Empfängerprüfer für Torn.Fu.b/f

Receiver tester (signal generator) for Torn.Fu.b1 or Torn.Fu.f

This device is very well descrbed on Dr. Arthur Bauer's site, but will also be given a few words here. This is the only device that has been found which tests the Torn.Fu.b1 or the Torn.Fu.f transceivers. Both of these transceivers have been produced since 1936/37. This test device is known to only have been manufactured in 1943, and in very small quantities. But this particular device was made in 1942. The question remains if there was an earlier device made for the same purpose.

The device in a closed position. Instructions read "When opening and closing, this side must be on top"



The device from another angle, showing the battery power connector. Size is that of a large stapler or tape dispenser.



Rear of the device.



The first side of the device when opened. On top is the part that gets inserted into the Torn.Fu.b1's bottom section, with the power connector inserting into the Torn.Fu.* receptacle, and the two pin connector inserting into the headphone socket. The signal cable is in very bad state, and will need to be replaced. It will be replaced with a similar shielded coaxial cable of the same color and dimensions. The grounding hook cable will also need to be replaced. Otherwise, the connector itself is in good condition.



Here both sides of the device have been opened and the cable removed. Now the instructions, and the meter panel can be seen.



Details of the meter panel. The year of manufacture is 1942, and the serial number is 492. Dr. Bauer's example was made in 1943, with a serial number of 520. It would be of interest to find more of these devices to get a better sense of the true number of units manufactured. Here is the meter, showing audio signal strength and a signal generator calibration control. Waffenampt 38.



A better view of the instructions, and cable storage section.



A better view of the transceiver interface.



Directions for Use


  1. Connect the test device to the transceiver as shown in the picture on the left, rotate the antenna mode switch to "Stab-Ant.", turn on the transceiver, check the operating voltages, wait 30 seconds.
  2. Receiver sensitivity test:
    1. Push a coin into the "HF Einstellung" control slot, and turn it until the arrow on the meter deflects to the green area on the left.
    2. Set the volume control on the transceiver to 50% of the Tg area (right side).
    3. Tune slightly around the specified frequency to the left and to the right until the meter deflects maximally with the loudest generated sound, with volume control adjusted to the green line.
    4. Set frequency to 5 deliniations; with the background (resting) noise, the meter must now deflect within the blue sector of the scale; then the sensitivity is sufficient.
    5. If the green line is not reachable in c) or when the resting (background) noise in d) exceeds the blue sector, then the receiver is not sensitive enough. Replace the vacuum tubes, and repeat the test.
  3. Receiver frequency test:
    When the generated tone in 2c) appears more than +/- 1 scale divisions away from the specified frequency, then the current calibration is not exact anymore.
  4. Transmitter output test:
    Set the transmitter to your favorite frequency, press the telegraph key, set the "Ant.-Abstimmung" control so that antenna current is maximum. Current must show at least 80mA.
  5. Transmitter frequency test:
    See Merkblatt D 940/5 and device description (D 940/3 for b1, D 940/4 for f) for these transceivers.
  6. Disconnect the power cable from the test device, to stop battery power consumption.



This is the age/environment damaged cable. Unfortunately, this type of damage is not restorable, and both cables need to be replaced.