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HELP! Spektrum DX7 radio failure?

Old 07-19-2007, 04:22 PM
  #51  
Lip84
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I was just thinking of a way to confirm that it was the TX and came up with an idea:

-If you know someone nearby you who owns a DX7 you can borrow their Tx and test all of your receivers that you had problems with in the same plane.

-Let your Tx be TxA and a friends be TxB.
-Let the 4 Recievers be Rx1-4
-Use 1 vehicle - and let that be aircraft A

-Take TxB, Rx1, and Aircraft A and test to see if you can reproduce the glitch. Do this with all four of your receivers. IF you cannot reproduce the glitch, THEN it follows that it was a fault with your transmitter and not the receivers. However, IF you CAN reproduce the glitch then it is either a) a problem with your receivers or b) a previously undiscovered flaw in the DX system or c) a problem associated with your field or d) something entirely different.

Obviously, the best scenario would involve trying to reproduce the exact conditions (ie same plane, batteries, servos, engines, flying location) but that is probably not doable since your p38 was totaled. But I seem to remember you saying it happened in multiple aircraft, perhaps you should do this experiment in one of those other craft.

Let us know if you do decide to do this and what your findings are, I am very curious and wish I could do this experiment

Best of luck,
Lip84
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Old 07-19-2007, 04:34 PM
  #52  
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Lip84 -- that's a good, solid testing approach. Unfortunately, my DX7 is already in the mail to Horizon... (Also, I don't know of anyone else around here with a DX7 -- though I'm sure I could find someone at the LHS.)

As for the Tx battery... When I had the two glitches on Sunday, with the P-51, I thought the Tx battery might be low... I seem to remember it was something like 10.4 volts.

I went home and charged it for 17 hours. The battery voltage was above 12 volts (I forget exactly what the DX7 said, but it was full). I flew that morning, and crashed the P-38.

Does anyone know if the DX7 has a low battery alarm? If so, I've never heard that alarm... :o
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Old 07-19-2007, 09:35 PM
  #53  
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Originally Posted by Lieutenant Loughead View Post
Does anyone know if the DX7 has a low battery alarm? If so, I've never heard that alarm... :o
I can't find anything in the manual that says it has a low voltage alarm, but I believe I remember hearing somewhere that it does. Anyway, the manual says not to fly with the voltage below 9 volts, so apparently it works well down to 9 volts.
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Old 07-26-2007, 08:20 PM
  #54  
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Well, I just received a phone call from the Spektrum technician. He says he spent several hours yesterday, testing my transmitter and six receivers -- all passed 100%.

During our 1-hour-long phone call, he pointed fingers at other components of my flight system:

First, he started with the LiPos, saying they were all "overcharged". (16.52 volts for a 4s, 12.02 volts for a 3s, and 11.68 volts for a 3s.) He told me, "3.0 volts per cell is considered a dead battery." He went on to say "all LiPo manufacturers agree on this point." I told him I have had 60+ cycles on these LiPos, and I charge them with a Triton charger -- the batteries are fine. He argued with me a little, but when I asked him if he's ever flown an electric airplane, he said, "no", and backed off.

Next, he started in on the Castle Creations speed controls. However, he quickly said this should not be an issue, since Spektrum sells Castle Creations speed controls.

Finally, he tried to tell me the failure has something to do with how I'm installing the second battery for that second flight. He didn't seem to understand why anyone would swap out a battery between flights. (Again, he's obviously not an electric flyer.) Who knows how I can install the battery correctly for the first flight, but not for the second one...

Then, we talked about servo loading, BEC usage (at one point, he told me I had it hooked up incorrectly), temperature failures, and lots of other things... He's stumped...

At this point, I've talked him into letting one of the Spektrum guys borrow the transmitter for the weekend to fly with it. We'll see what happens next.

I get the impression he thought I knew nothing about electronics, and was ignorant to how this stuff worked. He stopped in his tracks when I was able to pull up my flight log and tell him the details of every flight I've had for the last three years... ("Battery temp was 103.6 degrees, average discharge amps was 4.16 amps, after flight voltage was 12.02 volts, mAh used was 351 (out of #2 Tanic 3s 2220 mAh LiPo -- this particular battery's 71st flight), flight time was 5.1 minutes, the flight was July 15, 2007 at 13:45, and the wind was out of the east at 5 mph. It took 45 minutes for the Triton charger to charge the LiPo at 1 amp, with an average charge rate of 0.47 amps.")

