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Old 01-05-2012, 05:23 PM
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markhamregular
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Default 72 antenna question

I am building a F20 Tigershark with a 72 radio. Is it OK to run the antenna on one side inside the fuse, turn it on the tail and run it back on the other side?
Thanks,
Old 01-05-2012, 06:08 PM
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speedracerntrixie
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Default RE: 72 antenna question

Overlapping the antenna like that can reduce range. By your description it sounds like a small model so may not be an issue. Do a range check per manufacturers instructions.
Old 01-05-2012, 06:41 PM
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vicman
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Default RE: 72 antenna question

You don't want to fold it back against itself. I have seen some guys wind it around a straw and be ok as long as it doesn't cross over itself.
I think Hitec even includes a little bobbin type thing to wind the wire around with some of thier recievers.
Old 01-05-2012, 07:40 PM
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dbacque
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Default RE: 72 antenna question

I tried the Hitec bobbin and found it to have very badly reduced range.

What I do when I can't fit a full length antenna in my planes is to use a Dean's one piece whip antenna. It's kinda scary the first time you cut the antenna off your receiver but don't worry, they work great.

http://www.aeromicro.com/Catalog/dea...na_1719693.htm

Dave
Old 01-06-2012, 01:39 AM
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Default RE: 72 antenna question

Hi!
I lay all my antennas inside the fuselage on my models, but on smaller models like my Q-500 racers I just let the antenna hang ut at the back.
Old 01-06-2012, 03:47 AM
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Default RE: 72 antenna question

No. Do not overlap or cut the antenna!

I fly 72mHz Warbirds and if you don't know it already, we hate to have our antenna show. This is what I do, I try and have my receiver all the way forward in the fuselage far up as possible. What I do is I drill little holes in the framing and run my antenna down the side of the fuselage away from any metal pushrods, servos or electronic equipment. You can run your antenna in a "Z" pattern down the fuse, but don't ever loop it back.


I enclosed and took the time to draw you the basic way I do it in the fuselage. When I build kits I use a thin straw and glue it in the frame so I can run my antenna down and out of the rear bottom of the frame with very little part of the antenna showing.







Pete
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Old 01-06-2012, 03:59 AM
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Default RE: 72 antenna question

I have ran the antenna down the inside on one side up a bulkhead then down the other side with on problems
Old 01-06-2012, 04:09 AM
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exeter_acres
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Default RE: 72 antenna question


ORIGINAL: markhamregular

I am building a F20 Tigershark with a 72 radio. Is it OK to run the antenna on one side inside the fuse, turn it on the tail and run it back on the other side?
Thanks,

as you are running the antenna down one side and back the other and not Overlapping.....
yes, this should work fine.

as always perform a good range check
Old 01-06-2012, 04:39 AM
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Default RE: 72 antenna question

Exactly!

A good range check will always tell you if you did everything right. I'm one of those who does a range check before I fly anyway, it's a good habit to get into, never know what could go wrong.


Pete
Old 01-06-2012, 05:38 AM
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Default RE: 72 antenna question

I ran it on one side not touching any metal or batteries, I made a turn on the back of the fuselage and ran it bacl on the inside whitout overlaping.
I like the Z pattern too. Thanks.
Old 01-06-2012, 01:59 PM
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KitBuilder
 
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Default RE: 72 antenna question

When i flew DLG's (short fuses) on 72.. i would wrap around a large thick straw and not overlap as stated... this was using a hitec neon 3channel and the minu ultra recvr i think it was called or whaterver came with the neon. I Would cut a slit at one end.. pass antenna through. wrap with approx 1/4" apart to other end and pass through another slit so wouldnt unravel. No issues with range of say up to 300 yards up when thermaling. The boom was even carbon though the straw was in the pod front area. it was a Gambler

Pics of the model built by others
http://www.wrightbrothersrc.com/gallery/gamblerag.htm
Old 01-06-2012, 05:10 PM
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Gray Beard
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Default RE: 72 antenna question

I have gotten away with running it back through the fuse and wrapping it around a dowel but I got to the point I just run it through the fuse and out the bottom and hang out. Folding or cutting is a no no.
Old 01-06-2012, 05:47 PM
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dbacque
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Default RE: 72 antenna question

Just to clarify, I only mentioned cutting an antenna in conjunction with using a Deans whip antenna. The long wire antenna is cut off to about 8", a connector is soldered onto the end and a base loaded whip antenna is connected. The jet guys use them all the time and they are every bit as reliable and full range as a full length antenna wire.

