Lnewqban

How to troubleshoot intermittent radio glitches?

I have been flying the same model with the same Futaba 72 KHz Tx/Rx for three years, having not a single glitch, until last weekend.

During each flight, it suffers one unexpected radio glitch that last a fraction of a second, but it shakes all the control surfaces violently.

I had four flights Sunday and four more yesterday, and it happened during each one.

I have noticed that each time it happens, I have been pointing the antenna to the model; however, it does not happen each time I do it on purpose.

The batteries have been checked, and both are fine.

What it could be?
What to check?

DadsToysBG

My Feedback: (35)

Well first off. After the first one I'd quite. Why would you do 8 flights? In any case your best answer is to send it to Futaba with a letter telling them what happened. If it comes back with a clean bill of health, then start checking one servo at a time. Dennis

Lnewqban

Thanks, Dennis.

You are right; however, I did not believe was something internal, since I never had a problem before.

I thought it was an brief interference form some source, and it happened so briefly.

Now, I see it follows a pattern.

safeTwire

My Feedback: (2)

I would install a brand new switch harness, and a brand new RX/Airborne battery.

While system is on, tug(gently/as needed) on antenna to check for loose connection onto RX circuit board.

Look for metal-to-metal contact anywhere, especially up front/engine installation.

As suggested, pack it up and get it verified once again by the factory. Well worth the cost.

Lnewqban

Thanks, safeTwire.

I will replace those before the next flight, and will check antenna and metals.

The only recent change to the system has been the addition of a low battery / plane locator alarm.

For installing that alarm, I have manipulated the Rx, which has been untouched for two years or so.

How is the procees of sending it to the factory?
How much are the cost and time?

Again, thank you.

A.T.

"I have been pointing the antenna to the model; " is an absolute no no unless a rubber duckie antenna:
How well is the receiver protected from vibration? Rubber foam hopefully not plastic foam?
Antenna still nice and flexible, not broken part way causing an intermittent connection?
Remove and replace receiver crystal in case it has vibrated loose/dirty contact on legs.
At three years old, your batteries are at end of shelf life...running on reserve.
Was range test performed with motor running?

See also sub Sections
"Receiver - FAQ, guides and aids to best reception.."
"Range check and Range problem solving"
"Glitches & Jitter in Receiver, Servo & ESC - causes and cures " under
"Radio Systems, Accessories, Alterations and FAQ." at:
Alan's Hobby, Model & RC FAQ Web Links

Regards
Alan T.

Lnewqban

''I have been pointing the antenna to the model; '' is an absolute no no unless a rubber duckie antenna:
I have done it many times befroe with no problem. [sm=bananahead.gif] It is a regular antenna.

How well is the receiver protected from vibration? Rubber foam hopefully not plastic foam?
Rubber foam, perfect isolation.

Antenna still nice and flexible, not broken part way causing an intermittent connection?
It looks allright, but I have to investigate in detail.

Remove and replace receiver crystal in case it has vibrated loose/dirty contact on legs.
At three years old, your batteries are at end of shelf life...running on reserve.
Was range test performed with motor running?
Range test with engine spinning, no problems.
Have to check crystal.

See also sub Sections
''Receiver - FAQ, guides and aids to best reception..''
''Range check and Range problem solving''
''Glitches & Jitter in Receiver, Servo & ESC - causes and cures '' under
''Radio Systems, Accessories, Alterations and FAQ.'' at:
Alan's Hobby, Model & RC FAQ Web Links

Regards

Thank you for the links, Alan; that's great information.

BuschBarber

My Feedback: (2)

It does not matter how many times you have successfully pointed the antenna directly at the model, in flight. It is a KNOWN Fact that your Rx can loose the signal under those conditions. I do not remember the technical details as to why this happens, but it has been well documented for many years. It is even wise not to point the antenna of a 2.4 radio directly at the aircraft.

It is just one of several possible reasons why you might have glitches in the air. It is not the only reason.

If you know that a certain behavior is Suspect, just don't do it any more and you will have one less chance of having a problem.

Lnewqban

Indeed!

It is just a bad habit that never had consequences before.

Thanks, BuschBarber