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HELP! Spektrum DX7 radio failure?

Old 08-08-2007, 01:10 AM
  #151  
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Originally Posted by rea59 View Post
LOL

I have experienced many times where "theory" and "reality" don't co-exist but in this case I believe that the equipment is processing as advertised (theory) (witness the thousands of system in the field working perfectly) and that this radio has/had a specific failure which resulted in the symptoms being seen.
Yea, you are probably right. And I will probably break down and buy the DX7 even though I am worried about it and it will turn out to be perfect for me. Go figure...
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Old 08-08-2007, 01:10 AM
  #152  
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Originally Posted by Lip84 View Post
Thats the thing...the theory is all there and its awesome. If it really worked like that the world would be a better place but it obviously doesnt.
Sure it does.

The Lt has an isolated failure that stumped the guys at Horizon for a while, but that doesn't mean the technology isn't working as advertized, it just means his unit was broken in a really creative way.

Cellphones and all sorts of other devices use DSSS to maintain data integrity - stuff works.
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Old 08-08-2007, 01:13 AM
  #153  
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Originally Posted by UncleBob View Post
broken in a really creative way.
LMAO
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Old 08-08-2007, 01:33 AM
  #154  
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does anyone know of any statistics available as to the # of units in the field from each of the 2.4ghz producers? It would be awesome to see # of units compared to # of issues.
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Old 08-08-2007, 01:57 AM
  #155  
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Originally Posted by gfdengine204 View Post
I understand your frustration, and hope not to sound too harsh.....but.... <SNIP!>
Sorry to have offended you. I suppose I got my point across more strongly than I realized.

I am not a shill, or a troll... I'm just a guy who spent a bunch of money on a radio system that I can not trust -- it's a problem that I feel very strongly about.

I will "shut up" now...
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Old 08-08-2007, 02:19 AM
  #156  
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Originally Posted by Lip84 View Post
Yea, you are probably right. And I will probably break down and buy the DX7 even though I am worried about it and it will turn out to be perfect for me. Go figure...
I have a DX7 and currently plan to use it in my latest build. By the time it's finished I'll have right around six grand invested. I want to have a radio that I can trust so using a DX7 or a DX9 or one of the Futuba radios is not done lightly. I believe Spektrum makes a good product and sincerly "hope" it stays that way.

Originally Posted by Lieutenant Loughead View Post
Sorry to have offended you. I suppose I got my point across more strongly than I realized.

I am not a shill, or a troll... I'm just a guy who spent a bunch of money on a radio system that I can not trust -- it's a problem that I feel very strongly about.

I will "shut up" now...
Any large investment is made with some apprehension an then when it doesn't work you feel as if you were ripped off. This is normal and getting your confidence back in the product can be an up hill battle. I can only say that you are using the process correctly, in consulting with others and having the system sent to the experts for testing and repair. Should that coax turn out to have been the "root cause" your confidence should slowly come back.

Hang in there.
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Old 08-08-2007, 05:59 AM
  #157  
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Originally Posted by rea59 View Post
So when a Spektrum TX/RX "lock" onto each other is that a "channel lock" or just a data packet "encoding lock"?
As I understand it, the TX and the RX are bound together using a GUID number so that the Receiver only listens to the Transmitter operating on that GUID number. There are many millions of those GUID numbers available.

Then when you turn on your TX first and then your RX, they talk to each other to be sure they are using the correct GUID number.

When that has been established, they go looking for one frequency of the 80 available in the 2.4ghz spectrum that is not being used. Once they have selected an unused frequency and locked on to that frequency, they go looking for another unused specific frequency that is unused and they lock on to that frequency.

Now the RX and the TX are speaking only to each other on two frequencies that only they are using and the receiver signals that it is ready to fly with a beep.

Actually only 40 Spektrum transmitters can operate at any one time within range of each other, since there are only 80 discrete frequencies available. Of course this will probably never be a problem for 99% of us.

