schafe3624

I have a glider with a hollow carbon fiber tail boom about 1" in dia. I previously flew it with the RX antennae running through the tube with no problems. The antennae extended out the rear of the tube about 4". I am switching to a micro RX which has a much shorter antennae to gain space for a variometer system. I think I read or heard that it is a bad idea to run the antennae through a CF tube. Does anyone have experience or recommendations on this.

Thanks

LesUyeda

Range check, and see how the two conditions compare.

Les

JohnBuckner

My Feedback: (1)

Ya know no one is about to tell you its the right thing to do but there is no way in the world you would catch me doing that. Of course I cannot say definatively its a problem but I can say I have had problems in the past with antenna proximity to carbon rods on 72mhz. Well i can say at least the problem went away after rerouting the antenna.

There is one obvious and glaring solution, get rid of the antenna. That is one of the prime advantages to 2.4 that is often over looked. The antenna can be anything from a short nubbin three quarter inch long on the side of the Rx to a few very short wires or a six inch wire buda with a three quarter inch nubbin that only needs to extend out the airplane in a complete carbon fuselage.

This is a prime reason for you to convert to one of the many fine 2.4 systems now not later.

John

Oberst

Some electric ARF aircraft have the FM 72mhz RX antenna running through carbon fiber tube. ( Like the Art-Tech Wing Dragon) I've yet to have a problem. It's just superstition and not a proven fact. Speaking from experience I say you're OK. Just make sure your antenna isn't hitting or running through any metal or touching your servo's.


Pete

JPMacG

My Feedback: (2)

I can tell you that the dish antennas used aboard communications satellites are made from carbon fiber. Carbon fiber is a good enough reflector that there is no need to add the weight and complexity of a metal film on top of the carbon fiber surface. I imagine that there are a thousand different varieties of carbon fiber, and what we use may be different. But, I would not chance it.

BTW, bugs have antennae, airplanes have antennas. Very common mistake.

JohnBuckner

My Feedback: (1)

If it has a one inch diameter tail boom that a 72mhz antenna running inside protrudes out the end only four inchs as stated by the original poster, then this is no Art Tech Parky. Its very likely this aircraft will indeed be used to the extremes of visual control and a solid RF link is imperative. This is even more evident since an electronic vario down link is being used.


Schafe it is very poor idea to speculate and a crap shoot to run a 72 antenna inside a big Carbon Fibre pipe. You have a lot of money invested and pennywise indeed is pound foolish. The cost of a simple 2.4 module/receiver for whatever your make of radio is so cheap it makes no since at all not to avoid the problem altogether.


John

speedracerntrixie

My Feedback: (29)

Back in 1996 when I was getting ready for an F3B sailplane team trials I wanted to make the slip on nose cone out of CF. I made only one after I did a range check and that one went directly to the garbage can. That CF nose cone which enclosed 2 servos the RX and battery cut my ground range check in half.







Oberst. are you sure that the tube that comes in an ARF is CF? Just because it's black don't make it carbon

Oberst

Yes it is, matter in fact I have it right here in my hand now, and just took a saw to make to sure. It isn't fiberglass that's for sure. Maybe some helicopter owners can chime in, I've seen antennas being hid through carbon fiber tubes and they didn't seem to have a problem either. Tell me those Glow or electric 3D helicopters are cheap, John.



Maybe that not all carbon fiber ingredients are the same? Again maybe someone who knows how to make carbon fiber can chime in and give us a lesson.

Do a range check like Les wrote, then make up your own mind what to do.


Pete

speedracerntrixie

My Feedback: (29)

I think we are seeing a trend here. My experience was reduced range. On a high performance sailplane, IMAC airplane or a Pattern airplane that can easily get 3000 feet away from the TX I would say it is very likely an issue. With a helicopter ( Wich I have competitivly flow too) or a small electric as you pictured the model just dosent get very far away. When I was flying helis I would have NEVERrun the ant down a CF tube. I do agree that a range check needs to be performed. Do so as per radio manufacturers instructions but also at the flying site so that the noise floor while testing is the same as which you fly.

JohnBuckner

My Feedback: (1)

Fact is Pete I never called your airplane Cheap, I called it a "Parky". There of course are some increditably expensive Parkys but this is not about money, it is all about the likely ranges the aircraft are going to be operated at.

Simple fact is Parkys or helicopters glow or electric are virtually never operated at the limits of visual control as is commonly done with even low cost medium performance gliders. Agine a solid RF link is a must not one where range has been impaired.

Now calling my experiances with range reduction in a glider as I posted, using 72 with proximity to Cf pushrods as well as the other posters experiance with the same reduction in similar setups, Superstition!

Well thats your option, Have a nice day Pete.


John

Oberst

I'm only telling about my experience and about what I've seen. Again I'll say it again, I had no problems and I haven't seen anyone else have a problem running a RX wire through a CF tube. I've had my Wing Dragon only a tiny speck in the sky and I got it back with no problems. So some park flyers can fly at a very good distance. True Choppers don't fly that far away, but I'm sure they could if the pilot wanted to. From what I saw it worked fine in the 3D Chopper, and it worked fine in my Park Flyer.

So John, it isn't a opinion- I'm only sharing my experience.

You too have a wonderful day John.


Pete

JohnBuckner

My Feedback: (1)

Ah so you can share your "experiance" which I did not dispute but you have no intention of allowing anyone else to express their "experiance" which is exactly what I did and I beleve quite clearly. Of course you likely did not pay any attention to that part of either of my posts.

Well Sorry but you do not and cannot control anyones experiances or their opinions.

So to the original poster. It so simple you can avoid all this angst just by getting rid of the antenna, well most of it anyway just by utilizing one of the many fine 2.4 systems.

Indeed I am having a fine day catching up on some bench time with a project, thank you

John

Oberst

John,

Touche!


Pete