[Milsurplus] airborne radio activity

[David Stinson]

Telegrapher@QWEST.net wrote:

> Read an article about a B-24 pilot yesterday.  Said his "final 3
> missions were radio relay missions, with up to 14 radios in the
> aircraft". ... This was in the May 1945
> timeframe...

The theory is that airborne VHF repeaters had replaced
HF Liaison and Command functions on strategic bombing 
missions by 1945.

At least two eye witnesses say that a system of 
airborne VHF repeaters was used to relay liaison and command traffic.
I am certain they saw airborne VHF repeaters in WWII.
But there are good reasons why it could not have been 
an official replacement for bomber HF systems.

First- there is no documentation in any of the sectionals,
Airways guides or any other document 
I've seen for such a system, and I've seen many.
Never in decades of reading and collecting this information
have I seen a single instance of a WWII VHF radio 
with a duplex channel.  All have been simplex.  
If someone has the documentation, please share it with us.

Much more important- it's physically impossible for 
a VHF repeater to have carried bombing mission liaison traffic
or to have relayed VHF command traffic from the targets back to HQ 
late in the war in the ETO.

The radio horizon for an antenna at 23,000 feet is 214 miles.
If both transmitting and receiving antennas were at 23,000 feet,
the total line of sight distance for this system is 428 miles,
and the last 40 or so miles of that distance would be very
noisy even with modern receivers- an SCR-522 wouldn't stand a chance.  
The great circle distance from London to Berlin is 577 miles.
Even if you could get both antennas to 30,000 feet, 
you'd still be nearly 100 miles short.
Thus, the theory cannot be correct.

I didn't run the calculations for Sicily to Northern Italy
or for the Pacific theater, because the numbers would 
be similar.  It is physically impossible that this system 
replaced all strategic bomber HF functions.

Could this system, among other uses,
have helped with crippled aircraft over the Channel? 
Could it have been used for shorter, tactical missions
by medium bombers and ground support aircraft? Certainly.
I think it likely that the real purpose of the system 
was to keep tactical aircraft- like P-51s looking
for tanks to bust- in touch with the rear.  

Could it have replaced all HF Command and Liaison functions
in the strategic bombing campaign?
Absolutely and conclusively not.

73 DE Dave AB5S