Michigan Radio & TV Buzzboard

Background:
17 year old garage door. opener.
Didn't use with remote for 8-9 years
Started using again last year.
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I googled around and tried extending my antenna. I first used bare copper wire and ran it through a hole I drilled in the gable end to hang outside. Sort of worked but not well at all.
After reading more, I found a bit about RF interference (LED lights in particular) I replaced the bare copper with some insulated 12 gauge electrical wire I had laying around. Seems to work much better but the car still needs to be within 3-4 feet of the door and sometimes needs two or three tries to work but at least my wife doesn't need to get out of the car.

Now the question: I have an abundance of old coaxial cable. Would that work better than the 12 gauge electrical I have now?
Wondering if the added insulation factor would help or not.

Maybe a corroded battery connection or dirty switch is the issue? Maybe as you use more it gets better, and the antenna is not the real issue.

if you are going to extend with coax, connect the antenna to the center conductor, the shield (outer) to some metal of garage door opener and then strip off about the same amount of shield as the length of antenna, leaving the center insulation and center conductor exposed.

We'll call this project "ExtendTenna". Put the end of the ExtendTenna close to door/driveway as possible.

Oh, good to hear you cleaned out the garage after 8 years.

You've ruled out mechanical issues with the door?

To be clear the door opens and closes fine with the button attached to the garage wall. The remotes worked fine when I held them 2" from the little 12" dangling antenna wire. They just didn't work from the car.
I certainly changed out the 9 volt batteries in the remotes and there was no corrosion there.

I installed it in 2002 when I got a new car. As the car got older and my now wife was using it in Grosse Pointe (before we were married) the garage started to fill with "stuff". When we bought a new car in August of 2018 I cleaned up the garage to park the new car.