When I told him the TRANSMITTER voltage was 10.4 volts after the P-51 crash, he was obviously confused -- he thought I was talking about the flight battery voltage (despite saying "TRANSMITTER Battery" three times). When he finally figured out we were talking about the TRANSMITTER voltage, he said, "Oh -- it's above 9 volts, so it's fully charged." (WHAT?! "Fully charged" would be closer to 11 volts!!! OH WAIT -- that would be an "overcharged battery", right?! )

I asked him if I could use a seperate 2s 800 mAh LiPo to power the Spektrum receivers. He didn't know the answer, but advised against it. (The Spektrum web site says the operating voltage range is "3.5v - 9v" -- why would a 2s LiPo not work?!) He suggested using a 6-cell NiMh battery, because "using the 2s LiPo would put too many volts on the receiver, and cause a thermal issue."

I asked him how much current the AR6100 receiver draws -- he had no idea.

This conversation does not give me a "warm fuzzy" feeling about Spektrum... Anyone want to buy a DX7 and seven receivers (AR6100 x6 + AR7100 x1)??? I think I'm switching back to my 72 MHz system...

Last edited by Lieutenant Loughead; 07-26-2007 at 09:52 PM.
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Old 07-26-2007, 08:27 PM
  #55  
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Originally Posted by Lieutenant Loughead View Post
Well, I just received a phone call from the Spektrum technician. He says he spent several hours yesterday, testing my transmitter and six receivers -- all passed 100%.

During our 1-hour-long phone call, he pointed fingers at other components of my flight system:

First, he started with the LiPos, saying they were all "overcharged". (16.52 volts for a 4s, 12.02 volts for a 3s, and 11.68 volts for a 3s.) He told me, "3.0 volts per cell is considered a dead battery." He went on to say "all LiPo manufacturers agree on this point." I told him I have had 60+ cycles on these LiPos, and I charge them with a Triton charger -- the batteries are fine. He argued with me a little, but when I asked him if he's ever flown an electric airplane, he said, "no", and backed off.

Next, he started in on the Castle Creations speed controls. However, he quickly said this should not be an issue, since Spektrum sells Castle Creations speed controls.

Finally, he tried to tell me the failure has something to do with how I'm installing the second battery for that second flight. He didn't seem to understand why anyone would swap out a battery between flights. (Again, he's obviously not an electric flyer.) Who knows how I can install the battery correctly for the first flight, but not for the second one...

Then, we talked about servo loading, BEC usage (at one point, he told me I had it hooked up incorrectly), temperature failures, and lots of other things... He's stumped...

At this point, I've talked him into letting one of the Spektrum guys borrow the transmitter for the weekend to fly with it. We'll see what happens next.

I get the impression he thought I knew nothing about electronics, and was ignorant to how this stuff worked. He stopped in his tracks when I was able to pull up my flight log and tell him the details of every flight I've had for the last three years... ("Battery temp was 103.6 degrees, average discharge amps was 4.16 amps, after flight voltage was 12.02 volts, mAh used was 351 (out of a 2220 mAh LiPo), flight time was 5.1 minutes, the flight was July 15, 2007 at 13:45, and the wind was out of the east at 5 mph. It took 45 minutes for the Triton charger to charge the LiPo at 1 amp, with an average charge rate of 0.47 amps.")

When I told him the TRANSMITTER voltage was 10.4 volts after the P-51 crash, he was obviously confused -- he thought I was talking about the flight battery voltage (despite saying "TRANSMITTER Battery" three times). When he finally figured out we were talking about the TRANSMITTER voltage, he said, "Oh -- it's above 9 volts, so it's fully charged." (WHAT?! "Fully charged" would be closer to 11.5 volts!!!)

I asked him if I could use a seperate 2s 800 mAh LiPo to power the Spektrum receivers. He didn't know the answer, but advised against it. (The Spektrum web site says the operating voltage range is "3.5v - 9v" -- why would a 2s LiPo not work?!) He suggested using a 6-cell NiMh battery.

I asked him how much current the AR6100 receiver draws -- he had no idea.

