Partial answer dated 1941 for a recovered Me-109.
"The equipment described in the following article was installed in a German Messerschmidt 109 shot down over the Thames estuary. The aeroplane was shipped to the United States through arrangements made by Mrs. Winston Churchill, honorary sponsor of “Bundles for Britain.” Upon its arrival Lear engineers removed the radio apparatus, and the equipment was thoroughly tested by Mr. Lear in his laboratories at Lear Avia, Inc., Piqua, Ohio. A covering note accompanying the article says: “Mr. Lear's report on the German radio equipment stressed four points: (1) The Germans have apparently ‘frozen’ their military radio design since 1933, and standardized their tubes and components for ease of mass production and servicing. (2) Shortages of war materials are indicated by the use of ceramics instead of plastics, fibre instead of rubber and special alloys instead of aluminium. (3) The extremely limited range of the transmitter (around 5 miles) and the provision for higher power output, indicate that most German warplancs in a given squadron can talk only to one another, while only the leader can communicate with his base. (4) German aircraft radio apparatus found in the Messerschmidt cannot pass U.S. Government lest for even commercial radio equipment, and weighs more than comparable American apparatus.”
Source:
http://www.emeraldinsight.com/doi/pd....1108/eb030851
Ed