nucleusbrains

Okay. I'm currently flying a Tower Trainer.40 which I got from a friend who's long gone brother assembled. It flys well but now I'm assembling a CMP Corsair F4U 50. So how do I route an antenna through my plane for my radio? Im green on this so you may fire at will.
Any help is appreciated.
C.P

RussianFlyer

Routing the antenna to the outside of the fuselage is the best option in the interest of clear signal reception. You will need to make a strain relief for the antenna, which is nothing more than a piece of a servo arm. Sport Aviator e-zine has a good explanation for this
[link=http://www.masportaviator.com/ah.asp?CatID=1&ID=128&index=2]HERE[/link]

On a warbird, you may want to route the antenna out of the bottom of the fuse in the interest of preserving scale looks. HTH

opjose

Actually it depends upon the plane...

Most wood planes and most fiberglass fuselage planes are RF transparent, so you can safely route the antenna on the inside of the plane to the tail.

A Carbon Fiber or composite fuselage is a different story it seems.

It's best to have as straight of an antenna as possible so you can route it as far back as you can by fishing it through then out, up or let it hang.

-pkh-

My Feedback: (2)

Many ARFs have an internal antenna tube that runs the length of the fuselage, and exits out the bottom at the back, near the rudder. I've done the same thing with SPADs... just glued a long piece of push rod tubing insid the fuse and ran the antenna through it and out the back of the plane. I put a servo arm "strain-relief" on either end of the tube, so the wire doesn't move around.

mbilar1

You're saying there's no reason to have my antenna on my trainer outside the fuse and tied to the fin with rubber bands etc.?

-pkh-

My Feedback: (2)

You don't have to do that... but that's perfectly fine as well.

The internal antenna tube approach takes a little work, running it out a hole and banding it to a T-pin on the a rear stabilizer is a quick (but less attractive) way to do it. I like the internal approach for looks, and I feel I'm less likely to catch the antenna wire on something and pull on it.

As long as the antenna is stretched out straight for most of it's length, you've got some strain relief, and it won't catch on any control surfaces or linkage, you should be fine...

bruce88123

It's good to get the antenna AWAY from metal pushrods running back to the tail so routing it up to the top of the tail IS beneficial.

-pkh-

My Feedback: (2)

Why are you afraid of you're metal pushrods?

CGRetired

My Feedback: (1)

Any metal that runs parallel to the antenna can and will cause inteference or reduction in the received signal or both. It's always best to run the antenna as far away as possible from any metal pushrods... of course, within limitations.

What I often do is make a small channel right behind the wing in the wing saddle area, right in the middle of the fuselage, run the antenna up this channel and out. Then I put a little tape over that channel to keep the antenna centered and in the channel. I then run the antenna along the very bottom of the fuselage and tape it with blenderm or clear packing tape.. or even clear or matching color monocoat all the way back as far as I can get it. This will keep it centered and out of the way and, most importantly, in direct view of the transmitter for most maneuvers. I have NEVER encountered a problem running it this way.

One thing you want to make sure you do, no matter what you do or how you run the antenna. Never shorten the antenna. Use some sort of strain relief to prevent the antenna from snaking back into the fuselage. If this happens, well, what you will have on your hands is a rebuilding or repairing process on your hands. If the antenna snakes back in (caused by the inevitable vibration in any plane), it will probably bunch up right behind the receiver and will be totally useless.

I hope this helps a bit.

DS.

bruce88123

The pushrods are also constantly acting as antennas, they just aren't connected to a RX. But via "inductive coupling" they can transfer RF energy into the actual antenna. This energy can be detrimental to flight.

"In electronics, inductive coupling refers to the transfer of energy from one circuit component to another through a shared magnetic field. A change in current flow through one device induces current flow in the other device."

-pkh-

My Feedback: (2)

I don't see how it would cause interference. Unless you're running current through your pushrods, they're not generating a magnetic field to inductively couple into anything. If you ran the antenna right next to a push rod, it would block the antenna at a specific angle, but once you get an inch or more of separation, that's not even an issue. To each his own...

bruce88123

Well, you're not an Electrical Engineer. CGRetired and I both are. Just maybe we understand this better than you.

-pkh-

My Feedback: (2)

Actually... I am... I have an MSEE...

bruce88123

Then you should know better. You know that the coupling drops off sharply as the distance increases. This is why I said in my orig post to keep them away, not in the next county. If you run them at right angles that also improves the condition but hard to do within a fuselage.

opjose

Bruce is correct.

I've seen, first hand, engine generated noise affect the receivers, as the engine RF is being picked up by the pushrods.
This blankets the RX antenna, causing glitches.

It drove me nuts until someone pointed the problem out to me.

Change the intersection angle or route the antenna away from the metal pushrods and the problem goes away.

nucleusbrains

Where can I get a good antenna and everything else I need for this?

opjose

The antenna is part of the receiver.

Which receiver you use of course should conform to your TX...

Check out www.towerhobbies.com and www.horizonhobby.com to get you started.