This conversation does not give me a "warm fuzzy" feeling about Spektrum... Anyone want to buy a DX7 and seven receivers (AR6100 x6 + AR7100 x1)???
Holy Crapola, your above story makes me think I need to wait another year until Spektrum debugs their much vaunted DX7 and trains its service techs.
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Old 07-26-2007, 08:29 PM
  #56  
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Originally Posted by Prof100 View Post
Holy Crapola, your above story makes me think I need to wait another year until Spektrum debugs their much vaunted DX7 and trains its service techs.
THANK YOU! I'm glad it isn't just me that saw a problem with that conversation!
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Old 07-26-2007, 08:30 PM
  #57  
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Personally I would call back and ask to speak with an engineer or someone who actually knows how the system works. That guy sounded like a level 1 tech just there to answer phones and boneheaded simple questions. Spektrum from what I have read is always trying to make good on their products to keep their share of the market. Negative publicity would definitely damage their reputation.
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Old 07-26-2007, 08:33 PM
  #58  
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With 100% certainty my decision to buy a DX7 is on-hold indefinitely until I see how this is resolved. I am just sorry to read about Lt. Loughead's misfortunes.
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Old 07-26-2007, 08:34 PM
  #59  
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I agree, try to get in touch with a senior engineer at Spektrum.
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Old 07-26-2007, 08:37 PM
  #60  
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I can tell you for sure that some of the 5S FJ guys us a 2s lipo to power the RX's in their bird and I plan on doing the same thing.
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Old 07-26-2007, 08:37 PM
  #61  
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I agree with Barney. He could be a new tech as well. And from personal experience, being a new tech sucks, especially when you dont know the equipment yet. However, that sounds like the stupidest guy ever, he didnt even try to provide quality customer service and bring one of the higher level tech support guys or an engineer on the line. Someone in a tech support/customer service realm should NEVER argue with a customer, especially one as prepared and knowledgeable as you.

I would definitely call back and request speaking to a lead tech or an engineer. It sounds like you have all your numbers to back up any convo and answer all the questions they might ask.

You deserve a quality answer and they are required to give it to you.

Lip84

P.S. You might want to drop them a line in your next phone convo that there is quite a lot of anxiety on your forums in regards to this issue and that a positive resolution will mean more business for them. That might persuade them to at least treat you well.
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Old 07-26-2007, 08:53 PM
  #62  
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Originally Posted by Lieutenant Loughead View Post
Well, I just received a phone call from the Spektrum technician. He says he spent several hours yesterday, testing my transmitter and six receivers -- all passed 100%.

During our 1-hour-long phone call, he pointed fingers at other components of my flight system:

First, he started with the LiPos, saying they were all "overcharged". (16.52 volts for a 4s, 12.02 volts for a 3s, and 11.68 volts for a 3s.) He told me, "3.0 volts per cell is considered a dead battery." He went on to say "all LiPo manufacturers agree on this point." I told him I have had 60+ cycles on these LiPos, and I charge them with a Triton charger -- the batteries are fine. He argued with me a little, but when I asked him if he's ever flown an electric airplane, he said, "no", and backed off.

Next, he started in on the Castle Creations speed controls. However, he quickly said this should not be an issue, since Spektrum sells Castle Creations speed controls.

Finally, he tried to tell me the failure has something to do with how I'm installing the second battery for that second flight. He didn't seem to understand why anyone would swap out a battery between flights. (Again, he's obviously not an electric flyer.) Who knows how I can install the battery correctly for the first flight, but not for the second one...

Then, we talked about servo loading, BEC usage (at one point, he told me I had it hooked up incorrectly), temperature failures, and lots of other things... He's stumped...

At this point, I've talked him into letting one of the Spektrum guys borrow the transmitter for the weekend to fly with it. We'll see what happens next.

I get the impression he thought I knew nothing about electronics, and was ignorant to how this stuff worked. He stopped in his tracks when I was able to pull up my flight log and tell him the details of every flight I've had for the last three years... ("Battery temp was 103.6 degrees, average discharge amps was 4.16 amps, after flight voltage was 12.02 volts, mAh used was 351 (out of a 2220 mAh LiPo), flight time was 5.1 minutes, the flight was July 15, 2007 at 13:45, and the wind was out of the east at 5 mph. It took 45 minutes for the Triton charger to charge the LiPo at 1 amp, with an average charge rate of 0.47 amps.")

When I told him the TRANSMITTER voltage was 10.4 volts after the P-51 crash, he was obviously confused -- he thought I was talking about the flight battery voltage (despite saying "TRANSMITTER Battery" three times). When he finally figured out we were talking about the TRANSMITTER voltage, he said, "Oh -- it's above 9 volts, so it's fully charged." (WHAT?! "Fully charged" would be closer to 11 volts!!! OH WAIT -- that would be an "overcharged battery", right?! )

I asked him if I could use a seperate 2s 800 mAh LiPo to power the Spektrum receivers. He didn't know the answer, but advised against it. (The Spektrum web site says the operating voltage range is "3.5v - 9v" -- why would a 2s LiPo not work?!) He suggested using a 6-cell NiMh battery, because "using the 2s LiPo would put too many volts on the receiver, and cause a thermal issue."

