Re: [Discuss-gnuradio] Questions about receiving signals of Inmarsat I-4 Satellites

[Ralph A. Schmid, dk5ras]

I intend to make some tests with the antenna of my Inmarsat phone. When the phone receives something, I keep the antenna position and simply will plug the antenna to my SDR to see what happens. But I have no idea when I will find some time for this test…

 

Ralph.

 

 

From: address@hidden [mailto:address@hidden On Behalf Of Cheng Chi
Sent: Friday, March 28, 2014 9:41 AM
To: GNURadio Discussion List
Subject: [Discuss-gnuradio] Questions about receiving signals of Inmarsat I-4 Satellites

 

Hi,

I am trying to receive signal from I-4 satellites of Inmarsat.

I found that I-4 satellites have one global beam with 25 KHz bandwidth and several regional beams with 50 KHz bandwidth. However, I have scanned through frequency band 1525-1559 MHz and haven't been able to find those beams.

Anyone has experience of receiving Inmarsat satellites? Which downlink frequency should I tune to?

I have tuned to frequencies listed on this website, still without any luck. http://www.uhf-satcom.com/lband/

Setup:
- USRP N210 + WBX
- LNA with 30dB gain (ZHL-1217MLN)
- Iridium antenna (I am not able to get specific antennas for Inmarsat...Iridium is at 1616 -1626.5 MHz and Inmarsat is at 1525-1559 MHz. I have used this antenna to capture signals around 1531 MHz successfully. I guess this antenna would not kill signals from Inmarsat.)

 

Best regards,

Cheng Chi