When driving your RC car, the transmitter communicates with the car's receiver through a radio frequency. Most new RC cars are controlled using 2.4GHz digital radio technology. This technology allows multiple cars to drive simultaneously by assigning a specific frequency to each car.
Most popular brands of 2.4GHz radios use a direct sequence spread spectrum or DSSS. The DSSS technology allows the remote control and the car to pair up on a specific part of the 2.4GHZ spectrum. The DSSS system will scan for an open channel on the 2.4GHz spectrum and lock on it.
This means that other RC cars should not interfere with your car!
In this post, we will talk about radios, receivers, different technologies, and when RC cars could interfere with each other. Let's dive in!
Will two 2.4 GHz RC cars interfere with each other?
Two hobby-grade 2.4 GHz transmitters and receivers (two different cars) should not interfere with each other. Accordion to Spektrum RC, "When the transmitter is turned on, the module scans and locks on to any channel that is not in use."
If you are using high-quality transmitters and receivers, you shouldn't worry about another driver accidentally taking over your car and causing a significant crash. The equipment is designed to track down and use an available frequency that only your transmitter and receiver share.
27 MHz and 49 MHz Analog RC Cars
Beginner RC cars (and toy RC cars) may come equipped with a transmitter and receiver that uses older analog radio systems. Analog radios operate on the 27MHz and 49 MHz frequencies. That means if two cars on the 27 MHz frequency are trying to operate in the same area, they could interfere with each other if they are on the same channel. This is one instance where RC cars can interfere with each other.
If you want a new RC car, I suggest avoiding cars that use the 27 MHz and 49 MHz frequencies. That's because analog frequencies have few open channels to operate on, and there is a higher risk of interference.
Plus, all kinds of different gadgets use 27 MHz and 49 MHz frequencies. Garage door openers, automatic gates, and walkie-talkies use this technology to function. If you are serious about driving RC cars, steer clear of cars that use this analog radio technology and buy a car that uses 2.4 GHz digital radios.
Do I need to change the frequency of my RC Car?
Older Analog radios and receivers come equipped with a quartz crystal that assigns the vehicle to a specific channel.
That means if no one is using that channel, you can drive your car without fear of interference from another driver. If you have other crystal sets, you could change out the crystal on both the transmitter and receiver and use another channel if there are other drivers all wanting to use one specific channel.
Some crystal frequency options are:
- 26.995 (FRC-21)
- 27.45 (FRC-22)
- 27.145 (FRC-24)
- 27.195 (FRC-25)
- 27.255 (FRC-26)
The bullets above show independent channels on the 27MHz frequency. If there were five different drivers all using analog radios, each person must be on their own channel to avoid interference.
It is always a good idea to check with other drivers to see if they are using an analog radio. If they are, get to know them and ask what channel their crystal set uses. If all cars have a unique channel, you don't have to worry about changing the frequency of the RC car.
Can I Change the Frequency of My Digital Transmitter?
With modern technology, you don't have to worry about changing the frequency of your RC car.
Spektrum RC has a technology called digital spectrum modulation (DSM) that will eliminate interference from other drivers.
DSM technology uses direct sequence spread modulation that allows up to 79 drivers to operate simultaneously on the 2.4GHz spectrum. In other words, Spektrum DSM has 79 open channels with a range of about 3,000 feet.
Can I upgrade my radio to avoid interference with other RC Cars?
If you have an older car running with a 27 or 49 MHz radio, you can upgrade the car's receiver to a 2.4GHz system.
Accordion to Traxxas "Upgrading to a 2.4 GHz radio such as the Traxxas TQi 2.4GHZ Intelligent Radio System will help with poor signal and interference issues. The 2.4 GHz system is less prone to outside interference than 27 MHz radio systems."
You must make sure to buy a transmitter and receiver that is compatible with one another. Traxxas, Futaba, and Spektrum are great brands that make top-of-the-line 2.4 GHz radio systems.
I personally like to drive my Traxxas Slash with the TQi transmitter and Traxxas TSM stability management.
Can two RC cars run at the same time?
The answer to this question depends on whether the cars are controlled by analog or digital radios.
If the cars use analog 27MHz or 49 MHz radios, there is a much greater chance that the RC cars will interfere with each other. To ensure that they do no interfere, make sure all 27MHz and 49MHz radios are using their own channel (remember the crystal set?). If two cars have the same crystal channel installed, they will interfere.
If the cars are using digital 2.4GHz radio systems, there is much less of a chance for the RC cars to interfere with each other. As stated above, up to 79 cars can run at a time with the Spektrum DSM system.
If you are thinking about upgrading to a digital radio and transmitter, check out our post covering how to bind RC transmitter and receiver.
Conclusion on avoiding RC car interference with other drivers
RC cars can drive very fast and are dangerous when out of control. I believe it's important to understand radio interference and how it can affect your car and other drivers too.
The key take-home points to avoid interference are:
- Understanding the difference between digital and analog radios
- Knowing which types of radios can cause interference
- Learning how to check if another driver will interfere with your car
If you are using an analog radio system, make sure you have a backup crystal set in case you need to jump onto a different channel to avoid interference with another car. Also, make sure to ask your fellow drivers if they are using analog radios and what channel and frequency they are on.
If you can afford a digital 2.4GHz radio and receiver, installing it on your car will greatly reduce your chance of interfering with another RC car.
If you have to choose between an analog and digital radio system, go for the digital controller!