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E-638
Telefunken E 108 Lw/4
Telefunken, Ulm

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überarbeitet am 21.4.2012

The Telefunken E 108 Lw/4 is a very heavy and bulky VLF / mediumwave receiver mainly used for maritime and point-to-point communications constructed in the fifties - a few samples seem to have served with the Swiss Army.

Double conversion, 1st I.F. 80 resp. 320 kHz, 2nd I.F. 525 kHz

linear Analog dial, 2 kHz

AM, CW, SSB (with optional BP 102)

10 - 1800 kHz

Sensitivity
CW < 0,3 - 0,5 uV for 10 dB S/N

Selectivity -6 dB
9 / 3 / 1 / 0,2 kHz

RF-Gain, three speed AGC, crystal calibrator 20 kHz in the ranges 1, 2 and 200 kHz in the ranges 3 - 6

The VLF - mediumwave receiver E 108 covering 10 -1800 kHz in six ranges is a very near relative to the Telefunken E104 shortwave receiver with a similar design.

This receiver is extremely bulky and heavy, it's 555 x 480 x 590 mm wide and in it's desktop cabinet, the receiver has a weight of 75 kg - this will be the reason, many of the receivers have been cleared out.
The receiver can be powered from different AC voltages from 110 to 240 V.

The top third of the frontpanel is taken by the linear dial.
In the left lower quadrant of the front panel, you find the rotary controls in three rows: the BFO control with it's +/- 3 kHz range, the crystal calibrator switch and the reception mode selector combined with the mains switch. In the middle row, you find the control to adjust the level of the line out output and the AGC time selector and in the bottom row the bandwidth selector and the controls for audio and radio frequency (RF Gain) gain.
In the right lower quadrant of the receiver's front panel, you find the signal strength meter which can also be set to display the AF level. Below, You find the main tuning knob (with a coarse and fine tuning speed) and the rugged bandswitch, underneath an antenna switch to change from a long wire and 60 Ohms coaxial antenna to a DF frame antenna.

The receiver acts as a double conversion receiver with a first I.F. of 80 kHz in the ranges 1, 4 and 5 and 320 kHz in the ranges 2, 3 and 6, the second intermediate frequency is 525 kHz, the same as found in the E104 shortwave receiver.
After having passed the I.F. filter bank, the signal is fed to the AM detector, a BFO can be used to receive CW and single sideband signals.

There has been an optional FSK demodulator Fs Tg 127 for the reception of radioteletype signals and a BP 102 single sideband demodulator to match the E 108.

© Martin Boesch 21.4.2012