On Fri, 09 May 2014 16:07:54 -0700, Jim Thompson
wrote:

or this one is cheaper...
http://tinyurl.com/mj7dcg9

I like that one (for no obvious reason because there are no specs).

Is the metal part of the garage door insulated from the metal support
frame? Usually, that requires rubber or plastic wheels in the door
track. If so, you might be able to simply connect the antenna
connection to the overhead track arm, which is connected to the door.
The idea is to turn the metal door into an antenna. It won't be
efficient, matched, kosher, elegant, or otherwise according to the
textbook, but it will put the RF on the outside of the garage, which
methinks is the basic problem. Try it with a clip lead and hope that
the receiver tuning is sufficiently isolated from the antenna to not
become detuned (or oscillatory). My only worry is that if someone
dumps a static discharge into the door, it might blow up the receiver
front end.





--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558