|MadSci Network: Engineering|
Well Michael, I started out thinking: 'This should be easy -just hit the boat people and you'll get what you're looking for.' By boat-people I mean model boaters. They have a lot of single and multi-channel add on devices. Soon I realized that if this was easy, you would have found it. Here is the long and short of it. If you operate within the allocated RC frequency bands, and you have a telescopic antenna, you can have more range. If you operate outside those bands, and you are limiting the size to a key chain size transmitter, your range is limited to around 300 feet - that's about how far you can throw a baseball. Recommendations: 1) Don't try to build anything yourself. Without proper test equipment and training, you will be throwing your money away on schematics and parts. 2) If 300 feet is good enough, then I recommend you visit http://www.mpja.com and look at their key-chain transmitter (Part#5713-MI $16), and their PC board receiver (Part#5715-MI $22). Or visit home security/automation sites on the web for similar transmitters. The above receiver is easy to set up for battery operation. It also comes with a relay that can be taken out, and replaced with the solenoid of your choice. 3) If you need more range, then I recommend you relax your requirements, and choose a normal transmitter-receiver pair. Tower hobbies offers a couple of two-channel versions for low $40's. I'm sure there are tons more out there. 4) With this last one, I may be over-stepping my ethical engineering bounds, but what the heck, I used to fly model airplanes and I used to shoot rockets off of the wings. Now that was cool ! (and probably illegal) If you happen to get a key-chain transmitter like the one I mentioned above, you can increase the range by reducing the emitter resistor. Once you locate the emitter resistor, get an exact duplicate of it, and attach it parallel to the existing one. That should do the trick and give you the range you need. Also, try e-mailing www.Micrel.com and see if you can get that transmitter/receiver set as an evaluation set (for a club project) - if they are in a good mood, they may give you a set for free. Off of the above topic, try this site as well, it may interest you in something else to do with aircraft. http://www.smarthome.com/images/7647ebdgm.gif Of course, it may be out of the budget, but it's still fun to look at. In conclusion, with my RC flying experience, if you drop a bomb more than 300 feet away, you are not going to see it anyways. The closer you are when you unload the cargo, the more fun it is. May the winds be kind to you, and the earth kind to your plane. Let me know if I can be of further help. Abtin Spantman SPANTMAN@EXECPC.COM
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