[time-nuts] FTS4060 Continuing Saga

[Rob Kimberley]

Brooke,

GPS is affected by heavy rain. Signal will be attenuated, and some at low
elevations may be blocked. Snow is even a worse culprit especially if it
settles on the antenna.

Do you have antenna mounted in the clear or do you have any partial
obscuration from buildings or trees (especially wet ones!)?

Best

Rob Kimberley 

-----Original Message-----
From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
Behalf Of Brooke Clarke
Sent: 05 March 2006 20:03
To: Discussion of precise time and frequency measurement
Subject: [time-nuts] FTS4060 Continuing Saga

Hi:

After Tom helped me a month ago to get the trigger level correct for 50 Ohm
loaded TTL (1.25 volts), I've been seeing no aging on the FTS4060 s/n 1013
and have been tweaking the C field and all was going well, but today (heavy
rain) the jitter on each 500 second average has jumped up from about 9 ns to
more like 300 ns which means you can not believe the readings.  It's snowing
on the nearby mountains and heavy rain here.

Note that on prior days the daily spread in the Time Interval has been
around 10 ns peak to peak.

So does GPS suffer with heavy rain?

I checked TAC32 and the receiver settings are correct.

Interesting sidelight:
A couple of days ago there was a brown out the caused the SR620 counter and
the computer to reset, but the FTS4060/S24 (no backup battery) did not reset
(Lock and AC ON green LEDs) and the data shows that there was a recovery
that lasted about 1,500 seconds.  Not sure what was moving.

Have Fun,

Brooke Clake

--
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