extending servo wire

[bangka]

i have extended my servo wires so that i can place my servo at the back of the engine, and have my receiver at the front of the boat. i have extended it more or less 2feet. will this create problem? i have just read in another forum that this might cause radio interference. i have tried my boat in the garage, didnt notice any prob.
if it does creates problem, how do i solve or avoid one?
thanks!!
ernest

[Ron Olson]

I don't know what if any problems that it may cause. The fliers with the huge planes have their servos way back by the elevators and rudders so they must be running some really long extensions.
What kind of boat are you installing this in? Are you doing this just to get the rudder servo closer to the rudder? The people with front or midship mounted radio boxes have had to run long linkage back to the rudder. I went to a carbon fiber rod with titanium ends to avoid flexing in my Sport 40.

[Doc]

Ernest,
Can it cause problems? Maybe, but try it and see before wasting too much worry on it. Any wire or conductor can act as an 'antenna' if it's length is such that it picks up 'too much' of the RF signal. That unwanted signal can be rectified (sort of) and can mean some unwanted electrical impulses in that particular circuit. One way of 'curing' that is by wrapping the wire(s) around a carbon rod, or a ferrite rod, or by running the wire through a torroidal thingy made of either substance. That acts sort of like a transformer which will 'filter' out the unwanted signals. Grounding the wire through a properly sized capacitor does the same thing. Both depend on the frequency of the radio signal and can get sort of 'hairy' to figure out. Best thing is to see if theres a problem to start with. If not, then there's no problem. (Probably won't be a problem, in most cases.) If there is a problem then get ready for some of the oddest ways of correcting it you've ever heard of! Good luck...
- 'Doc

PS - none of the above is "correctly" stated as far as most electrical knowledgable people are concerned, but then if you're not an electrically knowledgable person it may make more sense than the correctly stated version. It will give you sort of an idea of what you can/can't do, and this is sort of a disclaimer to cover the most delicate part of my anatomy...

[bangka]

i will be using this on a gasser airboat. i have tested and so far so good, but i havent really run the boat yet, maybe this weekend, if it'll not rain here.
i have another question, in a gas boat, how long does the receiver battery usually lasts? i have 4- 600mah nicads for my receiver, with 3 standard s3003 servos, and just wanted to have an idea if how long will it last. 30 mins? 1 hour?
thanks! i dont want to have a dead boat in a river.

[Rex R]

I could be wrong...but from reading my radio manual and checking a few of the hi-tec spec.s I came up with rx 30ma, 3 servos(180ma ea), total 570ma, figure about an hr max.

[bangka]

thanks for that info rex. i have been looking and couldnt find out how much current a servo is using. is 180mah maximum current for the servo?

[Rex R]

thats a no-load operation, uses 8ma just sitting doing nothing, 180 to op no-load(or a very light load say fer instance throttle or rudder(with the boat not moving), current draw goes up with the load. but since you prolly wont be moving the servos continually...my guess is prolly a safe one. still I would play it safe for the first few runs and approach the hr mark gradually.