[ARC5] Re: Military Collector Group Post (Jan.19/2002)

[David Stinson]

(from the MilCollector Group Post) 
> To a small degree the use of the 300kc band for air traffic control
> still survived into the early days of WW-II but only because of some
> antiquated equipment that still existed in the system.

It is commonly believed that aircraft communication on
HF and Longwave were completely abandoned early in WW-2.  
This is a myth.
HF was, in fact, extensively used even into the Korean conflict.
Commercial and military towers guarded HF frequencies well
into the 1950s.  Towers broadcasting on longwave and listening
on either HF or VHF also survived into the early 1950s.
While the transition to VHF primary frequencies 
was well along by 1945, aircraft equipment
designed to receive the tower on Longwave or HF 
were still being commercially made, sold 
and installed long after the end of WWII.
Aircraft sectionals and military radio facility charts 
from 1945 show that, while VHF was installed at most
airports (not nearly all), HF was still very active
and was the primary communication band 
for a large percentage of these stations.  
This was especially true in the Pacific and Asia areas,
where coordination with the Brits was not a large issue.
I have photographs of Pacific towers in the 1944-1945
time frame using HF as primary communications, 
L-5 and other spotter aircraft equipped with RCA HF
and SCR-274N in 1945 and even a Mustang P-51D from 
the early Korean conflict with SCR-274N installed.

Moreover, in the cases of SCR-274N and AN/ARC-5,
it begs credulity that extensive and expensive
training, repair, overhaul and spare parts operations 
were maintained from 1940 until the mid 1950s-
over a decade- for a system that "was never used."
There have been unused systems for which training and 
support dollars were expended, but not over a period
of 15-20 years.
HF installations where specified in Navy aircraft 
even longer then in USAAF/USAF installations.
These people had budgets- they didn't spend money every year
for over a decade and a half on systems that "were never used."

I've been asked from where this myth came.
There are a few old stories floating around about 
radio techs who said this wasn't used or this didn't work.
You could find dumb installations and badly trained techs
if you looked for them- and some people did for reasons
that will become clear below.
But the fact that HF *did* work is outlined above.

I haven't found enough data yet to draw a firm conclusion
about the origin of this myth,
but I do have enough for a working theory.
The short version- Propaganda.
Many proponents of aircraft VHF (with various agendas)
collected and disseminated negative stories about aircraft HF
in order to "speed along" the conversion to VHF.
That propaganda lives on in the "HF wasn't used" myth.

73 Dave S. AB5S