HOLC Site Information Form
     International GPS Service for Geodynamics


0.   Form

     Prepared by (full name)  : Marin Clark
     Date Prepared            : 31-OCT-1997
     Report Type              : UPDATE
     Prepared Using           :

1.   Site Identification of the GPS Monument

     Site Name                : Holcomb Ridge
     Four Character ID        : HOLC
     Monument Inscription     : None
     IERS DOMES Number        : 40404M101
     CDP Number               : (XXXX)
     Date Installed           : 12-AUG-1994 hh:mm UT
     Geologic Characteristic  : (BEDROCK/CLAY/CONGLOMERATE/GRAVEL/SAND/etc)
       Bedrock Type           : (IGNEOUS/METAMORPHIC/SEDIMENTARY)
       Bedrock Condition      : (FRESH/JOINTED/WEATHERED)
       Fracture Spacing       : (1-10 cm/10-50 cm/50-200 cm/over 200 cm)
       Notes                  : (multiple lines)
     Additional Information   : 3/4" diameter, stainless steel rod with
                              : removable brass adaptor atop vertical rod. Hard
                              : limestone foundation, 4 10-12 foot stainless
                              : steel rods - one vertical, three oblique,
                              : welded above surface. Vertical datum is a filed
                              : notch in the vertical rod. Legs are isolated
                              : from shallow rock and soil by PVC in the
                              : uppermost ~5'. Antenna housing is Kearney-
                              : Powerglass fiberglass (rounded rectangular
                              : shape). Antenna is mounted low to the ground.
                              : SCIGN - Southern California Integrated GPS
                              : Network


2.   Site Location Information

     City or Town             : SE of Pearblossom, Los Angeles County
     State or Province        : California
     Country                  : USA
     Tectonic Plate           : Pacific-North American plate boundary
     Approximate Position
       X coordinate (m)       : -2459517.863
       Y coordinate (m)       : -4655992.343
       Z coordinate (m)       :  3589168.783
       Latitude (deg)         :   34.4582
       Longitude (deg)        : -117.8452
       Elevation (m)          : 1239.1697
     Additional Information   : ITRF92 coordinates. Epoch 1994.75


3.   GPS Receiver Information

3.1  Receiver Type            : ASHTECH ZX-II3 (Z12) Model 700570-6B
     Serial Number            : 03377 (Loaner # 1)
     Firmware Version         : NAV 1D00, CHN 1C01
     Date Installed           : 12-AUG-1994 hh:mm UT
     Date Removed             : (dd-MMM-yyyy hh:mm UT)
     Additional Information   : First measurements

3.2  Receiver Type            : ASHTECH Low Power Z-XII (Z12) Model 700845-6(1)
     Serial Number            : 04368
     Firmware Version         : NAV 1E24, CHN 1C70
     Date Installed           : 15-MAY-1995 hh:mm UT
     Date Removed             : (dd-MMM-yyyy hh:mm UT)
     Additional Information   : exchanged Loaner #1 for USGS rec/ant unit

3.3  Receiver Type            : ASHTECH Low Power Z-XII (Z12) Model 700845-6(1)
     Serial Number            : 04368
     Firmware Version         : NAV 1E24, CHN 1C70
     Date Installed           : 26-MAY-1995 hh:mm UT
     Date Removed             : (dd-MMM-yyyy hh:mm UT)
     Additional Information   : no changes to the rx, exchanged antenna

3.4  Receiver Type            : ASHTECH Low Power Z-XII (Z12) Model 700845-6(1)
     Serial Number            : 04368
     Firmware Version         : NAV 1E95 1D01
     Date Installed           : 24-SEP-1996 hh:mm UT
     Date Removed             : (dd-MMM-yyyy hh:mm UT)
     Additional Information   : firmware upgrade

3.5  Receiver Type            : ASHTECH Low Power Z-XII (Z12) Model 700845-6(1)
     Serial Number            : 04368
     Firmware Version         : NAV 1E95 1D01
     Date Installed           : 16-DEC-1996 hh:mm UT
     Date Removed             : (dd-MMM-yyyy hh:mm UT)
     Additional Information   : Removed Rx for inspection.

3.6  Receiver Type            : ASHTECH Low Power Z-XII (Z12) Model 700845-6(1)
     Serial Number            : 04368
     Firmware Version         : NAV 1E95 1D01
     Date Installed           : 17-DEC-1996 hh:mm UT
     Date Removed             : (dd-MMM-yyyy hh:mm UT)
     Additional Information   : Rx reinstalled; site back on-line.

