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Cateye Micro Wireless Bike Computer interference

Published on Sunday 09 November 2014
Categories: Radio and RF |

Cateye wireless bike computer

We recently purchased a pair of Specialized Crux E5 cyclocross bikes from Primera Sports in Bournemouth which we plan to use for longer road rides and some off road and keep our full suspension mountain bikes for just off road rides.

We purchased Cateye Micro Wireless bike computers (model CC-MC200W) to use on the bikes as they are a nice and compact computer and have enough functionality for our needs to keep track of speed and the distance of the rides.

The new computers seemed to be working without any problems until we came to switch on our LED Moon NOVA 80 lights and then the signal from the bike computers sender unit stopped reaching the Cateye computer and the display showed that no signal was being received. Turning off the LED lights restored the signal so there was a problem with the LED lights transmitting on a frequency close to or a harmonic of the wireless signal coming from the Cateye wheel sender unit which blocked the bike computer from receiving the senders signal.

When we returned home we experimented with different locations of the LED lights and also the bike computer and the computer would work with the LED lights running but only if the light and the computer was separated by over one meter. As this wasn’t possible on the handlebars we removed the computers and ordered a different brand of wired computer which runs without any problems regardless of the LED lights fitted on the handlebars.

In order to try to resolve these problem and find which frequencies are being used, we wrapped a wire around the sender on the bike computer to act as antenna and connected this to our scope. When passing the magnet past the sender unit a pulse was being generated at 19.16 kHz with a time period of approx. 3.4 microseconds.

The scope screen shot below shows the pulse from the scope.

Click to view large image of 3.3ms pulse on scope

The scope screen shot below shows the pulse showing the frequency and waveform.

Click to view large image of 19 kHz pulse from sender

We then wrapped a length of wire around the Moon Nova 80 LED headlight to capture the RF being emitted by the light and when connected to our spectrum analyser there was a general increase in RF noise between 0Hz and 10Mhz.

Connecting this to the scope showed several different spot frequencies being generated with a strong pulsing signal at 7.8kHz as shown on the screen shot below.

Click to view large image of LED Headlight RF generated

We then tried our more powerful SolarStorm LED headlights with have two CREE led units and found that the power cable was radiating a signal with a large primary pulse and a smaller secondary pulse at 49.3 KHz. This signal was only present when the LED light was on its medium or high setting but not on its lowest power mode. The screen shot below shows the RF being generated by the SolarStorm headlights.

Click to view large image of Solarstorm X2 RF generated

In order to test if it was a spot frequency or wideband noise causing the Cateye computers to fail we used our frequency generator with signals from 1 kHz to 100 kHz into an antenna near the bike computer but this didn’t stop the senders signal from reaching the bike computer. The signals being generated and leaked by the LED lights was not a “clean” signal and had a lot of harmonics and this must be causing the interference problems with the Cateye computers.

After searching for this problem online there are a lot of other posts on cycling forums relating to the Cateye wireless computers and LED lights. We don’t have any other brands of wireless bike computers to test so we don’t know if this a Cateye only problem.




18 November 2018 at 1:08 pm

Could wrapping silver foil around either light or computer have stopped this interference?


19 November 2018 at 10:32 am

Adding foil around the bike computer would have shielded it from its own transmitter sensor so it wouldnt work. The lights did already have shielding but the RF was still getting out.


04 January 2019 at 11:46 am

Have the same no signal issue with my Sigma ROX8.0 or 1606L wireless cycle computers and any of my LED bike light. Nice write-up and testing, long time since I've done anything like that, even for fun. Glad to say no such issues when using my Garmin GPS/cycle computers.


14 June 2019 at 5:26 pm

just replaced 2 Cateye wireless computers because of erratic readings. Turns out handlebar mounted iphone used for music was interfering with Cateye. Removed mobile phone, Cateye now reads correctly


07 July 2019 at 9:26 pm

Greg and anyone else. Have this EXACT problem with CAT EYE PADRONE wireless and Samsung Galaxy Note 8 right next to it on handlebars. When streaming music, cat eye reads erratic and miles at end are off by sometimes 6 miles and speed stops sometimes during ride. Has ANYONE come up with a solution other than 1) remove phone 2) Get a smaller wired computer? thanks


18 July 2019 at 11:10 pm

I have experienced this tonight with a Moon Meteor-X Pro front light and a Giant Axact 9w wireless cycle computer. Am thinking of wrapping the light in kitchen foil...


17 August 2019 at 12:33 pm

I had the same problem with my Android phone and Cateye wireless computer. Putting the phone in Airplane mode seems to have solved the interference problem and has the added benefit that I'm not bothered by calls and texts during the ride.

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