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Old Dec 09, 2007, 04:02 PM
I need a bigger hangar
Phoenix, AZ
Joined Jan 2007
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DX7/AR7000/AR6100 Range Test

Curious to see what the ranges are on the Spektrum system, I devised an
experiment to find out. Not completely scientific, but representative.

I mounted a AR6100 (v1.2) and a AR7000 on a piece of plywood and taped it to a cardboard box (see photos). The main receiver antennas were oriented left-right and the AR7000 satellite receiver antenna was oriented vertically. This assembly went on top of my Jeep with the servo extension leads run in thru the sunroof. On the seat of the car were two batteries and two servos with arm on them that had tape flags identifying which went to which receiver.

This gave me two receivers to compare and placed them far enough above the top of the car to eliminate most, if not all, metal interference. And the servos were attached to the throttle port on the receivers, both of which were bound to the same model on the DX7. The arms of the servos were horizontal (full throttle) when receiving a signal and popped vertical when signal was lost (fail safe position).

With my wife keeping watch on the DX7 sitting on top of her car, I drove my car with the receivers up a street away from her parking spot. I had direct line of sight for almost three miles with the exception of a hill about two miles away from her. Her spot was about 100 feet above the street I was on. See photo.

Results:

With the DX7 antenna vertical and the main receiver antennas horizontal
and perpendicular to line of sight:

Solid contact with no dropouts on either receiver for 1.7 miles. At 1.7 miles
the AR6100 began to drop in and out, the AR7000 was solid. Going behind the hill at 1.9 miles both dropped out, as you would expect. At 2.2 miles the AR7000 began to drop in and out and became solid at 2.4 miles while the AR6000 was in and out. At 2.8 miles, the max distance available for line of sight, the AR 6000 was in and out and the AR7000 was solid.

Same setup as above only DX7 antenna bent horizontal:

Both receivers solid at 2.8 miles, dropping in and out behind the hill at 2.2
miles, and then solid from 1.7 miles back to the start line. This put both main
receiver antennas and the DX7 antenna in the same plane. Before they were
perpendicular to each other. Radio theory says both should be in the same plane (geometric plane, not air plane) for max range.

Putting the receivers so all three antennas were horizontal and pointing at the DX7 caused dropout at 1.7 miles. This is worst case for expected range. However, turning a circle within 1.5 miles of the DX7 caused no dropouts with the receivers in normal orientation.

Conclusions:

AR6100 range is almost as good as the AR7000 up to 2.8 miles. The satellite receiver of the AR7000 made it more solid due to signal diversity and dual antenna orientation, as expected. It was not as susceptible to cars passing as the AR6000 was, again thanks to the satellite receiver.

Bending the DX7 antenna into the same plane as the receiver antenna improves range. This is mitigated by the continuous maneuvering of our models, so I don't consider it a concern. Plus at ranges where you can see your model the connection is solid regardless of antenna orientation.

Final conclusion: I guess I've got way too much time on my hands....
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Last edited by colecaz; Dec 09, 2007 at 05:27 PM. Reason: Typo in title saying AR6000 instead of 6100
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Old Dec 09, 2007, 04:58 PM
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Quote:
Final conclusion: I guess I've got way too much time on my hands....


Yep never been a range issue but a shadowing one just as your test indicates.

All I can say is life is good on 2.4!

Mike
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Old Dec 09, 2007, 05:01 PM
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Nice test.
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Old Dec 09, 2007, 05:21 PM
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So much for the 6100 being a park flyer. Haven't seen a park that big in a long time, let alone being able to tell what the model is doing that far away.

Notice the polarity mismatch and what it did to the range. With the AR7000 (and any other reciever with satellite) I would suggest making a + with the antennas which should maximize your signal reception and it looks like it might be good to have the main receiver oriented vertically.
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Old Dec 15, 2007, 10:04 PM
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Colecaz,

Great report. Thanks for sharing it. Since Spektrum provides so little useful guidance, it is tests like yours that become the information upon which users have to make their decisions.

I am going to use about 2000 feet as a good working range for the AR6100, and only in non-carbon planes.
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Last edited by aeajr; Dec 16, 2007 at 12:55 PM.
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Old Dec 15, 2007, 11:01 PM
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Norfolk, Va
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Interesting test. Makes me feel much better (:
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Old Jan 03, 2008, 10:21 PM
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I had my first experience with DSM2 today. I got a DX7 for Chirstmas, and installed an AR6100E in a 0.9m wingspan EPP sports plane with lots of grunt (200W at prop in 600g plane). Plane flew great at first, and I decided to push the range. I spec'd it out, which is not hard to do on a small red plane. I estimate line of sight range was about 350m... around 1000 feet. I flew about at the limit of my sight for about 30 seconds, and when in a dive, I had total loss of control. It dived about 200m towards the ground with me holding full up elevator the whole time. Eventually when most of the way to the ground with maybe a few seconds before impact, it pulled up. This was in the suburbs with lots of houses with probably lots of Wifi and cordless phones running 2.4Ghz.