All of these conditions are set by the FCC for anyone operating in the 2.4ghz frequency range. No one is allowed to use a specific frequency that is already in use. Anyway our GUID number says that the receiver ingores any transmission that does not contain that GUID number.

I do not know exactly how the Futaba FAAST system works since I use Spektrum.

Hope this helps.
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Old 08-08-2007, 06:39 PM
  #158  
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Default Another DSM Issue?

I to have suffered dsm radio failure lately. Two relatively new planes - less than ten flights each, new AR6100 receivers, one on two cells one on three cell MaxAmps - gentle handlaunch at 30deg, 80% power. Both planes traveled about 50 feet - 10 feet off the deck and lost complete power. One was a airfoilz yak the other an extreme flight yak. Both planes had "rebooted"? before I got to them and I actually straightened the motor mount on the extreme flight and immediately relaunched with no further problems. The airfoilz broke in half but was repaired and is now flying. After reading these threads I guess the one thing I'm doing wrong is launching the plane straight away from me. Naturally my trans is pointed directly at the back of the plane as it climbs away. Both receivers are externally mounted w/no obstructions. Both planes were "run up" prior to launch and all systems were go. One has a GWS 25 the other a Hyperian 20 Titan - both new but flight tested. Although the batteries were at full charge, verified by a WATTSUP prior to launch, a fellow flyer seems to think that the bat voltages are dropping below COV causing a shut down. I've not lost any $$ yet, only time; but, I'm now really concerned about putting these systems in a hi $$$ plane. Concerned in NC.
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Old 08-08-2007, 06:52 PM
  #159  
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As I understand it this is how it works:

The RX:

The RX powers up, self tests, puts outputs to failsafe and begins scanning the channels. If a Spektrum TX is found to be transmitting on a channel, the packets are decoded and the embedded GUID is compared to that stored in the RX. If they match, one of the two channels has been found and the process is repeated for the second channel. If they do not match the search for a matching GUID continues.

The TX:

The TX powers up and after self testing begins searching for two open channels. Upon finding them it begins transmitting properly formed data packets with among other things, the GUID associated with the currently selected model embedded.

If the TX cannot find two vacant channels it continues to scan until it does.

I assume there has to be some sort of collision detection and resolution, but Spektrum hasn't to my knowledge spoken about that. Perhaps that part of the system is defined by the 2.4 GHz regulations, I don't know.



Originally Posted by retired06 View Post
I to have suffered dsm radio failure lately. .... I've not lost any $$ yet, only time; but, I'm now really concerned about putting these systems in a hi $$$ plane. Concerned in NC.
This sounds more like a bad or inadequate BEC or something.
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Old 08-08-2007, 07:38 PM
  #160  
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Originally Posted by Rabbitcreekok View Post
All of these conditions are set by the FCC for anyone operating in the 2.4ghz frequency range. No one is allowed to use a specific frequency that is already in use. Anyway our GUID number says that the receiver ingores any transmission that does not contain that GUID number.
This makes me think that Loughead is even more correct in thinking there is a TX problem with his situation. In theory, no other signal should ever be able to create interference since the RX will only listen to the TX's GUID. This then puts the onus on the TX for having a fault.

I would guess some type of weak signal or intermittent signal. Perhaps from the faulty coax. I dont know much about the guts of radio EQ so I cant make much more than a barely educated hunch.

Lip84
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Old 08-08-2007, 07:43 PM
  #161  
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Originally Posted by Lip84 View Post
In theory, no other signal should ever be able to create interference since the RX will only listen to the TX's GUID.
Not disagreeing with your conclusion (TX issue) but the reasoning I'm not so sure of. Unless the GUID is used to seed the SS 'PN' value it wont come into play until AFTER the radio section. Interference is a radio section issue.

If the GUID (or some other bind-time shared data) is used to generate the pseudo-random sequence then that would add a big degree of noise immunity to the radio section, but Spektrum hasn't (as far as I know) specified that they have done this.
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Old 08-08-2007, 08:21 PM
  #162  
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Originally Posted by retired06 View Post
I to have suffered dsm radio failure lately.
I feel your pain!

