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Reasons for poor radio range
Reasons for poor remote range
Does your remote lack range?
Lets run down a few common causes and remedies before you call the gate doctor!
Author ; Huw Jones
What is going on?
I have been helping folk fix their gate problems from an engineer's perspective. It would be nice to blame the product, but scrutiny of the problem adds a deeper nuance.
First resort to problem solving is to isolate the the issue. If range is poor at noon, is it as bad at midnight. If your remote is poor, try another remote. If it doesn't work on tuesday, try on thursday. If the remote has low range within the your drive, try from outside. Gather evidence to help your engineer.
Look after your gate system and it will look after you. Your gate engineer is an expensive gardener, so do the leg work for him so that he comes prepared.
Bathtub curve
There is a term in failure science called the bathtub curved graph. A piece of equipment is likely to fail within a short time of going into service, then given no external damage, will perform for a long period, then the likelyhood of failure increases due to "ageing".
Consider your car. After a few months, any potential manufacturing fault will have revealing itself, then there is a period of reliable service, then after a decade or two, you are living on borrowed time.
Electronics components have a similar bathtub curve, plus there are external factors like insects, humidity, and heat cycle stressing that accelerate the process.
So if the range has deteriorated withing a month of it being put into service, or after several years of service, then a replacement might be in order.
When did it fail?
Consider also if the range is weather dependant. You should be able to expect a decent range regardless of the weather so long as the critcal parts are well insulated.
If the range collapsed suddenly, and has not reovered since, then weather is less likely. There is a change of circumstances that may coincide with a change in the area, like a new telecoms mast being commissioned or scaffolding next door.
Is the there a deeper problem?
When your car doesn't start, you wouldn't blame the car key, even though it is your first point of contact. Your gate remote may not work, but it could be a deeper fault, like .......
- there is no power to the gate panel, ie a blown fuse
- there is a safety sensor that has prevented the gate from moving
- the gate intercom or keypad may have overridden the gate panel
And, to state the obvious, maybe it is a problem with only one remote? Is there an indicator on the remote that no longer lights? There are also batteries in some safety photobeams and remote edges that you might want to check first.
Types of failure
If the radio system completely fails, there is likely to be a system failure, as opposed to a gradual failure to operate as expected.
the gate system has ever worked, the reason for it not working will be a small failure. You have to hope that a small failure did not lead to a more expensive breakdown.
Here are some obvious things to check first
- You are installing new equipment and cannot get the remote controls to function.
- The radio receiver has just been installed, but the radio range is well below expectation.
- The remote range has been acceptable, but drops suddenly from 40-50 metres down to 2 or 3 metres
- Some remotes give a much better range than others
- You have some remotes that have worked perfectly well, but new remotes will not programme into the control panel.
- You have some remotes that have worked perfectly well, but when a new remote is added, the old remotes stop working.
These are some circumstances. The texts below will refer to these scenarios as conditions for the possible problems you may encounter.
How to diagnose a problem
1. Visual inspection
A simple inspection will show if any thing has changed since the failure.
The radio receiver can be part of the gate control panel, or a separate receiver known as a standalone receiver. You should have a list of equipment from the original installer. If not, ask the next engineer to detail the components used and their function.
So long as the receiver is protected against weather and bugs, it is unlikely to fail. Conversly the aerial must be outside the control panel, and is far more likely to be the cause of poor or diminishing range.
2. Substitution
Try a different remote. If only one remote works, 90% of the system is OK. Obvious, but shows the principle.
Replacing the aerial with a length of wire relocated to avoid interference a is simple solution.
Some receivers simply plug in, so are a simple to replace. Standalone receivers also store the remote codes. They will require programming, so there are more difficult to swap out.
Transmitted power is a square of the battery voltage, so low battery power can make a big difference. Substitute that battery!
If you find the case doesn't close easily, it maybe the wrong battery type. Beware of disc batteries. The code often reflects the physical size.
3. Elimination
Remotes that work intermittantly, or not at all maybe a symptom of another problem. Is there an exit button, vehicle sensor, or keypad that works reliably?
Are ther times of the day, or days of the week, or weather conditions when the gate functions better?
Other devices wired into the control panel, or nearby maybe interfering with the signal. Your engineer can eliminate by disconnecting them.
A sheet of metal can be used to screen the receiver or aerial from various directions to see if range works from the opposite direction.
What to check
You can call your gate guy to come and fix the gate, but he will get to the problem quicker if you can help him out with some simple investigation. It may be something simple like pruning a bush. Giving him a good report will save time and possibly another callout should he need to make a return trip with a replacement part.
