PSN-L Email List Message
Subject: Re: trouble shooting GPS antenna
From: Hammonds hammond@...........
Date: Thu, 10 Jan 2002 06:59:54 -0900
Angel, I remember something about not exceeding a certain cable length
receiver and the antenna. Had to do with overall impedance, loss, and
loading. What I did
is keep the antenna cable length as it came from Synergy and move the
receiver then wire in whatever
length of RS-232 cable I needed to get to the PC.
At 06:50 AM 1/10/02, you wrote:
> I can't seem to find my coax loss table at the moment, but I suspect
> your problem lies
>with the RG174. You're probably loosing 5db of signal in the cable
>alone. RG174 has
>very poor characteristics even in the low VHF bands. GPS is high
>UHF. Add to this the
>inevitable losses from the splices and various junctions between the
>antenna and the
>first amplifier/mixer, and you end up with a receiver that can only hear
>are directly overhead, where the signal is the strongest, or none at
>coax is hard to find, and expensive, but worth it.
> > Hello,
> > Yesterday I got and SDR system up with one of the GPS systems we
> > bought as a group. To lengthen the antenna I spliced in about 20 ft of
> RG174 into the
> > little 5 foot cable of the antenna that came with the units. Hooked
> > it all up and It worked well.
> > Last night and today all got was and SDR error message stating "not
> > enough GPS stat's being tracked".
> > I replaced the antenna with one that I got from Synergy and had
> > reserved for another installation and the problem disappeared.
> > Any idea on how to test or trouble shoot this antenna???
> > Best regards,
> > angel mailto:angel@............
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