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Old Dec 22, 2011, 09:09 PM
Flying = Falling (Slowly)
dharban's Avatar
Tulsa, OK
Joined May 2004
2,604 Posts
I am setting up a Maxa Electric. I am using an Airtronics 2.4 receiver and am looking for anyone's experience at orienting the two antennas to provide adequate protection from shielding by the carbon wing.

Happy Landings,

Don
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Old Dec 22, 2011, 10:43 PM
Sherman Knight
Kirkland Washington
Joined Feb 2002
908 Posts
Antenna Orientation

I wrote an article for RCSD about a year ago concerning 2.4 antennas and how to place them in a sailplane fuse. A .pdf is attached. Hope you find this useful. Let me know if it was.

Thanks

Sherman Knight
Team JR
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Old Dec 23, 2011, 07:07 AM
Flying = Falling (Slowly)
dharban's Avatar
Tulsa, OK
Joined May 2004
2,604 Posts
Quote:
Originally Posted by duworm View Post
I wrote an article for RCSD about a year ago concerning 2.4 antennas and how to place them in a sailplane fuse. A .pdf is attached. Hope you find this useful. Let me know if it was.

Thanks

Sherman Knight
Team JR
It is a great article, but I was looking for information which is a bit more specific to antenna placement for carbon winged planes. And to planes which are as tight as the Maxa. Then, I'll have to make adjustments for the flight batteries and such.

I am suspecting that I will need to go with external whiskers so I don't want to drill this thing full of holes.

Happy Landings,

Don
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Old Dec 23, 2011, 10:30 AM
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R.M. Gellart's Avatar
Joined Nov 2005
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Don, I do not have a Maxa, but carbon wings to seem to be of little consequence in setting up a 2.4 set up.

Just observation, I know you are using a different animal than mine, in this respect I doubt they act any diffrent.

Marc
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Old Dec 23, 2011, 11:03 AM
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United States, CA, Folsom
Joined Jul 2007
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I agree with Marc. The focus of the radio install should be the 2.4 friendly fuse, not the tail boom or wing. On all of my Supras, I managed a perfectly good install with the satellite in front of the servo tray and main receiver behind the tray. Just be certain you have antennas in all three orthogonal (right angles to each other) planes. Then range check to be certain.

I realize the addition of a motor/ESC/flight battery adds some complexity to this simple formula, but with a little spacing of the components, it should still be possible to keep the 2.4 stuff unblocked.

JT
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Old Dec 23, 2011, 11:09 AM
or F, J, K, or even TD
FLY F3B's Avatar
Joined Jun 2007
2,912 Posts
Don, as Marc and Sherman mention, this method works. This is identical to my installs with the exception that I only use 3 antenni. Each is oriented 90 degrees from the other, so each axis is covered. My installs are in very tight carbon winged gliders like Pike Precision (F3B), and slight less tight Aspire Spread Tow. Rock solid Rf link on all of these installs. I use JR equipment; 11x DSMX tranny, 9310 Rx with one Remote Rx.

Cheers

Mike
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Old Dec 23, 2011, 11:44 AM
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webbsolution's Avatar
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Quote:
Originally Posted by dharban View Post
I am setting up a Maxa Electric. I am using an Airtronics 2.4 receiver and am looking for anyone's experience at orienting the two antennas to provide adequate protection from shielding by the carbon wing.

Happy Landings,

Don
Don, I have installed about 30 FHSS3 ATX RX in various sailplanes in the last three years. All have been non electrics though My best experiences have been when (on a full carbon nose pods) to wisker one antenna at 90 to the left and one straight up ahead of the canopy. This keeps it out of the way for dork landings and you have one atenna in view on launch at all times at the least. I have also wiskered a canopy but id avoid this as its a major pain if you are always inside the canopy for charging, tuning etc.

Knock on wood, I have never been locked out like this even on full carbon planes (xplorers, Orcas,Shadows)

Make sure you add a chunk of shrink wrap to the exposed antenna at the very least where the shielded insulation stops because with this approach you will invariably expose the antenna to more contact than normal. I broke one or two in three years but the actually antennas can be repaced without solder! They snap onto the rf board.

