Extending fob / alarm operating range.

6 years 6 months ago - 6 years 6 months ago #144138 by PQD44
The problem?
When I first got my MGF I changed the battery in the fob because I had to be stood next to the car (almost with the fob pressed up against the window) to operate the alarm / central locking. New batteries in and ..... didn't make any difference. Having put up with this years I decided to see what could be done about this annoying quirk.

Tools needed:
Cross head screw driver, soldering iron, heat shrink tubing or insulating tape.

The Fix
I read that if you remove the passenger foot well panel (retained by two screws),



locate the yellow aerial cable that is coiled and taped up to the main wiring loom, straighten it out and tape it you should find the operating range is increased.



:-? I searched for a couple of minutes but there was no coiled yellow wire?

At this stage I need to say that I have a MGF MY2000 ( Mk II ). Apparently on the original MGF this was where the yellow aerial cable was located. After a bit of research I discovered that MG Rover had the ingenious idea to "cure" the range problem on the MGF MY2000 and MG TF by routing the wire to the hazard warning switch's connector block. :slapme:

So pop out the hazard warning switch and ....



... sure enough, there is the yellow aerial cable pictured at the top left of the block. As you can see this has no corresponding connector on the Hazard warning switch. Disconnect this wire and attach a 52.5cm (see explanation below) length of insulated wire to it using a soldering iron. I then used heat shrink tubing to cover the joint and the other end of the wire (this has to be done so that the aerial wire does not touch anything metal)



The fob operates at a frequency of 433MHz in the UK which is a wavelength of approximately 70 cm, the standard aerial wire is a 1/4 wavelength or 17.5 cm. You can add 17.5 cm to create a 1/2 wavelength or 52.5 cm to create a full wavelength aerial.

Next feed the new aerial cable down to the passenger foot well.


I then tried the aerial extended under the glove box and got a good improvement in range. I then ran the aerial along the center of the car (it ended by the side of the handbrake lever). This gave even better results and I can now operate the central locking from about twenty feet from the car :woohoo:

If you want to try and further improve the operating range I have seen a way to extend the aerial in the fob , click here.

There is the old trick of placing the fob next to your head to extend the range but my quick fix means you can have an extended range and keep your dignity.
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6 years 6 months ago - 6 years 5 months ago #144142 by Baytown
Brilliant info. Thanks for this as Ive never been impressed with the remote range on my 04, even though Technozen were happy with my fob. I'll see if I can improve my Aussie car with the different 315 MHz fob.
I'll post how I go.
Well done.

Ken


Sent from my iPad using Tapatalk HD

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6 years 6 months ago #144143 by David Aiketgate
Nice one, Paul. :broon:
I hadn't heard of the aerial wire being in the hazard flasher plug before. :nonod: So well done. :clap:
Guess where I'm going now! :whistle:

David
:shrug:

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6 years 6 months ago #144147 by PQD44

Baytown wrote: ... I'll see if I can improve my Aussie car with the different mHz fob. Operates on a lesser freq than UK spec cars, in the 300 range.

Ken


I think yours will operate at 315MHz so it will have a wavelength of 95cm. Assuming it has a 1/4 wavelength aerial, 23.75cm to start with, you will need to add a multiple of this; 24, 47.5 or 71 cm to achieve an improvement.
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6 years 6 months ago #144150 by Badger

PQD44 wrote: The problem?
When I first got my MGF I changed the battery in the fob because I had to be stood next to the car (almost with the fob pressed up against the window) to operate the alarm / central locking. New batteries in and ..... didn't make any difference. Having put up with this years I decided to see what could be done about this annoying quirk.

Tools needed:
Cross head screw driver, soldering iron, heat shrink tubing or insulating tape.

The Fix
I read that if you remove the passenger foot well panel (retained by two screws), locate the yellow aerial cable that is coiled and taped up to the main wiring loom, straighten it out and tape it you should find the operating range is increased.







:-? I searched for a couple of minutes but there was no coiled yellow wire?

