Increase antenna reception?

Question

I want to increase the reception of my garage door opener. I have heard that if I wrap the existing antenna with copper wire, that this will increase the reception - is that true? Would splicing a longer wire into the existing one help?

If you know of a webpage that backs up what you propose, that would help me weed out the idiots from the real answers. Thanks.

Answer 1

Wrapping an antenna with copper wire will have no effect.

An antenna has components between it and the transmitter which do two things. They tune the antenna to the transmitter's frequency and they match the antenna's feed impedance to the transmitter.

Changing the antenna's length will upset both the tuning and the matching and make things worse - unless the length you add is exactly a half wavelength at the operating frequency.

That may produce an improvement.

Answer 2

In principle you could improve the antenna performance either at the remote control or at the opener end, or both. In practice this tough because neither is designed for antenna replacement.

Usually, the opener has a wire hanging out as an antenna. It should be 1/4 of a wavelength long, measured from where it leaves it's metal chassis box or circuit board. Mine has a plastic box around the metal one. (Probably should remove the plastic to see the starting point.)

At 300 to 400 MHz, the wire should be 7.4" to 10" long. Mine is in this range, so changing it won't help.

However, my antenna wire was hanging near the grounded power cord, & that's not good. I re-positioned the power cord, straighted the antenna wire & bent it so the it is hanging straight down.

The other thing you could try is adding a reflector behind the hanging wire. I've tried this on a WiFi b/g system & it worked well. Wrap a piece of letter sized cardboard (8.5" x 11") with aluminum foil & mount it vertically about 1/8 to 1/4 of a wavelength behind the hanging wire.

This should add a few dB of gain which could increase your range by 50%.