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Old Dec 16, 2005, 03:27 PM
Buyin', Tryin' and Flyin'
hilgert's Avatar
DFW, Texas
Joined Jan 2005
2,283 Posts
pda4u, I think flieslikeabeagl was refering to the 2.4Ghz WLAN link between the two buildings. flieslikeabeagl, that's one of the reasons I wanted to do this from the rooftops of the buildings, to be right inline with the 2.4Ghz WLAN link.

Well, I did the experiment, and here are the unscientific results (as I had no way of measuring acutal signal strength, etc.).

I had a friend on top of the far building. Each building is about 40 feet high, with no obstuctions in-between. This way I was able to minimize any ground interference, and still know the precise distance. We used cellphones to coordinate.

Test 1 (the "ideal" test) was at 3200 feet (0.6 miles), give-or-take (and measured via GPS on my laptop), with the receiver antennas at 90 degrees, etc. I had the TX on the other rooftop, with the antenna at 90 degrees as well. All servos worked without any drops whatsoever.

Test 2 was the same, except the TX antenna was at 45 degrees. Again, no glitches. I rotated myself left and right, without problem.

Test 3 was the same, except the TX antenna was at 0 degrees (to the ground), and when pointed directly at the RX there were some dropouts. This is to be expected with any whip-type antenna, as the signal is really a "plate" out from the side of the antenna, with the weakest signal straight out the end. There is an article by Peter Berg (of Berg receiver fame) on this HERE .

I repeated Test 1 and Test 2 (call them Test 1a and Test 2a), only this time I put my body in-between the TX and the RX. Test 1a had a couple of drops when I moved the TX antenna right next to my body, but if I rotated even slightly left or right (to all the TX to "see" the RX even a bit) it was locked-in. I am not using the term "glitches", since with this technology you are really concerned with drops or overswamping from another 2.4Ghz setup. Test 2a was roughly the same.

At all times the existing 2.4Ghz WLAN link between the two buildings was active, and we were standing right in line with the directional link (which means most of the link energy was pointing right at us). Impressive.

I walked to the other end of the building I was on, and my partner walked to the other end of their building, which put about another 1200 feet bewteen us (just a guess, as I did not have the GPS measurements from the far end of the other building. At that distance I had no problems again for Test 1 and Test 2 repeats, but there was much more sensitivity on 1a and 2a. For this part I must note that there was about 1200 feet of asphalt roof with HVAC equipment, etc. I did not do Test 3.

So, I have to conclude that with no obstructions that this thing *can* go at least 4400 feet without problems. HOWEVER, there obviously were *no other* DX6 units in the vacinity (as they are so new), and these were fairly ideal conditions. If there were another DX6 that was a mile away, and it happened to lock onto the both the same channels (since it did not see the other TX), then there would be problems if one flew in that direction too far. The GUID would protect from mis-signaling, but the signal strength would (could) be swamped from the other TX. Now, that's a few ifs and ands there; fairly unlikely in an open field arrangement.

The above does beg a question on how the DX6 selects the inital channels. If there was only one DX6 on the planet, and it was turned on, would it always select the same two channels each time? If so, then "fairly unlikely" would be accurate. If it randomly chooses channels each time, then "damned unlikely" would be the case. In a system like this, you would hope that there is a bit of randomness in how the DX6 selects initial channels if there is nothing else out there using them.

EDIT: Spelling edits...
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Old Dec 16, 2005, 04:05 PM
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Cincinnati
Joined Jul 2004
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Hilgert - thanks for taking the time to report your experience! Valid test data, even if not in a highly-controlled environment (but then who cares how it performs in a highly-controlled environment!).

I plan to use my DX6 only in park-flyers, but the thought has crossed my mind....once people start using the DX6 and they fly up to 1000 feet (give or take) without glitches, and then they fly their good-quality FM system the same way and get glitches, how is one to conclude that they are not better off using the DX6 in ANY model, simply on the basis of comparison....hmmmm.....


