HFU HF Underground

Loggings => HF Mystery Signals => Topic started by: CrackedLCD on August 02, 2016, 0934 UTC

Title: UNID 20 kHz wide signal centered on 10.130 MHz, USA
Post by: CrackedLCD on August 02, 2016, 0934 UTC

It sounds a lot like OTH radar, but I've never known one to go on for quite this long or sound quite this… buzzy.

I've got a one minute video of it on YouTube (https://youtu.be/91ozd1C3cMo).

This went on for at least five minutes around 0253 UTC (9:53 PM Central US) and pretty much covered up most of the 30 meter ham band.  The recording was made on the Gulf coast of Alabama, in AM mode but with the bandwidth set to 20 kHz to capture the entire audio portion. 

Title: Re: UNID 20 kHz wide signal centered on 10.130 MHz, USA
Post by: Josh on August 02, 2016, 1355 UTC

Are those psk carriers?

Title: Re:
Post by: CrackedLCD on August 02, 2016, 2351 UTC

I have no idea...

Sent from my XT1254 using Tapatalk

Title: Re: UNID 20 kHz wide signal centered on 10.130 MHz, USA
Post by: Token on August 03, 2016, 0019 UTC

This is a radar.  Specifically it is the British PLUTO radar from the island of Cyprus.  This is its 50 Hz mode of operation, probably equating to a maximum possible detection range of about 3000 km.

It is normal for this radar, and the similar Russian 29B6, to sometimes set on frequency for hours at a time.  They both follow propagation to maximize coverage in the desired target area, and if the conditions don't change it can set on a given freq for a long time, on the other hand sometimes it can also move to a new freq in minutes.  If you plot the freq vs time you will generally see that they both move down in frequency in the evening (for their locations) and up in frequency in the mornings.

Another video of it here in the same mode of operation:
https://www.youtube.com/watch?v=tU6UTZUCvsc


This video is of the radar in its 25 Hz mode, probably equating to a maximum possible range of about 6000 km:
https://www.youtube.com/watch?v=bDgQyvz31M4


The PLUTO radar is similar to the Russian 29B6 radar in sound, however they are different.  Some users have trouble telling them apart, so I did a short video on the differences between the two signals.
https://www.youtube.com/watch?v=RsmMvOuFtOs

T!

Title: Re: UNID 20 kHz wide signal centered on 10.130 MHz, USA
Post by: CrackedLCD on August 03, 2016, 0215 UTC

Wow, thanks Token!  A comment was left on the YouTube video of it being from Cypress.  Sure was a strong signal, I can only imagine the power they use to generate that kind of a signal.

I guess the military doesn't care when it lands in the ham bands or anywhere else; now that I know the name I'm seeing more videos of it online and a lot of them seem to fall within the ham radio bands and occasionally broadcast bands.

Title: Re: UNID 20 kHz wide signal centered on 10.130 MHz, USA
Post by: Token on August 03, 2016, 0314 UTC

Yeah, I left the comment on YouTube about it being Cyprus ;)

Typically PLUTO avoids the ham bands, however they do, sometimes, land in them.  When it does, people tend to notice and comment.  The same can be said for the Russian 29B6 radar.

T!