Servo extension wires

[middle_watch]

Apologies if this is one of those noddy questions but can you extend the control wires to a servo from the receiver?

The reason I am asking cannot be new, all texts advise keeping the speed controller, motors and receiver well apart from each other. On my troubled Leander build to conform to that I ended up with the rudder servo midships at the extent of it's cable, to turn the rudder I ran a rod aft to the rudder, the same technique used in RC aircraft.

But the wood rod bends when pushing against the rudder arm and then snaps straight, the consequences in manouvering have me shuddering. I have bought a piece of light metal hollow tube to replace it but really it would be better to site the servo closer, so: can I extend the cables or will that introduce the dreaded hunt onto the servo?

Thanks in advance.

[Andy G]

Apologies if this is one of those noddy questions but can you extend the control wires to a servo from the receiver?

Yes. And here's the noddy extras:

You can buy made-up servo extension leads. But they cost money, and that's an anathema. If you want to do it yourself -

Make sure the polarity's correct at both ends when extending a cable. D'uh!

Use replacement cable of at least the same gauge/type as the current ones.

Don't go mad with extending a cable - an extension of 50cm is never going to drop the volts enough to matter. 5m might. 50m (!) will.

Try to run your servo wires as far away from the power lines as possible.

You can shield the power cables if you experience problems. Box and/or conduit them in with metal to make a Faraday Cage. My mobile phone is dead in a lift - you could find that isolating the power side of things inside metal works for you.

In TV audio situations, there's a type of mic cable called star quad which was designed for a low susceptibility to interference. It carries two pairs of conductors, and it's twisted along its length with an earth wire wrapped around the outside. So you might find that twisting a long servo cable run along its length, while looking a little ugly, helps reduce servo chatter - if it's present at all.

I think you're doing the right thing with regards to reducing the length of mechanical linkages. I'd sooner trust the 'lectrics than whippy control rods.

Good luck!

Andy

[kennylibben]

i never trust myself to correctly wire it up right... i just buy the extensions.... they are cheap. Might wanna look in your radio box, i dont know about other companies but Airtronics always provides some extensions with their radios.

[Sean Hert]

I'd just buy servo extensions- but you can also buy servo wire. I've got some, for when I need to do a custom servo run (rotating turrets, Kenny). Re-soldering can be a pain tho.

I don't know of any brand of radio that either isn't compatible with or has it's own servo extension.

[middle_watch]

Great stuff thanks, my model shop does not stock extensions, I had already posed the question there and got blank looks, you would think these places would hire staff with an interest in what they sell! But then you would start expecting PC World to hire staff who know a EPROM from a highly deserved kick up the rear.

I will try a visit to Maplins and if necessary pick up some instrument cable, the point about using twisted pairs is well taken, thanks, I remember now they were standard on synchros back when we had analogue gear.

Bad news is more surgery on Naiad's deck, note to self, don't be so quick to nail the deck down next time!

[Andy G]

The Maplin website lists servo equipment (suitable for Futaba stuff) - and naturally they quote a price for a 20cm extension which is cheaper than buying a plug/socket pair and cable.

Still, three-and-a-half quid for 20cm would probably make life easier...

Regards,

Andy (now logged in again)

[kennylibben]

middle watch - if the other place doesn't have them you could always just buy some online, maybe grab anything else you need such as batteries and whatnot to help make the cost of shipping worth it more.

Also, there is a reason man invented screws!


Sean - i might be calling on you down the road then!

[Sean Hert]

C'mon by the store sometime!

[kennylibben]

hmmmmm, Columbus is mighty far to drive for a hobby shop!

However i suppose i could swing by some time while on my way to an escapade on High Street, or after one of the games.