I am a bit unhappy about this result. I do not normally fly at this range, but my old FM gear was fine at this range, so I have taken a backward step on range. Atleast I get no ESC/Motor induced glitches with DSM2, and the transmitter has much more control than my old JR XF421, which worked great for what it was.

I wish I had gone for the AR6200, even though install would have required more cutting of EPP.

Just my experience.

-- Adrian
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Old Jan 03, 2008, 10:36 PM
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I think there's something else going on that doesn't have to do with range.
Funny, I lost me ME-109 the other day doing a split-s. It went straight in after it didn't pull up.

I was told be the LHS that the low voltage lock out issue got me.
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Old Jan 03, 2008, 11:08 PM
I need a bigger hangar
Phoenix, AZ
Joined Jan 2007
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Adrianvos....
What are you using for a BEC?? How many cell battery?

As miseryQ seems to have found out, the digital rx's are unforgiving of low voltage.

If they run out of range or are shadowed, they resync instantly, mostly without you ever knowing they lost lock. BUT, if they get a voltage glitch, they take a second or so.
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Old Jan 03, 2008, 11:57 PM
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Setup is an old Castle Creations Phoenix 25 (about 2003, so one of the first) running off an Align 2100maH 11.1V 22C pack, with only 2 HS-85 servos. The LVC is set to auto Lipop, which cuts motor (full cut) at below about 9V, which should be plenty of voltage for BEC to have good output. I doubt there is any battery voltage problem related to motor load, as LVC would cut if this was the case, and it did not (as it would require zero throttle to reset). The only possible voltage problem would be if the servos draw enough current to cause low output from BEC. Since I only run 2 lowish torque servos, I think this is unlikely. Also, I have no such issues when doing highly aerobatic manouvres close to me. I only had this issue when flying sedately at long range. (I was in a loop, that was established a few seconds before problem, so no servo movement while holding elevator in loop with neutral aileron).

Also I am propped up for around 18A current draw at full throttle. Would be less on downward of loop.

All input appreciated, as I would prefer to sought this with AR6100 if possible

-- Adrian
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Old Jan 04, 2008, 01:24 AM
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Another interesting note:

If I power the receiver before the transmitter, the AR6200 in my other plane will establish comms within a second, but the AR6100 seems to often have a delay of 5-10 seconds before making a connection. This is with range of <3m. Is there any reason for this extended time to connect. I believe that a momentary < 1s singal dropout is something I would be satisfied with, but a time of many seconds watchin your plane hurtling out of control to the ground is unacceptable. Why does the AR6100 take longer to make a connection?
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Old Jan 04, 2008, 07:07 AM
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Quote:
Originally Posted by AdrianVos
Why does the AR6100 take longer to make a connection?
I'd like to know tgat as well.
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Old Jan 04, 2008, 07:41 AM
I need a bigger hangar
Phoenix, AZ
Joined Jan 2007
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I can't confirm the info, but other posts have mentioned that the 6200 holds the last used frequencies in memory and tries them first at startup, before scanning to find the TX. I would expect Spektrum to make improvements as they go along and the 6200 is among the latest to come out.
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Old Jan 04, 2008, 10:19 PM
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Anyone have more information on this?

SPEKTRUM INCORPORATING FAST CONNECT FIRMWARE IN NEW RECEIVERS

The following information about fast reboot for Spektrum receivers was found on
this forum, then verified by referencing the DX6i manual. http://www.runryder.com/helicopter/t392890p1/

I have sent a note to Horizon Hobby asking for verification.


The following is an excerpt from the bottom of page 22 of the Spectrum DX6i
users manual
http://www.spektrumrc.com/ProdInfo/F...nual-LoRes.pdf

Note: Receivers manufactured after July of 2007 offer a quick connect feature
that reconnects immediately when recovering from a low voltage "brown out."

This new firmware exhibits a slow blink when the receiver reconnects from a
brown out due to low voltage. The slow blinking on the remotes and the
internal radios means that they think that they have detected a brown-out.
These radios support "Fast Connect" this is a new feature where the receivers
check the last connected pair of frequencies and connect to them immediately.
The LEDs flash slowly to indicate that this has taken place.

Try connecting and then cycle the power. The receiver will connect immediately.
Cycle a servo whilst switching the power off and on you will see that it hardly
misses a beat.

Paul
Spektrum

I don't know who Paul is but he seems to speak with authority.
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Old Jan 04, 2008, 10:28 PM
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For the same price I always use the AR6000 and never use the AR6100. Just because of the issues I have witnessed and also read about the AR6100. I have only had one lockout using the 6000 and found it was most likely due to a large motor bearing failing along with the motor bell rubbing on the aluminum motor mount. I am using that same receiver in other models and have not had any issues since. (it's been about a year since I lost that eRaptor.) I was hoping the AR6000 was included in this range test but alas, it was not.
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