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dealing with antena length

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Old 05-05-2018, 05:07 AM
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r ward
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so I put my old futaba attack 4 in my high wing trainer. the antenna comes out of the fuseage at the trailing edge of the wing and back to the top of the vertical stab. I tension the antenna with a rubber band slip knotted around the antenna and then attached to the vert. stab so that it puts just a tiny bit of tension on the antenna (there is a stop on the antenna that sits in a notch so that the antenna is not being pulled out of the Rx.) there is about 8 inches of antenna that goes beyond the rudder with no way to put tension on it to keep it straight. is it better to redirect that portion of the antenna and attach it to something (I could run it down the trailing edge of the rudder) or let it dangle free in the air stream behind the plane ?.
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Old 05-05-2018, 01:52 PM
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Ward, It's usually full length even it's just dangling free. For the best reply try the Futaba factory direct forum. Dan.
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Old 05-05-2018, 07:37 PM
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Just let the excess antenna length trail behind the rear attach point. No problems, no harm. I had airplanes that I flew for years with that setup with zero problems.
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Old 05-07-2018, 12:14 PM
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Yep we just let that extra section of antenna dangle, no harm in doing so.
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Old 05-07-2018, 06:08 PM
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r ward
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sounds good,.... than-you.
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Old 05-07-2018, 06:46 PM
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All Day Dan
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I tried to relive my youth by rebuilding my first R/C model, a Berkeley Bootstrap. As you can see, the antenna was strung through the inner plastic push rod of a Sullivan push rod. Just don't use a metallic support. I got old anyway. Dan..

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Old 05-08-2018, 01:24 PM
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r ward
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Dan, I did the same thing, except I used the unfilled portion of an old ballpoint pen's ink tube. two micro zip ties hold it across the top of the vertical stab and the excess just drapes out the back end.
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Old 05-17-2018, 05:28 PM
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Very nice workmanship on the Bootstrap!!
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Old 05-20-2018, 04:03 PM
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Originally Posted by r ward View Post
so I put my old futaba attack 4 in my high wing trainer. the antenna comes out of the fuseage at the trailing edge of the wing and back to the top of the vertical stab. I tension the antenna with a rubber band slip knotted around the antenna and then attached to the vert. stab so that it puts just a tiny bit of tension on the antenna (there is a stop on the antenna that sits in a notch so that the antenna is not being pulled out of the Rx.) there is about 8 inches of antenna that goes beyond the rudder with no way to put tension on it to keep it straight. is it better to redirect that portion of the antenna and attach it to something (I could run it down the trailing edge of the rudder) or let it dangle free in the air stream behind the plane ?.
Realizing you're an experienced modeler based on other posts, thought to chime in here for the benefit of others that may venture across this thread: common practice with 72 MHz is to run receiver antenna through a closely spaced two-hole stop for strain relief close to the receiver itself that runs out through a hole in the vehicle and then goes through another one with two closely spaced holes and an open hole or "hook" for the rubber band (slack tensioner) close to an anchor point (I use a straight pin) outside the vehicle.

Some frown upon having free excess length of antenna flopping around in the breeze after the tensioner (which can put holes in unsupported covering of fast moving aircraft) so some degree of shortening may be in order...
Shortening - not in the sense of cutting - but rather by wrapping or coiling excess around something to take up unwanted length. The antenna wire must not cross over itself or in any way double-back over itself. Have even shortened to the point at which entire antenna remains inside the aircraft. As always, perform a transmitter antenna collapsed range-check before the first flight.

Never had a problem making this fairly common mod and flying to limits of visibility of model.



Last edited by H5606; 05-20-2018 at 04:19 PM.
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