MadSci Network: Engineering

Re: Where can I find a small hand held transmitter with at least 1000 ft range?

Date: Tue Oct 10 01:36:32 2000
Posted By: Abtin Spantman, , Electrical Engineering, L. S. Research, Inc.
Area of science: Engineering
ID: 970449351.Eg

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.  
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 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 
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 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 

Off of the above topic, try this site as well, it may interest you in 
something else to do with aircraft.
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

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