Corsair and Commando TXs

Posted on Feb 5, 2014

All about the famous Corsair and Commando Transmitters designed by Dave Martin of WNKR. This blog will show you how to make each of the transmitters and show you examples that other people have made for them selves. The circuit below is basically the first 2 stages of a Corsair, it must be noted that there is no low pass filter on the output. You s

Corsair and Commando TXs
Click here to download the full size of the above Circuit.

hould add one as even at these low powers harmonics can be a problem. A suitable filter will follow. 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, A LM386 audio IC is used to series modulate Q2. The LM386`s output on pin 5, sits at half the supply voltage. But is swung plus and minus with the audio being fed to it`s input. In the high current version Q4 allows Q2 to draw more current without damaging the LM386. The PA, Q3, is a IRF530 which is configured as a linear amplifier. To set up you should, by adjusting RV2, set the DC voltage at TP1 to 2. 5 VDC. Then by moving the turns on L6 further apart or closer together, get the RF power to read 10 Watts. It must be noted that Q2, Q3 & Q4 must have heatsinks and that Q3 & Q4 should be mounted using a TO220 insulation kit.

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