FM Crystal Controlled Transmitter DPT

Posted on Feb 6, 2014

The DPT Transmitter is a dual powered Voice Transmitter that came about from quite a few request for a transmitter that would function both at power when long range was needed and with a `switch that could be thrown` for a smaller battery consumption when longer battery life was required. It operates in the low power range of 100 MW and at the hig

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h power range of 250 MW. Frequency of operation is in the upper to high VHF range. This circuit uses a 5th overtone crystal. Example: If I used a crystal with a cut of 79. 25 Mhz - My end frequency ( Transmit ) would be 158. 5 Mhz. The circuit incorporates a X2 multiplier. Order your crystals - for a custom frequency at: 1/2 of your desired transmit frequency - SPECS: series resonance / 5th Overtone /. 001% Tolerance / and then specify you choice of crystal design, I. E. - various sizes. Order your crystal at 1/2 of the frequency of your desired transmit frequency! This circuit is fully functional from 150 to 170 Mhz. any small on/off type switch will do. When the switch is open, the transmitter has an output power ( R. F. Transmit ) of 100 M. W. When the switch is closed, the unit transmits an output power of 250 M. W.

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