Saturday, 19 April 2014

Experimental Gate modulated 48 Metre transmitter

Below is a experimental variation of the Corsair circuit. Instead of series modulating Q2 and using the final Q3 stage as a linear the gate of Q3 is modulated by by the output of IC1 the LM386.
You must use the 7808 voltage regulator otherwise the voltage to the gate of Q3 will exceed the safe level and destroy it.
If you already have a Corsair built, altering it to this circuit is easy.
If you build this please leave a comment letting me know how it went for you.
The original Corsair circuit is HERE.

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Below is a video of what a test transmission from the above circuit looked and sounded like received locally.

Dave Martin.

Toroid Ready reckoner

Ever needed to know how many turns on a toroid will give the required inductance?
Well below is a Ready Reckoner for just such occasions.

 Click on picture for large size.
Or right click to save.

Dave Martin.
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