Dx8 still has problems
How can you guys say that it is impossible for a TX to fail?
Even computers in manned spacecraft have failed. So have electronic instruments and ignitions in automobiles, computer hard drives, TVs, stero systems, electronic cameras and whatever other electronic device you care to pick, except the radio control aircraft transmitter according to what I've read here. What makes it so special that it's immune to failure?
I have yet to see an electronic device which is not subject to either total or intermitent failure.
How can you guys say that it is impossible for a TX to fail?
Even computers in manned spacecraft have failed. So have electronic instruments and ignitions in automobiles, computer hard drives, TVs, stero systems, electronic cameras and whatever other electronic device you care to pick, except the radio control aircraft transmitter according to what I've read here. What makes it so special that it's immune to failure?
I don't recall anyone saying that .
I have yet to see an electronic device which is not subject to either total or intermitent failure.
How can you guys say that it is impossible for a TX to fail?
Even computers in manned spacecraft have failed. So have electronic instruments and ignitions in automobiles, computer hard drives, TVs, stero systems, electronic cameras and whatever other electronic device you care to pick, except the radio control aircraft transmitter according to what I've read here. What makes it so special that it's immune to failure?
If radios failed a lot you would see a massive amount of planes scrapped. It is good thing that they are reliable or we would all be spending much more for this hobby.
9020 pins/connectors are the same as every other spektrum rx in my shop. I clearly posted the admitted issue with these, from horizon.
reversing polarity will burn the rx up.
I know for a fact that you can incorrectly plug into the 9020 as I did just that with the 9020 when I got my DX18. Once I re-evaluated the servo plug guide on the RX, I figured it out and plugged it up. All works perfectly.
While HH mentions that a very few RX have had issues, it does not mean that yours has that specific issue. Based on the description of what is happening to you, it could be a simple case of improperly plugged bind plug and power.
I would not dismiss this possibility out of hand. I would even be willing to post a picture of the bind plug and battery (Or ESC plug) in the correct sockets.
Rick
We have been getting shafted for far too long when it comes to 2.4GHz radio systems.
Now millions are using the 2.4GHz unlicensed band everywhere and there is more to come.
When the band is saturated error occurs, the industry calls it "BROWNOUT" and cleverly blames it
on the battery pack!
It is too bad that we can not reboot a crashed model airplane.
Just 10 short years ago everybody had to take turns flying. Huge events like IRCHA and Joe Nall were impossible for large numbers of pilots to fly at the same time due to frequency conflicts and interactions. 6-8 pilots at a time was all most fields could handle. Now you have events where easily 100 radios should be expected to be on at the same time, and probably far more, yet the modern protocols continue to work just fine. Shoot, we encouraged mass flights several times where they had 60-70 pilots flying the models in close proximity, and that was just in one corner of the field!
Yes, eventually it is possible to saturate the entire spectrum, but I really don't think we have to worry about that anytime soon. I know what kind of testing we do, and I would have no problem flying my models with confidence with many other radios on at a time. Look at how well E-Fest works - the building is full of steel (a harsh environment for 2.4gHz), a bunch of models are in the air at the same time, it's in a city setting, there are over 20 different wireless computer networks operating, and everybody flies just fine.
Andy
We have been getting shafted for far too long when it comes to 2.4GHz radio systems.
Now millions are using the 2.4GHz unlicensed band everywhere and there is more to come.
When the band is saturated error occurs, the industry calls it ''BROWNOUT'' and cleverly blames it
on the battery pack!
It is too bad that we can not reboot a crashed model airplane.
Brownout is a well documented situation thas has nothing to do with any type of RF interference.
If you have a brownout, the RX will be binking orange after the event, assuming the gear survives whatever happens. A lot of people sure forget to check that little detail.
Andy's well reasoned comments above explain the fact that band saturation is not a real issue. Some large and major events like Joe Nall have seen issues, when there were hundreds of radios turned on all over a large flying site, but that is a rare thing. Spectrum offering DSMX has nicely addressed that particular issue.
I have found from doing some voltage testing from the battery pack to any receiver,you will have a certain
amount of voltage drop due to connections and switches.I just setup a Wild hare Edge 540 50cc using Power HD 1501mg servos,DX8 and an AR8000 receiver with telemetry.
