Keyfob Range? 2 SOLUTIONS

StudioWizard

Member
Los Angeles, CA, USA
What kind of distance is everybody getting out of their OEM keyfob? I think mine is only transmitting about 20 meters or so. I have both original keyfobs and they both seem to have the same transmitting distance.

It would be nice to get more distance for those times when I can't remember where I parked! haha
 
Have you tried putting the key against your head whilst pressing the button ? Your body acts as an aerial. :lol: #

Seriously, it does work. I have great fun using my kid's heads to help unlock cars further away than usual.

There was one time we were on a ferry to a Scottish island and the tilt alarm went off on the car. I couldn't get close enough to the car to remote unlock it, but with the use of a handy child's head, the job was accomplished. :rofl:
 
I was just going to post that - i can double the range of mine by holding it against my head.
 
My Z4s have all struggled to operate at 5 metres!

From behind the car they often don't work at all. :(
 
Wait.... are you guys trying to PUNK me? haha OK, I'll try placing it against my head and see what that does.

My last car's keyfob (Chevy Volt) would work nearly 100 meters away - that's one city block! I could be on the wrong floor of a parking structure and make my horn go off. Of course, that made me look pretty stupid many times. haha
 
StudioWizard said:
Wait.... are you guys trying to PUNK me? haha OK, I'll try placing it against my head and see what that does.
It actually works you just look silly doing it!
 
I've pressed my fob into my chin and can also confirm that it increases the range. It's also a bit more subtle than pressing it into your forehead or above your ear!
 
Something of note that's just occurred to me is that the OP's range is due to being the wrong side of the Atlantic. Keyfobs over there are on a different frequency (300-odd MHz vs 433MHz) and I bet the allowable transmission power is a lot higher.
 
I tend to get up to 50 meters range for unlocking & locking, but usually somewhat less in areas with lots of interference from other vehicles with keyless entry. Remote opening of the zeds roof tends to be most susceptible. Had a couple of occasions when the interference has totally blocked the signal: e.g. near a construction site with remote controls operating lorry cranes.
 
Zulu4 said:
Have you tried putting the key against your head whilst pressing the button ? Your body acts as an aerial. :lol: #

Seriously, it does work. I have great fun using my kid's heads to help unlock cars further away than usual.

There was one time we were on a ferry to a Scottish island and the tilt alarm went off on the car. I couldn't get close enough to the car to remote unlock it, but with the use of a handy child's head, the job was accomplished. :rofl:

That was my first thought and yes it does work, stand so far away until the door wont open then give it a try :thumbsup:
 
UPDATE:
I can confirm that putting the key (metal part) to my forehead does indeed increase the transmission distance substantially. Normally, I'm getting anywhere from about a few meters to 20 meters transmission distance. With the key pressed to my forehead, it's triple. I've tired simply putting my fingers on the key part to see if that works, but so far it hasn't seemed to.
 
smorris_12 said:
Something of note that's just occurred to me is that the OP's range is due to being the wrong side of the Atlantic. Keyfobs over there are on a different frequency (300-odd MHz vs 433MHz) and I bet the allowable transmission power is a lot higher.

Very interesting. I wonder if it's possible to increase the power.
 
StudioWizard said:
UPDATE:
I can confirm that putting the key (metal part) to my forehead does indeed increase the transmission distance substantially. Normally, I'm getting anywhere from about a few meters to 20 meters transmission distance. With the key pressed to my forehead, it's triple. I've tired simply putting my fingers on the key part to see if that works, but so far it hasn't seemed to.

Age old trick - spread the word, people will think your nuts though :rofl:
 
Not easily unless you fancy learning some circuit theory. I suppose hanging a long antenna out of the key in place of the PCB one would give an instant gain but be wildly impractical.

To me the thought of accidently opening my car from a block away is anathema. Why not just tie a knot in your hanky to remind you where you left it like the rest of us? :wink:
 
You can extend even further with a container of water.
WARNING - you will look even sillier :D

Good explanation here:
https://www.youtube.com/watch?v=0Uqf71muwWc&ab_channel=SixtySymbols
 
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