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View Full Version : DIY Tip: Use Straw to Extend your Garage Door Opener Range


MMME30W
05-08-2008, 07:07 PM
Do you have problem's with the range of your garage door opener? It might not be your car.

If you have a remote control garage door opener, with external antenna, you can extend the range of operation with this simple DIY tip:

If you see a short length of wire coming off your unit, or coiled up on top, chances are that's your antenna.

Make sure that it is extended as much as possible, and as straight as possible as follows:

1) Obtain a simple plastic straw and small piece of duct tape
2) Climbing up to your garage door unit, locate the length of antenna wire
3) Extend the antenna wire and slip the plastic straw around it, route the wire through the straw, and out the other end.
4) Secure the end of the wire with the duct tape so it does not slip out
5) The wire should be nice and straight

That's it!

Why it works

Garage door openers typically operate in the 300 to 400 MHz range:

http://en.wikipedia.org/wiki/Garage_door_opener

What this means is that the wavelength of the radio waves are on the order of

wave length = phase velocity / frequency

For radio, the phase velocity is the speed of light, or approximately 3 x 10^8 m/s.

At 350,000,000 Hz, wave length is thus approximately 80 centimeters.

http://en.wikipedia.org/wiki/Wavelength

Without going into the Electrical Engineering, a typical low-cost antenna is called a quarter wave dipole, which is matched to wavelenth / 4 in length. This is a fairly cheap design (wire) that works well enough for the application (garage door opener).

http://en.wikipedia.org/wiki/Dipole_antenna#Short_dipole

For our notional 400 MHz system, a quarter wave is about 20 centimeters, or about a foot.

Since the antenna on your garage door opener is tuned to receive these signals, the closer you can get to match the transmitter in terms of signal (quarter wave dipole), the better. The antenna (wire) will work best if it's straight. The plastic straw helps to do that.

Try it - it works. :D

Fast Bob
05-08-2008, 07:18 PM
Thanks for sharing, Wing....( Now, if I wear a hat with an antenna on it, will it extend my ignition key`s door-opening range, like holding it to my chin ? :-)

Z4 Steve
05-09-2008, 12:33 AM
I remember setting up a dipole antenna in Company Radio Operators Course and talking to a unit in Okinawa and I was in Camp Pendleton.

MMME30W
05-09-2008, 09:52 AM
Thanks for sharing, Wing....( Now, if I wear a hat with an antenna on it, will it extend my ignition key`s door-opening range, like holding it to my chin ? :-)

Absolutely! :bigpimp: :D

LMC
05-09-2008, 10:53 AM
Excellent tip! :thumbup:

Now if we can just get a picture of Fast Bob in his new hat my day will be complete! :)

MMME30W
10-07-2013, 04:33 PM
Had to do this again today lol.

400946


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