Telefunken KTK 81 (ww1)

[RA3CC]

Gentlemen, could anybody tell me anything about the vintage crystal set that I have won on eBay a couple of years ago. The unit seems to belong to early XX century time period. The seller had no information of what it was.

The factory label says "Gesellschaft f. drahtlose Telegraphie m.b.h. Berlin" (i.e. Telefunken, Berlin) and "Type KTK 81" (why not "Typ"??):



Here are more pics of the insides of KTK 81:













And here is the KTK 81 schematic diagram that we have made:



There is a wire antenna wound around the wooden box of KTK 81, and the detector seems to be of the Perikon type where two crystals were squeezed together to form a p-n junction.

Any ideas of what purpose would this KTK 81 serve?

[Val]

There's in the Radiomuseum KTK81 entry. Unfortunately not
much info, only a guess:

"Gerät wird als unabgestimmter passiver Kontrollempfänger bezeichnet. Mit eingebauter Antenne und Ohrhörermuschel, um unmittelbar in der Nähe ausstrahlende Sender aufzunehmen (Schiffskapitän?)."

http://www.radiomuseum.org/r/gesells_dr_ktk81ktk_8.html

[RA3CC]

There's in the Radiomuseum KTK81 entry. Unfortunately not
much info, only a guess...

Know what, the RMorg info looks like a replica of the info from my museum site:
http://rkk-museum.ru/vitr_all/exhibits/923_e.shtml

I have compiled that text along with the "guess" around 2007 when I have got the KTK81. No new info for me, sorry...

[Val]

Telefunken catalog from 1919 lists that earphone type E.H. 141 on the page 13 by pdf reader and as it happens, today is also 13, friday.

It says "für Wellenmesser und Tonprüfer"

Also it lists two TonKontroller type KTK, on page 12 by the pdf viewer.

I guess your device is later.

http://www.cdvandt.org/Tel-Buch-1919-Teil2-5.pdf

[RA3CC]

Telefunken catalog from 1919 lists...

Val, thank you very, very much for the clue! Now everything is okay about E.H.141 Telephone, and about "KTK" prefix which stands for "Tone Controller".

Will now try to find some Telefunken info of 1920's. We have recently revised all my eBay book purchases of 2004-2008 and now have an Excel file of 2,300+ entries.

Today I have found two names in connection with Telefunken --- "Handbuch für Funkfreunde..." of 1927 and a sales catalog of 1931-32. On Monday will ask my guys to find those books on our museum bookshelves and see whether there is any info on KTK devices.

Will also expand the KTK81 description on our museum site and find some time to improve the radiomuseum.org information and upload the pictures of KTK81 there.

Thanks again for givihg me a hand on that misterious sample in our collection!

73 - Valeriy Gromov, RA3CC.