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Old Dec 25, 2012, 05:46 PM
Flying a Chipmunk in Portugal
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Joined Sep 2010
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down with the tip pointing to the ground just in front of the pilot??
If you fly gliders overhead, then the tip to one of the sides. antenna horizzontal..
also it depends how the antenna(s) are placed in the model..
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Old Dec 25, 2012, 05:55 PM
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Originally Posted by jhsa View Post
down with the tip pointing to the ground just in front of the pilot??
That would be the second-best position, if a horizontal orientation couldn't be achieved for some reason. The disadvantage is the "hole" above and behind the pilot's head, where planes do occasionally end up.


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Originally Posted by jhsa View Post
also it depends how the antenna(s) are placed in the model..
Why would that affect the choice of Tx antenna orientation? The model turns all the time, thus presenting just about all profiles to the Tx, and that makes it important to pick the best compromise orientation at the pilot's end.
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Old Dec 25, 2012, 06:02 PM
Johninarky
Rogers,Arkansas
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Does anyone know if a Manual exists for the 9xr yet. Also has anyone started on a review of the Txm?
John
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Old Dec 25, 2012, 06:03 PM
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Originally Posted by H2SO4 View Post
Given the torroidal radiating pattern and the fact that most pilots tend to face their planes, a horizontal antenna is optimal. The entire quadrant in front of the pilot is painted with signal, irrespective of the plane's height.

Weak spots are at right angles, off to the pilot's far left and right, but that doesn't matter since the plane isn't there - the pilot will subconsciously turn to point the Tx at the aircraft.

Or do you have a better suggestion for the antenna's orientation?

Agreed, the toroidal pattern does leave a null area to the "front" of an antenna and it is optimal in particular circumstances. However, a horizontal antenna placed where it is, attenuates a good portion of the toroid, hence a good portion of the signal. An antenna pointed vertically, with the null directly vertical, or down, tilted a bit so as the toroid is "in front", will give better signal integrity at further distances. For typical close flying, the horizontal placed where it is is fine, but it is not optimal for further distances.
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Old Dec 25, 2012, 06:07 PM
Hey, Watch this....
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United States, UT, Alpine
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A link to the manual is on a previous post on this thread.
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Old Dec 25, 2012, 06:18 PM
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Originally Posted by KKUSA View Post
However, a horizontal antenna placed where it is, attenuates a good portion of the toroid, hence a good portion of the signal.
Can you perhaps explain that in more detail? Why would a horizontal antenna have that effect?

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Originally Posted by KKUSA View Post
An antenna pointed vertically, with the null directly vertical, or down, tilted a bit so as the toroid is "in front", will give better signal integrity at further distances.
Again, why? Signal"integrity" is surely a function of signal strength? Why would a vertical antenna provide a stronger signal at extended ranges?
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Old Dec 25, 2012, 06:37 PM
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Originally Posted by H2SO4 View Post

Why would that affect the choice of Tx antenna orientation? The model turns all the time, thus presenting just about all profiles to the Tx, and that makes it important to pick the best compromise orientation at the pilot's end.
Indeed. The issue however is not its orientation as an absolute but relatively to the orientation of the TX antenna.
If the Tx antenna is horizontal, it is better to also have the model antenna horizontal "in most frequent" flight configuration (i.e. normal horizontal flight, upside up) so run the antenna along the fuse.
If the Tx antenna is vertical, then a vertical (hanging for example) antenna is best.

