Tuesday 16 June 2009

The Commando Transmitter by Dave Martin.

The "Commando" is the higher power,high level modulated version of the "Corsair"
and was designed by Dave Martin in 2003.

Below is the circuit for the basic 48M version.
The table below it gives the changes that are needed for other bands.
(Click on pictures for larger size.)
Commando TX

Next is the circuit for the modulator, it is based around a
TDA2003 stereo power IC running in bridge configuration.

The Transformer, AL21219 above, is from a PYE Westminister W15AM PMR set. It may be available from "Garex" . As an alternative you may construct your own using a small transformer such as mains to 12v 1amp.Remove all the original winding and wind the primary with 80 turns of 24 SWG enamelled wire, this will be the audio side that connects to the TDA2003's pin 4's. The secondary winding is 180 turns of 22 SWG enamelled wire,
this is the side that gives the modulated VDC.

The above modulator is
needed if you intend
running portable with a 12 Volt car battery.
If you are to run from hom
e with mains AC you can
construct the series modulator below instead.


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1 comment:

Mike Brain said...

Unfortunally it isnt possible to get the origin transformer anymore. It would be great if you could announce a similar type. Keep up the good work...

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