Battery is a Hobbico Life 6.6v 2100 with 2 switches.One switch is a JR chargeswitch(JRPA004),the other is a switch I bought from
the Perry r/c swapmeet for $10.00 that looks like a JR chargeswitch but is not.with the telemetry I can see what voltage is at the receiver from the DX8.It records min and max voltage automatically on screen.With just the $10.00 switch on my voltage was dropping to 3.9v from 6.6 while operating all servos.With just the JR switch on the voltage would drop to 5.6v from 6.6 while operating servos.with both switches on it would drop to 5.9v from 6.6 while operating servos.
voltage drop is servo load and from resistance in cheap switch,you also have some resistance in all the connections between receiver and battery.keep connections to a minimum.Also use HD servo extensions with gold plated terminals for a very good connection.
And try not to plug/unplug connections often.each time you plug/unplug,it expands the female side and eventually it will loose its tension.
With a 4.8v pack with a bad connection or cheap switch it will be enough to make the receiver reboot/brownout whatever you want to call it. With a 6.0v pack with loose/dirty/ connections or a cheap switch it still can drop enough voltage also.
I have setup all my planes that are on Spektrum using this way and never seen a problem,
by checking to see what voltage is at the receiver,I know what is there.You can not put a 6.0v pack on a system
and hope you get 6.0v there.you make sure you get the voltage there by testing it with a voltmeter at the receiver.
People just hook everything up and say its got a 6.0v battery,should be good. May have 6.0v at battery,but by the time it gets to the receiver,it will be less.You just need to take the time and make sure you are getting as much as that 6.0v from the battery to the receiver while under load(moving servos) as possible through by CHECKING VOLTAGE AT THE RECEIVER NOT THE CHARGE JACK OR BATTERY.
As far as my credentials on this,
no I am not an electrical engineer
but
I am a GM Mastertech
ASE Mastertech
specialize in
Electrical repairs
I am constantly looking at problems on GM products
pertaining to voltages/voltage drop within the GM high speed
and low speed communications between computer modules.
are the usaul battery ends.I have 1 regular connector run to a JR HD switch then to the receiver.I have the deans
plug ran to an arming switch then to the receiver with HD 22 gauge wire with gold plated connectors.
here is the arming switch I am using. http://www.rcaccessory.com/AS1-K12.aspx
Reason to use this rather than a switch,you have almost no voltage drop
and the only way it will fail if the deans arming plug comes out.
Now when checking voltage at the receiver I have very little voltage drop. 6.6v no load//6.2v all servos under
load.
I flew this plane for the first time this weekend and did not have any loss of connection or brownouts.I did switch out the servos
from the Power HDs to Hitec 5645 due to a Power HD servo failure on another plane a few months back.
Also flying an Escapade,E-Flite Extra260 electric,Parkzone Extra 300 electric and a Hanger 9 Ultra Stick on Spektrum 2.4
I bought the DX8 that came with 3 receivers and telemtry,then bought another DX8 with 3 receivers/telemtry and sold
the DX8.almost got enough receivers to convert everything over.
My opinion,keep receiver voltage above 4.8v and you will not have any problems,
BUT you have to take the time and make sure it is at the receiver by testing/checking it.
Just my .02 Roy
Somebody did mention that some receivers will catch the problem and display it on an LED. Very short brownouts can reboot the receiver even though your volt meter does not see the problem.
Another gadget is sold called the "Tattletale" which captures the lowest voltage reading every 10ms until it is reset. I use one in all new installations for awhile and plug it in any questionable battery.
I built hobby radios for 15 years (1968-1983) and one time received a call and was told by the customer that his elevator servo had reversed itself in the air (before reversing switches). I told him it wasn't possible but send me the radio. He sent the radio and he was right. The magnet in the servo motor had loosened and rotated 180 degrees under vibration. I never told anyone after that a malfunction was IMPOSSBLE.
I have read all 5 pages of this forum and I don't think anyone has mentioned that testing voltage with an analog or digital meter is NOT going to catch a very fast "brownout" that can occur in the power supply system whether you are using 4.8 volts supply or 6.00volt supply.
Somebody did mention that some receivers will catch the problem and display it on an LED. Very short brownouts can reboot the receiver even though your volt meter does not see the problem.
