[time-nuts] GPS shielding by power lines?

[Didier Juges]

Alan,

I don't believe you have said what type of antenna you are using. If you are
using a true timing antenna (Symmetricom, Trimble Bullet) I would expect
little or no direct effect from the power lines, but if you are using a puck
or other inexpensive commercial antenna (which have little or no filtering
or shielding), you may well be affected directly by the field from the power
line on the antenna itself. The Thunderbolt itself should have enough
filtering to protect you from a direct effect, the Thunderbolt has been
designed to be co-located with other equipment, particularly cell
transmitters, so I would expect it to be fairly immune to stray fields.

Didier KO4BB

> -----Original Message-----
> From: time-nuts-bounces at febo.com 
> [mailto:time-nuts-bounces at febo.com] On Behalf Of Alan Melia
> Sent: Sunday, August 10, 2008 4:28 AM
> To: Discussion of precise time and frequency measurement
> Subject: Re: [time-nuts] GPS shielding by power lines?
> 
> Hi Tom Brilliant I hadnt thought of the fields actually 
> affecting the operation of the electronics! that is certainly 
> something that might be interesting to check. I note there 
> lines have three "phase" feeds but no neutral wire so they 
> must use ground as the return path to any unbalance
> currents.(?)
> 
> Thanks Alan G3NYK
> ----- Original Message -----
> From: "Thomas A. Frank" <ka2cdk at cox.net>
> To: "Discussion of precise time and frequency measurement"
> <time-nuts at febo.com>
> Sent: Sunday, August 10, 2008 6:38 AM
> Subject: Re: [time-nuts] GPS shielding by power lines?
> 
> 
> > Alan;
> >
> > I have no idea if this is a cause of your problem, but in 
> some work I 
> > have done, I found that the high field strengths (electrostatic and
> > magnetic) found under power lines can adversely effect electronic 
> > equipment that should otherwise be unaffected by the 
> presence of power 
> > lines and their low frequency signals.
> there.
> ----------snip
> 
> 
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