Would radio interference on a non pcm radio if someone turned on the same channel cause servos to lock up or become jittery. Would the aircraft fly in a squirrly path or lock and go down rather quickly. I was flying a stearman and she went into a left bank I tried opp ail but got nothing tried full up elev got nothing after the crash all controls worked perfectly. It was a very humid morning could I have stalled out after a series of loops and rolls. It was a 10 year old jr 5 channel radio.

Tim

I have been flying 20 years so I did everything properly on my end it was on ch18 a lower no. maybe a crane or fire truck got me!

Tim,

did you do a range check beforehand? Is your antenna sheilded in some way from receiving the TX signal?

What are your on off switches like? IF they are cheap nasty ones or have dirty contacts that can cause servos to "lock" as they pull current.

If someone had turned on a TX on your freq then yes the plane would be uncontrollable as you describe. Do you fly at a club that uses a freq board with pegs etc?

I'm not sure how the radio spectrum is manged in your country but here each band is specifficaly assigned to users with class licenceces. Though we use mainly 36Mhz and you guys are on 72Mhz it still falls broadly into a HF band.

Here the only users who could interfere would be military.

I would think fire trucks etc would be on UHF freq - around 850 Mhz so they should not be a problem and CB radios are 27Mhz. It is possible for a harmonic freq from a badly out of tune radio to jam your freq but it would need to be very close to you.

I recall in france that some disgruntelted nut got a scanner, copied down all the R/C plane freq of a club who flew near to him and then set up a sweep generator coupled to a linear power amp and TX on that band and systematically shot down every plane he could. He went to jail however.

Best bet is to get a scanner, maybe your association has one and monitor the band at your club and ask if anyone else is having probs.

good luck
Peter

Hello Tim. Have you checked out your crystals (Tx/Rx)? I had a problem with a plane last year. After repairing it after a "hard" landing, I notice that the controls were jittery. I thought it might be some kind of interference (a microwave tower is near the field). It cleared-up after I got the plane started. So I decided to fly.....BIG MISTAKE!! As I started to turn on final for a landing, the plane continued to bank even with the stick in the center. Nothing I did with the Tx made any difference. The crystal in the Rx had been damaged from the previous crash. It must have been the vibration from the engine that finally made the it fail. The jittery controls during start-up was a dead give away (in hind sight). It was the Rx losing communication then regaining it. Long story short, try replacing at least your Rx crystal to see if that clears up the problem. $10 or $15 is a small price to pay to insure that you stay in communication with your plane. My 2 cents worth. Good luck.

Later,

Mike

I bought a brand new radio a futaba skysport fm and ordered a new stearman. I fly alone and do not belong to a club. I was flying an old radio which has been in other crashes since I had flow 20 flight wo incident i thought it would be ok. New radio with a 1400ma pack should give me confidence. The same thing happened to me twice before in a 10 year span. I fly at a local soccer complex with full permission and there is a cell towewr in the corner but I have not had any problems when i use newer equipment. I think the x-tals after years of vibration get out of tune. 10 years is a long time to keep a set in use. Im getting rid of all my old gear and will not use it except for the servos which should be ok

I am using an mpi switch with a built in charge jack. also the kit says to mount the rx and batt back to back on a piece of ply. Is this a good idea or should I mount the batt up front by the tank/ Im running a saito 100 so no ign interference to worry about

It probably wont hurt. I would say place the Rx and battery where ever you can without interfering with your CG.

Jim

Hi!
Hope you have lots of foam rubber around the Rx and batteries....!?
Have you range checked your equippement...I use JR myself ...since 1980...since they started and have had no problem whatsoever with my 3 JR radios...Now using a JR 388.
It sounds to me that you ran out of range...could be one dead cell in the batterie pack ..have you checked the voltage in each cell in the pack?!
Range with a good JR radio with the antenna collapsed chould be around 100m...without any servo jidder!

Regards!
Jan K
Sweden

One thing to check is your throttle cable. Are your using a metal cable, if you are make sure that it is not touching anything metal. I was having problems and it ended up being that the throttle cable was rubbing on the engine case.

with cells shrink wrapped how do i check indiv. voltage w/o taking wrap off

You have to take the shrink wrap off. OR, use meter leads with a sharpened tip to poke thru the wrap. I have had a battery pack open up between cells (broke the weld bond). It was about 3 years old in a trainer I used for skydivers and dropping toilet paper (funflys). There was no bad vibration and the battery was insulated in foam. It just happens. I am also hearing about this more often now from others at the club and here. Since I've gotten into giant warbirds I spend time checking the packs visually at the weld points and cycle them a few times when new just to be sure.
Edwin