Sheilded Cable for Extensions?
03-09-2005, 04:57 PM
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Sheilded Cable for Extensions?
Is anyone out there using sheilded cable to make their extension?
I just talked to a well known RC retailer, and when I told them that I needed 4' HD extensions for my jet, he said "why not just use sheilded cable....... cut the connector off the servo, solder the wire in line, and put the lead on the other end to plug into the receiver."
Is anyone out there really doing this? What are you guys with the really big birds (Bryce???) doing?
I just talked to a well known RC retailer, and when I told them that I needed 4' HD extensions for my jet, he said "why not just use sheilded cable....... cut the connector off the servo, solder the wire in line, and put the lead on the other end to plug into the receiver."
Is anyone out there really doing this? What are you guys with the really big birds (Bryce???) doing?
03-09-2005, 06:44 PM
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RE: Sheilded Cable for Extensions?
If you have a long servo cable run, you can lay down a strip of sticky backed aluminum foil, then the servo cable, and another layer of foil on top. Not only does it secure a long cable run down the length of the fuse, but it can shield it too, subject to the two foil layers making electrical contact thru the adhesive layer. The question is, do you connect the foil to the -ve/GND supply to your Rx ?
A ferrite bead would suffice also. But a ferrite bead has weight and will be whipped around at high G manouevers, so secure the connections etc.
It's not as if these jet models are as bad as gasser/weedwhacker models.
A ferrite bead would suffice also. But a ferrite bead has weight and will be whipped around at high G manouevers, so secure the connections etc.
It's not as if these jet models are as bad as gasser/weedwhacker models.
03-09-2005, 06:58 PM
#3
RE: Sheilded Cable for Extensions?
Mark,
I've been using 3 conductor shielded cable for years with excellent results. I currently have them in my KingCat from the elevator and rudder servos, the full length of the boom into the fusealge. By cutting a 6" extension cable in half you have your male and female plugs to solder onto the shielded cable. When you solder the connector onto the rx end, also solder the shield onto the negative wire. On the servo end cut the shield off and do not solder it to any wire. Any stray rf is then grounded. A big plus is cost, last time I bought cable I paid 11 cents per foot. The brand that I have used is Belden 8771 3C22, which is 3 conductor 22 ga.
You may want to rethink the idea of soldering a long extension directly to the servo pigtail. If you need to change the servo you would have to do more soldering. Having a long extension with plugs on both ends is more versatile.
I've been using 3 conductor shielded cable for years with excellent results. I currently have them in my KingCat from the elevator and rudder servos, the full length of the boom into the fusealge. By cutting a 6" extension cable in half you have your male and female plugs to solder onto the shielded cable. When you solder the connector onto the rx end, also solder the shield onto the negative wire. On the servo end cut the shield off and do not solder it to any wire. Any stray rf is then grounded. A big plus is cost, last time I bought cable I paid 11 cents per foot. The brand that I have used is Belden 8771 3C22, which is 3 conductor 22 ga.
You may want to rethink the idea of soldering a long extension directly to the servo pigtail. If you need to change the servo you would have to do more soldering. Having a long extension with plugs on both ends is more versatile.
03-09-2005, 07:30 PM
#4
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RE: Sheilded Cable for Extensions?
Been doing it the same way for about 15 years. Started on an open class sailplane that had over 50" between the receiver and aileron servo, the thing would go nuts while you held it getting ready to launch. Going to the shielded cables cured it. I now use the shielded cable for anything over 12" in a jet. I typically use one of the 12" extensions for the connectors since you can get them with gold plated contacts, and then cut each end to the length needed and solder it to the shielded cable.
In my KingCat I did it a bit different. I ran the signals for one aileron and one flap through one cable, and the signals for one rudder and one elevator in another, and then ran a pair of 14 gauge wires all the way to the back that supplied power from a separate battery. This was of course duplicated on the other side. You have to be careful to do the ground correctly in this setup. This way the power to the receiver and ECU is not effected by the draw of the flight servos.
Steven
In my KingCat I did it a bit different. I ran the signals for one aileron and one flap through one cable, and the signals for one rudder and one elevator in another, and then ran a pair of 14 gauge wires all the way to the back that supplied power from a separate battery. This was of course duplicated on the other side. You have to be careful to do the ground correctly in this setup. This way the power to the receiver and ECU is not effected by the draw of the flight servos.
Steven
03-09-2005, 09:19 PM
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RE: Sheilded Cable for Extensions?
Thanks, guys for easing my mind here! 
Mike, where did you buy your wire? This project is for a jet that I'm getting ready for BITW, so time is running short!
Duke, that's a great link! I'll spend more time checking it out......
Mike, where did you buy your wire? This project is for a jet that I'm getting ready for BITW, so time is running short!
Duke, that's a great link! I'll spend more time checking it out......
03-09-2005, 10:36 PM
#7
RE: Sheilded Cable for Extensions?
Mark,
Belden cable is available at most electronic stores. Generally, places like Radio Shack do not stock shielded cable. Places that cater to electronic technicians, ham radio operators, etc. is where you'll find the shielded cable. A quick glance in your Yellow Pages will help you.
Belden cable is available at most electronic stores. Generally, places like Radio Shack do not stock shielded cable. Places that cater to electronic technicians, ham radio operators, etc. is where you'll find the shielded cable. A quick glance in your Yellow Pages will help you.
03-10-2005, 04:39 AM
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RE: Sheilded Cable for Extensions?
I also been using Shielded cable for years and wouldn't do a big or expensive project without it. I buy mine from B&B Specialities. don't have the number handy, but easy to find on web. Dick has a web site and can purchase from there but I would call him and ask away.
Chuck.
Chuck.
