[Milsurplus] Question on A/C fixed antenna

[Michael Hanz]

I might respectfully suggest that the question might be better worded as 
the internal fuselage run length of the HF antenna to the transmitter.  
All of the large WWII US aircraft that I'm familiar with used antenna 
relays which provided the receiver with a signal almost as an oh by the 
way issue.  You'll see a lot more effort put into keeping the antenna 
lead short to the transmitter, not the receiver.  That makes sense, 
since you have a lot more trouble consistently loading a transmitter 
with long lengths of bare (or bead insulated) transmission line running 
all over the place.  The receivers pretty much worked fine with whatever 
insulated wire it took to get from the antenna relay, and routing in the 
various photos I have don't seem to show a lot of the care devoted to 
the transmitter lead-in.*

*(That all changed with the end of the war, prompted by the requirement 
for using coax for the VHF sets earlier in the war. Except for the 
legacy AN/ARC-8 set, postwar HF sets evolved into coax to a generally  
remote antenna tuner.  That made the HF antenna connection very short 
and freed up options for transmitter placement within the airframe.)

I can't suggest a more graphic depiction of the relationships of 
transmitter to antenna than in the _Airborne Radio Equipment Handbook_ 
(April 1943) pages 57 through 68.  For example, below is the one for the 
B-24.  You can see the relative positions of components and roughly 
estimate distances from previous aircraft dimensions in the handbook.

  - Mike  KC4TOS

On 6/1/2019 4:17 PM, Hubert Miller wrote:
>
> The leadin from the fixed antenna on large U.S. aircraft such as B-17, 
> PBM, PB4Y, PBY – how long was the run of the internal leadin, from its 
> entrance to the airframe to the
>
> radio receiver? In general ?
>


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