Overview
Experiments with the Qualcomm OmniTRACS Ku-band satellite fleet tracking system.
The OmniTRACS Network (developed for Omninet Corporation, Los Angeles, CA) provides mobile users with a cost-effective, two-way message and position location service using existing Ku-Band satellites. An optional position-determination device integrated into the mobile terminal allows the position to be transmitted automatically to the hub. A variety of preformated and free-form text messages of up to 2000 characters are supported. An optional printer will permit transcription of messages to hardcopy.
The mobile uplink frequency is in the 14.0-14.5 GHz range. The RF power output was around 1 watt (+30 dBm) into a steerable "pill box" antenna with around 19 dBi of gain. The antenna has a 40° 3 dB bandwidth in elevation and 6° 3 dB bandwidth in azimuth. The system uses two transponders on the GTE Spacenet GSTAR-1 geosynchronous satellite.
The mobile downlink frequency is in the 11.7-12.2 GHz range.
The uplink transmission is spread spectrum BPSK over a 48 MHz bandwidth.
OmniTRACS Model No. 10-2221-1 is the unit with the three RF power amplifier transistors used in the San Diego Microwave Group modifications.
Notes / Links
- Technical Characteristics of the OmniTRACS The first operational mobile Ku-band satellite communications system. (391k PDF)
- 2010 Medal of Honor Winner: Andrew J. Viterbi Helped develop the OmniTRACS system along with OmniNet.
- Pillbox Antenna and Antenna Assembly U.S. Patent 4,876,554 (376k PDF)
- Fujitsu FMC1819 Ku, K-Band RF Power GaAs Module Similar pinouts to the RF power module used in the newer Qualcomm OmniTRACS units. (167k PDF)
- Qualcomm Q3236 PLL Synthesizer Backwards compatible with the Q3036 and Q3216 PLL chips used on the OmniTRACS RF/synthesizer board. (2.8M PDF)
- HP IAM-81008 5 GHz Double-Balanced Mixer Marked "M810" on the OmniTRACS RF/synthesizer board. (60k PDF)
- NEC UPC2721 General Purpose L-Band Downconverter Marked "2721" on the OmniTRACS RF/synthesizer board. (96k PDF)
- NEC UPC1659 1.5 GHz Bandwidth MMIC Amplifier Marked "1659" on the older OmniTRACS transmit IF amplifier board. (313k PDF)
- Mitsubishi MGFK25V4045 14 GHz 0.3 Watt GaAsFET Pre-driver (labeled "K25M") used in OmniTRACS units, Model No. 10-2221-1. (84k PDF)
- Mitsubishi MGFK30V4045 14 GHz 1 Watt GaAsFET Final amplifier (labeled "K30M") used in OmniTRACS units, Model No. 10-2221-1. (84k PDF)
- Mitsubishi MGF1423 Small-Signal GaAsFET Drives the MGFK25 in OmniTRACS units, Model No. 10-2221-1. (267k PDF)
- Mitsubishi MGF1302 Low-Noise GaAsFET Drives the MGF1423 in OmniTRACS units, Model No. 10-2221-1. (216k PDF)
Modification Notes
- San Diego Microwave Group - Technical Articles and Projects Lots of good Qualcomm OmniTRACS info and modifications.
- Modifying the Qualcomm 1 Watt Ku-Band Power Amplifier For use at 3.4 GHz, 5.7 GHz, or 10.3 GHz, by Kerry Banke, N6IZW
- W1RIL's Qualcomm 10 GHz Mods by Kenneth Schofield, W1RIL
- 10 GHz Qualcomm Modifications Notes by Dale Clement, AF1T
- Converting a Qualcomm Ku-Band Transverter for 10 GHz X-Band Amateur Radio Operation by Jeff Keyzer, KF6PBP.
- A 10 GHz Dual-Conversion High-Side LO Transverter from Surplus Qualcomm OmniTRACS Units by Kerry Banke, N6IZW. Potential usable OmniTRACS Model No. 10-30050-2, 10-30060-17, 10-30060-13. (Original)
- Numero Special: Amplis 1 W Qualcomm Very detailed information on modifying the OmniTRACS power amplifier section, but it's not in English! (1.1M PDF)
- Stock OmniTRACS +10 VDC Power Supply Module with -5 VDC Bias Generator Schematic drawing for Model No. 10-2221-1.
- Above and Beyond, Microwave Stripline Retuning Procedures by Chuck Houghton, WB6IGP
- The Qualcomm "Omnitrack" DRO Synthesizer by Chuck Houghton, WB6IGP (3.8M PDF)
- 10 MHz TCXO Stable Time Base Using the TCXO from a Qualcomm OmniTRACS unit.
- OmniTRACS RF/Synthesizer Board Conversion Converting the RF/synthesizer board in a Qualcomm OmniTRACS unit to another frequency.
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