Mounting location for AR7000 satellite receiver

[manike]

Maybe I spend too much time working a CAD station, but I don't believe those antennas are in the same plane.

If you run a line down the axis of the antennas they are at 90 degrees from each other when viewed from above.

If they were in the same plane they would ALWAYS be parallel to each other.

[fogger]

On Pete's machine we made a little bracket out of a servo horn, velrco-d it in between the two front cyclic servos, and then velcro-d the remote rx to it. Sticks up above the servos and it's 90 deg out from the main rx which is on top of the electrical box like others have shown. I'll try and get a pic this weekend. It just fits under the canopy this way.

-Fog

[manike]

A picture paints a thousands words... so I made 4 pictures. ;)

The blue is the same axis as the aerial on the AR7000. The red is the same axis as the aerial on the satellite. The green is the aerial if the satellite were to be rotated around by 90 dgrees.


First in iso view. I made two blue aerials to show aerials that are in the same plane and how they will always have the same relation to each other. You'll see them end on, or they will be parallel.

http://i49.photobucket.com/albums/f283/manike/iso.jpg

The next image is looking down from above. This is down the Z-axis.You can see the green is end on to the blue, and the blue and red are at 90 degrees.

http://i49.photobucket.com/albums/f283/manike/z-axis.jpg

The next image is looking down the X-axis from the front of the heli. You can see the red is end on to the blue and the green and blue are at 90 degrees...

http://i49.photobucket.com/albums/f283/manike/x-axis.jpg

The last image is looking down the y axis, from the side of the heli.

The blue are both end on in relation to the view and the red and green are at 90 degrees to each other.

http://i49.photobucket.com/albums/f283/manike/y-axis.jpg

In essence, we get the same orientations with the satellite as it is now, or with it rotated by 90 degrees.

What we DON'T want is two aerials like the blue ones. I believe any combination of red, blue and green is acceptable though as long as you just have one of each. :thumbup:

[brgsstm]

What I am saying is that The Bum has no antenna in the vertical plane.

Tom

[brgsstm]

Ok the first two pictures show the heli in the level flight config. Mine has an aerial in 2 planes and the Bum has his in 1

The second two pictures show in the nose up attitude. Again I have still maintained 2 planes where The Bum has still 1 plane.

I still don't see how anyone can tell me that my arrangement is not more effective than The Bums. (I'm not trying to turn this into a mine is better than yours thread :P)

If I am wrong then someone explain to me but until that time I am sticking to the method I was advised to when I built my bird. Also Manike, by the looks of the photo you posted you also have 2 planes of reception.


Tom

[TheBum]

Maybe I spend too much time working a CAD station, but I don't believe those antennas are in the same plane.

If you run a line down the axis of the antennas they are at 90 degrees from each other when viewed from above.

If they were in the same plane they would ALWAYS be parallel to each other.
A picture paints a thousands words... so I made 4 pictures. ;)

The blue is the same axis as the aerial on the AR7000. The red is the same axis as the aerial on the satellite. The green is the aerial if the satellite were to be rotated around by 90 dgrees.


First in iso view. I made two blue aerials to show aerials that are in the same plane and how they will always have the same relation to each other. You'll see them end on, or they will be parallel.

http://i49.photobucket.com/albums/f283/manike/iso.jpg

The next image is looking down from above. This is down the Z-axis.You can see the green is end on to the blue, and the blue and red are at 90 degrees.

http://i49.photobucket.com/albums/f283/manike/z-axis.jpg

The next image is looking down the X-axis from the front of the heli. You can see the red is end on to the blue and the green and blue are at 90 degrees...

http://i49.photobucket.com/albums/f283/manike/x-axis.jpg

The last image is looking down the y axis, from the side of the heli.

The blue are both end on in relation to the view and the red and green are at 90 degrees to each other.

http://i49.photobucket.com/albums/f283/manike/y-axis.jpg

In essence, we get the same orientations with the satellite as it is now, or with it rotated by 90 degrees.

What we DON'T want is two aerials like the blue ones. I believe any combination of red, blue and green is acceptable though as long as you just have one of each. :thumbup:
Thank you. I think we're approaching the same problem from different angles (pun intended). The only really important part is that the reception straight out from the poles of the antenna is the worst case, but by having two antennas at 90 degrees to each other in any way, be it left-right/fore-aft or left-right/up-down, you avoid having the poles from both antennas pointing toward the transmitter at the same time.

[manike]

Brgsstm, I don't see why your arrangement would be any more, or any less, effective than 'The Bums'. There are so many orientations and angles that we fly in relation to the heli that I think the relationship between the signal and the antenna on the heli will always be one of an infinite number of variables. We are never just squarely side on, or below, or behind (etc.) the heli.

Ok the first two pictures show the heli in the level flight config. Mine has an aerial in 2 planes and the Bum has his in 1

The second two pictures show in the nose up attitude. Again I have still maintained 2 planes where The Bum has still 1 plane.

I still don't see how anyone can tell me that my arrangement is not more effective than The Bums. (I'm not trying to turn this into a mine is better than yours thread :P)

If I am wrong then someone explain to me but until that time I am sticking to the method I was advised to when I built my bird. Also Manike, by the looks of the photo you posted you also have 2 planes of reception.