At this stage I need to say that I have a MGF MY2000 ( Mk II ). Apparently on the original MGF this was where the yellow aerial cable was located. After a bit of research I discovered that MG Rover had the ingenious idea to "cure" the range problem on the MGF MY2000 and MG TF by routing the wire to the hazard warning switch's connector block. :slapme:

So pop out the hazard warning switch and ....

Attachment not found



... sure enough, there is the yellow aerial cable pictured at the top left of the block. As you can see this has no corresponding connector on the Hazard warning switch. Disconnect this wire and attach a 52.5cm (see explanation below) length of insulated wire to it using a soldering iron. I then used heat shrink tubing to cover the joint and the other end of the wire (this has to be done so that the aerial wire does not touch anything metal)



The fob operates at a frequency of 433MHz in the UK which is a wavelength of approximately 70 cm, the standard aerial wire is a 1/4 wavelength or 17.5 cm. You can add 17.5 cm to create a 1/2 wavelength or 52.5 cm to create a full wavelength aerial.

Next feed the new aerial cable down to the passenger foot well.


I then tried the aerial extended under the glove box and got a good improvement in range. I then ran the aerial along the center of the car (it ended by the side of the handbrake lever). This gave even better results and I can now operate the central locking from about twenty feet from the car :woohoo:

If you want to try and further improve the operating range I have seen a way to extend the aerial in the fob , click here.

There is the old trick of placing the fob next to your head to extend the range but my quick fix means you can have an extended range and keep your dignity.


This is still WIP for the Pektron unit, we have a thread still going from a couple of weeks ago; I doubled the length of the aerial cable as per my calc in this link www.the-t-bar.com/forum/9-mgf-tf-pitstop...?limitstart=0#142469

There is a slight improvement but it's still poor, however I have found there should be a multiplier of around 0.91 in the sine wave calculation for multicore plastic sheathed cable and I am still playing around with the cable length, hopefully have some good info for the Pekton unit by the end of the week.

Brian.
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6 years 6 months ago #144155 by Badger

PQD44 wrote: Thanks Brian, hadn't seen that, I've only been back on the T-Bar for two weeks.

If we use your 0.91 multiplier for the multicore cables then the length to add should be;

~48cm for the UK and ~65cm for countries using the 315MHz frequency. :broon:


It think it should be multiply the sum by 0.91, so would be something like 314mm for 1/2 wave @ 433mhz. or:

300 / 433 / 2 x 0.91 = 0315242 which will give about 315.2 mm for 1/2 wave

Will let you know if it's any better when I progressively chop it down.

Brian.

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6 years 6 months ago #144156 by PQD44
Look forward to your findings. Let me know and I'll update the best length to add in the original post of this how to. :broon:
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6 years 5 months ago #144164 by peter81
I asked myself where is the yellow wire for 5 years in my F, amazing discovery! :woo2:
:clap:

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6 years 5 months ago #144537 by DavesZed
Well done, great find!
Did this this morning and it works a treat!! Much improvement over what I was doing before. Not so good from the rear but still better though B) :drive:
Thank you :beer:
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6 years 5 months ago #145054 by Uncletone
Excellent Paul well done that man. Now I can open the doors from anywhere. m

Beats standing on your head with the fob between your knees any day.

Great job

Tone
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6 years 5 months ago #145066 by John and Sue
A great how to, but we really don't have a range problem on our TF. Works from about 10 metres away from any direction of approach.

Maybe they got it finally sorted at the end of production?

It will be all right in the end. If it isn't all right yet, then it is not yet the end..

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6 years 5 months ago #145071 by Badger

John and Sue wrote: A great how to, but we really don't have a range problem on our TF. Works from about 10 metres away from any direction of approach.

Maybe they got it finally sorted at the end of production?


Hi John, we had another thread on this at the same time (TF Pekton unit related)

This was the reply from Paul (Technozen)

"The Pektron SCU has no external antenna, the internal radio receiver board has an antenna on the circuit board. Poor radio range on these units is usually caused by the radio receiver board itself, it's a common problem" (Thanks Paul)

Brian.
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