Coiled antenna in Supra

[jofo1]

I wanted to get a few opinions on this antenna solution for my new Supra. I've taken a .75in sq x 6 in long section of blue foam and coiled the antenna around it, about an 1/8" between wraps, and placed it inside the carbon/kevlar pod. A range check at 75' with the tx antenna down showed no glitching at all. I will check to see what the glitch free antenna down range will be, my guess will be well over 100', but I wanted to see what others thought.

The rx is a JR 790 scan select, tx is a JR 8303.

Thanks in advance.

jofo

[glderguy]

Not sure about the coiled antenna but Im getting between 250 to 300
feet on my range check with antenna running outside of Supra pod.
Walter

[rdwoebke]

Err... I think coiling your RX antenna is a really bad idea. I could be mistaken, but I don't think you will like the results when you fly the thing.

Ryan

[ClayH]

Jofo,

I'd like to hear how your tesing goes. My antenna exits the side of the pod under the wing and I leave about 8 inches hanging down loose.Reception is awesome,but I would like to clean it up. I wish I'd run it through the wiring harness into the wing.

Clay

[Robglover]

jofo -

The coiled antenna sounds scary to me, especially inside the hybrid cloth. But, if it works then it works.

I'd carefully check antenna down ground range with other folks transmitting nearby. I've found that with one of the other manufacturer's synth rx the range was really good without other transmitters in the area, but really lousy when other folks started showing up.

I'm currently running my (lengthened) Supra antenna out the bottom of the fuselage aft of the towhook. Then back to the rudder, up the trailing edge to the top of the rudder. I use 30 gage stranded wire, and tape or lacing cord where necessary to keep everything in place.

I'm getting well over 200 paces of antenna down range - I generally walk out to the turn around at close to 300 paces and it looks to still be working but my eyes aren't good enough to see if there is any chattering at that distance. I've been getting this result with a variety of receivers and a Futaba 14MZ transmitter. I had similar results with prior tranmitters from JR and Multiplex.

[jofo1]

Thanks for the responses. I will see what the terminal range is on the ground and report back. Btw, these synth rx's are a great advance for our hobby. I'll let you all know.

[rdwoebke]

I will see what the terminal range is on the ground and report back.

Also, when you do your range test, don't just sit your plane on the ground. This has a grounding effect that JoJo documented. It is best to have it on some kind of stand (a box or something) or have a friend hold the plane.

Ryan

[DLD]

You might be interested to know that power pylon racers have been coiling their antennas for years with excellent results. Their fuselages are very short and they don't want the antenna sticking out in the wind. The most important thing seems to be not let the antenna wire go over itself, make sure as it is coiled that the coils stay slightly separated. Quickie 500s fly at over 160mph, mostly close in, but when the race is over they climb to tremendous altitude, wait to run out of fuel and then glide down for a dead stick landing. If you can get a good range check it should be fine.

David Layne

[Brian Wa]

I didn't think Quickie 500's had carbon/Kevlar fuselages, that would make a big difference.

Personally I would not use a coiled antenna.

Brian

[David Forbes]

Check this out http://www.rc-cam.com/ant_exp.htm

[S-1-11B]

hey Joe,

When will we get to maiden our new planes?

[schrederman]

Another point about the pylon racers is that they don't fly at the limit of sight, as we sometimes do...

Jack Womack

[DLD]

Jack and Brian,

You haven't been to too many pylon races, have you? Modern pylon racers are made from the same high tech stuff as sailplanes, they can pull upwards of 30Gs, and after the races many of them are flown to heights that many thermal flyers would consider speced out. The fuselages are not usually all carbon, but the have carbon reinforcements down the sides. The carbon is undoubtedly more of a problem than the coiled antenna. Like I said before, as long as the wire is kept seperate on the part that is wound it will work fine, and only wind as much as you need to shorten it to the length you need. I would not recommend winding the entire length.

DLD

[jofo1]

hey Joe,

When will we get to maiden our new planes?
I will be ready this weekend, waiting on a 6-pin connector from soaringusa. Other than that, she's ready to go, and looking very fit for the task I might add. :)

[jofo1]

I will get to testing this setup soon and will put up some pictures and data on the range check.

[glderguy]

Hey Joe, where are you going to maiden your Supra? I have to work Sat but if
you are flying Sunday Id be happy to bring my winch out for you. If you havent yet found a high start and want to use one for your maiden I have one of those you could use as well although it is more of the short bungee type. I am sure your Supra will be just fine on maiden but I usually dont like to maiden planes on high starts, especially mega bungee types as if by chance there is an issue its pretty hard to abort the launch w/high start. Dont ask how I know.
Walter

[jofo1]

Hey Joe, where are you going to maiden your Supra? I have to work Sat but if
you are flying Sunday Id be happy to bring my winch out for you. If you havent yet found a high start and want to use one for your maiden I have one of those you could use as well although it is more of the short bungee type. I am sure your Supra will be just fine on maiden but I usually dont like to maiden planes on high starts, especially mega bungee types as if by chance there is an issue its pretty hard to abort the launch w/high start. Dont ask how I know.
Walter
Walter,

Thanks very much for the offer. Unfortunately I have international travel starting on Sunday. I will probably will go for a few test glides and maybe try to get some slope time with the Supra on Saturday to trim it out (weather permitting of course). I would love to get on the winch the following weekend if you can swing it. My friend Sean also has a new Pike Superior he wants to maiden, I will ask him to join us if you don't mind.

jwf

[glderguy]

Sounds good if you want for the following weekend, your friend is more than welcome. Give me a PM when you get back in town.
Walter

[Stan Myers]

An internet friend of mine who has designed high performance gliders and electrics(I'm not mentioning his name as I don't have his permission) gave me the following advise about antenna's as the relates to carbon sailplanes. He suggests that you wind the antenna down the boom on the exterior. That way you will not blank out the signal when the sailplane is positioned from you from various angles as you fly.

I have the antenna exiting my Supra from the pylon and have it taped to the top of the boom. So far I've not hand any trouble with loss signal but I'm going to relocate it as he has advised.

Enjoy your plane, your going to love it.

Stan