GPS antenna is located here in googleearth.
The status of many other Z3801A's are listed here.
Jeff Mock

HEWLETT-PACKARD,Z3801A,3542A10020,3543-A      Life count: 25059 hours
------------------------------- Receiver Status -------------------------------
 
SYNCHRONIZATION ............................................. [ Outputs Valid ]
SmartClock Mode ___________________________   Reference Outputs _______________
>> Locked to GPS                              TFOM     3             FFOM     0
   Recovery                                   1PPS TI +2.5 ns relative to GPS
   Holdover                                   HOLD THR 1.000 us
   Power-up                                   Holdover Uncertainty ____________
                                              Predict  3.3 us/initial 24 hrs
                                                
ACQUISITION ............................................ [ GPS 1PPS CLK Valid ]
Satellite Status __________________________   Time ____________________________
Tracking: 6        Not Tracking: 2            UTC      04:25:02     24 Jul 2008
PRN  El  Az   SS   PRN  El  Az                1PPS CLK Synchronized to UTC
  2  74 146  171    17  14  67                ANT DLY  130 ns
  4  52  58  140    29  11 263                Position ________________________
  5  47 313  219                              MODE     Hold
  9  45 222  165                              
 12  62 322  193                              LAT      N  37:47:32.109
 30  21 309  107                              LON      W 122:25:32.786
ELEV MASK 10 deg                              HGT               +98.55 m  (MSL)
HEALTH MONITOR ......................................................... [ OK ]
Self Test: OK    Int Pwr: OK   Oven Pwr: OK   OCXO: OK   EFC: OK   GPS Rcv: OK