Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!csd4.milw.wisc.edu!bionet!agate!ucbvax!hplabs!hpfcdc!hpfcdj!myers
From: myers@hpfcdj.HP.COM (Bob Myers)
Newsgroups: sci.electronics
Subject: Re: Stereo vs. Mono: Q about AM Stereo
Message-ID: <11170006@hpfcdj.HP.COM>
Date: 4 May 89 18:53:05 GMT
References: <4046@bgsuvax.UUCP>
Organization: Hewlett Packard -- Fort Collins, CO
Lines: 40

>	I'll concede that AM has all kinds of garbage in it whenever
>there is a thunderstorm, or your next door neighbour cranks up their
>Electrolux.  Sometimes.  It's not AM's fault, though it is a uniquely
>AM problem.  An AM signal at 108 mHz with the appropriate carrier
>to noise ratio would be just as clean as a wasteful :-) FM channel
>occupying nominally 200 kHz.

Not to pick nits, but.... :-)

David, are you saying that AM is *not* inherently more susceptible
to noise ("static", etc.) than FM?  Ever try AM vs NBFM on 10 meters?
(Assuming a decent FM detector, of course.)  Certainly, AM can be clear
as a bell given the "appropriate carrier to noise ratio", but for equal
power transmitters located similar distances from my receiver, I believe
FM has at least a small advantage as far as noise rejection.

The "capture effect" of FM is also a nice feature in most instances,
as the listeners are not plagued with the heterodyning that you usually
have to put up with on the AM band at night.  (Although admittedly, moving
AM broadcast to a much higher frequency band, one not usually subject to
long-range propagation, would help muchly here!)

One other item - and this is really getting picky, but what the hell - 
I really don't think that either an AM or an FM signal would do particularly
well with a 108 milliHertz carrier, do you?  (Add several :-)s here)


>	AM has taken the (well deserved) rap entirely too long
>because of the available receivers.  It is not, however, as bad
>as suggested.  FM stereo coverage problems, short spacing, intermod,
>and so on are problems unique to FM, they do interrupt service and
>spoil reception more or less permanently.


....but no argument here whatsoever!


Bob Myers  KC0EW   HP Graphics Tech. Div.|  Opinions expressed here are not
                   Ft. Collins, Colorado |  those of my employer or any other
{the known universe}!hplabs!hpfcla!myers |  sentient life-form on this planet.