Troubleshooting radio transmission problems in access control

Radio transmission is what we call the unsung hero of access control. You want to run less cables? You want to install outdoors? You want a cost-efficient solution? Tick, tick, and tick – radio transmission does it all.

But it’s not an infallible technology, and as an installer it’s important for you to know how to proceed when you encounter issues. In this blog, we’ll look at common installation and maintenance difficulties, and a step-by-step procedure for effectively troubleshooting and solving them.

How radio transmission works in access control

Radio transmission systems generally consist of three essential components: the transmitter, the receiver, and the action. The transmitter is the thing that sends a trigger signal. The receiver is the thing that picks up that signal. And the action is the thing that moves or changes as a result: for example, the electronic lock that releases, or the light that comes on, or the automatic door that opens. What distinguishes this from other systems is that the signal from the transmitter to the receiver is sent wirelessly through the air on radio waves.

As a result of that method of communication, the environment in which a system is installed is extremely important to the operation of the products. Signal strength must be sufficient to reliably send and receive messages. And there are a lot of things in an installation environment that could negatively affect that signal. It’s important for you to understand them, notice them, and work around them.

Common symptoms of radio transmission issues

What kind of issues might you encounter on a radio transmission job? Usually, they can be split into four kinds:

Intermittent access. Sometimes it works, sometimes it doesn’t. Extremely frustrating for your customer!
System delays. You press the transmitter button, and it works… eventually. Not exactly the slick solution you envisioned.
Short read range. If you have to be right next to the receiver for the signal to transmit successfully, where is the value in having the system at all?
Interference. Radio signals are whizzing around us everywhere, and crossed invisible wires can cause erratic or unreliable operation.

Common root causes of transmission problems

Most issues in radio transmission installations can be diagnosed with a root cause of one of this following list. And that’s a good thing, because it means it’s easy to systematically troubleshoot and check each of these factors in turn.

Physical obstructions. When signals are transferred wirelessly, they travel through the air to reach their destination. If there’s a wall, metal door, or dense building materials between the transmitter and the receiver, the signal may struggle to pass through smoothly. The quoted range of a transmitter is usually measured at e.g. 250m in open field. If it’s not passing through an open field, that range may be reduced.
Interference. Radio waves are all around us, constantly. Just sitting in your home, you likely have Wi-Fi, Bluetooth devices, microwaves, and other devices pinging signals through the air. Those signals can interfere with one another, and cause unreliable operation in a radio transmission system.
Power supply. If either your transmitter or receiver are not powered properly, you may lose signal strength and see intermittent operation. Transmitters are often battery-powered, while receivers are more likely to be connected to a mains-fed power supply – here, low voltage can cause issues with the receiver’s functions.
Antenna positioning. If you have an antenna in your system, the way it’s placed and angled can affect the transmission of the signal, as well as any physical damage to the antenna.
Environment. We’re in the UK. The weather is… changeable. If you have any components installed outdoors, they are susceptible to precipitation, humidity, and temperature changes. All of these factors can affect operation if components aren’t properly protected.
Hardware. Physical damage to components will naturally have a knock-on effect to the operation of the system, and should be regularly checked to ensure good condition.

Step-by-step troubleshooting guide

Follow these eight simple steps to troubleshoot your radio transmission access control solution. Usually, you’ll find the problem before you reach the end of the list!

1. Verify power supply

Double check the power supply to the receiver and make sure all the components are receiving the voltage recommended in the installation manual. Plus, check the batteries in any remote items like hand-held transmitters.

2. Check signal strength

There are lots of tools available for checking the strength of a radio transmission signal. The most high-tech tool is called a spectrum analyser and measures radio frequency power in decibel-milliwatts. This will give you a good indication of whether your system problems are down to signal strength.

3. Inspect antennas

If you have antennas in your system, look at them in detail. Are they placed in the right location? Are they aligned and oriented in the optimal way to send and receive signals?

Check as well for any signs of physical damage which could be affecting operation.

4. Test different credentials

You want to rule out any possible issues with faulty transmitters, so test out your system with a few different ones. If one fails where others operate as expected, you know you’ve probably got a faulty transmitter or a dead battery.

5. Reduce interference

If you think interference from nearby radio frequency devices is affecting your system, first see if you can alter the frequency channel your system is operating on. If one particular frequency is in a very busy zone, switching to another might solve your problem. Relocating the equipment could also help reduce the effects of interference from other devices.

6. Evaluate the environment

Stand at the transmission location, and look towards the receiver location. Is it a clear and open field? Or is there something in the way? Does your signal have to pass through buildings or large metal objects? Has something changed in the environment since the last time the system was working well?

7. Update firmware and software

If relevant, ensure that any firmware and software is updated to the latest version. This avoids compatibility issues that may be interrupting the operation of the system.

8. Replace suspect hardware

If you’ve got this far and you still can’t figure out what the problem is, it’s possible you have hardware issues. If anything has sustained physical damage, or could have been exposed to rain or extreme temperatures, it may be time to replace it.

Preventative measures to keep radio transmission working well

Often, small and regular maintenance goes a long way to keeping transmission solutions working well for longer. Here are some key actions to carry out regularly so your systems stay in tip-top condition.

Regular maintenance. Every couple of months, or after any extreme weather events, have a walk through your system and check on all of the components. Ensure they’re clean, clear of debris, and securely fixed in place. You may also wish to carry out regular signal testing to track any changes.
Shielding from interference. Keep an eye on the physical environment around your system site, and where possible keep potential interference sources away.
Keep firmware and software up to date. If your system requires firmware and/or software, regular checks to ensure it’s at the latest version will keep the system operating at its best.
Training others in maintenance and troubleshooting. Make sure other users or staff members on the site are aware of the system and how it works. Give everyone your troubleshooting checklist so that any possible issues can be picked up and resolved as quickly as possible.

Conclusion

The majority of operational issues with radio transmission systems in access control contexts stem from interference, power issues, or hardware damage. If you’re confident in how to install and maintain systems to avoid and resolve these issues, your systems will be more reliable and durable.

Remember that when you come up against a problem in the system, guesswork isn’t the right approach. Use a systematic troubleshooting procedure to rule out different factors one by one. This will help you narrow down the issue and find an appropriate solution as quickly as possible.

If you are ever stuck or unsure, our technical support team are on hand to help. We’re available from 8:45am to 5:15pm Monday to Friday. You can contact us on the phone, with an email, or on our live web chat on the CDVI website.

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