Many thanks to SWLing Post contributor, Bruce (VE6XTC), who is trying to identify noises he’s hearing on the HF bands. Perhaps readers can help.
By request, Bruce has provided me with two recordings via his Kenwood TS-440S:
Recording 1: 7,335 kHz at 0500 UTC on September 13, 2020
Recording 2: 7,405 at 0500 UT on September 13, 2020
Post readers: If you can help Bruce by identifying these HF noises, please comment!
Hi again Bruce,
I was wrong, as I found a video of Cuban jamming signals, and that is what you are hearing for sure
Brilliant! Much clearer audio, and I’ve learned something myself.
Definitely not local QRM, much fading on the signal and it’s obviously jamming a female voice (showing up twice in the second clip) that sounds like that’s some kind of “alphanumerical” number station. Whether or not that station is being jammed or the noise is the signal… who knows…
Same signal obviously recorded elsewhere 5 years ago https://soundcloud.com/zeitkunst/7405-khz-lsb-545utc. Maybe try using webSDRs worldwide to learn more about the origin of the two signals
Jerry, N5RV could be correct, I can hear it now (4:50pm UTC, so around noon in FL) pretty stable on the not so bad FL Kiwis, seems to get weaker the more north the SDR location is, pretty much gone N of the Carolinas. However, it’s fairly weak in the Dom. Rep. or Bonaire so…. NVIS beam antenna? Dead zone? Or maybe not so much in Cuba more in FL? Whatever it is, it will likely remain a mistery. 🙂
O_o …or a mystery.
The voice is just the rig reading out the frequency 😉
uh…wait…what? I kind of feel rick-rolled now. Well it’s pretty jammed by the jammer on my laptop speakers and I didn’t really listen, because what’s the point of listening to numbers stations, or jammers… also there was an earthquake. A terrible flood. Locusts! IT WASN’T MY FAULT, I SWEAR TO GOD! 🙂
Cuban jammers probably jamming radio Marti.
Sounds like pager intermod from local pager.
It is a little difficult to identify like this ..
What mode are you receiving ( AM/SSB? ) How wide is the signal ( if you tune up & down how far does it go) does it cover just a specific freq or the whole band? It is on multiple frequencies at ones ( or multi bands).
I would be best it there is a video of this sort of thing rather than just an audio recording, if you REALLY want to identify it.. The video should show.
a) the frequency & mode
b) signal strength – including comments on any QSB ( fading) on the signal
c) tuning up and down across the signal ( in both AM & SSB)
d) we also need to know the location of the receiver and the time ( UTC and/or local)
e) is it a rural or a metropolitan location.
*my guess* on this one is that it is a local source – to me it sounds like the dreaded “internet over powerline” noise, or leaky vDSL in AM mode at a time when there is traffic ( when it idles it is more “bursty” ) . If it is that then it will be wide and cover a lot of spectrum ( note that that sort of noise is also actual RF and it can propagate too! Your neigbours may have just installed some internet device that uses the powerlines to talk.
However, If it is just on a 5khz wide spot on in a broadcast band, then it will probably be deliberate jamming 🙂
Apologies as I have yet to listen to the samples, but of note, have they been checked against the usual suspects via the ARRL EMI/RFI noise database?
http://www.arrl.org/sounds-of-rfi
I can tell by the fading that these aren’t RFI. The signal was on 9805KHZ for a while but it isn’t there anymore. That suggests to me that the MUF won’t let that signal propagate.
It’s Cuban jammers. You will also find them jamming 9955kHz with the same type of jamming in the evenings US time. They will jam any frequency that they consider US propaganda against the island, even if the broadcaster has ceased doing so in the past decade or so, or it is only an hour a week they will jam it for hours on end just to make the frequency unusable. It’s quite annoying…..
Without more information, I’m going to take a guess that the source is within the shack (RFI), and likely either a charging device, a wireless device/router, or (remotely) a monitor. A few things to try: disconnect the antenna shield and, if still there, disconnect the antenna fully. If it seems to be local, turn off everything in the shack except the radio to see if it goes away.