Here are some FAQs that may help
1.
Is the remote compatible?
This come under "types of failure 5". The clue is that old remotes still work. The new remotes may not be compatible. They may look the same, and the vendor has described them as 'univesal', but buyer beware. Came remotes have a part number on the reverse.
2.
Frequency
This is also about compatibility. There a few frequencies legal in UK but only two commonly used for 'telecommand' purposes - 433MHz and 868MHz, both supported by Came.
All the remotes are available in either frequency, and some can be set by the user to 433MHz or 868MHz. They look very similar, so check the part number on the back of the remote. The colour of buttons or rings around the buttons are NOT a style choice! They denote the version of remote, and hence compatibility.
Obviously, the receiver needs to be the same. It is not user programmed. Old frequencies 27MHz are obsolete. 30.6MHz and 315MHz from USA are not licenced.
3.
Coding
Rolling code remotes send a unique code when a button is pressed. Every rolling code remote ever made has a unique code. Each manufacturer has buys a licence key that means that only their remotes will work on their receivers.
Depending on the model, fixed code remotes are set by switches inside, or learn a code from a similar remote. Once set, the code remains the same. Code length and pitch can change between products. Some third party 'learning remotes' will copy from a Came remote, but is hit and miss.
Receivers are either Rolling Code, or Fixed Code. Once a Came control panel coding type has been set, it cannot take the other type. Attempting to change will clear the remote's code memory.
4.
How many remote can i programme onto a control panel?
Early panels would only take one fixed code. Adding a remote would delete the previous code. See "types of failure 6". But all remotes could be set as clones of the active code, so any number of remotes could be used.
The advent of rolling code remotes meant control panels needed to store multiple codes. Each rolling code remote needs to be taken to the control panel to be learned by the receiver.
5.
Which remotes have the best range
The lower the frequency the better the range, so in theory 433MHz is the better choice. The more powerfull the transmitter, the further you can expect the signal to go, but there are legal limits set by each country on the permitted power output at each licence free frequency.
Some people report that rolling code remotes give better range, but the science does not back that up. There are unbranded remotes that claim ranges up to 1000m. They either test them on the moon, or the remotes transmit over the permitted power, or they are not on 433MHz or 868MHz where higher powers are permitted.
6.
What can i do to improve range
The best solution for good range is to use a good aerial and mount it high up away from metal gates or railings. Receiver sensitivity also varies from brand to brand, but it is difficul to get sensible data.
Radio signal deteriorates down the aerial cable, so always use the right coaxial cable and keep it short. A good solution is to mount a standalone receiver inside a plastic box within inches of the antenna.
7.
What is an aerial?
Cars used to have a whippy aerial, and when that broke off we used to push in a metal coat hanger. Car radios could tune to any frequency, so the aerial length could not be optimised to a specific channel.
A 433MHz aerial is cut to a specific length to suit that frequency. It is usually a half, quarter, or eighth of the wavelength (divide speed of light by frequency).
Point to point antennae are vertically or horizontally polarised. They have a series of parallel bars (like TV aerials) that make the signal stronger in one direction, so are useless for hand held remotes.
An antenna is an aerial that both transmits and receives, like your mobile phone.
8.
What is radio noise and how does it affect range?
Radio noise is only relevant at the receiver frequency. RF transmissions from mobile phone masts, or wifi should have no effect on a receiver with a fixed frequency of 433MHz or 868MHz.
Poor range is often a due to other products nearby transmitting at the same frequency. Interference is anything that gets to hide your signal. Unlike in a crowded bar, your transmitter is not permitted to shout louder, so you can only get closer to reduce interference.
Common causes are RF doorbell buttons, kids toys, other telemetry. Have you lost a remote recently? Could it be buried in the garden sending a constant signal? There are many Chinese products that send constant 433Mhz or 868MHz signal which is against the licence free conditions. Remote telemetry applications like gate remotes is licenced for occasional use only.
9.
Can i test for radio noise?
You can buy small handheld RF sniffers that show signal strength in a line of LED's or a meter needle. They need to be pre-tuned to a particular frequency, or tuneable. They are useful for locating sources of interference. Interference is anything that gets to hide your signal.
10.
What is radio screening?
Radio waves pass through air, and poorly through water. Most metals block radio waves. Steel railings are not much better than a solid sheet of steel; the gaps do not count.
Aerials should be mounted higher than steel railings or chainlink fencing, or near metal fire escape stairs. If the range is worse when the gate is open, it suggests the gate is affecting the radio signal. To state the bleeding obvious, do not mount the aerial inside a metal housing.