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RF Interference

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Old 10-20-2006, 07:08 AM
  #1  
ecrt123
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Default RF Interference

I am getting alot of RFI on a 60 size plane with a G20. The rudder jitters very badly. Also the alierons move back and fourth only when the engine is running. I got some rings to stop it and I have moved the reciever as far back as I can. Any more suggestions?

Thanks

Ray
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Old 10-20-2006, 07:13 AM
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Default RE: RF Interference

Do you have a metal connector on the throttle arm?
I made this mistake years ago. My plane had exactly the same symptoms.
When I changed it out with a nylon connector, the problem went away.
Doug
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Old 10-20-2006, 07:36 AM
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Newc
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Default RE: RF Interference

I also have had the problem with metal throttle connectors - though not all the time!! - and have fixed it with a nylon clevis.

I got some rings to stop it
Not sure what this means, but from your description they don't seem to work.
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Old 10-20-2006, 09:05 AM
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ecrt123
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Default RE: RF Interference

They are the ferrite rings, supposed to stop the glitching. It did seem to slow it down but it still is glitching. I will try the nylon connectors.

Thanks

Ray
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Old 10-20-2006, 12:03 PM
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Rodney
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Default RE: RF Interference

Ferite rings will do little or nothing to stop this kind of interferance. Check you plane over carefully for any metal to metal contacts that can vibrate or move relative to each other (a tight connection will be okay). Such things as flying wires rubbing togeter, metal clevis in metal horns, metal throttle pushrod (keep any metal wires or pushrods well away from any of the ignition wiring). Vibration can also cause the receiver to malfunction, be sure it is well padded with rubber foam or equivalent. Shock mount the battery also.
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Old 10-20-2006, 12:16 PM
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Newc
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Default RE: RF Interference

Where do these ferrite rings go and what are they supposed to do and how?
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Old 10-20-2006, 12:39 PM
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Default RE: RF Interference

Yea the rings do work to some extent. Hitec told me that they would help and they do. The reciever is packed in foam and zip tied so no viration going on there. The push rod (throttle is gold n clevis so no metal) all other pushrods are not going towards the engine or EI. As a mater of fact I took the reciever out of the plane and held it in my hand out of the plane with the engine running and still I get the jitters. The Feriate rings are metal rings that are magnatized to stop RFI. Electric pilots will swear by them.

Ray
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Old 10-20-2006, 01:39 PM
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Default RE: RF Interference

Ray,
My RFI problem was on a Super Hots with an Enya .60 glow engine. The throttle pushrod was a Nyrod.
But the metal clevis vibrationg on the metal throttle arm was cuasing the whole problem!
Now, I use a ball link on all of my planes and helis. There is virtually no slop and the RFI problem has never occured again.

I would also recommend soft mounting the engine. Since the spark plug lead is not shielded, you may want to buy some shielding and put it over the wire.
It is available from Aircraft Spruce and Specialty.


http://www.aircraftspruce.com/menus/el/braid.html

Keep us posted!
Doug
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Old 10-20-2006, 03:09 PM
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Default RE: RF Interference

I don't have a metal connector to the throttle, and the wire has a sheld arround it.

Ray
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Old 10-20-2006, 05:27 PM
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Newc
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Default RE: RF Interference

throttle is gold n clevis so no metal
I don't have a metal connector to the throttle
Got some bad news for you. The Gold 'N Clevis is indeed metal. See http://www2.towerhobbies.com/cgi-bin...p?&I=LXRU46&P=
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Old 10-20-2006, 06:53 PM
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Default RE: RF Interference

the ferrite beads should not be magnetized.they just reduce any rf generated by long servo leads most computer monitors and laptop power supples have the ferrite beads on them to reduce rf noise.again they just reduce it not eliminate it.if you have standard length leads you should not have a need for the beads if your intallation is properlly set up.how close to the rx is your tx when things jitter ?sometimes if you are too close you can swamp the rx.is the g2o an ignition engine?if so then there is a whole lot of things that need to be done to eliminate rf noise.
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Old 10-20-2006, 09:47 PM
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ecrt123
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Default RE: RF Interference

No the clevis is nylon, the rod is metal but the throttle arm on the engine is plastic. The reciever is 18" away from the EI module. I do not have standard length servo leads. The thing jitters close and far away with and without the antenna up.

I am thinking of getting a spectrum 7 as this will take care of the problem I think.

Ray
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Old 10-21-2006, 03:11 PM
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Default RE: RF Interference

you should have a metal shieldcovering the firewall,the ei should be mounted on the shield to prevent any rf from entering the fuselage.the pushrod to the engine should be nyrod,not metal or cable,a threaded rod at the end for the clevis is ok as long as it does not enter the radio compartment.the spark plug should be a resister type with a bocsh cover check the giant scale forum for even more do's with ignition engines.totally different than glow.also your two kill switches should be mounted on the metal shiels also.basically there should be no metal or wires going directly from the engine side of the firewall to the radio compartment.buying a new radio is not going to eliminate the rf problem,some people switch to pcm and think they are ok because the glitching is not picked up but thy do not solve the problem and at some point it comes back and bites them hard
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Old 10-22-2006, 11:48 AM
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Default RE: RF Interference

I found the problem it was the flying wires, I linked them together on the tail, I moved them apart and problem solved. Thanks for all the suggestions.

Ray
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