open sesame

April 7, 2005 9:08 AM

There is a gate leading to a parking garage. Gate is opened by remote control, but the range on the garage door remote is not sufficient to open the gate from inside a car (unless said car is < 1 inch from gate). How to fix?

Preferably I would like to modify the garage door remote itself (basic cheapie from sears), as opposed to modifying the gate antenna (don't know where this is). I have no qualms about making the ugliest hacked remote known to mankind so long as it works from about 5-10 feet from the gate. Pictures of gate are at http://www.creativemethod.com/gate.jpg and http://www.creativemethod.com/gate2.jpg. I have access to a soldering gun if needed, whatever it takes.

posted by striker to home & garden (14 comments total)

New batteries?
posted by caddis at 9:19 AM on April 7, 2005

I had the same problem with my garage door. Fixed it by replacing the batteries in the remote.
posted by boo_radley at 9:20 AM on April 7, 2005

The first thing I would try is doubling the length of the antenna, or possibly making an external antenna. Also, there might be a variable resistor in there that is limiting the output. Look for a very small screw on the circuit board of the transmitter.

It is also possible that the transmitter isn't quite tuned correctly, and there might be a screw for this, also.

Have you tried changing the battery? Was the range ever better than it is now?
posted by bh at 9:20 AM on April 7, 2005

Have you tried a different remote with the same code?
posted by weapons-grade pandemonium at 9:21 AM on April 7, 2005

Oh, one other thing to try: Hold the remote to your chin when using it. This can increase the range. Press hard.

Yes, it looks stupid, but it works. An RF engineer (that made various car remotes for a living) taught me this trick.
posted by bh at 9:29 AM on April 7, 2005

It'd be preferable to improve the receiving antenna on the garage door over increasing the strength of the antenna in your remote.

Some garage door openers have a little piece of wire sticking from them to receive the signal. You could try lengthening this, or, if you want to go nuts, hook it to the center pin of some coaxial cable, the sheild of the coax being hooked to the case of the garage door opener. On the other end of the coax, which you would run outside, add an antenna (or, you could try just stripping back the same amount of sheilding as the original exposed wire length was).

But I'm not an RF engineer.
posted by shepd at 10:08 AM on April 7, 2005

shepd - I'm not an RF engineer either, but I think the problem with lengthening the receiving antenna is that you get more noise, which can lead to more false openings in a noisy environment. This mostly depends on how old the equipment is. Newer gear is less likely to open after receiving a stray signal.
posted by bh at 10:17 AM on April 7, 2005

After the battery change go for the chin trick as mentioned by BH. It works wonders.
posted by lorbus at 10:35 AM on April 7, 2005

As long as the control is not of a "rotating code" type, you can buy replacement controls from a hardware store for $15 - $20 that have nice, strong signals (you can program them to send the same code as your current remote). Then, you also end up with a hedge against losing your current control.
posted by curtm at 10:47 AM on April 7, 2005

Thanks for the responses. This is a brand spankin' new remote (have tried a couple of different kinds now). I have no idea where the antenna is for the unit, and it is not solely my property, so I would like to modify the remote if possible. This is a problem with everyone in the building, not just me - management is terrible and will not get the thing looked at. I'm thinking the cement wall has something to do with it, but again, I don't see where there is an antenna on the actual unit.
posted by striker at 10:53 AM on April 7, 2005

Why does the chin thing work? Does it boost the signal by using your head a transmitter? This seems dubious.
posted by quadog at 10:55 AM on April 7, 2005

According to this, the chin thing (also, apprently, the temple thing) works because your body is acting as an antennae.
posted by bachelor#3 at 11:21 AM on April 7, 2005

if there's a scientific explanation for the chin thing I haven't heard it but it's pretty widely known and accepted, though I usually hear it about car alarm remote rather than garage door openers. A recent caller to CarTalk claimed, I believe, that there was some improvement from opening her mouth as well. So perhaps it's a directional effect. Perhaps there's some RF reflection and it just increases the percentage of signal going in the direction away from the chin that would otherwise have gone in the direction of the neck.

You might try putting the remote on a larger piece of tin or in a can to make yourself a ghetto directional antenna.
posted by phearlez at 11:28 AM on April 7, 2005

The chin thing increases the ground plane. As it was explained to me, anyway.

striker - If this is a problem for everyone in the building, it changes the equation a bit. I would definitely try the chin thing, followed by doubling or tripling the antenna length on the remote. You are probably correct - it could very well be an issue witht he cement.

Open up the remote, you will find the antenna. You might also have some luck looking up the FCC ID of the remote; this should give you the frequency and manufacturer.
posted by bh at 11:58 AM on April 7, 2005