Quantic Q-5200/SM Timing GPS Receiver

Brooke Clarke, N6GCE

Quantic 5200 GPS front

General Information
Technical Information
Start Up

General Information

The problem is that this receiver used a very special antenna that needs both a DC and reference frequency input on the coax connector and contains a mixer so that the signal send down the coax is much lower in frequency than the GPS L1 frequency.  This is great for allowing long coax run length with low losses, but since these antennas are about a common as hen's teeth it's a problem for getting the receiver to work.  One idea is to see if the incoming coax signal is converted to some other IF signal which might be an injection point for a more easily generated frequency.

"Timing GPS Receiver. Fixed Price subcontract from Quantic Industries (under Prime Contract No. F04701-92-C-0067 from U.S. Air Force Space and Missile Systems Center, Los Angeles AFB, California). I3C teamed with Quantic Industries and Stellar Navigation to design, develop and support a Timing GPS Receiver to replace all LORAN-C receivers worldwide in the Defense Satellite Communications System. I3C's responsibilities included total management of all ILS requirements for the multi-service program."
The construction is heavy on the EMC/EMI Tempest side with a lot of shielding of all ports including the fan input and output.
There are 4 major electrical parts:

Technical Information

The Q5200 sends both +15 Vdc power and a 11.114 MHz reference frequency up the cable to the Antenna Module. The Antenna Module receives the satellite L1 frequency and down converts the signal to an IF of 153.028 MHz which is sent down the cable to the receiver.

This is a 6 channel receiver.  I think each STEL chip can handle 3 channels and there are two chips.

So far it looks like the Antenna Module is not a single mixer, maybe is a double conversion scheme.

Maybe the AN/CYZ-10 Data Transfer Device (DTD) could be used to load GPS keys into the Q5200?

Start Up

In order to get power to the unit I needed to replace the line fuse holder because the cap was missing and the new fuse holder cap did not work.
Now the fan runs and the front panel  2 row by 40 coul. LCD backlight comes on and the display is all 5x7 dot patterns.
The power supply outputs are:
Wire Color
to chassis
to chassis
Yel & Blue
Gray & Brown

The AC Power and Loss of GPS LEDs light constantly and the Key Accepted and Key Rejected LEDs blink in unison.

After removing the GPS and Clock boards to take the above photos and reassembling the receiver, it now is working .
See Hints & Tips for why this happened.
The Display now shows the power up screen: Quantic/Stellar Timing GPS Receiver, 6 Jan 80 (power up date) 00:00:54 (clock that started at power up), Version 1.6 19 SEP 94 (date of version 1.6), Fault AB00.

Pressing ESC on the keypad brings up the Main menu screen:

  • Main Menu
  • Links

    Absolute Time
    They do not return email and their phone and fax numbers are out of service.  Maybe out of business, but the web page is still alive?
    Terry Osterdock Jr is the contact for the absolutetime.com URL.
    - Global Positioning System (GPS) in the Defense Communications System (DCS) Proceedings of 1993 IEEE June 2-4 1993 pp 40-44
    - Model 300 (about same as 5200?)
    - Using a new GPS Frequency Reference in Frequency Reference Operations -

    US Patent 5440313 - One of the neat things this patent covers is the idea of using the carry out of an NCO which is integrated in a low pass filter to form a 48 bit D/A converter.  You can not buy D/A converters with this many bits.  Also instead of jamming a change into the 1 PPS timing they lock the 10 MHz internal oscillator to the GPS 1 PPS resulting in slower changes.  There is a provision for an external standard input that's trimmed by the GPS 1 PPS and if the GPS fails the external standard is still trimmed by the last valid amount.

    Quantic Industries, Inc.
    990 Commercial Street, San Carlos, CA 94070-4084
    Telephone  650.595.1100
    FAX 650.592.4669
    They are still in business, but have sold off this product line to Absolute Time.

    800 Charcot Avenue, Suite 110, San Jose, CA 95131
    Telephone  (408) 383-1520 (408) 383-1515 -> disconnected
    FAX        (408) 383-0706 -> disconnected

    USNO - List of GPS timing receiver manufacturers -

    Stellar GPS - receiver?

    Information on NTP Time Servers and Radio Timecode Receivers -

    Stanford Telecommunications 5001 NAVSTAR Test Transmitter - included is a block diagram showing how L1 and L2 are generated without encryption.

    TrueTime Model Mark V GPS receiver, has some similarity. 

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    Page created 23 July 2001.