Electric gate fob range - what to expect?

[DerekPCB]

We have electric gates, driven by FAAC control unit that uses remote key fobs to open the gates. The fobs are FAAC XT2 433 SLH LR. As the name suggests they operate on 433 MHz. However, the range is non-existent. Literally need to be next to the gate to open it. This does not seem correct to me, as ideally it would work good 10-20m away so you can open the gate as you drive up.

Had a brief call with FAAC and they said this is known issue/range of 433MHz which is what they are allowed sell/operate in UK. In the rest of Europe they use 868MHz and "this is much better". Is this correct or was I fobbed off? (excuse the pun!) Does 433 mean you can only achieve a few (<3 meters) or is something wrong with our setup? I will get the installers back next month but want you clever people to let me know what I should be expecting.

There is a lighting pole about 7 metres away from the control board, and of-course the board is affixed to a brick wall. Both might cause interference. Related, our garage door uses 868MHz and works fine, but that is not directly in the area of the electric gate. Is there is a difference between 433 and 868 (in terms of range/interference)?

Anything I can do? Perhaps get an external aerial but it will be unsightly no doubt.

Thanks

 

[bernardgreen]

Wireless propagation is a black art. There are so many things that can affect range over which the system will work reliably,

Most suppliers quote a maximum range for their equipment when operating in free space such as an open field with nothing that can affect the signal.

Add some metal into the free space and the effect on maximum range can be drastic .

A 69 cm length of metal is the wavelength at 433 MHz and can either extend the range or reduce the range depending on where it is relative to the transmitter and receiver, Half and quarter wave length metal will also affect the range.


Fitting a 433 MHz stub aerial may help but there are legal and technical constraints involved when aerials on Licence Exempt equipment are modified.

google quarter wave stub 433MHz

 

[Diver Fred]

433MHz is in a 'shared' band - with Industrial, scientific and Medical users, and Radio Amateurs, as secondary users which means interference may be expected but little can be done to resolve such. The Primary users are fixed point to point, radio location and mobile communications.

Such 'Key Fobs' are usually known as 'Short Range Devices' (SRD).

A couple of information sources relating to 433MHz RSGB and OfCom.

I'd expect the range to be greater than under 3mtrs for your key fob, say up to 10mtrs with an average of around 5mtrs - are operating the sender inside your car - does your car have metalised glazing (many French cars do). 868MHz is a legal frequency for Key Fobs in the UK, it's in the 'Harmonised' band for such purposes.

If you know of an active Radio Amateur in your vicinity ask him if he's interested in helping you to check for interference.

 

[Harry Bloomfield]

We have electric gates, driven by FAAC control unit that uses remote key fobs to open the gates. The fobs are FAAC XT2 433 SLH LR. As the name suggests they operate on 433 MHz. However, the range is non-existent. Literally need to be next to the gate to open it. This does not seem correct to me, as ideally it would work good 10-20m away so you can open the gate as you drive up.

Had a brief call with FAAC and they said this is known issue/range of 433MHz which is what they are allowed sell/operate in UK. In the rest of Europe they use 868MHz and "this is much better". Is this correct or was I fobbed off? (excuse the pun!) Does 433 mean you can only achieve a few (<3 meters) or is something wrong with our setup? I will get the installers back next month but want you clever people to let me know what I should be expecting.

I would not expect there to be much difference in range, between the two frequencies, so FAAC would seem to be making it up. My garage roller door uses 433 and I can open that as I pull up to open the drive gates around 20m from the receiver. The receiver is radio hidden, behind the metal roller door, my transmitter is mounted tucked away in my cars dash. My 433 weather station reports in reliably every few seconds, from at the top of a pole at the far end of my garage, to a receiver in the house, through two walls and 35m of air. My cars own 433 lock/unlock remote receiver is on the floor, between the seats, behind the handbrake - range of that varies between 10 and 50m, depending on the surroundings.

Assuming neither transmitter (fob), nor receiver is faulty, you should be looking at how and where the receiver is mounted, plus what barriers are between the two. . The existing antenna will likely be nothing more than a few inches of wire soldered onto the receiver pcb - is that in a metal or plastic box? A metal box will screen much of the reception. Where is the box mounted, could the box be mounted higher so it is clearer of obstructions? Radio transmissions at these frequencies travel line of sight - is the line of sight reasonably clear?

 

[Harry Bloomfield]

A 69 cm length of metal is the wavelength at 433 MHz and can either extend the range or reduce the range depending on where it is relative to the transmitter and receiver, Half and quarter wave length metal will also affect the range.


Fitting a 433 MHz stub aerial may help but there are legal and technical constraints involved when aerials on Licence Exempt equipment are modified.

The rules do not apply to receiver antennas, only to the transmitter antenna - so he can add what he likes to his receiver.