I asked him how much current the AR6100 receiver draws -- he had no idea.

This conversation does not give me a "warm fuzzy" feeling about Spektrum... Anyone want to buy a DX7 and seven receivers (AR6100 x6 + AR7100 x1)??? I think I'm switching back to my 72 MHz system...
That is comical, sounds like the same conversation I had with them. I think they are trained not to admit any fault because it opens the company up to liability issues. Even though in my scenario, I had 2 different planes with different components...even an external BEC in one of the models. The ONLY component they had in common was the spectrum receiver. Yet they still didn't admit that there's a posibility that it could have been their equipment. I charge from a balancing charger, so I know what volt each cell is carrying. Also, I don't think it matters what voltage your battery is at, the bec will regulate it down to either 5v or 6v. Only time you may have issue is when your battery gets drained so much that it can't supply the bec with even the min. voltage. In my case, I think it was due to a bad/damaged antenna. But to the credit of spectrum, it only happened on one day (cloudy/overcast) weather may have had something to do with it. I'm still flying the DX-6...haven't had any issues since. I wouldn't throw out your unit just yet.
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Old 07-26-2007, 09:17 PM
  #63  
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Originally Posted by Lieutenant Loughead View Post
Anyone want to buy a DX7 and seven receivers (AR6100 x6 + AR7100 x1)??? I think I'm switching back to my 72 MHz system...
I'm certain the problem is resolvable but if you're serious PM me.
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Old 07-26-2007, 10:00 PM
  #64  
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Guys -- thanks for your support. Here's the message I sent to SpektrumRC... I think I came off a bit strong (certainly stronger than I intended), however I'm a little upset after that 1-hour phone call!

The message is as follows:

I just had a 1-hour conversation with one of your service techs. Please see the following link for a transcript of the conversation: http://www.wattflyer.com/forums/show...4&postcount=54

I am not happy with the quality of service I am receiving from Spektrum -- the problem my DX7 is experiencing obviously requires a senior Spektrum engineer for a reasonable resolution.

As a degreed engineer (an an engineering manager of 60 design engineers), I can tell you these FOUR in-flight failures are SPEKTRUM related. All of these aircraft flew many happy flights on a 72 MHz radio system.

I am not some ignorant kid who throws airplanes in the air and expects them to magicly fly -- my aircraft are ENGINEERED to work properly -- how many of your customers have thrust benches, torque benches, RPM gauges, watt meters, and can tell you how many millAmpHours they pulled from their battery on a random flight three years ago? I can even tell you the after-flight temperature of that battery, and I can SHOW you exactly which battery I used for that particular flight!

I have lost several hundred dollars worth of equipment, and several months of my time (building), due to these MULTIPLE SPEKTRUM radio failures. I am not willing to accept my DX7 back, with "no problem found" from SPEKTRUM SERVICE. I want my SPEKTRUM radio fixed, or I want my money back.

The internet is watching, and waiting for your solution to my issue -- please note this post in particular --> http://www.wattflyer.com/forums/show...1&postcount=58

Sincerely,
(name witheld)
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Old 07-26-2007, 10:04 PM
  #65  
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Seems pretty reasonable to me but then my social antenae are known for being misaligned.
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Old 07-26-2007, 10:16 PM
  #66  
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I think you are right on!
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Old 07-26-2007, 10:44 PM
  #67  
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It might be a tad strong, but then again that is how things get done. When you push and they push back...sometimes times you need to push harder.

Best of luck and keep us posted!
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Old 07-27-2007, 03:37 AM
  #68  
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It was NOT too strong. I think you have been more than patient. Too strong would have read as follows:

" I found the tone of your service tech to be demeaning and condescending to me as customer who has bought not only the DX7 radio but (insert number) receivers. I have destroyed 4 planes in conditions that seem to clearly point to a problem with your highly touted and promoted DX7 Spektrum radio system. I cannot believe you run a business where the service technicians know less than their customers do about the base technology and application in which their product failed. What is even more frustrating is your service technician appears to be untrained in a range of skills, including but not limited to product knowledge. This particular tech needs to be trained in the fundamentals of customer support. Arguing with the customer or stonewalling (read denying the customer’s experience) just won’t cut it. I would believe the problem is simply a lack of training and standard protocol for him to follow should the standard FAQ type answers not work. Therefore, consider providing training in the product plus basic problem analysis and problem solving. He also needs to know when to say he doesn't know but will find out by escalating the problem to a higher authority. If the training doesn’t work you could consider psychotherapeutic intervention or, at worse, termination.