Try flying the same airplane with a 72MHz radio. You might be able to prove (as I have) it's the Spektrum receiver!

THEN, put your watt meter between the BEC and the receiver. "Load" the servos, and look at the minimum voltage the watt meter records -- if it is above 4.5 volts (as mine was), your BEC is fine.

The Spektrum tech I spoke with told me the antenna pointing directly at the airplane (or both antennas pointing directly at eachother) will not affect the operation of the radio. When Spektrum "test flew" my transmitter and receiver, I asked about the orientation of the transmitter antenna -- the Spektrum tech said, "It was pointing straight out." I mention this because I'm not sure it makes that much difference... :o
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Old 08-08-2007, 08:29 PM
  #163  
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Originally Posted by Lieutenant Loughead View Post
.... I'm not sure it makes that much difference... :o
I think technically (absolute signal strength) it does, but practically (you should get adequate signal in any case if range test passes) it probably doesn't.
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Old 08-10-2007, 05:23 PM
  #164  
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I received my DX7 from Spektrum in yesterday's mail. My radio equipment was "professionally packaged" in a hashbrown potato box, with my five AR6100 receivers touching the side of the exterior box (no padding/protection during shipping).

I found the coax cable which Spektrum says is causing my problem -- there is a very small crease in the outside plastic, but I don't think I can get a good picture of it...

For what it's worth, when I think of "coax", I'm thinking of the cable which comes out of my wall, and enters my television... Spektrum "coax" is much smaller -- you can see it where your external antenna bends... (Very small!)

Anyway, I have an airplane, the radio, and my test plan in my car. I plan to run a test during lunch today -- when it's hottest outside. I'm going to try to run a static test to see if I can get anything (AR6100 receiver, Phoenix 25 ESC, Himax 2025-4200 motor) to overheat. I will also be checking the minimum voltage to the receiver, at various points during this test.

Step 1: Try again…
GWS P-51, on ground.
Use WattsUp meter
WOT for 5 minutes
Load the servos
Test BEC voltage.
Test temperature of motor.
Test temperature of ESC.
Test temperature of AR6100.
Repeat four times.
I will also range check several times, after turning off and on the transmitter, in an attempt to test the possibility of a noisy channel...

I will post my results later today.

This is the first of four test to rebuild my trust in Spektrum.
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Old 08-10-2007, 06:08 PM
  #165  
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Good luck.
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Old 08-10-2007, 07:28 PM
  #166  
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Actually I had a buddy who had issues with his DX6 - it WAS the creased coax in the bend in the antenna on the TX.

So you never know....

Mike
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Old 08-10-2007, 07:34 PM
  #167  
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how do you know when you get your tx if there is a creased coax? do you think something like that would be covered by warranty if you opened it up and checked?
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Old 08-10-2007, 07:50 PM
  #168  
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Originally Posted by Lip84 View Post
how do you know when you get your tx if there is a creased coax? do you think something like that would be covered by warranty if you opened it up and checked?
Ummmm If you are not having any "issues" I would say sleep well. If you have trouble it is certainly something you could investigate.
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Old 08-10-2007, 08:52 PM
  #169  
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Angry Day 24...

*&^%$#@! ?? <-- these are all emotions I am feeling right now...

As listed above, I went out to test the Spektrum DX7 and AR6100 receivers I received yesterday (in the mail) from Spektrum...

Before I started the test, I performed a range test -- EXACTLY AS LISTED IN THE DX7 MANUAL!



Test aparatus:
AR6100 receiver (originally in the GWS P-51)
#2 Tanic 2220 mAh 3s LiPo
Spektrum DX7 transmitter
WattsUp meter in-line between the Phoenix 25 BEC and AR6100 receiver

Notes:
Transmitter antenna was left straight.
Receiver was turned on before transmitter.
All tests were with the Tx BEHIND the aiplane (so the motor was NOT between the Rx and Tx).

