[GPS_Standard] Re: My new controller

[Bert, VE2ZAZ]

Hi Edwin,

If you cannot disable FLL operation using the button in the Control window
of the Montrol software, then you have a communication problem in the
PC-to-board direction. You must find your problem first, otherwise you will
not be able to setup the GPS Standard board. Probe the link from the PC up
to the PIC processor's pin 18. When probing, use the "Parameter Read Back"
button in the Control window to make Montrol to send data to the PIC.

Since I don't own a HP Z3801A, I am not quite sure of what you are trying to
achieve, but I guess you are trying to demonstrate that feeding an accurate
10MHz signal into the system should make the firmware happy... If the system
transitions repeatedly to Holdower, this is because the H parameter is set
too low for the GPS unit you use. In other words, your GPS board may produce
more second-to-second frequency deviation (spread) than what the H parameter
is set for. Please read my website page, the sections called COMMENTS ON GPS
RECEIVER BEHAVIOR and COMMENTS ON FLL PARAMETERS . You should then better
understand what I mean by frequency deviation caused by GPS 1PPS signal.

What GPS board are you using? And what RS-232 conversion circuit are you
using?

Bert, VE2ZAZ


----- Original Message -----
From: "Edwin B. Walker" <ebwalker614 at earthlink.net>
To: <GPS_Standard at mailman.qth.net>
Sent: Thursday, December 21, 2006 10:55 PM
Subject: [GPS_Standard] Re: My new controller


Bert,
    I was never able to disable the FLL operations button with stability and
thus follow your advice.

What else.........

I took the 10 MHz output of the HP-3801A, reduced it 15 dB and feed it into
the control board.  The Montrol is showing a drifting between lock of FLL
and holdover over a period of a minute roughly. This goes on hours on end.

Thanks for the help.

Ed

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