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ferrite rings

Posted: October 27th, 2017, 9:27 pm
by Arthur Fielding
Hi
I would appreciate sum advise please
I have a power box ignition kill switch working with a OS 33 petrol engine , the engine has started to miss fire, and I notice the red ignition light goes out. Now as this unit works through the RX I believe it is picking up interference from the ignition unit( yes it is 2.4 meg) so I wont to fit a ferrite ring, my question is, what lead do I put it on ,the one from the ignition unit to the power box or the one from the power box to the RX?
Thanks for your time
Arthur.

Re: ferrite rings

Posted: October 28th, 2017, 10:54 am
by Barrie King
Before going down the ferrite ring route I would check the plug lead for earth continuity, I have found in the past that any break in this area will give rise to Miss fires and radio glitches even on 2.4

Re: ferrite rings

Posted: October 28th, 2017, 1:05 pm
by Tony Collins 1073
Hi Arthur. Although I have never used a powerbox kill switch, the reason for glitches is normally that RFI is getting back into the receiver through the powerbox to receiver signal lead. The normal procedure would be to place your ring on receiver plug lead close to the receiver. It won't hurt to put one on the ignition to powerbox lead close to the powerbox.
I personally think that a hex inverter which inverts the signal and then inverts it again and also boosts the receiver signal is a far better idea as eletronically it completely isolates the receiver from any RFI trying to get in. A simple 4069 hex inverter is all that is required. An even better way would be to use a mechanical switch. No connection to receiver and therefore no interference can get back in.
Tony
PS. You must also ask yourself why a system that was previously working OK has decided to play up.
HT lead/plug connection maybe.