It would be easy for me to declare your product as a piece of junk and demand my money back for the radio and receivers plus a credit or refund for the cost of the airplanes that were destroyed. However, all I want is the problem solved so the promises of a glitch free reliable radio system are fulfilled. Thank you and have a nice day."

Last edited by Prof100; 07-27-2007 at 11:41 AM.
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Old 07-27-2007, 04:37 AM
  #69  
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Interesting experience. I feel your frustration with the amount of money and time you have dedicated into your fleet. Is there any way to use it static and get a glitch counter for this?
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Old 07-27-2007, 01:52 PM
  #70  
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Dave -- what is a "glitch counter"? Where could I get one?

I am certainly not opposed to static testing -- however, I think that is something Spektrum should do at this point.

Thank you for your nice words. One thing that many people don't realize about my aircraft, is that I spend the extra time, energy, and expense to fiberglass them! I got the impression that the Spektrum technician thought of my aircraft as cheap, disposable toys...
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Old 07-27-2007, 01:55 PM
  #71  
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Originally Posted by Lieutenant Loughead View Post
Dave -- what is a "glitch counter"? ,,,

Thank you for your nice words. One thing that many people don't realize about my aircraft, is that I spend the extra time, energy, and expense to fiberglass them! I got the impression that the Spektrum technician thought of my aircraft as cheap, disposable toys...

You put your heart and soul into your hobby. That's what some people don't realize.
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Old 07-27-2007, 02:36 PM
  #72  
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Originally Posted by Lieutenant Loughead View Post
Thank you for your nice words. One thing that many people don't realize about my aircraft, is that I spend the extra time, energy, and expense to fiberglass them! I got the impression that the Spektrum technician thought of my aircraft as cheap, disposable toys...
Hey Loughead...I had a revelation while reading this most current post. I have seen information that the 2.4 Ghz systems (all of them) have difficulties when the receivers are put in a fiberglassed or carbon fiber fuselage. I am not too learned in the art of Radio and interference but, the argument I have heard is that the 2.4ghz band is more easily blocked, deflected by objects due to the higher frequency. For instance, a 2.4ghz signal has no problem passing through balsa or foam but COULD end up reflecting off of a carbon fiber or fiberglass fuselage.

I am not suggesting that this is your definitive answer, I simply remember reading this while doing research on the 2.4ghz systems as I am interested in getting one. I just wanted to throw it out there for you.

Keep fightin the good fight!
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Old 07-27-2007, 03:32 PM
  #73  
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Yeah, that thought had occured to me. Fiberglass blocking the signal explains the P-51 and the P-38, but not the Depron "flat foamie"...

The fiberglass issue has not come up in my communication with Spektrum, and at this point I don't want to give them an easy out -- so I am not going to mention it, unless they ask me...
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Old 07-27-2007, 03:56 PM
  #74  
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I had another thought this morning...

Those of you with a DX7, please look at the "bind button" on the back. Let me know if you think that button could accidentially be pressed when sitting on the ground (or on a harder surface, like the floorboard of your car).

Here's my thought -- what if I'm turning on the transmitter while it's sitting on the ground? If I do that, I'm going to be pushing down on the transmitter a little -- if the "bind button" becomes depressed, it links, and then I immediately fly on it... Well, what would happen then?
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Old 07-27-2007, 04:06 PM
  #75  
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There has been a wonderful job done of troubleshooting in the thread.

I would like to just expand a little for the novice (beginners forum) some posts earlier in this thread.

Antennas and their radiation pattern:

1. The tip of an antenna is the weakest point in the field. See attached pic.
2. Antenna Length is critical to the transmitted pattern.
(Length is based on frequency; Typically 1/4 wavelength)
3. RF radiation is Electrical/Magnetic in nature and any object that can pass an electrical current can either transmit or receive radiated RF.
4. The higher the frequency the shorter the antenna.
(1/4 wavelengths; 27mhz=104"; 72mhz=39"; 2.4ghz=1.17"
5. The distance of an object to a TX/RX antenna can either add to or subtract from the a) TX radiation pattern or b) The RX antenna signal strength.
Note: This is how a TV antenna on your roof multiplies the signal strength. (The rod lengths and spacing have a "gain" effect.

In short (I don't want to get to technical) as we get to using higher and higher frequencies, smaller and smaller objects will cause us more problems. I have a DX7 and Love it, but have to be extra careful about placement.

Just my $0.02 (be gentle with me)


Last edited by rea59; 07-27-2007 at 04:30 PM.
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