From: pierson@empror.enet.dec.com (dave pierson)
Subject: Re: Was RADARs' impact on the Battle of Britain overstated?
Organization: Digital Equipment Corporation
Date:  4 JAN 93 17:47:56    

In article <1993Jan4.191812.25928@cbnewsi.cb.att.com>,
acura@cbnewsi.cb.att.com (james.r.feeney) writes...
>A friend was telling me about a book he read that described the exploits of the
>British code-breakers during WW2. One of the things he said was that this 
>group had broken most of the German codes including the first generation
>ENIGMA by the end of the battle for France (a substantial amout of help came
>from anti-nazi German military personnel).
	This does not match what i have read.  Hut Six Story, Gordon Welchman,
	for one (one of the persons involved in the operation) indicates that
	they were lucky to be only 24 hours behind in the decryptions.  In any
	case that might be for one or two nets, not "all".  There might be days
	when they were doing well, against paticular nets, usually due to
	operator error (called "sillies": picking "keywords" like AAAAAA,
	ferinstance.).  The days would go by with little result.  The consistent
	performance during Battle of Britain indicates, to me, that the RADAR
	with its consistent performance, was a key player.

	The ENIGMA story (summarized, from multiple books):
	ca 1935, a commercial machine goes on sale
	ca 1938, the Germans ship one in the diplomatic bag to their Russian
	embassy.  The Poles engage in "practical cryptography": steal the
	******* machine, copy, reship.  The Pole's do brilliant work in figuring
	out how to break traffic.
	ca 1939, Poland falls, Polish experts evaxuate to France, Then with
	the French to Britain.  The British build up an organization to
	gather the traffic, figure which is worth attacking, and break the keys,
	all of which leads toward the computer...
	In parallel the Germans are making things difficult (The Navy used
	extra wheels, everybody changed keywords more often) and easy: the
	sillies, losing a Uboat with engima, in shallow enough water for the
	British to recover, etc...

> This was such a closely guarded
>secret that the British went to great lengths to conceal it from the Germans.
>Apparently once the Battle of Britain began the British were intercepting the
>very attack plans that the German bomber crews were getting, including
>evasion and diversion tactics. This was what allowed the British fighter
>groups to attack so efficiently. The quality of the RADAR at that time did
>not provide anywhere near the definition required for the precise defence
>tactics that the British used. However the RADAR network was given exclusive
>credit as a cover to the real source of information. This is one reason why
>the German attempts to confuse the British to the targets selected usually
>met with failure.
	Perhaps.  But the British also spent a lot fo time lying about the
	RADAR, to keep the Germans from knowing how effective it was.  In any
	case, some of the radar was capable of great precision, being usable for
	gunlaying (used, forinstance, in the cross channel duels of the coastal
	batteries.).

	There was never just one sort of radar.  While the Chain Home sets may
	have lacked ultimate precision, other fighter control radar was
	available, and being constantly added to.

	As important as the radar, in any case, was the technique of timely
	reporting and control, centering around the "filter centers", so that
	the radar data could go to the fighter controllers could be useful.

>Has anyone else heard of this? I always thought that it was the British RADAR
>network that saved them but it always seemed a little strange that the Germans
>were unable to counter this as the British and later the Americans were able
>to do.

	The Germans were on the offensive, originally, and had not perhaps
	thought defensively.  They were also fooled into thinking that the
	UK radar was less effective than it was.  (one story has them using
	their last airship (Graf Zeppelin II) on a ferret syle mission, ca 1938.
	The British carefully kept the radar off mostly and, in any case, the
	search receiver was later determined to have broken down.  Noone on
	board would admit it, so they just reported nothing found.)

	By the time the US and UK were firmly on the offensive, folks had
	figured out lots of nasty, offensive things to do to air defense radar,
	and had the time and resources to employ WINDOW, jamming, etc... and to
	the radar system (having german speaking (mis) controllers on the
	fighter control frequencies, etc.)

thanks
dave pierson			|the facts, as accurately as i can manage,
Digital Equipment Corporation	|the opinions, my own.
40 Old Bolton Rd		|I am the NRA.
Stow, Mass, USA	
01775				pierson@msd26.enet.dec.com
"He has read everything, and, to his credit, written nothing."  A J Raffles
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