a écrit dans le message de news:
...
On Jan 15, 4:13 pm, "François Guillet"
wrote:
....
It is not DSB AM or SSB+carrier. It is real AM with the two side bands.
Some
stations have a frequency shifted by the modulation. It looks like old TX
with VFO pilot (not synthetized). QSB is probably the cause of carrier
fading and modulation distorsion.

Some other samples but not good, band is very noisy, transmissions are
not very long (1mn max), with long pauses so it is difficult to monitor
them:http://exvacuo.free.fr/div/Radio/Arc...les/Divers/AM%
20Ru...http://exvacuo.free.fr/div/Radio/Arc...les/Divers/AM%
20Ru...http://exvacuo.free.fr/div/Radio/Arc...Divers/AM%20Ru...


| If this was back 20+ years ago, I would say it could be
| some sort of high seas radiotelephone transmissions. Only one side of
| the conversation is heard in general. But, majority of them,
| (practically all) were in USB as a rule. The other party has almost
| always used another frequency. None of the offical radiotelephone
| transmissions were so brief. None of the official operators spoke with
| such a hurry. The s/n ratio is very poor. Power levels seem to be very
| low and transmitters don't sound stable enough for reliable
| communication .

Yes it sounds like transmissions in the 60's. Nevertheless I don't think
they come from break in space-time :-)
My location is possibly at 4000-8000 kms from these stations. This explains
the weak signals.
Signals from russian ham stations are not much stronger here on 80 mtrs (but
SBB modulation is much better and also 3.6 Mhz is less noisy).

| If it is not maritime traffic, it may be something
| different. Bootleggers, pirates, or traffickers of some sort
| probably. May be we can use D/F them,or establish some pattern .What
| time of day or night do they pop- up?

I receive them weekdays and weekend every evening from around 17h-18h to 23h
UTC (not tried later, time to sleep). It is probably not their full period
of activity but the time at which the 3 Mhz band is open between France and
Russia.