Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!ncar!tank!uxc.cso.uiuc.edu!uxc.cso.uiuc.edu!m.cs.uiuc.edu!kenny
From: kenny@m.cs.uiuc.edu
Newsgroups: sci.electronics
Subject: Re: Weather Satellite Receiver Question
Message-ID: <21000043@m.cs.uiuc.edu>
Date: 29 Sep 89 01:01:00 GMT
References: <744@anasaz.UUCP>
Lines: 18
Nf-ID: #R:anasaz.UUCP:744:m.cs.uiuc.edu:21000043:000:774
Nf-From: m.cs.uiuc.edu!kenny    Sep 28 20:01:00 1989


/* Written  2:51 pm  Sep 27, 1989 by paul@hpldola.HP.COM in m.cs.uiuc.edu:sci.electronics */
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?
/* End of text from m.cs.uiuc.edu:sci.electronics */

No.  Short-term deviation of 30KHz is common in metsat signals.  It's
still not as wide as commercial FM broadcast, but it's lots wider than
NBFM.

A-T