[600MRG] HADGPS Fingerprint, 458 kHz

[Paul Signorelli]

I have been monitoring the Pueblo, CO, HDGPS station on my HP spectrum analyzer.

The fingerprint is quite unique.

The center frequency is 458 kHz and probably about +/- 20 kHz.

The transmission begins as a swept carrier (of data) going from 438 to 478 kHz that takes 3 seconds.

Then like a blanking pulse, a broad spectrum (438 to 478) of energy (same amplitude) is

transmitted for 1 second, then reset back to 438 kHz to restart the 3 second sweep up to 478 kHz.

It is a continuous repetition of this cycle.

This protocol is documented some where but I don't have access to it.

They must have done some  work on the antenna to make it broadband.

The only existing transmitter site around Pueblo was the old GWEN (URC-117) tower, 300 feet high.

Paul   wa2xrm