80 W. S. a

(80 Watt Sender a - Telefunken)

The 80 W.S.a is a vehicular-type, medium-frequency, radio transmitter. Interconnections between the transmitter and receiver permit the transmitting antenna to be use for reception in the "off" and "standby" positions of the main switch. Both voice and telegraph transmissions are monitored by the receiver (Mw.E.c, Torn.E.b and Lw.E.a).

The transmitter is enclosed in a metal casing. A brass strip, approximately 2 cm wide and 24 cm long runs from front to back on each side of the top of the metal casing and insures good ground contact with the metal frame into which the casing is fitted in the vehicle.

Eight controls on the front panel are:

  • 3-position band switch
  • Main tuning knob
  • 5-position antenna coupling knob
  • 5-position antenna tuning knob (coarse tuning)
  • Continuously-variable antenna tuning knob (fine tuning)
  • Frequency check switch (thrown by raising the lid over the headset jack which is used during frequency calibration)
  • 4-position main switch
  • Output power decrease switch (from 80 to 10 Watts)

The telegraph key is inserted in the two-contact jack at the extreme lower left corner of the front panel and the microphone plug is inserted in the three-contact jack beside it. The frequency dial is calibrated in kHz and is numbered every twenty kHz. The dial is illuminated by a blue pilot light which is removable through a spring-hinged lid in back of the dial.

For telegraphy operation, the key completes the circuit to a 12 volt relay which in turn by-passes to ground the excessive grid bias applied to the grids of the RF oscillator and the RF amplifier tubes. In telephony operation, the suppressor grids of the RF amplifier tubes are modulated. A pair of RV12P2000 tubes in parallel acts as a single speech amplifier with transformer input and transformer output.

 
Specifications
 
YEAR INTRODUCED :
1938
   
MANUFACTURER: Telefunken
   
FREQUENCY RANGE:

1.12-3.0 MHz in 3 bands as follows:

  • 1.11-1.55
  • 1.53-2.15
  • 2.13-3.01

NUMBER OF CRYSTALS:
None

PRESET FREQUENCIES:
Two with click-stop settings

ANTENNA:
Stationary, 8-meter vertical mast with star capacitance hat; mobile, vehicular rod or roof antenna.

TUNING:
Master Oscillator = ganged tuning of RF oscillator and RF amplifier.

SENSITIVITY:

SELECTIVITY:


POWER SOURCE:

Dynamotor U-80a with output of 800 Volts, 0.3 Amperes and 240 Watts;

Motor, input 12 Volts , 35 Amperes and 420 Watts and biasing voltage of - 300 volts, 0.005 Amperes


SIMILAR SETS
30 W.S.a, These two sets are similar in design and identical in operation. The American sets SCR-177, SCR-188, SCR-193, SCR-197, SCR-299 cover the greater portion of the frequency range of the 80W.S.a and have comparable transmission ranges.

POWER OUTPUT:
Either 80 or 10 Watts

TUBES (TYPE and NUMBER):

6. Three RL12P35 (35 Watt pentodes) and three RV12P2000 (knob-type pentodes). One of the RL12P35 pentodes is in a tuned grid oscillation circuit which is capacitatively coupled to a pair of the same type tubes in parallel as an RF amplifier. This RF amplifier has a tuned grid circuit. Two of the RV12P2000 tubes are used as speech amplifiers and the third as frequency check oscillator which can be put into operation only when the main switch is in telephony position. The filaments of all tubes are connected in parallel. The cathodes of the RV12P35 tubes are connected internally to the metal bases of the tubes.


USE:

In tank division and tank brigade radio sets especially in liaison operations with reconnaissance cars and tanks. It is replacing the 30W.S.a in the German Army. German receivers appropriate for use with this transmitter are types Torn.E.b, and Mw.E.c.


TYPE OF SIGNAL:
CW and Voice

RANGE: (MILES)

At 10 Watts, 10 to 30 miles (stationary), 5-15 miles (mobile); at 80 Watts, 40-100 miles (stationary), 20-50 miles (mobile) (Estimated figures -- lower distance using voice)


TO COMMUNICATE WITH:
8 W.S.a, 30W.S.a, 100W.S., American SCR-177, SCR-188, SCR-193, SCR-197, SCR-299 cover the greater portion of the frequency range of the 80W.S.a and have comparable transmission ranges.

TO REPLACE IN PART: 30W.S.a and 100W.S.
   
TRANSPORTATION:
Armored command car or reconnaissance car.
 

THE PREMIER MANUFACTURER

OF PANZER RADIO EQUIPMENT

 

 

Front of the transmitter.

 

 

Cover off - closer view.

 

 

Data plate and Waffenamt stamp.

 

 

More signage.

 

 

Top of the case.

 

 

Marking inside the case.

 

 

View from the top.

 

 

Left side.

 

 

Right side

 

 

Photo from below.

 

 

Cable connection diagram which includes the 80W.S.a

 

 

1. Simplified Schematic

The numerals identify the part numbers in the schematic (see exhibit 4)

High-frequency section:
The high-frequency oscillations are generated In the oscillating induction coil. The oscillating circuit is comprised of spool 66 and variable capacitor 62. The reverse feedback voltage from the cathode current flows through spool 67 and is made inductive through spool 66 of the control grid of the oscillating tube 5. When in a non-keyed state, the generating tube is locked in with highly-negative bias voltage. This voltage is delivered from the Umformer through resistor 39. As long as key 177 is closed, the blocking voltage of the oscillator tube passes through resistor 39 to ground through the activation of relay 96. The bias voltage is driven over resistors 45 and 47. The control grid of the oscillator tube 5 is capacitively coupled through capacitor 48 with the oscillating circuit. Simultaneously, it serves as the high-frequency bridging capacitor for resistor 47. Capacitor 46 removes unwanted high frequency to ground from the control grid circuit. The screen grid voltage of the oscillator tube is taken from voltage dividers 25/26. The anode voltage is driven through resistor 24. The voltage supply is filtered for high frequency with capacitor 27 to ground.

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

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