Hi,  me again.

I'm doing great guns in picking apart the practical issues of building a RC set. The  transmitter encoder is straight forward, and the receiver decoder is fairly easy to start with. I'm now ready to start trying some form of RF trails, but RF design is something I've only the rudimentry understandings in.

My main questions are geared towards building a low wattage (<500mW) transmitter which uses a removable crystal (27 or 40MHz) for frequency selection. The receiver would need matching capabilites (frequency modification via crystal subtitution) and AGC. I've a grasp on the concepts of FM Tx and Rx using PLL, but no practical experience. I have built my fair share of crystal sets, and so have an understanding of AM detection, but no experience using IF and subsequent mixers.

If someone has a URL for a "dummys guide to basic RF design" or something that would help (circuit diagram for RC Tx/Rx sets, or crystal based Tx/Rx pairs in the HF bands), I would appreciate it.
I'm using 27MHz and 40 MHz since they are the standard frequencies for RC cars in Australia. I plan on using crystals for RC cars (from high Q in Sydney) in my circuits. This way I'll be avoiding my experiments causing any issues with DOTC. My designs will use the RC methods of encoding to get the first iteration up and running. The next iteration will use the "data in" and "data out" lines of the Tx/Rx to transmit data from my microprocessor to a matching processor on the testbed.

If you want to send me stuff and avoid propagation the OTish nature of my request, please send info to des.bromilow@citec.com.au  but I think the circuits for a simple reliable short range (up to 1 km line of sight) serial data link with crystal frequency setting would be something most experimenters would have some need for.

Many many thnaks in advance,
Des Bromilow