[ARC5] Re: [Milsurplus] Signal Corps Info Golden Nuggets.

[David Stinson]

Hue Miller wrote:
> -Dave, is there really a question of whether aircraft transmitted
> (NOT broadcast - that is a separate question) 
> on the MW broadcast band frequencies?
No, there is no question that some transmitted on 
MW broadcast frequencies.  The question is *why*.

> My previous posts on this mentioned 2 incidents from  WW2 Pacific
> War, where US planes having made a discovery, in one account, of
> an enemy ship force, and the  second, of the Indianapolis survivors -
> and the planes then sent homing signals for other US aircraft...
> what frequencies were
> being used by the aircraft that was sending the homing signals?
All U.S. combat aircraft were equipped to DF on at least 200-400 KC.
Most could also DF on broadcast frequencies, but navigation 
beacons were 200-400 KC, frequencies a properly accessoried 
large transmitter such as the ART-13 or BC-375 could accommodate.
There was an accessory to make the ART-13
transmit in the BCB.  I don't remember if the GO series 
of large Navy aircraft transmitters could or not.

The fact that some *could* transmit DF signals 
in the broadcast band proves nothing about whether 
they actually did or did not do so. 
They most certainly had the ability to
send DF signals on 200-400 KC, and all aircraft had the 
ability to DF on those signals.  So what is the motivation
to provide this expensive extra system which gave 
no added benefit?  And if the MW ARC-5 transmitters were
specifically designed to send DF signals, why was not 
a model built that would cover at least part of 
the standard 200-400 KC band?  The design would work 
just as well there as at 1000 KC; that basic MOPA design
at LF goes back to the early 1920s.  So why,
if they were for DF, not build one for the standard DF band?

A gentleman on this group was around at that time and 
says the Navy used BCB frequencies for communications.
I have not one, single shred of evidence to tell him
he is wrong.  I don't know *why* they would do such a 
thing; contrary to what may be believed, the BCB was
quite crowded at that time and BCB stations were 
easily heard all over the Pacific.  My father listened
to KWKH in Shreveport, Louisiana most of the way to Europe.
Australia and Southeast Asia weren't exactly silent on the BCB.
Aircraft BCB DF used the existing, precisely located
broadcast stations for navigation.  And why would a
patrol aircraft generate a BCB DF signal, which would 
almost certainly be subject to QRM, when he could 
just as easily generate one on, say, 376 KC?
I could go on, but without hard documentation
we're just trading speculations.

> As for actual "broadcasts" from planes - this AFAIK is a Cold War
> innovation....
This past year I have collected another account 
from a WWII vet that broadcasting "give up" radio programs
to bypassed enemy garrisons was common.
I concede the stories are apocryphal and are not in themselves
conclusive evidence- 60 year old memories are misty things.  
But they do add their own weight to the continuing case.

> It seems to me the case is closed on why aircraft had transmit
> capability on LF and MF...
If I've learned anything in a lifetime of studying the 
history of these radios, it's that the book is *never* closed.
We are trying to speculate with our 2002 preconceptions
about the motivations of sixty years ago.
Unless and until one of us comes up with that magic 
piece of paper that says "We want you to build aircraft transmitters
for 500-2100 KC to do this job:", then we cannot say 
anything with certainty, no matter how much it may "make sense."
Remember it wasn't that long ago that the books were "closed"
on the notions that SCR-274N wasn't really used in combat 
and all mil gear are TVI machines.  
Both of those notions have proven to be hogwash.

I respect that your reasoning differs from mine, Hue,
and we both have honest reasons for our positions.
Until we have solid documentation one way or the other, 
we will just have to be content with our speculations.

73 Dave S. AB5S