Intermittent radio loss during alliance

There is intermittent loss on radio link. Brain firmware 1.13 and joystick 1.04. During individual practice it looses sometimes for 1 to 2 seconds. During any alliance practice the frequency seems to have increased. I have checked information on both controllers (System Info … Channel, Losses). The channels were 10 and 2. There were 6 losses on ours, which was consistent with our issues. Sometimes if it is in a drive this during loss, the robot continues its motion until the controller gains its link. It also gets stuck and does not return. At that time either the bars on display is either 1 tall only or all 4 as small dots. Normally its bars …

Edit: Yesterday I took a peek on the brain this time when this happened. It was searching for the remote that was held 1 feet away. After a few seconds it found it and then all bars were solid.

Please advise. Thank you.

Hi surgeon,

We’re sorry that you have encountered this issue. Are you having this problem on multiple sets of Controller and Robot Brains, or is this only an issue between a single Controller and Robot Brain?

If you are having this issue on multiple pairs of Controllers+Robot Brains, it is possible that there may be a source of radio interference in your building area. To see if this is a problem, please take your Controller+Robot Brain pairs to a remote area, such as the end of the parking lot or in the middle of the outdoor sports fields at your school. Do the same problems occur there? If there are no radio issue there, then the communication issues inside might be due to radio interference from a different device that may operate on the same frequency. For example, some cordless telephone systems may operate at 900 MHz or 2.4 GHz.

If you are only having issues with a single Controller and Robot Brain communicating, then there might be be issue with one of the two radios. To test this, please take a Controller and Robot Brain that work well, and remove a single radio. Then take one radio from the Controller+Robot Brain that are having communication issues, and swap it into the good pair. Then test to see if the problem persists. If there is no problem, remove the radio you were testing and try the other radio. This will help try to isolate a single radio.

If you are still having issues or questions, or if you find a particular radio that is not working well, then please contact VEX Technical Support at or by calling +1-903-453-0802 so we can provide additional assistance.


  • Art