[time-nuts] Trimble GSPDO - ISSUE

[ordnit]

Hi there,
thank you for valuable information I get everyday from the list.

After a very long time I managed to power up a Trimble GPSDO, connected
to an aexternal antenna.

UCCM >*IDN?
TRIMBLE,57964-15,86854165,V3.0.0.11-01
Datecode: 0814 (pretty old, but still in its teen years)

Some output from "common commands":

UCCM >SYSTem:STATus?

-------------------------------------------------------------------------------
57964-15     serial number  86854165     firmware ver  3.0.0.11-01LINK 
  mode
-------------------------------------------------------------------------------
Reference Status __________________________   Reference Outputs 
_______________
XX Ref 8KHz 0: [LOS]
XX Ref 8KHz 1: [LOS]                          TFOM     4            FFOM 
      1
XX Ref 8KHz 2: [LOS]                          UCCM A Status[OCXO WARMUP]
XX Ref 8KHz 3: [LOS]
 >> GPS: [phase:-3.3E-05, settling]
ACQUISITION ...................................................[GPS 1PPS 
Valid]
Tracking: 8 ____   Not Tracking: 3 ________   Time 
____________________________
PRN  El  Az  C/N   PRN  El  Az                GPS      11:44:34     27 
Jul 2021
  32  39 107   46     3  10 226
   1  28 284   37    16   6 189                ANT DLY  0 ns
  10  40  51   42    14   8 327                Position 
________________________
   8  79 239   45                              MODE     Hold
  23   7  49   38
  21  52 297   43                              LAT      N  43:35:11.819
  27  55 153   43                              LON      E  13:31:1.250
  22  32 230   41                              HGT              +225.27 
m (MSL)


ELEV MASK  5 deg
-------------------------------------------------------------------------------

UCCM >POSSTATus

---------------------------------------------
  07/27/2021  11:44:57
---------------------------------------------
  Position: LAT(N  43:35:11.819) LON(E  13:31:1.250) H(        +225.27 m 
MSL)
---------------------------------------------
  Geometry: PDOP(0.0) HDOP(0.0) VDOP(0.0)
  num of visible sats >  10
  num of sats tracked >  10
   -------- Receiver Channel State --------
  CH  0 > SateID(03) TrackMode(pos avail) SigValue(36)
  CH  1 > SateID(32) TrackMode(pos avail) SigValue(47)
  CH  2 > SateID(01) TrackMode(pos avail) SigValue(37)
  CH  3 > SateID(16) TrackMode(pos avail) SigValue(34)
  CH  4 > SateID(10) TrackMode(pos avail) SigValue(42)
  CH  5 > SateID(08) TrackMode(pos avail) SigValue(44)
  CH  6 > SateID(14) TrackMode(tracking ) SigValue(20)
  CH  7 > SateID(23) TrackMode(pos avail) SigValue(37)
  CH  8 > SateID(21) TrackMode(pos avail) SigValue(44)
  CH  9 > SateID(27) TrackMode(pos avail) SigValue(43)
  CH  10 > SateID(22) TrackMode(pos avail) SigValue(40)
  CH  11 > SateID(00) TrackMode(tracking ) SigValue( 0)
---------------------------------------------
  Rcvr Status(1):
---------------------------------------------
  Antenna Voltage:  5000.00mV   , Antenna Current:     0.00mA

UCCM >status

                - UCCM Slot STATE-

1-1. #Now ACTIVE STATUS ---------------- [OCXO Warm]
1-2. #Before ACTIVE STATUS ------------- [Alarm]
2-1. #Reference Clock Operation -------- [Not Used]
2-2. #Current Reference Type ----------- [GPS]
2-3. #Current Select Reference --------- [GPS 1PPS]
2-4. #Current Reference Status --------- [Good Accuracy & Stable]
      #GPS STATUS ----------------------- [Available]
      #Priority Level ------------------- [LINK > GPS]
      #ALARM STATUS
      #H/W FAIL [ LINK ]
      #OPERATION ALARM ------------------ [Antenna]
3-1. #PLL STATUS ----------------------- [DISABLE]
3-2. #Current PLL MODE ----------------- [OFFSET OBSERVATION MODE]


The issue I'm facing is following: even after a long uptime, I never com 
to a "fast blinking led" and PLL status "enabled". Monitoring device 
with LHv6, shows an "operation mode" alternating Locked (few seconds" 
and "recvery". TFOM is quite always 3 or 4. Power supply is linear, with 
output voltage 5.6V or 6V. I made many tests but had no luck.

Sys:stat showa a "phase" value moving from -1.4E-05,settling up to
-4.3E-06, settling. On an old post I read that it might be caused by the 
oscillator drifting due to age.

Any guess? Do I have to throw the unit from the window? For your 
reference, I have a samsung unit connected to same antenna via a 
splitter. The GPSDO is performing very well.

Thank you in advance for help.
Best regards.