Digital IC QRP TX

Submited By Nadisha 4S7NR

Lew Smith - N7KSB's experimental W CW Transmitter uses a 74HC240 high speed CMOS octal buffer. One section servse as a crystal oscilator; four sections amplify the signal; three sections are not used. IC dissipate about 900mW it needs a heatsink. Make sure you use a voltage sorce of 7.8v to 8.0v to power this single chip transmitter. If you wish it can directly drive a power mos fet to get about 10-15W output.

All coils are wound on3/8 diam form air core. Use no 14 wire. This can be modified to work on 40m and 80m band, any ideas?


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