33a) German radio-link equipment
33b Carrier frequency equipment
k61 Richtfunk-Verbindungen

SEG2T/DMG2T 475MHz to 525 MHz "Elster" RL-transceiver



DMG2T early radio link transceiver. It has the following valves 2x DS310, 2x RL2T2, RV2P800
DS310 is an odd type acorn valve, same base as 955 =typ4671 and 958, but it must draw 20mA, so
non of the actual replacements will give much result in the receiver, 6F4 has a different socket.
RV2P800 is triode-connected for a mysterious reason , and could well have been RL2T2 instead

Lt. Henning, The High-Frequency War mentions on pg.78 the
60cm Emergency Transmitter
Type SE54231 Lorenz (at Agerholm, Denmark)
From the picture I cannot see any difference from SEG2T/DMG2T

SEG2T Betriebsanweisung

Norbert Cajumi writes:

Got my SEG2T working again after 50 years, and it still works fine.
The frequency range is, as you mentioned, really from about 475MHz to 525 MHz.
At WW2 they called it the 60cm wavelength range. The output power is about 80 mW
into a load of about 600 Ohms. The Chireix Mesny antenna represents a very high
impedance load. An alternative solution would be a full wave dipole (high input
impedance, too) is also working very convenient.

Measurements.
The measured receiver sensitivity was really a surprise to me: 1µV into 50 ohm (with
an adequate transformation up to 600 ohm) for a readable signal and about 100 µV for
an absolutely noisefree signal! I think, it has been an outstanding transceiver during WW2.

have enclosed some pictures (and three audiofiles). and some pictures of the transceiver itself.
The audiofiles are recorded at some different inputpower situations to show the sensitivity of the rig
(f.i. -107 dBm equals 1 µV at 50 ohm). I hope, it will be of some interest.
(received wav-files, but may consider them later for the page, last week it was visited by 18).

Reference:
Die deutschen Funknachrichtenanlagen bis 1945, Band 2 [Fritz Trenkle] pp.122-125

SEG2T Type plate.

Spectrum measurement of SEG2T transceiver.
The pictures show the measurement of the transmitting spectrum (more than 1 MHz bandwidth!),
the spectrum at the antenna input, when the SEG2T is operated in receiving mode (-30 dBm at the antenna connectors!)

RX spectrum no input signal	RX spectr/-70dBm sig, 2MHz/division
TX spectr. 500MHz, 200kHz/div	TX spectrum 500MHz, 500kHz/Div

TX/RX-section of the transceiver

1) The transceiver seen from above. 2) TX current meter deflection

RL2T2

DS310

NTG2 (Netz Gerät Zwo)
It is supposed to be an AC operated remote control unit for the SEG2T/DMG2T radio link transceiver.

Bought the NTG2 from LA1II in 1963 as a power supply for Kw.E.a

The picture was taken with telegraph relay Trls43a removed from its socket



4ba.jpg The picture shows different variants for German telegraph relays. Trls43a was found in NTG2, but I haven't the faintest
idea where Trls44a has been used, found it at work amongst a lot of old components, so it may have been used for telecommunications

Unit from DMG5 "Michael"

See 33b for carrier frequency equipment

Richtfunk-Verbindungen für den Flugmeldedienst in Süd-Norwegen im Mai 1945

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last update: 2004.04.03