Range Test #1, Site #1:
Range test failed multiple times, with a minimum distance of 38 feet.
WattsUp meter measured minimum voltage during test at 4.92 volts.
Each failure required more than 10 seconds to self-correct.

Range Test #2, Site #1:
Moved AR6100 OUTSIDE of aircraft.
Verified AR6100 antennae were pointing UP and DOWN (not at DX7 antenna).
Moved DX7 antenna to 90 degrees left (looks similar to the number 7).
Turned Rx and Tx off.
Turned Rx on.
Turned Tx on. (Noticed that the ESC "armed" about 10 seconds after power-up)
Range test failed multiple times, with a minimum distance of 35 feet.
WattsUp meter measured minimum voltage during test at 4.92 volts.
Each failure required more than 10 seconds to self-correct.

Range Test #3, Site #1:
Turned Rx and Tx off.
Turned Tx on.
Turned Rx on. (Noticed that the ESC "armed" almost immediately)
Range test failed multiple times, with a minimum distance of 37 feet.
WattsUp meter measured minimum voltage during test at 4.91 volts.
Each failure required more than 10 seconds to self-correct.
Drove to site #2 -- approximately 4 miles away.

Test aparatus:
AR6100 receiver (originally in the GWS P-51)
#2 Tanic 2220 mAh LiPo
WattsUp meter in-line between the Phoenix 25 BEC and AR6100 receiver
Spektrum DX7 transmitter
Notes:
Transmitter antenna was left straight.
Receiver was turned on before transmitter.



Range Test #1, Site #2:
Range test failed multiple times, with a minimum distance of 45 feet.
WattsUp meter measured minimum voltage during test at 4.92 volts.
Each failure required more than 10 seconds to self-correct.
Range Test #2, Site #2:
Moved AR6100 OUTSIDE of aircraft.
Verified AR6100 antennae were pointing UP and DOWN (not at DX7 antenna).
Moved DX7 antenna to 90 degrees left (looks similar to the number 7).
Turned Rx and Tx off.
Turned Rx on.
Turned Tx on. (Noticed that the ESC "armed" about 10 seconds after power-up)
Range test failed multiple times, with a minimum distance of 30 feet.
WattsUp meter measured minimum voltage during test at 4.91 volts.
Each failure required more than 10 seconds to self-correct.
Range Test #3, Site #2:
Turned Rx and Tx off.
Turned Tx on.
Turned Rx on. (Noticed that the ESC "armed" almost immediately)
Range test failed multiple times, with a minimum distance of 24 feet.
WattsUp meter measured minimum voltage during test at 4.92 volts.
Each failure required more than 10 seconds to self-correct.
I called Spektrum back, and spoke with the tech. He still gives me the same "run around" story -- "Well, it worked here..." I told him I really hoped this worked out, but I'm tired of taking a "wait and see" attitude for a month -- he assured me it would not take that long... (I wonder if he realizes it's already been 3.5 weeks?!)

Tomorrow morning I will perform two more tests:

AR6100 receiver (originally in the GWS P-51) will go in a different airplane, and a range check will be performed.


AR7000 receiver (new) will go into the airplane tested today, and range check will be performed.
If the AR6100 fails, but the AR7000 passes, it's the AR6100.
If the AR7100 fails, but the AR6100 passes, it's the airplane.
If BOTH fail, it's the transmitter.
If it turns out to be "the airplane", I'm going to be pretty upset with Spektrum equipment! My 72 MHz radios never had trouble with this airplane -- why would a Spektrum radio?!

I eagerly accept any wisdom you guys can share with me -- how else can I test this radio?
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Old 08-10-2007, 08:59 PM
  #170  
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Man loughead...that sux a big one. I guess the only questions is whether or not the airplane you were testing with has either a fiberglass or carbon fiber fuse. Either of those COULD pose a problem for 2.4ghz transmissions.

IS there anyway that your ESC could be causing problems like this or that you might have a bad link between the battery? ( I am guessing no on all of these).

