[time-nuts] GPS shielding by power lines?
Henk ten Pierick
henk at deriesp.demon.nl
Sun Aug 10 10:11:25 EDT 2008
In car radio capacitive antennas are used. The required LNA rejection
for the power line frequency is in the order of 100dB.
On Aug 10, 2008, at 15:16, Alan Melia wrote:
> Hi Didier, thanks for that idea, yes they were all "pucks" all
> Garmin two
> intended for marine use and one was a old Garmin GPSIIplus with a mag
> "puck". I have a Trimble Palisade that I have not got round to
> working on
> yet, but I understand that there are problems putting this version
> into NMEA
> mode...so will have to be careful.
> Thanks Alan G3NYK
> ----- Original Message -----
> From: "Didier Juges" <didier at cox.net>
> To: "'Discussion of precise time and frequency measurement'"
> <time-nuts at febo.com>
> Sent: Sunday, August 10, 2008 12:52 PM
> Subject: Re: [time-nuts] GPS shielding by power lines?
>> I don't believe you have said what type of antenna you are using.
>> If you
>> using a true timing antenna (Symmetricom, Trimble Bullet) I would
>> little or no direct effect from the power lines, but if you are
>> using a
>> or other inexpensive commercial antenna (which have little or no
>> or shielding), you may well be affected directly by the field from
>> line on the antenna itself. The Thunderbolt itself should have enough
>> filtering to protect you from a direct effect, the Thunderbolt has
>> designed to be co-located with other equipment, particularly cell
>> transmitters, so I would expect it to be fairly immune to stray
>> Didier KO4BB
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