In 2.4 friendly pods you can orient them 90 inside the canopy assuming there is room. Check the Xplorer or shadow threads for some pics of my antennas for ATX. (edit) wow waste of time looking for that content. Just click on my nick and search for all my attchments you will see a few variant installation pics and three external wiskered pics!

I assume based on pics and the Prototype I flew in Cali that your bird has an all carbon nose?

I would avoid getting the antenna really close to the wings or laying them flat on carbon or battery surfaces. Sorry for spelling it out like that...I have seen a lot already and would prefer a pound of prevention since I dont know you (yet)

Good luck.
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Old Dec 23, 2011, 12:13 PM
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Like WS, I shrink tube all my ant. just to guts them up, and especially if you have them outside, it is a good idea.

Marc
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Old Dec 23, 2011, 12:54 PM
Sherman Knight
Kirkland Washington
Joined Feb 2002
908 Posts
Carbon wings and 2.4

Don,

The plane in the article is a Tragi 801 (Cluster) with an all carbon wing. It is the only way they are sold in the US. The fuse is 2.4 friendly just like the Maxa.

The Airtronics receiver you are using is a great receiver, but 2.4 antenna are 2.4 antenna no matter which brand you use. Chipping methods, guidís, and hopping methods and a bunch of other stuff may change from manufacture to manufacturer, but all of them use the same antenna that suffer from the same placement issues. This is a antenna issue, not a receiver issue.

There is absolutely no need to place external antenna on the plane. The need for whiskers has come and gone with 2.4 friendly fuselages. The testing we did showed that a top mounted external antenna above a carbon wing was the worst place you could put an antenna.

Using the tubes is a great way to make sure the antenna placement winds up where you want it. (the original Airtronics SD-10G manual also shows mounting the 2.4 antenna inside a straw) Again, the testing shows that installing tubes before the rest of the stuff goes a long way to maximize good antenna placement.

Call me if you have any questions.

Sherman Knight
Team JR
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Old Dec 23, 2011, 01:36 PM
PaulG
Newcastle, NSW Australia
Joined Dec 2004
315 Posts
Looking Down

I think it is important to remember that most of the time the plane is above you, so I always place one antenna on the bottom of the fuselage, usually under the receiver behind the battery. I normally tape it down making sure that there is enough tape to cover some of the coax so the antenna itself is not strained at any time. The other I put in a tube outside the servos and wiring. I now use the SD10G with 10 channel FHSS3 receivers. Do a proper range check. It is nearly always possible with only two antennas to get a spot where the reception is poor but when the plane is in the air it will see one of the two antennas as the transmitter is looking up at it. I have never had any reception problems with this system even at the limit of vision. When I used the Spectrum system the very best place for the satellite is in the vertical fin in my opinion. I never had any problems and if you take the case off the satellite it is thin enough to get inside a fin. I fixed it in place with double sided tape.
If you have to do an installation in a 2.4Ghz unfriendly fuse I use the antenna guides from Servorahmen in Germany. They make the servo frames that a lot of us use, as well as other nifty bits. The guides are curved and streamlined and made out of silicon, so flexible. They are a bit short however and I always have to slip a bit of thin plastic tube over the very end of the antenna. The antenna takes on a slight curve but this never affected reception for me. I am not an expert on these things but I think it is important to get the antennas as far away from the carbon wing as possible. A friend who uses Spektrum gear always places one antenna right up at the nose over the battery and this is the antenna with the least fades on his logger. This seems odd to me having a lump of battery underneath but it does work for him in his Supras.
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Old Dec 23, 2011, 03:17 PM
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webbsolution's Avatar
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If the Maxa is 2.4 friendly then a 90 degree application as per the manual, one antenna down the servo tray lengthwise and one either horrizonal or vertical and a range check will be fine. There should be enough room in the maxa for an easy installation.



To date I have never had to re orient an installation on a 2.4 fuse with an FHSS3 R/X (ATX). The best low power range checks are typically 50+ paces with the previously mentioned install methods - again in the pics referenced in my profile you will see also a bunch of internal ATX installations.
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Old Dec 23, 2011, 04:27 PM
Sherman Knight
Kirkland Washington
Joined Feb 2002
908 Posts
I have also had good results placing one of the antennas as far forward as possible even if it placed alongside the battery. On many aircraft, the battery cannot go all the way forward. If you run a tube clear to the nose, often the antenna is out in front of the battery.

