I believe the "Holdover" function only occurs when you you loose just
the satellites
Once locked disconnect the antenna for a minute and you will see the
holdover LED light.
IF the unit looses POWER it has no way of of powering the oscillator and
its ovens ( to do a holdover) and has no way of knowing how long the
unit has been off when re-powered until it goes through a complete
acquisition/re-sync cycle.
DAVE
manu...@artekmanuals.com
On 12/18/2016 8:01 AM, Dr. David Kirkby (Kirkby Microwave Ltd) wrote:
My 58503 GPS time/frequency reference had its power disconnected a few
times yesterday as I moved things in the lab. At the modem the status of
the LEDs are
* Power green
* GPS lock - not lit
* Holdover - not lit
* Alarm - not lit.
That is what the manual says will happen when power is first applied, but
I'm puzzled why.
The SYSTEM:STATUS? shows the information at the end of this email. What I
can't understand is why the holdover light is not lit, when clearly its not
tracking any satellites. It seems logical to me that holdover should be on,
when GPS lock is not, and visa versa. But that does not seem to be the
case.
Looking at the data below, the date/time is obviously wrong (01 Jan 1998),
the height at -14.04 m (MSL) is wrong, but latitude and longitude look
about right, although they are certainly not exactly agreeing with Google
maps, which show 51°39'04.1"N+0°46'36.4"E.
I must be misunderstanding the purpose of these lights.
I'm also a bit puzzled it has been on about 1.5 hours, and can't seem to
find a single satellite. The antenna is fairly clear of anything else, and
it was certainly working yesterday, with the power and GPS lock LEDs both
lit.
Any ideas what's going on?
scpi > SYSTEM:STATUS?
------------------------------- Receiver Status
-------------------------------
SYNCHRONIZATION ........................................... [ Outputs
Invalid ]
SmartClock Mode ___________________________ Reference Outputs
_______________
Locked TFOM 9
FFOM 3
Recovery 1PPS TI --
Holdover HOLD THR 1.000 us
Power-up: GPS acquisition Holdover Uncertainty
____________
Predict --
ACQUISITION .............................................. [ GPS 1PPS
Invalid ]
Tracking: 0 ____ Not Tracking: 1 ________ Time _____ +1 leap second
pending
PRN El Az UTC 12:59:16 [?] 01 Jan
1998
*32 -- --- GPS 1PPS Invalid: not tracking
ANT DLY 0 ns
Position
________________________
MODE Survey: 0%
complete
Suspended: track <4
sats
INIT LAT N 51:39:03.825
INIT LON E 0:46:36.278
ELEV MASK 10 deg *attempting to track INIT HGT -14.04 m
(MSL)
HEALTH MONITOR ......................................................... [
OK ]
Self Test: OK Int Pwr: OK Oven Pwr: OK OCXO: OK EFC: OK GPS Rcv:
OK
scpi >
Dr. David Kirkby Ph.D CEng MIET
Kirkby Microwave Ltd
Registered office: Stokes Hall Lodge, Burnham Rd, Althorne, Essex, CM3 6DT,
UK.
Registered in England and Wales, company number 08914892.
http://www.kirkbymicrowave.co.uk/
Tel: 07910 441670 / +44 7910 441670 (0900 to 2100 GMT only please)
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--
Dave
manu...@artekmanuals.com
www.ArtekManuals.com
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