Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!ames!pasteur!ucbvax!hplabs!hpfcso!hpfcdj!myers
From: myers@hpfcdj.HP.COM (Bob Myers)
Newsgroups: sci.electronics
Subject: Re: naive question about RF propagation
Message-ID: <17660043@hpfcdj.HP.COM>
Date: 15 Jan 90 19:06:10 GMT
References: <28774@amdcad.AMD.COM>
Organization: Hewlett Packard -- Fort Collins, CO
Lines: 14

>We all know that AM broadcast radio fades when you drive under a bridge
>but FM doesn't tend to nearly as much. Why is this? Does RF at the FM
>broadcast frequencies propagate better? I thought the higher the frequency,
>the more it exhibited "line of sight" behavior. Or is it because AM

The "higher frequency = more line of sight" is basically correct, but it's
also true that the higher the frequency, the shorter the wavelength - and
shorter-wavelength EM waves can "get around" edges and "into" semi-enclosed
spaces better than their longer cousins.  (Think of waveguides, etc..)


Bob Myers  KC0EW   HP Graphics Tech. Div.|  Opinions expressed here are not
                   Ft. Collins, Colorado |  those of my employer or any other
myers%hpfcla@hplabs.hp.com               |  sentient life-form on this planet.