Mike
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Old Dec 16, 2005, 04:44 PM
Illinois
Joined Jan 2005
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Quote:
Originally Posted by pda4you
You can turn it off with the switch. But to test range you select the bind button, it decreases output for the range test.

MIke
He may be refering to the WiFi running between the two buildings??

David
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Old Dec 16, 2005, 06:19 PM
Buyin', Tryin' and Flyin'
hilgert's Avatar
DFW, Texas
Joined Jan 2005
2,283 Posts
dribbe, you are correct, and these results are a testiment to how good this inexpesive system is.

And, as you see, I did get my DX6 finally (actually, I just picked up another one, so now I have eight S75 servos and two receivers, along with a TX for my daughter).
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Old Dec 16, 2005, 06:45 PM
Mark 12:30
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United States, GA, Alpharetta
Joined Jan 2004
676 Posts
Hilgert ,something else to think about on your original test with the car and friend...I'm sure some of those houses had 2.4ghz devices up and running , more good info and results. Thanks !!
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Old Dec 16, 2005, 07:18 PM
Buyin', Tryin' and Flyin'
hilgert's Avatar
DFW, Texas
Joined Jan 2005
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TipStalled, where I ran the test there was nothing in-between except two fields, a stream, and a couple of shorter buildings (basically a non-residential area). However, just to be clear, I did run the test with the TX just behind the 2.4Ghz bridge on my end, and the RX was just behind the bridge on the other end. The antennas on the bridge units (a "bridge" is the term for two wireless devices being used to join networks) are highly directional, and have about a 10 degree "cone", so unlike normal 2.4Ghz wifi this would be sending most of the energy my way. So, I think it really was a good "bad case" test.

A few comments:

First, since each TX/RX pair operates on a GUID (globally unique id), even itwo TX's used the same two frequencies, they would not have the same "code" (GUID) as each other, so if any signal made it through from the first TX it would be able to provide control to the RX. The issue would be if the RX was so much closer to the second TX that the second TX "swamped" the first TX's signal.

Second, I would *hope* that Spektrum/JR was smart enough to randonize the channel selection with there was no interference, perhaps with the random "see" being the GUID of the TX itself. That woud further reduce any likelyhood of two TX's being on the same two channels. Otherwise, if both TX's were turned on and did not "see" each other, or anything else (ie - out in the country for instance), then they would alway start on the same two frequencies. It would add practically no sophistication to have done this with a randomized channel selection, but also could have been easily overlooked.

dribbe, do you have any information on this (are channels randomized if there is nothing else detected, or are they always the same two in such cases)? This is a good opportunity to clarify something on the DX6.
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Old Dec 16, 2005, 07:43 PM
LSF - IV
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United States, TX, Highland Village
Joined Jan 2003
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Quote:
Originally Posted by hilgert
TipStalled, where I ran the test there was nothing in-between except two fields, a stream, and a couple of shorter buildings (basically a non-residential area).
So what did Fawn say when she caught you up there
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Old Dec 16, 2005, 08:11 PM
Buyin', Tryin' and Flyin'
hilgert's Avatar
DFW, Texas
Joined Jan 2005
2,283 Posts
After the last in-warehouse plane flying she said "don't ever let me CATCH you doing that again", and she has not...
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Old Dec 16, 2005, 10:48 PM
Mark 12:30
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United States, GA, Alpharetta
Joined Jan 2004
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Hilgert , post #9 , the one I was referring to in my reference to your "very first test with friend and car " says you were in a residential neighborhood. I was trying to point out that in a "residential neighborhood" there may be other 2.4 ghz devices operating. I was not talking about your "rooftop" tests .
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Old Dec 16, 2005, 11:21 PM
Buyin', Tryin' and Flyin'
hilgert's Avatar
DFW, Texas
Joined Jan 2005
2,283 Posts
Sorry - I missed that. To be clear, where I live there is a very nice undeveloped field, surrounded entirely by homes - nice homes, the kind of homes that will be filled with wireless networks, and with new electric planes at Christmas, as well as BCX helis and such on 72Mhz. Already some have come out to watch me fly, saying "I got my kid a plane for Christmas - can't wait to come out here and fly with you". Oh goodie...just don't forget to to PLEASE check with everyone before you turn it on...