Another gadget is sold called the "Tattletale" which captures the lowest voltage reading every 10ms until it is reset. I use one in all new installations for awhile and plug it in any questionable battery.
I built hobby radios for 15 years (1968-1983) and one time received a call and was told by the customer that his elevator servo had reversed itself in the air (before reversing switches). I told him it wasn't possible but send me the radio. He sent the radio and he was right. The magnet in the servo motor had loosened and rotated 180 degrees under vibration. I never told anyone after that a malfunction was IMPOSSBLE.
...
Another gadget is sold called the "Tattletale" which captures the lowest voltage reading every 10ms until it is reset. I use one in all new installations for awhile and plug it in any questionable battery.
...
http://www.rcgroups.com/forums/showthread.php?t=1164449 (more details)
$19.95 http://www.xtremepowersystems.net/pr...=XPS-TT&cat=10
Extremely small and reasonably priced. A person could easily buy one and swap it between planes and find out some good information about what is going on with their power systems. I'm running the Spektrum telemetry. I don't know how fast the voltage reading updates but it will read voltage drops - even with 2300 mAH A123's - when swirling the sticks.
If I didn't have this telemetry I would buy a Tattletale.
Paul
Digital servos can make the problem worse. Next, if the power source cannot deliver more than 3 to 5A, and maintain an acceptable voltage at the receiver, it's likely not enough.
As to slide switches - - there are a bunch out there that are cheap switches ,and cause problems. One of the things to do is to use a double pole switch, and wire the two poles in parallel.
If you add a main power safety jumper, remember that the additional wire to go two and from the jumper socket adds some resistance. The additional loss can be significant on an electric powered model that draws 50 to 100A or so.
I found something interesting in the DX8 manual,
“CAUTION: When using the DX8 with parkflyer receivers (the
AR6100 and AR6110), it’s imperative that these receivers only be flown
in parkflyer-type aircraft (small electric airplanes or mini and micro
helicopters). Flying receivers designed for parkflyers in larger aircraft
could cause loss of connection.”
Between this and the extensive instructions on power requirements for receivers I think backs up the theory
that the problems are not the DX8 but more in the receiver power. I recently purchased a new DX8 and love it. I am not loyal to any manufacturer and this can be proven in my driveway. I have Chevy, Ford, and Honda. Everything I have is linked to Spektrum so rather than change everything to another brand I bought the DX8 to replace my DX7. I did read all of this thread before my purchase. As far as recalls they all have them but the nice thing with the DX8 is the fact that you can download programming upgrades and load the yourself instead of sending it to the factory. If you use Windows this is not an unusual process. Recently I reloaded <place>Vista</place> to an old laptop I had and found close to 200 updates for it on the Windows site. Now all of them are not repairs for bugs. A lot of them are improvements on the original program. This upgrade online, is one of the things I like about the DX8. I just thought I would throw in my 2 cents.
Rick
I had lost control of my Eflite T-34, at first I thought it was just a fluke of the wind, but after having it happen on another day with calm winds, I realized what the problem was, not the wind, but an actual loss of control. After a couple more glitches I finally was able to bring it down, and not so nicely either, busted the firewall, cracked the center wing ribs, and munched the cowl. Before I did anything, I popped off the canopy and saw the orange LEDs blinking.
I found something interesting in the DX8 manual,
βCAUTION: When using the DX8 with parkflyer receivers (the
AR6100 and AR6110), itβs imperative that these receivers only be flown
in parkflyer-type aircraft (small electric airplanes or mini and micro
helicopters). Flying receivers designed for parkflyers in larger aircraft
could cause loss of connection.β
Between this and the extensive instructions on power requirements for receivers I think backs up the theory
that the problems are not the DX8 but more in the receiver power.......
The small park type RX receivers do not have the remote aux satellite RX units of the larger AR6200, AR7000 and up or the extended RX antenna of the larger AR500 and AR600 RX units.
This makes it much easier for the small park type RX units to be "shadowed" while in a larger model and have their 2.4 TX signal possibly blocked by large metal engines, large lipo battery packs, large fuel tanks, large mufflers, large carbon fiber engine cowls and such.
The larger antenna "footprint" of the RX units above the AR500 size and up avoid this issue.
The AR6100 and AR6110 work perfectly with small electric models and small glow models, but could easily cause an issue in larger models.