Re: [aprssig] Re: [amsat-bb] RE: AO16/LO19 Uplink w ANY PC!

[Stephan Greene <sgreene@xxxxxxxxxxx>]

On Sun, 19 Sep 1999 schoon@amgt.com wrote:

> So, would it be safe to say that by replacing some filters with 20 khz
> bandwidth and a decent preamp, one could forget about doppler??

For the microsats, no.  You'd still need some kind of AFC on the downlink.
This *does* work for an FM downlink; I recall from several years ago that
we used a fixed-freq Hamtronics receiver with wide filters to set up a
no-tune unatendded Eyesat/AO-27 reception station.  You will get poorer
signal-to-noise performance from the wider than necessary IF.

So in theory, you could use a wide IF for no-tune APRS reception on any FM
downlink satellite set up for digipeating or Mic-E position reporting.

73 Steve  KA1LM

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Stephan A. Greene                            sgreene@patriot.net    
Senior Systems Specialist, VA Linux Systems  sgreene@valinux.com
Mid-Atlantic Region                          703-980-3475
Amateur  KA1LM@amsat.org  Grid FM18hx        38 59'83.33"N 77 23'6.15"W
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