[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?
>> 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
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/ 
> time-nuts
> and follow the instructions there.

More information about the time-nuts mailing list