alternatehistory.com

http://www.armchairgeneral.com/radio-kills-rommels-621st-radio-intercept-company.htm
A German platoon detached at Tobruk achieved success in May when a decoded message told of the breakout routes that an Allied unit was going to use. That unit suffered heavy losses when it tried to do so.
The intercept platoon rejoined in late June. Seebohm positioned both intercept platoons barely a half mile behind the front line at a place called Tel el Eisa. The site was on high ground, great for intercepting and for communicating with the evaluation center and the liaison team with Rommel.
The British took notice of the unit, with air reconnaissance flying over its position. They also intercepted and decrypted the Enigma traffic between the unit and the evaluation center. The British became aware of the company’s mission and planned a raid.
Australian troops led the raid on the night of July 10th. Italian troops co-located with the intercept platoons fled. Seebohm happened to be visiting the platoons at the time. Both he and his unit fought as best as they could, but rifles and machine guns were no match for tanks.
Seebohm was wounded and died soon after. Seventy-three men of the intercept platoons were captured, along with their equipment and a treasure trove of documents detailing what the unit had done.
So why didn’t they flee? Seebohm had been dressed down by a colonel when the unit had previously pulled out of a position. The colonel did not know the unit’s mission, but Seebohm vowed that it would not happen again. Any really safe position would not have been as effective an intercept position, either. Rommel was furious that the unit had been wiped out.
The loss decimated the 621st. The equipment and men were replaced, but they simply were not as experienced as the original intercept crews. Equally important, the British were completely aware of their vulnerabilities and made further radio security changes. They started with a week’s radio silence.

https://en.wikipedia.org/wiki/First_Battle_of_El_Alamein#Tel_el_Eisa
Possibly the most important feature of the battle, however, was that the Australians had captured Signals Intercept Company 621. This unit had provided Rommel with priceless intelligence, gleaned from intercepting British radio communications. That source of intelligence was now lost to Rommel.[69][70]

A major source of Rommel's success in the Desert Campaign was intelligence both from SigInt and the breaking of US diplomatic codes; both sources were lost during 1942, the former with Radio Intercept Compnay 621 being captured on July 10th after failing to pull out when their Italian co-located defenders retreated. What if they had pulled out and not been captured? Would they have made any difference in the coming battles?
Top