of nasty distortion from carrier-less modulation.

That being said, I'm currently doing just that - making recordings of my old Belka DSP and my new -DX version. Comparing the first recordings I'm pretty impressed how well it works. It's actually a pity that you never know how much bad reception it prevented until you did this kind of retrospective comparison.

73, Ollie (13dka)

John AE5X said...

Hello Ollie,

First of all, thank you for your very detailed review of the Belka. It influenced my decision to buy the Belka-DX and I have not regretted it for a second. Its performance:size ratio is incredible.

Regarding your recordings, do you have a YouTube channel or some other place where they'd be publicly accessible?

Tnx again,
John

Anonymous said...

Hi John,
That's the kind of video I like, and a tall order to run the Belka against the IC-705! :) I recently compared the Belka DSP with the IC-705 using extremely weak signals off the 14 and 18 MHz IBP frequencies and I was amazed how close the little Belka got to the 705 at least on 14.100 and I'd say they are also very close in BDR, or very close in running out of bits (since they're SDRs). It still boggles my mind how good this little radio for less than 1/10th of the price for a 705 is!

73s,
Ollie

Anonymous said...

Hi again John,

I'm glad you liked the review! I'm just back from a second "recording session" at the North Sea dike, I'm planning on posting some clips on the SWLing Post in the near future. :)

73s,
Ollie

Unknown said...

Sorry, it took a while to put that into some article. :)
https://swling.com/blog/2021/09/guest-post-a-synchronous-detector-crash-course/
73!
Ollie

John AE5X said...

Excellent write-up, Ollie - thanks!

73,
John