Mysterious signals from West Africa on 28 MHz

http://rx.linkfanel.net/

KiwiSDR radio network. Click on balloon, then click on description.

 

Not that I'm all that active talking, listening a LOT...but there are times hams could take a lesson from the lowly CB guys. Though not always but often if 27 Mhz is up then so is 28 Mhz. The CB guys will be talking away for hours on end and when you tune into the call frequency on 28.400 NO one! Giving even a general call, NOTHING! Maybe...if we'd check the band a little more often instead of assuming nothing is going on we might get to use it more often than not! Just because the notice on QRZ says that HF band propagation is poor doesn't always mean it is. With all that line of garbage this doesn't mean DX "communications open to other countries" is up but just local, "country wide" is better than nothing. By the way 20 m is up right now. I'm listening to XE1RK from Mexico City knocking down some contacts at the moment.

 

Anything is possible these days,cool posts all,73's Jimi

 

I have just purchased a CB (SSB/AM) for that very purpose, if I can hear East Coast or Midwest truckers on 19 then 10M has to be good too, just waiting to get my old Gonset G-28 running on 29.000 Mhz!

 

Was curious where the term the band is "up" originated. Not surprisingly I just found the answer.

The band is "open" must be so...yesterday!

 

It is possible that those signals generated by Russia's Wagner mercenaries...

 

Propagation to the IARU R1 monitor DK2OM from Gabon, was most likely combined Sporadic E (Es) and some common TEP in the equatorial Africa region.
2019 is a peak year for Es propagation, and the Sporadic E this summer in Europe was very strong.

In my experience, the most likely source of the signal is actually quite mundane:
It is a simple low power telemetry transmitter at a remote site.

These types of utility RF links are commonly utilized for monitoring the status of remote pumps, fluid levels, generators, or other types of remote infrastructure devices.

They are more common in the High Band VHF and UHF range, but older units were often in Low Band VHF and 27 MHz.
I don't think it is unusual to see such a signal in the 28 MHz band.
After all, most hams aren't really using that part of the 10 metre band much so it is a relatively clear frequency.
The 25 to 40 MHz part of the spectrum is a good choice for low power remote telemetry in the kind of terrain found in Gabon.

If it was originally set up on solar power, at this point in time, it could be a zombie transmitter! (not maintained, not utilized for original purpose, but still transmitting).
Likely a converted crystal-controlled CB radio repurposed as a cheap telemetry transmitter.

I derived the following info from the waterfall plot:

• AM transmitter carrier drifts when it is first keyed (normal for older crystal controlled gear).
• AM pulse modulated with a 494.5Hz tone (within the common range for telemetry).
• Rate of pulsed modulation = 201.7 milliseconds (or 4.9 dits per second).
• Harmonic content of modulation indicates the modulation tone is square wave or clipped sine wave.

The waterfall plot in the IARU-R1 Monitoring Report, shows the characteristics:

 

I HEAR IT!!! (AND MY RADIO ISN'T EVEN TURNED ON)

 

Me too! And I dont have any radios!!

 

I'm hearing that old woodpecker sound like we use to hear back in the 1980'sand 1990's on the 60 meter band. Every night on 5.371.50 and 5.403.50 it will alternate between these 2 channels. Yes we share the 60 meter band with military and government agencies, but this sounds exactly like the old Russian woodpecker!

 

I thought the term JOB stood for Just Over Broke

 

We here in Germany listen for that signal in 10 M band longer time ago. We investigate and finally we found out, this signal have been produced by fisherman. They marked her fishing net with a transmitter in the 10 M band. With a direction finder later on the find the net again. So maby you test it also in this direction. VY 73 Joachim from Hamburg Germany

 

Driftnet buoy beacons have been observed for a long time, sometimes (illegally) intruding on amateur bands, including 10 meters. Heard in FL quite prominently on 160m too.

https://www.iaru-r1.org/index.php/iarums-news/297-illegal-fishery-buoys-on-28-mhz

https://www.sigidwiki.com/wiki/Driftnet_Buoy_Radio_Beacon

 

I've been hearing it across the 40M band nightly now.

 

I was hearing it around 7.074 (I think) last night about 04-5z. Showed up nicely on the waterfall display.