Are These From Satcom?

[RadioDitch]

Hey all,

During the chaos surrounding Kabul Airport ramping up, a friend send me this link. The recordings on the page are interesting. Obviously digital. I'm not a big military monitoring guy, so I was curious if these were recorded off Satcom or if anyone could identify the system/method used? Thanks...

https://soundcloud.com/metal57%2Fmojo

https://soundcloud.com/metal57%2Fpython-62

Mojo 88

 

[RaleighGuy]

Yes Satcom

 

[RadioDitch]

Yes Satcom

Thanks. Do you or anyone have any links to a good primer or any articles on monitoring U.S. SATCOM?

 

[RaleighGuy]

I do not, but Nooelec sells a great antenna (from reports I've heard) for inmarsat.

https://www.nooelec.com/store/sdr/sdr-addons/antennas/inmarsat-antenna.html

inmarsat

www.rtl-sdr.com

 

[vagrant]

I don't know about you, and although it has been years, the last time I visited a fast food drive through it sounded like that first recording...and somehow my order was correct.

The RadioReference Wiki is a good place to start for information.
Military Monitoring
Satcom

 

[fires999]

Hi Radioditch,
Just to save confusion , Satcom can be the term used for monitoring the old 250mhz uplink/downlinks not often used by Military as once was - Satcom title also used when monitoring the Inmarsat link around 1500mhz (I know, it is a very loose explanation , but many people get confused between the two)
Few of us over here in UK monitor 1.5ghz - can be quite a process to set up but there are several good videos on YouTube - try searching Inmarsat Jaero L band
Good Luck,
Fires999

 

[prcguy]

I listened to the recordings and have never heard anything like that on UHF satcom so I doubt its that. Its extremely rare you will hear anything in the clear and if you do it will be FM mode and it will sound pretty normal. If its encrypted, which is 99.9% it can have a brief beep then the hiss of digital modulation and sometimes no beep, just hiss.

 

[reconrider8]

I listened to the recordings and have never heard anything like that on UHF satcom so I doubt its that. Its extremely rare you will hear anything in the clear and if you do it will be FM mode and it will sound pretty normal. If its encrypted, which is 99.9% it can have a brief beep then the hiss of digital modulation and sometimes no beep, just hiss.

It's satcom but it's not satcom lol. It's inmarsat

 

[prcguy]

Aah, so its just sat, not satcom. Got it.

It's satcom but it's not satcom lol. It's inmarsat

 

[T0matoPaste]

Thanks. Do you or anyone have any links to a good primer or any articles on monitoring U.S. SATCOM?

UHF SATCOM Downlinks Receivable in North America

This is a few years old so some of the information may be out of date but it's a starting point.

 

[spacellamaman]

I listened to the recordings and have never heard anything like that on UHF satcom so I doubt its that. Its extremely rare you will hear anything in the clear and if you do it will be FM mode and it will sound pretty normal. If its encrypted, which is 99.9% it can have a brief beep then the hiss of digital modulation and sometimes no beep, just hiss.

out of curiousity, what is happening with the beep? some sort of periodic data/timing update or something? the randomness of that has always made me wonder.

 

[TampaTyron]

It is the sync tone for the crypto to synchronize. TT

 

[TampaTyron]

LMR has similar where is sounds like "gleep shhhhhhhhhhh" then "gleep shhhhhhhhhhhhhhhh" etc.