Xref: utzoo talk.religion.newage:1388 alt.flame:1199
Path: utzoo!hoptoad!amdcad!decwrl!labrea!husc6!linus!philabs!ttidca!quad1!oleg
From: oleg@quad1.quad.com (Oleg Kiselev)
Newsgroups: talk.religion.newage,alt.flame
Subject: Re: Platygaeanism
Keywords: platygaeanism, am & fm
Message-ID: <1414@quad1.quad.com>
Date: 6 Jan 88 19:04:24 GMT
References: <2534@killer.UUCP>
Reply-To: oleg@quad1.quad.com (Oleg Kiselev)
Organization: HASA
Lines: 30

In article <2534@killer.UUCP> allen@sulaco.UUCP (Allen Gwinn) writes:
>>... it's AM (lower frequency) transmissions that bounce off the
>>ionosphere, not FM.
>I'll have to remember that, Malcolm, the next time I use my aircraft
>radio (+- 110-130 MHz AM).  To think that I might have been cleared for
>takeoff by L.A. Tower when I was in Dallas makes me mighty nervous  :-)
>
>And while I'm at it, I have decided to junk my 10 Meter FM amateur radio
>transceiver since you have convinced me that FM signals don't bounce off
>of the ionosphere (or ionoplane  :-) ).  

Lest some other poor souls get confused by all this (I assume Allen knows
wherefor he speaks, as seems to be indicated by the smilies):

AM and FM refer to the method of information "encoding" and transmission,
rather than the frequency of the carrier wave.  Unfortunately, for most people
not well informed FM has become synonimous with 88-108 MHz carrier frequency.
And the same way AM became sysnonimous with 530-1600 KHz.  Which is rather sad,
because AM and FM, although being preferred modulation methods at certain
distinct frequency ranges, are not frequency specific.

So, in discussing ionosurface (;-) reflections of E&M waves, the frequency and
not modulation methods should be kept in mind.  And yes, signals at 100+ MHz
(AM or FM) will not bounce off the ionosphere, while 10 Meter (30 MHz?) very
well may be reflected.
-- 
Oleg Kiselev  --  oleg@quad1.quad.com -- {...!psivax|seismo!gould}!quad1!oleg
HASA, "A" Division

DISCLAIMER:  I don't speak for my employers.