[time-nuts] Galvanic decoupling of GPS antenna

Bob Camp lists at rtty.us
Fri Jun 18 16:32:26 UTC 2010


A lot of this depends on just what Yuri really needs to do. I can think of a
variety of different situations where you might have to isolate things, each
with their own inherent issues. 


-----Original Message-----
From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
Behalf Of Christian Vogel
Sent: Friday, June 18, 2010 8:30 AM
To: Yuri Ostry
Cc: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Galvanic decoupling of GPS antenna

Hi Yuri,

> I'm trying to put gps (for a coarse timing sync and RTC
> auto-setting) to a small controller that must be completely
> galvanically decoupled from outside world. Antenna power must be
> supplied from separate power source (ground potential of isolated part
> of circuit can slowly float up to +/- 250 volts referenced to ground
> of antenna power supply).

I don't see any need for isolation in the signal chain as long as your
antenna and cable are properly insulated. I have a fully sealed antenna
here on a Thunderbolt and nothing -with exception of the BNC connector
at the cable end- exposes the system ground. So I could easily float
the TBolt and connected PC at +250V without anyone "outside" noticing.


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