[Milsurplus] Signal Corps Info Golden Nuggets.

[Hue Miller]

----- Original Message -----
From: David Stinson <arc5@ix.netcom.com>

> 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.

My turn to forget, but wasn't this tuner covering LF and MF both.
Didn't
the ATC/ ART-13 only tune 1.5-18.5 without it? Maybe i'm wrong.

> I don't remember if the GO series
> of large Navy aircraft transmitters could or not.

GO had 300-600 kHz on the LF side, A1 and A2.

> The fact that some *could* transmit DF signals
> in the broadcast band proves nothing about whether
> they actually did or did not do so.

This is true, but we are back to the fact that the gov't provided
LF AND MF transmit capability to many - larger - planes.

> 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?

Was the extra TU for the BC-191/ 375 or  GP that expensive?

 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?

I don't know. "Perhaps" some class of plane that carried no
larger transmitter, needed DF capability. Perhaps coils would
be too large and high voltages too high in the 'Command Sets'
package. Purest guesswork on my part here.
>
> 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 think he would have to convince me too.  Claims require proof,
not disproof. ( That should apply to EVERYTHING. )

 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.

At night, Dave. You have driven thru the Southwest or Mountain
states and experienced that on the AM band.

> 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 don't know. But 376 kc is about 900 meters wavelength, 1000
kc would be 300 meters wavelength. Makes the reel antenna
quite a bit more efficient, loading coils smaller, HV on the
antenna leadin less.

> 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.

That would involve a choice of radio frequencies.  Do you try to
reach civilians,   or military?  If civilians, why? If military, what
freqs do you choose? The panzer frequencies, around 9 meters?
The troop mobile radios, around 3 - 7 MHz? The command tank
and scout car frequencies, around 1 - 3 MHz ?

I have a 'yearbook' type book from a US broadcast group that
travelled by truck convoy and made mobile broadcasts by a
1 kw broadcast band transmitter. Never thought about "surrender"
messages before, i'd always thought this was a pure news and
propaganda mission, but maybe this group was involved in such
"surrender" broadcasts, or maybe this group was the  genesis of
such stories. Wasn't there a case, up near Calais, where a German
stronghold was persuaded to surrender by radio broadcasts? Thot
i'd read about this in Pop Com. In any case, i'm sure the latter was
NOT effected by aircraft radio broadcasts - and i think i remember
the article saying as much.  BTW, how long would a WW2 broadcast
equiped aircraft stay aloft? Because you want to be repeating the
message for a while. This work would require native - language
speakers too.  Strange that such an interesting story never made
it out?

> 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."

Dave, we can rule out some nonsense with not too much work.
Remember the idea that the LF command sets provided
compatibility to the Rejkjavik airport?
Further, even if the "Command Set" or other LF/ MF transmitter
was used once or even twice to broadcast surrender
messages, that surely was not the envisioned intent, do you
imagine? That the many LF/ MF transmitters were provided
to have this capability? That's many thousands of transmitters.

BTW, 600 meters / 500 kHz seems easy, a giveaway. Seagoing
ships would DF on this. If an aircraft were lost,  searching for a
ship, or in distress and going down, being able to transmit 600
kHz, over sea,  would seem to  be very useful. I note that one
Command Set covered this wave, also the GO included it at
the high end of its LF coverage. 800- 1300 kHz in a Command
Set would seem more difficult to explain, altho if you want to
reach an enemy  population, or even military force, in this band,
you would probably want to include the 1300 - 1600 kHz top
end of the BC band, and also the 1600 - 3000 kHz used by
many German and Japanese tactical radios.

> 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.

Okay- i will be interviewing a couple Navy A/C radiomen this year,
will see what they have to say about this.
BTW, i enjoy these go-rounds greatly.
Regards, Hue