The objective of this project is allowing the Heathkit SB or HW transciever to send the current frequency to a computer, in order to use n1mm or other log programs.

Preliminary considerations.

The current frequency on the HW and SB series radios is calculated by subtracting the LMO and BFO frequencies from the HFO frequency.

I will use a microcontroller to do the counting, math and ci-v processing.

The microcontroller for the first testing is a PIC18F2520. This will present us with some challenges that I plan to overcome either with some logic or a different PIC in the future namely:

• Frequencies being read, this pic will not read more than 1.7 MHz directly, so, I’ll need a divisor.
• Number of external timers, only one is available, so I’ll multiplex the readings. (or use a different pic)
• Input sine wave, must be converted to a square wave to be properly read.

Bellow is a concept of the project.