In any case there is no perfect solution, nor absolute wrong, all matter of compromise and adaptation to particular cases. That is also the reason why vertical is better for distance (with vertical Rx antenna too) and horizontal for closer quarters.
It's a matter of putting the stronger lobe where the model is most if not all the time. However transmission is always an affair of both antennas (Tx and Rx)
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Old Dec 25, 2012, 06:55 PM
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Australia, VIC, Melbourne
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I like the integrated antenna. How many people do you see where they have the antenna straight and pointing at the plane? Heaps. The integrated antenna fixes this issue neatly.
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Old Dec 25, 2012, 07:02 PM
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BTW a bit disappointed that Hobbyking didn't keep the developers of er9x in the loop. Would've been nice to have them on board and behind this as well. Hopefully HK end up giving them the credit they deserve and would be good if they gave a donation to the project.
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Old Dec 25, 2012, 07:04 PM
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New Zealand, Bay Of Plenty, Tauranga South
Joined Jan 2011
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Have I missed it? Or has no-one brought up the problems with the copyright on the er9x software that HK has dropped into this radio? If not rectified this could seriously damage future use, upgrades, compatibility with this radio.
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Old Dec 25, 2012, 07:07 PM
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Originally Posted by BrettAltea View Post
BTW a bit disappointed that Hobbyking didn't keep the developers of er9x in the loop. Would've been nice to have them on board and behind this as well. Hopefully HK end up giving them the credit they deserve and would be good if they gave a donation to the project.
You have some evidence that these things have not ocured?
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Old Dec 25, 2012, 07:12 PM
Lt Col, USAF, Retired
United States, IL, Swansea
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Originally Posted by 00tman View Post
Have I missed it? Or has no-one brought up the problems with the copyright on the er9x software that HK has dropped into this radio? If not rectified this could seriously damage future use, upgrades, compatibility with this radio.
It's open source. Anyone can download the source files and modify if they wish.
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Old Dec 25, 2012, 07:13 PM
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Originally Posted by Michael V View Post
Indeed. The issue however is not its orientation as an absolute but relatively to the orientation of the TX antenna.
Understood and agreed.

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Originally Posted by Michael V View Post
If the Tx antenna is horizontal, it is better to also have the model antenna horizontal "in most frequent" flight configuration (i.e. normal horizontal flight, upside up) so run the antenna along the fuse.
Yes, except that during flight the aircraft will yaw its way N-NE-E-SE-S-SW-W-NW all over the sky, thus ensuring that the (single) Rx antenna will sometimes present its best (long) side to the Tx, and sometimes its worst (pointing at the Tx).

To my way of thinking, that completely negates any advantage from orienting the Rx antenna in a particular horizontal direction - any horizontal Rx (single) antenna placement is as good as any other horizontal placement (assuming they're all kept away from conductors and interfering noise sources).

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Originally Posted by Michael V View Post
If the Tx antenna is vertical, then a vertical (hanging for example) antenna is best.
Yes, I can see the logic there, assuming:
  • There's only a single antenna in the aircraft - no satellite Rx's and/or antenna diversity of any sort. That is not a common configuration for aircraft at longer ranges.
  • The aircraft is flown sedately, with its wings always close to level with the horizon. In other words, the logic does not apply to 3D, pattern, or aerobatic flight of any sort.
  • The aircraft always stays in the same horizontal plane as the Tx, or close to it. If the aircraft should start climbing into the sky, thus increasing its angle of elevation w.r.t. the Tx, the advantage is progressively lost. In other words, if you're relying on both the aircraft's (single) Rx antenna and the Tx antenna to present their best sides to each other on account of both of them always being vertical, make sure you're either flying very very far away, or very low, or both

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Originally Posted by Michael V View Post
In any case there is no perfect solution, nor absolute wrong, all matter of compromise and adaptation to particular cases.
Absolutely, which is why antenna diversity is a common solution at the Rx end. The orientation of the Rx antennas cannot be assumed, with the exception of the special-case scenarios I mentioned above, so the best we can do is to treat the Rx as a point, and to ensure optimal Tx antenna orientation.

Vertical Tx antenna orientation is increasingly disadvantageous with increasing angle of elevation to the aircraft. A horizontally oriented Tx antenna does not suffer from the same problem - the "lobe" is the same irrespective of how high the aircraft climbs in the sky.
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Old Dec 25, 2012, 07:13 PM
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Originally Posted by kc10kevin View Post
It's open source. Anyone can download the source files and modify if they wish.
Open source does not equal free for all uses. I could be open source meaning as long as not used for commercial purpose. I don't know the details in this case.
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Old Dec 25, 2012, 07:19 PM
Lt Col, USAF, Retired
United States, IL, Swansea
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Open source does not equal free for all uses. I could be open source meaning as long as not used for commercial purpose. I don't know the details in this case.
Read all the 9x code sites on google. Free for use under the GNU v2.0 License. That's the whole idea of open source. Check the open pilot and ardu pilot sites. Both open source and other people are even copying and selling the hardware.
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