In addition, the LiFe batteries seem to have minimum impact on signal. I am not sure of how the chemical composition of the battery will effect 2.4. Maybe JT can jump in here with some comment. (I have not tested other types of batteries) The signal is impacted by the battery, but not completely blanketed. I always put one antenna up in the nose. Itís fades on the data logger are small.

Sherman Knight
Team JR
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Old Dec 23, 2011, 04:36 PM
Flying = Falling (Slowly)
dharban's Avatar
Tulsa, OK
Joined May 2004
2,604 Posts
Part of the problem is that the nose is packed with a motor, two servos, an ESC and a battery pack. The back of the battery pack ends about 4 inches behind the back of the canopy. (And the canopy is CF) I have not had any problems yet with the Airtronics two antenna setup -- but I don't want to start with this plane.

Happy Landings,

Don
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Old Dec 23, 2011, 08:37 PM
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webbsolution's Avatar
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Quote:
Originally Posted by duworm View Post
I have also had good results placing one of the antennas as far forward as possible even if it placed alongside the battery. On many aircraft, the battery cannot go all the way forward. If you run a tube clear to the nose, often the antenna is out in front of the battery.

In addition, the LiFe batteries seem to have minimum impact on signal. I am not sure of how the chemical composition of the battery will effect 2.4. Maybe JT can jump in here with some comment. (I have not tested other types of batteries) The signal is impacted by the battery, but not completely blanketed. I always put one antenna up in the nose. Itís fades on the data logger are small.

Sherman Knight
Team JR
Sherman, (merry Christmas btw) I am concerned you are blending context here between brands. They are not the same.

While this might be an effective approach for JR installs which are typically leveraging an extra rx I don't suggest any pilot does this with ATX gear. Here is why...

Batteries can move, and they can crush cut and otherwise jam into the nose. Especially TD and J ships. While you offer the advice of running it along side th battery you have no idea what kind of battery, how much heat it could build etc...if it was a 4 cell AA pack which for ATX non electrics that wold be ample...then its a really tight fit!

The context in this install is a 2 antenna setup not 4 or six so my concern is that while running a straw or tube works for you it might be working because you have added redundant extra receivers...

If you have data that correlates to a single rx - 2 antenna setup with one running beside a battery - and a year of no holds/fades or wadded aircraft then I would suggest for a JR install this is a good route. In this case I stand corrected.

dharban - Since this is going to be an electric version and not going to be in a contest landing, I would see about a non carbon canopy no sense in it being carbon if its not going to get a regular pounding into the sod If you can swing it that's one less shielding scenario gone.

Second if the nose is that full you might note the tragi installation in my pics - its the red one with the antennas aft of the servo tray - the antennas are inside shrink tube which is glued to a chunk of 1/32 door skin. Again this was an ATX 10ch fhss3 RX in that picture. a Solid year of contests on that bird and never a challenge. the picture in question is IMG_3559.jpg have a look. This is at least ATX specific.

dharban if you try this setup and you dont get a 30 place on the low power range test then PM me your number. I will call you and we can work it out.

David Webb

Team Airtronics Pilot - Reseller - Canadian F3J Team 2012 (ahem)
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Old Jan 15, 2012, 10:54 PM
Tragic case
davidleitch's Avatar
Sydney Australia
Joined Feb 2002
5,875 Posts
Any more comments on the flying performance of the Maxa? Particularly in wind? I've done a small amount, less than 1 hour in the air, on a 68 oz electric maxa and so far it seems a bit slower round the sky than an older Supra. The Maxa handles great. I'm not used to such lightly loaded planes and not sure how to judge penetration. We've had some heavy 15-20 mph wind days down here so its hard to judge in those conditions particularly when you don't really know what you are looking for.

Ended up putting a wire keeper in for the elevator bell crank because spending 10 minutes set up time trying to shake it out of its hiding place in the fin is a bit of a pain.

The upside down wing mount has turned out to be good system with natural locating from the bolt insets.
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