Tom

The way you are defining planes, is very different to what I am used to and how I've always been taught, and taught others in the world of Engineering/CAD.

I believe we all (including The Bum) have 2 planes of reception.

A plane when defined to an axis is at the normal to the line which creates the axis.

So for instance, if we look at the last three images I posted, the 'plane' is actually the white back ground or even the flat surface of your screen if you would like when you are looking end onto one of the "tubes". I don't agree with the way you have defined the planes of the axis for the antenna on the AR7000 in your images.

I'm not an electrical engineer, I'm a mechanical engineer and have spent all my adult life designing in CAD, so I'm not looking at it from a signals point of view, and thus might be wrong when it comes to the actualy wavelength interactions, but in terms of planes in relation to Axis' I know how the engineering world looks at it. :)

Another image for you showing the planes relating to each of the antenna axis'.

http://i49.photobucket.com/albums/f283/manike/planes.jpg

The planes relating to the actual axis' of the antenna are shown in yellow(ish).

Your images tried to show the plane for the AR7000 as per one of the turquoise planes shown on the higher blue aerial. If you were to define a plane that way there would actually be an infinite number of planes for an axis as there is no way to define it and it could rotate around the central axis giving you either of the blue options. You'll note that the blue options are also the same as the planes for the red and green antenna... This is not correct in my opinion, and why would you pick one as your "correct' definition instead of the other?

To have a plane, you have to have at least 3 points. You can not define a plane with a straight line. A plane is infinite. A plane is usually defined as "normal" to a straight line. Since any point on a line has an infinite number of normals, that's how you get a plane (in basic terms).

[brgsstm]

There is still a greater chance of the antennae on The Bums setup coming end on to the radiation from the transmitter. I wish I had a CAD program to show you what I mean but I don't. Like I said in one of my previous posts I see no reason why The Bums setup will have problems but the image below shows what I am trying to get across. Please be aware I am not trying to have an argument here, just trying to understand the best method :hug:

Anyway you can see in the image a top down view of The Bums setup on the left and mine on the right.

As you see in level flight The Bums setup is subject to angular radiation from the Tx. My vertical antenna though is not as it is vertical and the radiation is hitting the antenna of square on. This is the point I am trying to get across. I am well aware that you will never have the perfect setup but I do believe my setup offers a better reception.

Tom

[TheBum]

I see what you're getting at, but going back to one of my earlier comments, the only time my setup will have a disadvantage vs. yours is when the heli is fairly far out and it's in a tail-in or nose-in orientation. I don't know about you, but it's hard to see the heli when it's oriented that way. Side-in, there's absolutely no difference between yours and mine: we both end up with the pole of the main antenna pointing directly at us.

I've actually kicked around the idea of tilting the satellite's antenna at a 45 degree angle down toward the front. There's nothing in the geometry that would violate the 90-degree rule. It would have no impact on side-in, but nose/tail-in would benefit at the slight expense of bottom/top-in. Plus, I could still keep the antenna wires out from behind the muffler.

[manike]

brgsstm, I see what you are getting at, but I think the issue is partly that you are looking at it in 2D (at least that's the impression I get from those images) when it's really a 3D problem. It's a very varied 3D problem too. :shock:

I'm not taking offense, and nor do I mean any. I do like sensible discussion on technical issues though. :hug:

I have some things to do tonight so I don't have time right now, but how about I model up in 3D the antenna system and then do some orientations in relation to someone on the ground. That way we can look at all the angles of incidents at different flying points.

Someone pick a set of altitudes and angles... I can see this getting very complex when we start working on inverted and rolls etc too. :rolling

Overall I'm yet to be convinced it matters as long as the aerial are on axis' at 90 degrees to each other, but we may find one set up to be better for a beginner not flying inverted or whatever. ;)

Maybe this is overkill? :thinking:D lmao.

[TheBum]

Maybe this is overkill? :thinking:D lmao.
MAYBE?! I'm about ready to grill up some horse burgers.

(Just kidding, to all you horse lovers. I realize some people may not get the "beating a dead horse" reference.)

[boosst]

i am ready to mount mine tonight....did you guys solve anything today or just argue:YeaBaby:
if the main receiver is mounted with the antenna going horizontal to main blades. then does the sat receiver need to be mounted opposite or do we still not know yet?

[TheBum]

I followed through on my idea of reorienting the satellite at a 45-degree angle. We'll see how it does this weekend, unless the forecast takes a turn for the worse.

If you're worried about it, just mount the satellite with Velcro. That's what I did, so it was a piece of cake to rotate it.

[brgsstm]

I'm not taking offense, and nor do I mean any. I do like sensible discussion on technical issues though. :hug:


Maybe this is overkill? :thinking:D lmao.

Yeah go for it :thumbup:

As for the first comment the same here. Just looking to find if there is a better mounting location/orientation.

Thanks

Tom

[psych-lick]

http://www.smugmug.com/photos/245000707_rNSH4-M.jpg

Here is a good shot of my setup. I have tested with the logger after several flights and very low fade numbers (<60).