Inmarsat weak signal (settings help?)

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imokruok
Posts: 1
Joined: Thu Jul 30, 2020 4:42 pm

Inmarsat weak signal (settings help?)

Post by imokruok » Thu Jul 30, 2020 4:52 pm

Hi there, I am trying to check out the various forms of monitoring on Inmarsat, and even with my kit (RTL-SDR v3, plus an Outernet patch antenna on a NooElec amp, bias tee is on, gain is cranked, 3.2MBPS sample rate), this image seems to be about the best that I can do with a clear view of the sky. I have also tried an active patch that gets me nothing, nada, zero - I can't even get the peaks that you see in the screenshot.

I can't get anything on the EGC channel, and the other channels seem muddled / messy. I live in a city, so maybe there is interference, but am wondering whether I can get a sense of what you might see from this waterfall that is an issue, as well as a general sense of where the settings should be to make this work, just in case I have something wrong. Thanks!
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2020-07-30.png (1.39 MiB) Viewed 331 times

tim_rtd
Posts: 144
Joined: Fri Jun 30, 2017 11:34 am

Re: Inmarsat weak signal (settings help?)

Post by tim_rtd » Fri Jul 31, 2020 1:59 am

Your picture of the L band signals is considered very good with the hardware your using. You can clean up the waterfall by adj the contrast. All is good.

rtlsdrblog
Site Admin
Posts: 2706
Joined: Mon Nov 19, 2012 11:54 pm

Re: Inmarsat weak signal (settings help?)

Post by rtlsdrblog » Mon Aug 03, 2020 6:33 am

Don't use the 3.2 MSPS sample rate, that will cause USB packet drops which will kill any digital signal demodulation.

Use 2.4 MSPS maximum to ensure no packet drops.

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