[time-nuts] Low SNR GPS reception and cheap LNAs

Magnus Danielson magnus at rubidium.dyndns.org
Sat Apr 26 15:30:43 UTC 2014


On 04/26/2014 12:52 PM, Attila Kinali wrote:
> On Sat, 26 Apr 2014 12:25:11 +0200
> Magnus Danielson <magnus at rubidium.dyndns.org> wrote:
>> If you have a passive antenna, put a LNA right at the antenna, since any
>> cable damping will cause the S/N to go down. Also, if you put an
>> aditional amplifier in line, your want that too up at the antenna.
>> Then, low-loss cable should be natural.
> My current antenna is an cheap patch antenna. It has an LNA, but aparently
> it's not enough. I talked with a few gnuradio people and they basically
> told me that the GNSS-SDR software needs a strong signal for acquisition.
> Ie. i realy need to put the antenna somewhere with good skyview.
> I ordered 4 of those lna4all, so that problem should be solved.
> I'm also getting a better antenna and we'll see how much signal i can
> get out of this place.

I'm just about to put my double-frequency choke-ring antenna on the top 
of the antenna-pole, with support-lines, and then LMR-400 cables to go 
into the lab/shaft/mancave.

I hope that will beat the old setup.

I intend to rebuild one of my single-frequency antennas with a new 
element and suitable LNAs, and the lna4all looks very interesting.


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