 

[DerekPCB]

Fitting a 433 MHz stub aerial may help but there are legal and technical constraints involved when aerials on Licence Exempt equipment are modified.

google quarter wave stub 433MHz

I was going to try something like this, from the mainboard run to somewhere on top of the brick wall (I need to open the box but I do believe it has an aerial input on the mainboard)

does your car have metalised glazing

Not sure to be honest. German car.

868MHz is a legal frequency for Key Fobs in the UK, it's in the 'Harmonised' band for such purposes.

Does that mean I could have purchased an 868 control board? FAAC insisted they could only sell 433 in the UK. However, from the discussion above, 433 vs 868 does not seem to be the issue.

The existing antenna will likely be nothing more than a few inches of wire soldered onto the receiver pcb - is that in a metal or plastic box? A metal box will screen much of the reception. Where is the box mounted, could the box be mounted higher so it is clearer of obstructions? Radio transmissions at these frequencies travel line of sight - is the line of sight reasonably clear?

Correct. I can see minimal short wire on the pcb. It is plastic box. The box is mounted on the wall inside my boundary. There is actually 2 boxes (one for each gate, and both have same range issue).
If it is line of sight, I think an aerial run from atop of the wall, down to the pcb seems the only real solution.

Although like you, I have a motor garage door which works from many meters, and not necessarily line of sight without issue (but 868)

 

[lloyda]

I presume you have tried new batteries in the transmitter?

 

[Harry Bloomfield]

Correct. I can see minimal short wire on the pcb. It is plastic box. The box is mounted on the wall inside my boundary. There is actually 2 boxes (one for each gate, and both have same range issue).

With regard to the suggestion of metallized windows in the car (above), have you tested the range from outside the car, to be sure the transmitter is not being screened?

The wall might be stopping the signal too - can you possibly as a test, release the boxes from the wall and set them on top of the wall?

Rather than buy an add on antenna, especially as it probably doesn't have a socket for such and antenna, they are quite easy to make with a bit of solid core coax.

Connect the centre in place of existing wire antenna, screen to the earth terminal, then at the other end strip the outer and screen back to expose the centre core for 346mm to make a half wave, or 173mm to make quarter wave antenna. Then seal the coax to prevent water ingress where you have cut the outer and screen.

If that works, drill a suitable hole in the bottom of the plastic case to take the coax out. All boxes outdoor should always have hole in the bottom, to allow drainage of any water that gets in - it always does.

 

[winston1]

Connect the centre in place of existing wire antenna, screen to the earth terminal, then at the other end strip the outer and screen back to expose the centre core for 346mm to make a half wave, or 173mm to make quarter wave antenna. Then seal the coax to prevent water ingress where you have cut the outer and screen.

Use 1/4 wave mode. A 1/2 wave is a mismatch when connected one end to coax.

 

[sparkymarka]

I find it very strange as all the faac equipment I’ve fitted in the last 10 years all had 868 radio receivers, even on the website all the receivers are 868 …..

 

[Harry Bloomfield]

I find it very strange as all the faac equipment I’ve fitted in the last 10 years all had 868 radio receivers, even on the website all the receivers are 868 …..

No reason why they could not sell them in the UK, 868 is a licence exempt throughout the EU and the UK. From memory - 868 was not always allowed licence exempt UK.

 

[DerekPCB]

I presume you have tried new batteries in the transmitter?

Yes, they are brand new fobs and tried with replacement fobs too.

With regard to the suggestion of metallized windows in the car (above), have you tested the range from outside the car, to be sure the transmitter is not being screened?

The wall might be stopping the signal too - can you possibly as a test, release the boxes from the wall and set them on top of the wall?

Rather than buy an add on antenna, especially as it probably doesn't have a socket for such and antenna, they are quite easy to make with a bit of solid core coax.

yes, tried it outside the car standing about 5 meters from the box and still it did not work. I tried this on the inside of the wall i.e. line of sight with the box

I'll see if I can do a test when I have some time free this week. Not sure what spare cable I have to hand, but worth a try.

I imagine the radio receiver would be built into the control board? i.e. it's not something that could be faulty on its own and replaced, or even say I could test an 868 module in the same location?

 

[Handymanjo]

Has your gate receiver got an external aerial connected .

 

[Handymanjo]

check compatibility with your receiver, you could always piggy back another receiver and transmitters onto your setup.

 

[DerekPCB]

View attachment 271515check compatibility with your receiver, you could always piggy back another receiver and transmitters onto your setup.

I don't have an external aerial, and I did see that receiver you posted, so that was going to be the end solution, if I could make it all work with a length of wire. I want to first check there isn't something wrong with the control boards, which would be odd in two different units i..e two gates