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

Hello,
 
I need a small transmitter that could trigger a switch such as a 
solenoid...servo etc.
I fly model radio controlled aircraft and am aware of various 'traditional 
transmitters'.
 Example: I want a separate transmitter to activate a switch to open the 
hatch. I know transmitters have many channels for such a task....BUT, I 
want a separate device to activate a switch,
 
The criteria is: 
1. Transmitter must be a separate unit from the one I'm flying the model 
with.  
2. Transmitter needs to be  as small as possible...(small enough to clip 
on my belt.)
3. must have similar range (100'- 1000' ft) I don't need the full range 
that most transmitters have..which is more than a mile I'm sure...just a 
range that could reach the model in flight.
 
Example:  Some cars have a transmitter to 'pop' open the trunk.  the range 
is small, however.

I need the transmitter to function a switch only once per flight!
  
 Sincerely,
Michael Roberts

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