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Antenna for inmarsat reception.

Posted: Sun Aug 27, 2017 8:16 am
by James_from_France
Hello,

I would like to try to receive and decode inmarsat.
Would this antenna be suitable : https://www.cdiscount.com/high-tech/acc ... #mpos=9|mp

Would it be possible to power it with my rtl-sdr v3 dongle?
Would I need an extra LNA?
Would I need to modify the antenna?
What's the exact frequency for inmarsat?

Thanks for your help.
Regards,

James from France.

Re: Antenna for inmarsat reception.

Posted: Sun Aug 27, 2017 9:11 am
by rtlsdrblog
That's a GPS antenna, you'd have to remove the internal filter before you could use it.

Instead i'd recommend buying this https://outernet.is/products/l-band-ant ... saw-filter. LNA, antenna and filter for Inmarsat all built into one.

Re: Antenna for inmarsat reception.

Posted: Mon Aug 28, 2017 9:15 pm
by James_from_France
Hello,
Thanks for answering me. The antenna that you suggest is 5 times the price of a GPS antenna...
Is it easy to remove the filter from a GPS antenna? Would a GPS antenna work without an LNA?
Thanks for your help.

Re: Antenna for inmarsat reception.

Posted: Tue Aug 29, 2017 4:19 am
by rtlsdrblog
James_from_France wrote:Hello,
Thanks for answering me. The antenna that you suggest is 5 times the price of a GPS antenna...
Is it easy to remove the filter from a GPS antenna? Would a GPS antenna work without an LNA?
Thanks for your help.
There's a tutorial at the bottom of this post for modifying a GPS antenna, it's not too difficult if you're somewhat familiar with electronics and soldering https://www.rtl-sdr.com/rtl-sdr-tutoria ... -messages/.

Though performance is not great, but can be close enough to work on the weaker STD-C channel if you add a metal ground plane.

The 3-5V GPS antennas already have an LNA built into them, you should not use a second LNA unless you know what you're doing. You need to power those GPS antennas with the bias tee on the V3, or with an external bias tee. Same power method for the Outernet antenna.

Re: Antenna for inmarsat reception.

Posted: Tue Aug 29, 2017 11:53 pm
by James_from_France
Hello again,
I've just ordered a cheap GPS antenna from Aliexpress (2,12 euros). If it doesn't work, it doesn't really matter.
I'll see if it works in about a month's time...
It would be great if you could sell a cheap L-Band antenna (with a LNA and with the filter already removed) on the rtl-sdr.com website.
With a simple dipole antenna, I can see a few signals in the region of 1,5 Ghz but I don't know if they come from a satellite or if they are some sort of interference.
Thanks again for your help.