[time-nuts] time-nuts Digest, Vol 78, Issue 7
Burt I. Weiner
biwa at att.net
Mon Jan 3 22:33:51 UTC 2011
The system in question is being used for navigation, but a little
more than your typical find a restaurant type of navigation
system. The symptoms are that they will lock on birds erratically,
maybe for a few seconds at a time As I may have mentioned in an
earlier post, for my frequency standards at home I have two separate
DATUM 9130 systems running all the time with their antennas only
about 1-2 feet apart on my roof and have absolutely no issues. It's
just this one repeatable situation in the car that's a curious
issue. Whenever my associate and I run radial measurements in his
car, our two GPS systems refuse to behave nicely. One at a time,
they're each fine. I often run a Magellan 4250 and my Delorme system
in my car with the two antenna/receivers less than a foot apart
without problems. I'm beginning to wonder if it's something unique
to the Garmin's GPS128 and its antenna that's affecting both
systems. I'll have to do some more playing.
At 01:04 PM 1/3/2011, time-nuts-request at febo.com wrote
>Well, I have two HP conical antennas 4 feet apart and just
>below the roof level, with an elevation cutoff of 30 degrees
>for the large and growing oak trees on 3 sides. Fifty feet
>of RG-8 each connects to two Z3801A receivers.
>I've had no trouble in a dozen years, here in Minneapolis.
>T1 to GPS runs at about +4E-008 for both from GPSCon.
>My son runs a 50' deep sea fishing boat out of Ocean City, MD.
>It has two GPS navigation antennas less than 4 feet apart up
>on the signal mast. It also has portable GPS receivers used
>by fishermen who want to learn his fishing spots, but these
>are about 10' away. He has had no trouble with navigation.
>What would be the symptoms of interference? A disturbance in
>PPS signals at the 10E-12 level?
Burt I. Weiner Associates
Broadcast Technical Services
Glendale, California U.S.A.
biwa at att.net
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