[time-nuts] Symmetricom TimeSource 2700

[SAIDJACK at aol.com]

Hello Mark,
 
you could connect the Fury 1PPS output to the 1PPS external sync input of  
the PRS-10 Rb and let is self-discipline to GPS. Set the Fury 1PPS jumper 
JP4 to  raw-1PPS (pins 2 and 3), and that will make the Fury GPSDO generate 
the raw 1PPS  signal from the Motorola GPS receiver albeit without sawtooth 
correction. You  won't need sawtooth correction if you set the PRS-10 time 
constant to say 10,000  seconds.
 
bye,
Said
 
 
In a message dated 5/1/2012 10:55:34 Pacific Daylight Time,  
mspencer12345 at yahoo.ca writes:

Sorry to  resurrect an old thread, but I thought someone might find this of 
 interest.

I purchased a 2700 intending to harvest the  PRS10.   Prior to cracking 
open the case I powered up the unit to  ensure it was basically working so I 
could return it if needed.   I  noticed that despite not having an antenna 
connected it seemed to find and  track CDMA signals and after a few hours the 
10 Mhz output was in a few parts  of 10E-12 of my GPSD0.

After a bit of investigation I found the  following

Adding an external antenna didn't seem to make much  difference to the 
performance.   

The 1pps output is approx.  75ms out of sync with the 1pps output from my 
Fury GPSD0. 

>From time to  time the 10 Mhz output experiences phase jumps of several 
tens of  ns.   Manipulating the unit (ie. connecting to the RS 422 port) may  
induce this.  Power cycling the unit seems to cure the problem and the  unit 
usually takes an hour or two to re lock.  It's possible that the  lack of a 
proper ground in my instalation may be causing some of the issues as  well.  
 This problem would be a show stopper for me in terms of  using this unit 
to replace my GPSDO's.  I'm not sure if this issue is  specfic to my unit or 
not.

I've attached some initial ADEV plots  showing the typical performance of 
the 10 Mhz output vs three of my other  references.  (I wouldn't put a lot of 
emphasis on the results of taus of  less than 100 seconds or more than 
6,000 or so..)  I doubt I'm going to  put much more time into this unit but it's 
an interesting novelty in it's  original state.   The results of other 
units may well differ  (:

Regards
Mark  Spencer