UHF SatCom Reception                                                            


FLTSATCOM was a satellite communication system of the U.S. Navy.
Which was used for UHF radio communications between ships, submarines, airplanes and ground stations of the Navy.
In the late 1990s, FLTSATCOM satellites were gradually replaced by the UFO satellites.

Most of the 12 transponders that operate in the UHF range between 240 MHz and 270 MHz on these satellites are simple repeaters,
with no authentication or control over what they re-transmitted and continue to provide UHF communications.

Because FLTSATCOM 7 and FLTSATCOM 8 Transponders are open (no access control) they are often used by unauthorized radio users,
most often by people in Brazil, Spain and Russia located in remote areas.
It is very common to hear Spanish,Portuguese and Russian transmissions.

Back in 2009, 39 Brazilian pirates were busted, but the activity continues.

Contents

Antenna


To receive SATCOM, you need a receiver that can tune the frequency range between 240 MHz and 270 MHz in narrow FM.
A wide range of antenna's can be used most popular are Yagi and Turnstile's Antenna's.



Yagi Design from Scannerforum.nl






Some Turnstile examples:

https://ua3reo.ru/antenna-dlya-satcom-iz-podruchnyx-materialov/

https://diebastelkammer.wordpress.com/2018/09/11/uhf-milsat-satcom-eine-faltbare-turnstile-antenne/

Bandplan


FLTSATCOM 8/USA-46 located at 15.5 deg west is using the Fleetsat Bravo bandplan.



http://www.satellitenwelt.de/uhfmilsat.htm#Positionen

http://qrg.globaltuners.com/?q=milsat

https://uhf-satcom.com/satellite-reception/uhf

http://www.satellitenwelt.de/UHF_MilSat.pdf

SDR Radio




AirSpy R2 SDR Radio should work fine for SatCom reception.

Software

SDRSharp is by far the best operating SDR software for SatCom Narrow Band mode.







The Milstar satellites transmit a digital mode nicknamed the “waterdripper.”
Between 243.785 and 243.825 MHz it is visible in the spectrum.



Fleet Broadcast is a 16 channel 75Bd multiplex transmitted from SATCOM satellites on 250.450/550/650 MHz. Modulation is DBPSK 1200Bd.

Fleet Broadcast Decoder v0.5

Usefull Links


http://www.satellitenwelt.de/yagi260mhz.htm

https://www.brianswx.com/index.php/11-other-hobbys/116-250mhz-satcom-7ele-yagi

https://www.qsl.net/py4zbz/ec/ec.htm

http://www.radioamatoripeligni.it/i6ibe/milsat/milsat.htm

MonitoringUHFSat