[time-nuts] Lucent KS-24361/Z3812A GPSDO initial setup

Bob Stewart bob at evoria.net
Sat Oct 25 00:57:57 EDT 2014

(I do not understand why Yahoo responds to the list for some of you and for others it responds only to the sender.  This is a resend to the list.)

Hi Hal,
That should have been Satstat, and yeah, after looking through the Z3801 User's Guide, I decided to just let it play by itself.  It found the right date after it started acquiring sats, so I guess all is good.
I think I figured out why only the REF-0 unit was responding.  And that's because there are two units, and the one that's not active doesn't reply.  At the moment, REF-0 which is responding has the ON light lit, and REF-1 says it's in STBY.
So I think I finally have a better phase reference than the 10811 I've been using.  At least the phase plot against my GPSDO project is pretty stable over the last 2500 seconds, and a proper ADEV curve is starting to develop.  Unfortunately, I've been battling what I think is a thermal problem, so it could all fall over sometime tonight.  OTOH, the survey isn't complete, and I have no idea about the performance of this Z3812A during survey.
And thanks for the Linux ideas.

      From: Hal Murray <hmurray at megapathdsl.net>
 To: Bob Stewart <bob at evoria.net>; Discussion of precise time and frequency measurement <time-nuts at febo.com> 
Cc: hmurray at megapathdsl.net 
 Sent: Friday, October 24, 2014 10:55 PM
 Subject: Re: [time-nuts] Lucent KS-24361/Z3812A GPSDO initial setup

bob at evoria.net said:
> The mode says "Power-Up: GPS Acquisition", so I guess that's OK.  I think
> things are progressing.  It's attempting to survey, but reporting
> "Suspended: poor geometry".  I suppose with a little more time this will
> work itself out?  It seems to be slowly tracking more sats, as it's now up
> to 5. I wonder if there's a way to shortcut the survey process using
> Satstat?  I've got a 48 hour survey done on this antenna with the LEA-6T, so
> I should be able to input those figures, right?  I'll see if I can find
> anything in a Satstat manual I found. 

Or just wait and see how well the location it finds matches your current data.

The Z3801A manual is easy to find and contains a good description of the SCPI 
commands.  Yes, I think there is a way to load the location and bypass the 
survey.  I think there is a slot in Satsat where you can type in commands by 

You don't need Satsat.  You can talk to it from the command line.  On Linux, 
for a Z3801A, I do things like:
  ln -s /dev/ttyS2 /dev/hpgps1
  stty -F /dev/hpgps1 19200 cs7 parodd parenb igncr
  stty -F /dev/hpgps1 19200 oddp igncr -echo
  On one window:
    cat /dev/hpgps1
On another window:
    echo -e ":ptime:tcode:format F2" > /dev/hpgps1
    echo -e ":diag:gps:utc 1" > /dev/hpgps1 # Needs reboot?
    echo -e ":SYSTEM:STATUS?" > /dev/hpgps1

# fix for week wrap - maybe only works before survey
echo -e ":GPS:INIT:DATE 2011,12,26" > /dev/hpgps1

These are my opinions.  I hate spam.


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