mystery station ? 6270.0 0320 UTC 29 May 2018

[Ray Lalleu]

0320 carrier, spot on 6270.0, maybe with audio
0328 still the same signal
0330 same, but ut. QRM on 6273
0340 having tried everything, no audio for sure
0347 music ? 0352 if not an artefact, then from which side of the world ?
0356 now talking ?, 0400 music, back to talking.. if not an artefact
0406 audio on both sidebands, sounds latino-american?

0420 rather an early morning programme with news, Africa ??
(I tune off)

[Ray Lalleu]

According to Glenn Hauser (in 2014), it would be an intermodulation in the transmitting center of Radio Habana Cuba, mixing the signals on 6060 and 6165.

So something equivalent should be found on the other side, on 5955, if that frequency is clear.

Is there any place on HF Underground for the spurious and harmonic transmissions ?

[kris]

Hello Ray - this is a topic for the technical segment, but I will describe my experience because once again the issue of "ghosts" appears.
I often see mirror or intermodulation signals on my RTL.
I noticed that the change (increase) of the Input Sampling Rate reduces or eliminates them. Unfortunately setting for example 3,2 Mc reduces the signal strength. Usually these unexpected signals are not exactly according to the frequency grid, which raises suspicion about their actual existence.
Momentary tuning of the receiver so that it is different LO FRQ and return to the observed signal also often shows that it no longer exists. The same is obtained by changing the Setting LO <> Tune Offset. Is this a real signal also verified by listening on the Icom PCR 1000 receiver which due to different architecture will not reproduce the "ghost" signal. Using a signal attenuator at the RX input does not solve this problem. I have to run a set of HF 12 pcs with bandwidth filters (2MHz bandwidth) and I hope to significantly reduce these signals.
I have set LO <> Tune Offset 1MHz and sometimes a strong station from other band at such a distance gives me a mirror.
Write about your experiences. But at 6270 something was playing with me too .
73!

[Ray Lalleu]

Hello Kris,

We heard a real station around 21UTC.

Helicaster often hears a real signal around 03 UTC, and I heard it too about the same time, but extremely weak here. It appears this is not an image frequency, not an intermod in the receiver, but an intermod in the transmitting station.

I take good note of your problems with an RTL dongle SDR, but that's a quite different thing. So far, I don't use any SDR, and I'm not tempted by a low cost RTL dongle, except maybe to play with its native VHF-UHF ranges.

Anyway, the station at 21 UTC should be split from the station at 03 UTC, and that's what I did, just leaving remarks that they were both on 6270 kHz, if by chance we find something more about them.

BTW, the European station on 6270 was identified by JBK, UKdxer.. as R. Joey on Saturday and as R. Verona (I.E. the same op under two aliases) on Sunday.


Well, maybe we could move the discussion about RTL dongles in the SDR section?


Ray