Dave
Old 01-07-2012, 08:01 AM
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Default RE: 72 antenna question


ORIGINAL: dbacque

Just to clarify, I only mentioned cutting an antenna in conjunction with using a Deans whip antenna. The long wire antenna is cut off to about 8'', a connector is soldered onto the end and a base loaded whip antenna is connected. The jet guys use them all the time and they are every bit as reliable and full range as a full length antenna wire.

Dave

Yes I've seen them Dave. Always wondered why they didn't just run the antenna through the body like some of us do. Is it because the jet engine, carbon fibers and electronics cause issues with the range? Just curious.

Please correct me if I'm wrong, I think what the author of the post is trying to do is hide the antenna like he's running a 2.4GHz RX.

Just remember markhamregular that you do want about 1"-2" sticking out at the end. It doesn't matter if you just have it hanging out or pressed against the fuselage.

Take Care,


Pete
Old 01-07-2012, 12:01 PM
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dbacque
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Default RE: 72 antenna question

I don't know about the jet guys, but I use the whip antennas when I can't get a full length antenna run in my fuselage. So the antenna is hidden inside all my planes. Larger fuselages I have a red NyRod tube built in and just run the regular wire antenna up through it. Shorter fuselages I install a Deans antenna. Looks nicer and nothing external to damage. Ever seen someone step on a dangling antenna wire and rip it out? I have!

Dave
Old 01-09-2012, 09:57 AM
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Default RE: 72 antenna question


ORIGINAL: dbacque

Ever seen someone step on a dangling antenna wire and rip it out? I have!

Dave

A few times I've seen it. Plus I think a dangling antenna looks terrible, but that's only my opinion.


Pete
Old 01-09-2012, 10:52 AM
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markhamregular
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Default RE: 72 antenna question

Peter,

Why is it important that only 1 or 2 inches hang outside?
If the 90% os the antenna is inside and work, what exactly make that small portion play an important role?

Thanks,
Old 01-09-2012, 03:26 PM
  #18  
Oberst
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Default RE: 72 antenna question

ORIGINAL: markhamregular

Peter,

Why is it important that only 1 or 2 inches hang outside?
If the 90% os the antenna is inside and work, what exactly make that small portion play an important role?

Thanks,

From what I understand it's good to have a little peeking out of the fuselage. The reason? It is so you will have a better chance of getting the full range, and less chance of a glitch or interference from your own electronics, pushrods and etc.

I have not ever completely hidden a 72mHz antenna in a fuselage, and for me to say to do so is not copasetic. Different radios have different signal strengths, so to be safe I suggest that you have at least 1-2" sticking out of the fuselage or get a whip antenna to be safe.

If you don't believe me read this:

http://www.rc-cam.com/ant_exp.htm

It talks about the different antenna experiments and explains the basics on how your RX works. You can come to your own conclusion about it like I'm sure you will, I only gave you my experience in what I do to hide the antenna without loosing range. If you were to look at my planes sitting on the ground, you would think I was running 2.4GHz until you saw my transmitter.

I have a inch exposed, but you wouldn't see it on the ground or in flight- you would only see it if I flipped the plane over, and pointed it out to you like I did when I took the pictures.

Having a inch or so sticking out helps to get a better signal in my opinion, less junk the signal has to go through. I don't know if that's true or not, but that's what I believe, and to me it makes sense. Hope it does for you?



Pete

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