3.x  Receiver Type            :
     Serial Number            :
     Firmware Version         :
     Date Installed           : (dd-MMM-yyyy hh:mm UT)
     Date Removed             : (dd-MMM-yyyy hh:mm UT)
     Additional Information   : (multiple lines)


4.   GPS Antenna Information

4.1  Antenna Type             : ASHTECH L1/L2 P Model 700718-B (Lg Ground Plane)
     Serial Number            : 10293
     Antenna Height (m)       : 0.0876
     Antenna Reference Point  : BPA
     Degree Offset from North :
     Antenna Radome Type      :
     Date Installed           : 12-AUG-1994 hh:mm UT
     Date Removed             : (dd-MMM-yyyy hh:mm UT)
     Additional Information   : field measurement 10.35 cm to base of wide part

4.2  Antenna Type             : ASHTECH L1/L2 P Model 700718-B (Lg Ground Plane)
     Serial Number            : 10485
     Antenna Height (m)       : 0.0870
     Antenna Reference Point  : BPA
     Degree Offset from North :
     Antenna Radome Type      :
     Date Installed           : 15-MAY-1995 hh:mm UT
     Date Removed             : (dd-MMM-yyyy hh:mm UT)
     Additional Information   : field measurement 10.30 cm to base of wide part
                              : of antenna base reduced by 1.6 cm correction
                              : (to base of narrow part)
                              : exchanged Loaner #1 for USGS rec/ant unit

4.3  Antenna Type             : ASHTECH Model 700936-A (Metal Choke Ring)
     Serial Number            : 11477
     Antenna Height (m)       : 0.0850
     Antenna Reference Point  : ARP/BPA
     Degree Offset from North :
     Antenna Radome Type      :
     Date Installed           : 26-MAY-1995 hh:mm UT
     Date Removed             : (dd-MMM-yyyy hh:mm UT)
     Additional Information   : same filed notch used as vertical datum. DM type
                              : antenna installed, old LGP antenna removed.

4.4  Antenna Type             : ASHTECH Model 700936-A (Metal Choke Ring)
     Serial Number            : 11477
     Antenna Height (m)       : 0.0850
     Antenna Reference Point  : ARP/BPA
     Degree Offset from North :
     Antenna Radome Type      :
     Date Installed           : 24-SEP-1996 hh:mm UT
     Date Removed             : (dd-MMM-yyyy hh:mm UT)
     Additional Information   : no changes to antenna at this time.

4.5  Antenna Type             : ASHTECH Model 700936-A (Metal Choke Ring)
     Serial Number            : 11477
     Antenna Height (m)       : 0.0850
     Antenna Reference Point  : ARP/BPA
     Degree Offset from North :
     Antenna Radome Type      :
     Date Installed           : 16-DEC-1996 hh:mm UT
     Date Removed             : (dd-MMM-yyyy hh:mm UT)
     Additional Information   : no changes to antenna at this time.

4.6  Antenna Type             : ASHTECH Model 700936-A (Metal Choke Ring)
     Serial Number            : 11477
     Antenna Height (m)       : 0.0850
     Antenna Reference Point  : ARP/BPA
     Degree Offset from North :
     Antenna Radome Type      :
     Date Installed           : 17-DEC-1996 hh:mm UT
     Date Removed             : (dd-MMM-yyyy hh:mm UT)
     Additional Information   : no changes to antenna at this time.

4.x  Antenna Type             :
     Serial Number            :
     Antenna Height (m)       : (m)
     Antenna Reference Point  : (ARP/BCR/BPA)
     Degree Offset from North :
     Antenna Radome Type      :
     Date Installed           : (dd-MMM-yyyy hh:mm UT)
     Date Removed             : (dd-MMM-yyyy hh:mm UT)
     Additional Information   : (multiple lines)


5.   Local Site Ties

5.x  Monument Name            :
     Site Ref CDP Number      : (XXXX)
     Site Ref Domes Number    : (XXXXXXXXX)
     Differential Components from GPS Mark to Site Reference (ITRS)
       dx (m)                 : (m)
       dy (m)                 : (m)
       dz (m)                 : (m)
     Accuracy (mm)            : (mm)
     Date Measured            : (dd-MMM-yyyy hh:mm UT)
     Additional Information   : (multiple lines)


6.   Frequency Standard

6.1  Standard Type            : INTERNAL
       Frequency              :
       Effective Dates        : 12-AUG-1994 - dd-MMM-yyyy
       Notes                  : (multiple lines)

6.x  Standard Type            : (H-MASER/CESIUM/QUARTZ/INTERNAL/RUBIDIUM)
       Frequency              :
       Effective Dates        : (dd-MMM-yyyy - dd-MMM-yyyy)
       Notes                  : (multiple lines)


