Balloon telemetry data using radio teletype or RTTY (Baudot)

[johnmaetta]

Hi Mike,

It doesn't take too high of a step to "go over my head". Anyway, I am using the 16F648A and I am not sure about DDS and PWM, but I did see that some people generate sine waves with PICs. I recall seeing a PIC schematic with four resistors bridging four PIC output pins. Then I believe each pin is pulsed in sequence with varying amplitude while being swept over time. Is that the premise?

I want to learn...

73

John
N6VMO

[Dave]

johnmaetta, Why not just use a 10F222 to generate the frequency's with a fiilter? That saves a lot of parts and board space. A couple of years ago I used one to generate a 125khz carrier to send temperature and depth data to the surface from a device towed by a boat to emulate a cannon ball for Salmon fishing.

Dave Purola,
N8NTA

[johnmaetta]

Thank you to all who made suggestions and provided me help. Here is the prototype PIC RTTY Telemetry project:

http://www.n6vmo.com/PIC/SARCHAB7.zip