How to: Increase OEM keyless entry range

Being a ham radio guy... I question the validitity of this. Simply adding length will change the frequency the antenna is resonant at, and may actually degrade performance. Ideally you'd want an antenna that is as high up as possible, and resonant at the frequency of the transmitter. Since it's a UHF (if that 400-500mhz is correct) it will be pretty short... Chances are it just doesn't matter much as you're landing close enough to a multiple length of a 5/8 wavelength that it still works.

I just out my transmitter to my head. Or use the key in the door as the security system installed drives me crazy.

 

It works though. I used to have to do the same shit. Now I can lock/unlock my truck from at least 100 feet away, max of about 500 feet under the best conditions. Did this mod 3 or 4 years ago and still works great.

@PcBuilder14 did the same mod but used shorter wire that wasn't coiled and while there was an improvement, it wasn't as drastic. So maybe the coiled wire helps. Not sure lol.

 

Does the stock wire run up the length of the A pillar or is it stuck in the footwell? Most of the benefit will be from having the antenna be higher up / within direct line of sight of the transmitter. higher frequencies are all about line of sight.

I'd also have concerns about accidentally unlocking my truck when I'm 100ft away and the button gets pressed in my pocket.

 

From what I remember, the antenna wire was stuck up in between the area above the footwell, somewhere around where the upper part of the dash is. It was in a wire loom that is next to the body.
When PCbuilder did his, he created maybe an extra 5/6 feet of straight wire and put it in the headliner. He said it didn't make as big of a difference as my method. It maybe doubled his range, but it didn't make insane range like my version does. I'm not entirely sure why.

Also if you're concerned about mashing buttons when you're far away, never get a Ford or a Chevy.. some of those remotes have insane range.

 

You say that as if I needed another reason not to get a Ford or Chevy

From what I know about antenna geometry/propagation.... it may be that your coil causes a significant amount of gain in one direction (concentric to the coil).. I would be curious to see if you have a greater range in some spots around the vehicle vs in others.

The other reason his didn't work as well could be that he fell upon a length that isn't resonant at all... IE close to a full standing wave. I wouldn't be surprised if trimming his antenna slightly shorter may actually improve his performance.