7.   Collocation Information

7.x  Instrumentation Type     : (DORIS/GLONASS/PRARE/SLR/VLBI)
       Status                 : (PERMANENT/MOBILE)
       Effective Dates        : (dd-MMM-yyyy - dd-MMM-yyyy)
       Notes                  : (multiple lines)


8.   Meteorological Instrumentation

8.1  Humidity Sensor Model    :
       Manufacturer           :
       Data Frequency         :
       Accuracy (% rel h)     : (% rel h)
       Effective Dates        : (dd-MMM-yyyy - dd-MMM-yyyy)
       Notes                  : (multiple lines)

8.2  Pressure Sensor Model    :
       Manufacturer           :
       Data Frequency         :
       Accuracy (mbar)        : (mbar)
       Height Diff to GPS (m) : (m)
       Effective Dates        : (dd-MMM-yyyy - dd-MMM-yyyy)
       Notes                  : (multiple lines)

8.3  Temperature Sensor Model :
       Manufacturer           :
       Data Frequency         :
       Accuracy (deg C)       : (deg C)
       Effective Dates        : (dd-MMM-yyyy - dd-MMM-yyyy)
       Notes                  : (multiple lines)

8.4  Water Vapor Radiometer   :
       Manufacturer           :
       Distance to GPS (m)    : (m)
       Elev Diff to GPS (m)   : (m)
       Effective Dates        : (dd-MMM-yyyy - dd-MMM-yyyy)
       Notes                  : (multiple lines)

8.5  Other Instrumentation    : (multiple lines)


9.   On-Site, Point of Contact Agency Information

     Agency                   : U.S. Geological Survey
     Mailing Address          : 525 South Wilson Ave.
                              : Pasadena, CA 91106
     Primary Contact
       Contact Name           : Kenneth W. Hudnut
       Telephone (primary)    : 818-583-7232
       Telephone (secondary)  :
       Fax                    : 818-583-7827
       E-mail                 : hudnut@usgs.gov
     Secondary Contact
       Contact Name           :
       Telephone (primary)    :
       Telephone (secondary)  :
       Fax                    :
       E-mail                 :
     Additional Information   : (multiple lines)


10.  Responsible Agency (if different from 9.)

     Agency                   :
     Mailing Address          :
                              :
                              :
     Primary Contact
       Contact Name           :
       Telephone (primary)    :
       Telephone (secondary)  :
       Fax                    :
       E-mail                 :
     Secondary Contact
       Contact Name           :
       Telephone (primary)    :
       Telephone (secondary)  :
       Fax                    :
       E-mail                 :
     Additional Information   : (multiple lines)


11.  More Information

     URL for More Information :
     Hardcopy on File
       Site Map               : (Y)
       Site Diagram           : (Y)
       Horizon Mask           : (N)
       Monument Description   : (Y)
       Site Pictures          : (Y)
     Additional Information   : (multiple lines)
     Antenna Graphics with Dimensions


             ASHTECH: Metal Choke Ring Type
             NOTE: Dimensions and Offsets Presumed to be same as
                   for TURBOROGUE DM-T (tests pending)

                         -----
                     /     +     \                        <-- 0.128  L2
                    |      +      |                       <-- 0.110  L1
  +--------------------------------------------------+    <-- 0.102  TCR
  |                                                  |
  |                                                  |
  |                                                  |
  |                                                  |
+-+--------------------------------------------------+-+  <-- 0.038
+-------------------+-------------+--------------------+  <-- 0.035  BCR
                    |             |
                   =|             |
                    +------x------+                       <-- 0.000 m ARP
                                                             -0.085 m ARP to
                                                                vert datum mark
<--                      0.381                       -->


 LGP antenna replaced by DM type antenna on 5-26-95
               ASHTECH: GEODETIC L1/L2 P Large Ground Plane

                           ^
                 +-------------------+
+-+--+-+-------+-----------+-----------+--------+-+--+-+    <--  0.064 TGP=L1=L2

+-+--+-+------------+-------------+-------------+-+--+-+    <--  0.??? BGP
                    |-------------|
                    |-------------|
                    |-------------|
                    |-------------|
                    +------x------+                       <--  0.000 ARP=BPA
                                                              -0.087 m ARP to
                                                                vert datum mark
                  <--    0.080    -->
<--                      0.3474                      -->


   ARP: Antenna Reference Point
   L1 : L1 Phase Center                   L2 : L2 Phase Center
   TCR: Top of Chokering                  BCR: Bottom of Chokering
   TGP: Top of Ground Plane               BGP: Bottom of Ground Plane
   TPA: Top of Preamplifier               BPA: Bottom of Preamplifier