Short Wave Adapter WM-20

• alternative name: Hitachi Sales Corp. of America

Short Wave Adapter WM-20 receives 90, 60, 49, 41, 31, 25, 19, 16, and 13 meter bands, and converts them to the Medium Wave band.  The Adapter is connected between the car aerial and the existing car radio receiver, and in conjunction with the receiver forms a double superheterodyne system.  During operation, the receiver used with the adapter is switched to the Medium Wave band, and the required station is then tuned in with the manual tuning control of the receiver.  Operation of the OFF button de-energizes the Short Wave Adapter but leaves the car radio receiver operational.  Two slide switches are fitted on the underside of the adapter, and can be set for Positive or Negative ground, and 6V or 12V battery supply. 

The Oscillator stage uses a 2SA351 PNP Germanium transistor, while the Mixer stage uses a 2SA350 PNP Germanium transistor, both operating internally with a Zener limited/stabilized 6VDC power supply. The current consumption of the unit is just 6mA from a 12VDC supply.

Here you find 1057 models, 947 with images and 242 with schematics for wireless sets etc. In French: TSF for Télégraphie sans fil.
All listed radios etc. from Hitachi Ltd.; Tokyo