The simple answer - unless you are very experienced in analog RF design - is BUY IT. It is one thing to build a small short-range transmitter-receiver for experimental work around your lab, but the approval process you would need to go through to be able to SELL the product would be prohibitive in the extreme. With spectrum space as scarce as it is these days the international governing bodies are very strict about what is allowed to broadcast. There are a few blocks in the microwave area which can be used by individuals (garage door/car door openers and the like) but even they must be type approved by the FCC. Anything which could work over a 2 km range would use more than the allowed output power and or have a very state-of-the-art receiver. Roy J. Gromlich (once WA2CMB, and an analog circuit designer) ----- Original Message ----- From: "Josh Koffman" To: Sent: Saturday, January 10, 2004 7:03 PM Subject: Re: [EE:] 2km UHF transponder ideas > I don't know that much about making your own RF stuff. If you have the > budget, I'd suggest using premade modules, unless you have a particular > need for space or tight integration. In either case, a good book might > be the ARRL handbook. I believe their website is http://www.arrl.org. > It's a pretty good reference on many things RF. > > Hope that helps. > > Josh > -- > A common mistake that people make when trying to design something > completely foolproof is to underestimate the ingenuity of complete > fools. > -Douglas Adams > > Rob Stockley wrote: > > Trouble is I don't know where to start :( > > > > I'm comfortable making my own PCBs and programming PICs but don't know > > much at all about RF circuits. Would someone care to point me to a good > > starting point? A website or a readily available book would be nice. A > > similar project I could examine would be even nicer :) > > -- > http://www.piclist.com#nomail Going offline? Don't AutoReply us! > email listserv@mitvma.mit.edu with SET PICList DIGEST in the body > -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email listserv@mitvma.mit.edu with SET PICList DIGEST in the body