Larry Dodd K4LED / AAR4IV
 www.101science.com

The charts on this page are from a surplus HP Z3801A GPS 6 channel satellite receiver with a highly stable oscillator locked to multiple (up to six at one time) rubidium NIST standard GPS satellite clocks.  This receiver is located at my station.

The extremely stable GPS locked 10 MHz oscillator output is used as an external frequency standard for external clocking of station frequency counters and signal generators. Highly accurate frequency control is therefore available to the station. 

Transceivers like the Kenwood TS-2000 for example are easily tuned with their front panel controls to the exact desired frequency within +- .01 of a hertz using a GPS locked frequency counter.  That takes a very careful and light touch of the XIT control but it can be done in less than a minute or two.  Using the XIT function is the only way to see a read out in cycles on the transceiver and only then if the rig fine tuning function is turned on.  You must use the external GPS locked frequency counter to read the frequency down to .01 HZ.  The limit is quickly reached at that point because of the limits of stability of the rigs oscillator and the coarseness of the XIT control.  Under everyday circumstances an accuracy of +- .1 HZ is easily obtainable and maintainable using this method.  Even this level of accuracy is well beyond current amateur radio and MARS operational requirements.

Receiver Total Power-on time

Days Hrs Mins Secs

 

To learn more about the software which generates this data, please visit K8CU at: www.realhamradio.com

           HEWLETT-PACKARD,Z3801A,3542A05626,3543-A. Life count: 9132
------------------------------- Receiver Status -------------------------------
 
SYNCHRONIZATION ............................................. [ Outputs Valid ]
SmartClock Mode ___________________________   Reference Outputs _______________
>> Locked to GPS                              TFOM     3             FFOM     0
   Recovery                                   1PPS TI -4.1 ns relative to GPS
   Holdover                                   HOLD THR 1.000 us
   Power-up                                   Holdover Uncertainty ____________
                                              Predict  3.1 us/initial 24 hrs
                                                
ACQUISITION ............................................ [ GPS 1PPS CLK Valid ]
Satellite Status __________________________   Time _____ +1 leap second pending
Tracking: 4        Not Tracking: 4            LOCAL    18:13:01     31 Aug 2005
PRN  El  Az   SS   PRN  El  Az                1PPS CLK Synchronized to UTC
  8  24 313   62   * 3  40  48                ANT DLY  0 ns
 19  70  77   31    11  19 158                Position ________________________
 23  29 187   45   *13  Acq .                 MODE     Hold
 27  56 323   58    28  13 267                
                                              LAT      N  33:47:00.632
                                              LON      W  84:06:17.662
ELEV MASK 10 deg   *attempting to track       HGT              +292.55 m  (MSL)
HEALTH MONITOR ......................................................... [ OK ]
Self Test: OK    Int Pwr: OK   Oven Pwr: OK   OCXO: OK   EFC: OK   GPS Rcv: OK