Tambov SDR/657 jamming.
They blocked 1413 Vesti FM, but already since I am aware of this SDR. I remember that I read in a forum that the reason is that many people then use it to listen to Vesti FM, but that doesn’t really make sense
for me. An SDR is intended that people use it to listen to stations.
I think (just a rumor) they don’t like the station itself and therefore notch it out. They also notched out 7050/7055 where people from Ukraine and Russia insult each other.
If you use 4,5 kHz bandwidth on the right side band of the AM demodulator you still reach the area that is notched out. KiwiSDR then blocks the entire audio. Decrease the bandwidth on the right side band
and you can listen to 1404. That also applies to the left side band if you listen to 1422.
On this SDR I can now listen to Italy (sounds like that) on 657. I see a carrier-like signal at 659 kHz. The Pskov SDR, where a stronger signal was audible (about 1 kHz lower than 657), is currently offline (normal
there, was already some days ago). Maybe the IP address isn’t correct and the update (I assume DynDNS) doesn’t work.
On the Химкм SDR near Moscow I can also see that signal at 659 kHz, but audio doesn’t work at all at this time on this SDR.
On the Skopanie SDR in Poland is a string interference visible, but I can’t hear it, audio also doesn’t work there (many other KiwiSDRs work, so I don’t think it a problem at my side).
On the Dorohoi-SDR close to the Ukrainian border I can listen to 657 and 1278 very well, there is no jamming audible at this time.
All public SDRs in Ukraine are currently offline.

Marco (2022-03-16)