[ARC5] FW: HF/MF Mission Speculations

[Robert P. Meadows]

Most all aircraft radio frequencies before WWII were HF.  There were no VHF
radios in existence before then.  After WWII due to development of VHF that
was actually VHF, most all frequencies were reallocated, and we have that
system today, with FM entertainment radio frequencies up to 108 Mc, then the
now almost defunct VOR assignments, then VHF aircraft communications which
is still AM and will probably stay that way for a long time.  Of course the
channelization for VHF comm is now up to 1440 discrete frequencies, with
much of Europe demanding more, and of course the Frogs wanting to take the
amateur 2Meter allocation.  Most US military aircraft communication is
225-400 Mc, and that "band" is utilized by most shipboard local/tactical
communications within a "battle group".
Amelia didn't understand radio communications procedures, direction finding
requirements or much else about radios.  She left her trailing wire antenna
behind as it was deemed not important.
The frequencies she was to use were well known and documented, however the
frequency stability of the gear was not what it is today, and her failure to
understand that a "long count" for DF was more than counting to ten a few
times.  Hence the Shipboard DF never heard the signal.

I know I used Mc, I have great disdain for the renaming of the one thing in
all of the physical sciences that was rather clear in its name to hertz...
R

-----Original Message-----
From: arc5-bounces at mailman.qth.net <arc5-bounces at mailman.qth.net> On Behalf
Of Hubert Miller
Sent: Monday, May 4, 2020 1:09 AM
To: arc5 at mailman.qth.net
Subject: [ARC5] FW: HF/MF Mission Speculations

I don't know about El Salvador, but I know Lae PNG and Iceland both had HF
airfield operations by late 1930s, and I can prove it. I'm working on El
Salvador......
I note that Amelia Earhart, on her round-the-world last flight, for all the
obscure airfields she flew to, only had
3105 and 6210 kHz transmit equipment. 
( If she'd had a 500 kHz transmitter and trailing antenna, very possible
they would have survived. However,
500 - 800 and 800 - 1300 kHz, were unnecessary. ) 

-Hue 
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