I am picking up RF interference while doing a ground range check, at less than a 100' with antenna down and engine off, the servos are chattering. After over 3 weeks of flying with absolutely no problems, now I have interference, the radio is a Futaba 9CAP with fully charged tx and rx batteries. No changes to radio or aircraft have been made. I did change receivers when I got home to eliminate a possible receiver problem, no change. Are there any ideas out there?

I guess no one out there has radio interference problems

Well your second post does not encourage responses. Not everyone reads or posts here everyday, besides the fact that this question has been posted and answered numerous times on this forum. You should familiarize yourself with the search function before chastising others for a failure to respond...

I'll give you some common troubleshooting techniques to try if you want;

1. The most common failure is switches, especially on previously working systems, try eliminating the switch from the system.

2. Trying another rx is a good idea, if you have one, try another tx as it is possible that is the problem or make sure the tx works without problems on another model. That does not specifically rule out the tx and they are seldom the problem, but it does occasionally happen.

3. Bad servo extensions, broken leads, etc. can occur at any time and may create RF that is causing your problems.

4. Try disconnecting all but one servo and run your range check to see if it jitters, if not, add one servo at a time until the problem is duplicated and you have your offending circuit/servo identified.

5. Sometimes temporarily relocating the antenna will stop the problem and give you a better idea of where to look, i.e. bad servo extensions running to the tailfeather servos.

6. Do you always attempt the range check in the same area, i.e. where you fly? If so, try another location as it's possible some new source of local RF interference is affecting your channel.

7. Do the simple stuff first, if none of it works, remove the entire radio system and put it on a bench. If it still glitches and you cannot isolate the problem by running it one circuit at a time, the whole system including the tx may need to be sent to a service center for repair. Try contacting Futaba support after you've tried the common troubleshooting items for possible assistance and/or return for service information.

Oh, for what it's worth Futaba recommends doing range checks with at least one section of the antenna extended. Running the tx with the antenna fully collapsed for a period of time will overheat the output circuit components according to Bax on the Futaba support forum. You can browse that forum or do a search for the specific post regarding that collapsed antenna question...

Zeeb, I thank you for your response, I do appreciate the info and will follow up on your recommendations, thanks again.