🚀 go-pugleaf

>I am interested in building a system to receive WEFAX APT
>pictures from at least the polar orbiting weather satellites
>and maybe also from the geosynchronous ones. One question
>I have is: what is a good receiver to use? I have a scanner
>that can receive 137.5MHz but it's bandwidth is either 6kHz or 200kHz.
>I understand that the appropriate bandwidth would be about 50kHz.

I'm curious about this bandwidth thing too.  I have trouble believing
the FM signal actually has a short-term deviation of 50kHz - but I
*can* believe this might be wide enough to copy the signal during
the doppler shift from AOS to LOS (I haven't calculated this though, or
looked it up).

Would a NBFM (6kHz mentioned above) receiver work just as well as
one with a 50kHz bandwidth as long as the center frequency was
periodically changed to account for the doppler shift?

	-Paul Bame
	paul@hpldola.hp.com
	hplabs!hpldola!paul