I am trying to boost the range on the fob, and my first thought was to solder in an antenna but I can't quite tell where in the circuit I should add it. I am also open to any other ideas on how to increase the range, however I unfortunately cannot access the receiver/ opener motor. Any help is appreciated!

 

Use your head to boost the range.

 

I am familiar with the United States law that governs devices like your fob.

Most likely and addition to it or modification that would extend its range would violate those laws.

An external passive yreflector at the receiver might help by making the receiving antenna more efficient. I am sorry that beyond those thoughts I don’t have any other ideas.

You might consider making a (legal) repeater rather than modifying your fob.

 

When needing to increase the distance covered, there are two options: Speak louder or listen better.

 

When needing to increase the distance covered, there are two options: Speak louder or listen better.

or you could use a tapered acoustic impedance matching device.

 

A better antenna with an RF amplifier could boost the sensitivity quite a bit. So please avoid the nasty ....

 

"" I unfortunately cannot access the receiver/ opener motor. ""

Why ???
Are You trying to open your neighbor's Garage-Door ?

It's far easier to just extend the Receiving-Antenna, even to the outside of the House.
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Something here does not smell right. Most garage door systems are in the 300 megahertz frequency band and in the fob the antenna resonates. So changing the antenna will probably disable the control.And usually the range is quite adequate. So it seems that perhaps the receiver is to be used for a different purpose.

What is the real purpose of extending the range? Could it be to stay out of the blast-zone??? Cheap RC toy receivers have been used to trigger IEDs for many years now, this could be ????

 

Amazon has lots of garage door opener antenna extenders.

 

Amazon has lots of garage door opener antenna extenders.

Yes, right next to their 800+ mile range TV antennas.

 

I am trying to boost the range on the fob, and my first thought was to solder in an antenna but I can't quite tell where in the circuit I should add it. I am also open to any other ideas on how to increase the range, however I unfortunately cannot access the receiver/ opener motor. Any help is appreciated!View attachment 314228View attachment 314227View attachment 314228View attachment 314227

Adjust the device a bit so you can use two batteries in series rather than one, or some other way of using a higher voltage. Be prepared to destroy the device potentially, but I imagine these devices use the battery they do, for mechanical minimalism not some inherent limit on the circuits voltage handling.

 

I agree- something is fishy if the opener cannot be "accessed"... OP's SAW resonator NDR422 is 318MHz.
My ancient 372MHz opener suffers from poor range. Remotes have a trimmer cap on the board for tuning that needs tweaking now and then. They have components to limit TX power to something very low, even with 6V 2xCR2032 power. I'm quite happy with 50ft range though. Prevents distant hacker attacks.

 

I had one of those cheap wireless doorbells that wouldn't reach from the front door outside to the hallway. So I added 2 feet of AWG30 magnet wire just to the coin cell ground and that worked. So I tucked the wire behind the door frame. You might extend the Rx antenna wire from inside the cover out too.

 

A potential pitfall with adding "antennas" is the resulting system becomes more susceptible to false triggering by local electrical noise. If the receiver is made more sensitive (which is what an antenna does) then small spurious bursts of RF that today are ignored, might, tomorrow be misinterpreted and lead to undesirable door opening.