Quote Originally Posted by Squibcakes
I've been using the 433Mhz UHF transmit / receive modules for serial data, and that works quite well for CW modulation.

To improve the range, I am thinking of sending data using VHF, by sending serial data into the mic af, and keying the radio before transmission.

Has anybody done this before, and what type of results did you get?


Cheers
J
A few years ago, I bought a truck load of Motorola P10 modules. They are single channel NBFM modules about the size of a small cigarette pack transmitting in the 458 MHz range. With one watt of output, and a sensitive receiver strip, I routinely ran links out to a mile or so from simple whip antennas. I used a FSK scheme with the transmit frequencies generated by a PIC, and at the receive end, a XR2211 FSK demodulator. It worked incredibly well, and my client even wrapped the antenna lead around a 2 gig 250mW transmitter antenna with no loss of range. The modules run around $50.- each, but even if you don't use them, use the FSK mode of comms. It is much more reliable. Also, your transmitter and receiver can drift somewhat with no deliterious effects.

Ron