RE: [amsat-bb] SarSat Epirbs

["Tom Clark, W3IWI" <w3iwi@xxxxxxxx>]

> How is this information collected from the
> early generation
> of satellites on 121.5 and 243.0.  How are locations
> pinpointed in the early
> generation of birds that only receive the older style of
> elt/epirbs?  I know
> through my research on the net and as an amateur satellite
> enthusiast that
> amateurs pioneered direction finding from satellites using Oscar-7.

The early technique just involved the measurement of the "S-shaped" Doppler
curve as seen on several LEO satellite passes. Marty Davidoff's Satellite
Handbook (ARRL) has a description on page 8-6.

The early amateur verification of the technique was done with the 2M-to-10M
bent-pipe transponders on AO-6 & AO-7 by two groups. The Canadian effort was
led by Larry Kayser (VE3QB, now VA3LK) in Ottawa and the US effort was here
in Maryland under the WA3LND (now W3IWI) call.

Larry's effort took a small 2M beacon out in a car and the location was
measured to within ~1 km. Our Maryland effort used a fixed, but well known
site near Greenbelt and showed repeatability at the sub-km level.

73 de Tom, W3IWI


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