Good Morning Andrey,
This 2-volume work is the only comprehensive source on the Luftnachrichtentruppe. It was published long ago and in very limited quantities so you may only find it in a few research libraries today.
Hoffmann, Karl Otto,
Ln: Die Geschichte der Luftnachrichtentruppe, 3 Bde (Neckargemünd, 1965-73).
Band II/Teil 1: Der Flugmelde- und Jägerleitdienst 1939 – 1945, c. 762 pages.
Band II/Teil 2: Drahtnachrichtenverbindungen Richtfunkverbindungen 1939 – 1945, c. 694 pages.
Other that this, there are some postwar studies of the Ln written by German Ln. officers and Allied officers for A.I.12 (Post Hostilities)/Air Ministry, London. These were in mimeograph format and never published, and today can be found in both the British and U.S. national archives.
There are also several websites that cover or deal with the Ln., including:
http://www.gyges.dk/ which is excellent and the product of fellow TOCH member SES (a retired Danish Air Force fighter pilot). You can search on the internet for the others.
Larry
