[Milsurplus] tank radio skip?

[Bob Camp]

Hi

The State Police radio experiments are pretty well documented. The main  
reason is the involvement of Dr. Dan Noble in the experiments. He went  
on to be the "father of Police FM" at Motorola. He was still talked  
about in hushed tones when I was there in the 1970's. The experiments  
started out on AM and moved fairly quickly to FM. The Police were set  
up with both kinds of radios (as in my CT Police Super Pro's). It is  
conceivable there could have been a connection.

Again there may be several versions of this story so the one I read may  
not be the one that everybody else has read. The one I saw described  
*daily* traffic intercepts running for several months. I have spent a  
lot of time on six and ten meters over the years and yes they do open  
up. Daily openings over that range during a sunspot down turn are  
something I have not seen ....

I don't doubt that the Brits could have had trouble with US hams in  
training before the war. The prior sunspot cycle crashed in 1939. The  
summer of 39 probably was a good time for skip at these frequencies.  
The summer of 1940 may have been ok, except the Germans were not in  
North Africa in 1940. The main action in North Africa was in 1941 and  
1942. I find it a bit of a stretch to read the charts as "vhf friendly"  
by summer 1942.

That said here are a couple of web references:

http://www.mindspring.com/~cummings7/chop.html - the reference is to  
strategic communications (I read that as HF not VHF) in North Africa.

http://users.pandora.be/dave.depickere/Text/sasraids.html - The top of  
the list for SAS targets in  late 1941 was radio intercept stations  
....

http://www.defence.gov.au/news/armynews/special_elements/on_this_day/ 
july.htm July 9 1942 - It's the Aussies that grab the intercept unit.

http://africanhistory.about.com/library/prm/bldesertfox1.htm - Mainly  
deals with an American lapse, but talks about the VHF intercepts  
towards the bottom of the first page and then again at the bottom of  
the second page.

http://stickymedia.com/Scripts/rommel.htm - see "act 3" - directly  
refers to VHF intercepts. ...  coming to you soon on late night cable  
TV ....

http://www.iwm.org.uk/upload/package/21/creteegypt/standegypt07.htm -  
Just in case you had any doubts that it was the Aussies that saved the  
day.


a couple of random book titles that would be interesting to track down:

Macksey, Kenneth, The Searchers: Radio Intercept in Two World Wars

ALLIED AND AXIS SIGNALS INTELLIGENCE IN WWII,  David Alvarez, C

That's just a quick web search, but I think it pretty well supports the  
fact that the Germans did have some pretty effective signals  
intelligence work going on in North Africa for a while.

Now for the only really interesting question - What kind of gear did  
they use?

	Take Care!

		Bob Camp
		KB8TQ


On Jan 29, 2005, at 10:08 PM, Hue Miller wrote:

>
> ----- Original Message -----
> From: "Bob Camp" <ham at cq.nu>
> Subject: Re: [Milsurplus] tank radio skip?
>
>
>
>> 1) There is repeated reference to the German efforts at intercept in
>> North Africa. ...There > are both German and British sources to back  
>> this up.
>  It'll take me a  while to dig them up but I probably can.
>
> I have somewhere a book on this subject alone, from the Afrika Korps  
> perspective,
> in German...dunno where it went during my recent move....I'll give the  
> title (again)
> when i recover it....
>
>> 3) One version of the story has a connection between the Connecticut
>> State Police VHF radio experiments tying into the intercept plan.
>> Another version has a couple of hams picking up the signals.
>
> I'd suggest the SWL scenario more likely. I suspect at this date the  
> Police Dept.
> experiments were with FM, since low-vhf police radio was already well
> established. Plus crystal-controlled receivers. The tank equipment was  
> all
> vfo'd, and no doubt frequencies frequently changed.
>
>> 4) Like it or not propagation is affected by sun spots. If you check
>> out the period in question it was not anything like a sunspot maximum.
>> That does not say that the contacts were impossible, only that they
>> were a lot less likely.
>
> Nevertheless, there have been a good number of vhf dx contacts during  
> 1939-1942.
> Like in 1940, coast-to-coast on a walkie talkie ( SCR-194 ).
>
>> 5) Unlike our new friends the Germans didn't seem to think that a
>> couple of KW of RF was needed for tank to tank communications. What
>> ever they were doing, it was with low power sets.
>
> Actually, in terms of radiated power, the output of the German vhf  
> tank sets
> and the English HF equipment, the German radios probably radiated more,
> for dx work, but for close in, i suspect the greater ground wave of  
> the English
> HF equipment reached out more. The German radios were rated at about  
> 5, 10,
> and 20 watts output depending on set. The 19 set, i dunno exactly,  
> maybe input
> 15 watts, then thru a highly inefficient bottom loaded whip, with a  
> shielded
> load coil!,  operating somewhere between 80 and 40 meters,  
> approximately.
> ( An additional feature of the UK tank equipment: you could listen to  
> the BBC
> and whatever else, after working hours. )
>
> I recall reading, i think it was in Short Wave Magazine ( U.K. ) that  
> in an early
> battle, this before the US entered the war, U.K. tanks received QRM  
> from US
> stateside hams! -Hue Miller
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