Actually, I look forward to helping new folks, as I have been helped by so many people. After all, this hobby should include a desire to help others I think, so I'll be out there Christmas day flying and assisting others.

THAT's really why I got this radio system, so I can still walk 150yard or so and fly instead of having to drive somewhere. I actually invested in a Royal Evo 9 and three Shawdow 3 receivers, all of which are synthesized so I could change channels if needed. But I am selling them to a friend who flys reeeeaaaaallllllyyyy high, and at more secluded fields, so he can actually use their capabilities. For me, 3200 feet is far enough (too far, actually...).
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Old Dec 17, 2005, 01:27 AM
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Pittsburgh Allegheny, Pennsylvania, United States
Joined Mar 2004
1,402 Posts
Quote:
Originally Posted by bluesky123
These servos and their twin brother E-Sky 0500 were discussed several times over at 3D Flying group. One of the discussions is this:
http://www.rcgroups.com/forums/showthread.php?t=451492
S75 was $15 last time I checked, while identical E-Sky servos are $7.50. I like my E-Sky servos, work great.

Boris
Boris, Where did you get the esky servos for $7.50?

Terry
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Old Dec 17, 2005, 12:30 PM
Illinois
Joined Jan 2005
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Just FYI, The E-Sky servos are NOT made in the same factory, or from same tools as the E-Flite/Spektrum ones (S75). They are 'near-clones/copies', but not the same.

David
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Old Dec 17, 2005, 01:26 PM
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Pittsburgh Allegheny, Pennsylvania, United States
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Clones... schmons. Who cares. If they work and are cheaper bring'em on.

Can anyone post a link to the cheap clone servos?
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Old Dec 17, 2005, 03:26 PM
Mark 12:30
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United States, GA, Alpharetta
Joined Jan 2004
676 Posts
Early Christmas...

Talked my boys into letting me test the new radio out since I was maidening my Alfa Mig with new power system , consisting of 4S1P TP2100 and HiMaxx 4200 brushless motor. I also have to run a U-Bec with this setup which is known to cause more problems with "glitches". I am happy to say the system performed flawlessly. Flew the plane higher than I normally would and had no problems with glitching or signal loss....at least not that I could tell. I did the failsafe set up as recommended and this procedure went as advertised..no surprises. The radio definitely has a strange feel...probably lack of antennae length is the biggest thing , and no neckstrap. The neckstrap thing will soon be corrected. The reciever was installed with the antennaes 90 degrees as recommended. However , one antennae could not unfurl to its full length and I just finished the antennae run by letting it run lengthwise the fuse after it had run straight as far as it could. I have included and pic. YOu can see the U-Bec and how the ant. that runs to the fuse is not able to unfurl completely.
I am quite confident that this system can handle anything a ParkFlyer can throw at it....
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Old Dec 17, 2005, 04:03 PM
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United States, TX, Highland Village
Joined Jan 2003
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Impressed

Had a chance to wiggle the sticks on Hilgert's new setup today. I was impressed. Just swapped out the recievers and we were off to the races. We flew two planes, first one required no changes, second plane needed to reverse the servos. Those menus were figured out with the quickstart manual, no fuss no muss.

No glitches, solid very straight forward performance. I didn't push it on the distance as we were flying a twitchy little foamie with a brisk brushless setup. But I was easily at 1,000' altitude and 2000' lateral distance.

I fly sailplanes both handlaunch and TD for the most part, I'd like to drop one of these into a beater and see how far I can go. Bigger airplanes can get out there pretty far so I wonder. Sure is cool technology!!

Thanks for letting me play!
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