I would make spektrum give me a new radio. Sorry buddy
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Old 08-10-2007, 09:05 PM
  #171  
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Originally Posted by Lip84 View Post
Man loughead...that sux a big one. I guess the only questions is whether or not the airplane you were testing with has either a fiberglass or carbon fiber fuse. Either of those COULD pose a problem for 2.4ghz transmissions.
Yes -- the fuselage is styrofoam, covered in fiberglass, covered in Microlite covering. The Spektrum tech said carbon fiber and fiberglass has no effect on 2.4 GHz radios. He went on to say that there are people flying full fiberglass aircraft, with no issues.

Also, part of my test was to move the receiver OUTSIDE of the fuselage -- it was in OPEN AIR, and still failed the range test!

Originally Posted by Lip84 View Post
IS there anyway that your ESC could be causing problems like this or that you might have a bad link between the battery? ( I am guessing no on all of these).
If you read my previous post carefully, you will see the minimum voltage the BEC supplied to the receiver was 4.91 volts, during ALL tests performed today. The Spektrum tech agrees that is "acceptable" voltage. (I guess I finally proved to Spektrum it's not my SmartBEC, or the internal BECs to my Phoenix 25's and Thunderbird 18!!!)

Originally Posted by Lip84 View Post
I would make spektrum give me a new radio. Sorry buddy
I've tried going that route several times. The Spektrum tech keeps stonewalling me. It seems I can't "make" them to anything!

LOL -- sorry to vent -- I'm certainly not mad at you! I'm unbelievably mad at Spektrum! I haven't flown in nearly a month, and I need my fix!!!
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Old 08-10-2007, 09:33 PM
  #172  
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Originally Posted by Lieutenant Loughead View Post
Yes -- the fuselage is styrofoam, covered in fiberglass, covered in Microlite covering. The Spektrum tech said carbon fiber and fiberglass has no effect on 2.4 GHz radios. He went on to say that there are people flying full fiberglass aircraft, with no issues.

Also, part of my test was to move the receiver OUTSIDE of the fuselage -- it was in OPEN AIR, and still failed the range test!

If you read my previous post carefully, you will see the minimum voltage the BEC supplied to the receiver was 4.91 volts, during ALL tests performed today. The Spektrum tech agrees that is "acceptable" voltage. (I guess I finally proved to Spektrum it's not my SmartBEC, or the internal BECs to my Phoenix 25's and Thunderbird 18!!!)

I've tried going that route several times. The Spektrum tech keeps stonewalling me. It seems I can't "make" them to anything!

LOL -- sorry to vent -- I'm certainly not mad at you! I'm unbelievably mad at Spektrum! I haven't flown in nearly a month, and I need my fix!!!
At this point I would REQUIRE them to refund all of the money you spent on the equipment. Send it back in again for an exchange not "repair" I seriously doubt that it has anything to do with the area or your birds. If that were the case then we would see many more problems then have been reported.

I'm sure there is a person that you could talk to that could make this happen and as a company they should be wondering why your radio fails. Seriously, let us know how it turns out. I ordered a x9303 in June and don't want to have to deal with a company like this.
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Old 08-10-2007, 09:36 PM
  #173  
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Just a suggestion.

I noticed in all cases, you turned on the receiver first. I always turn on the transmitter first, then plug in the battery in the plane to turn on receiver.

This may not make any difference, but try it.
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Old 08-10-2007, 09:40 PM
  #174  
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In his last post he tried it both ways. He said when he turned on the RX then the TX it took longer for the ESC to arm. When he turned on the TX then the RX the ESC armed almost immediately.
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Old 08-10-2007, 09:45 PM
  #175  
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Originally Posted by brnyrbbl View Post
In his last post he tried it both ways. He said when he turned on the RX then the TX it took longer for the ESC to arm. When he turned on the TX then the RX the ESC armed almost immediately.
Thanks for beating me to the answer to his question!

I would like to add that the Spektrum tech said it made no difference in which order you turn on your Tx and Rx. In my testing, both ways failed the range test.
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