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