Well, this is probably a dumb question, but I gotta ask. I have an optically isolated switch that I am thinking of useing on this Fox 4.8 gasser. My question is: Do I put the switch up close as possible to the engine, which will mean the control lead to the RX will be coming from up by the engine, possibly bringing back interference, or do I put the switch back closer to the RX, which will bring the power lead from the ignition back near the RX circuit? I have always been very careful about not having anything from the engine circuit anywhere near anything from the RX circuit, but there seems to be no way around it with one of these. I hope I was able to make my concerns plain. Let me know what ya think please.
Thanks,
Jim

I'm not sure what type of apically controlled SW you have. The one I installed in my Carden Extra (BME44) is as follows:
SW (with charger harness), fiber optic coupler (A) and battery were installed as close as possible to the engine. The fiber optic cable was ran so that the other fiber optic coupler (B) was installed as far as possible from the engine interference (near the receiver, more than 12" from the spark plug). This device has two fiber optic couplers (or if you want to call them fiber optic repeaters) the fiber optic coupler B is the one that is connected to the receiver channel.
Does this make sens?
Does it match your optic system?
I hop this helps.

Friar_Tuck

Yes, the kill switch component of the unit goes as close to the engine as possible. The send unit then goes near your receiver, and of course the optical cable runs between the two units with the sending unit then being plugged into your receiver.

I have two pictures I was going to include to show you, but they're too big to post in a message (byte wise). If you'd like these pictures I'd be glad to send them to you in Email. They are of a typical installation of a Fiber Optic Kill Switch in a 40% Edge.

PS. The reason behind a optical kill switch is to prevent interference from reaching your receiver. (Hence the fiber optic cable that runs from the switch to the send unit.)

Friar_Tuck

Figured out how to do it in two messages...

Friar_Tuck


Picture of the sending unit, near receiver(s).


Disclaimer> Not my pictures. My thanks to the owner for use.

we are talking two different beasts here, although I like the looks of that fiber optics setup too. What I have is a swicth that is controlled by the RX, with the ignition side of the switch being optically isolated from the RX side. So, physically, the RX feed, and the Ignition feed, come out of different ends of the same board. Hope this is clearer.
Thanks,
Jim

Friar_Tuck

Actually if I read your post a little closer I would have picked up on that, but of course I didn't. Sorry about that. :disappoin

I any case, the Fiber Optic Kill switch has been around for awhile and is around $55. It's just about bullet proof for no interference.
ElectroDynamics EDR-107.

In any case, the bright spot here is someone maybe able to use this info.