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2.4 ghz interference: It can happen!

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2.4 ghz interference: It can happen!

Old 02-21-2013, 12:31 PM
  #26  
Truckracer
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Default RE: 2.4 ghz interference: It can happen!

ORIGINAL: radfordc


ORIGINAL: Truckracer

One of the most popular plugs in use today, the CM-6 is a non-resistor plug. Just about every new engine uses it and with great success.
All the ignition systems I have used have a resistor installed in the lead going to the spark plug. Serves the same purpose as a resistor plug.
You are correct but some still insist that a resistor plug is also needed ..... where it just isn't so with the CM-6 when the resistor is installed in the cap.
Old 02-21-2013, 02:38 PM
  #27  
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Default RE: 2.4 ghz interference: It can happen!


ORIGINAL: dirtybird

You need to perform more tests to determine that 2.4 was actually interfered with. Remove the servo connections and monitor the servo outputs with an oscilloscope. I see you are in AZ. If you don't have an oscilloscope meet me somewhere and we can use mine.
I strongly suspect the interference was coupled directly into the servo leads and interfered with the drive pulse.
Another way to test it but not as good is to remove the servo from the receiver and drive it from a servo tester. If you still have the problem you will know it is not coming from the receiver. This is not a sure test though because you don't have a full system and the output impedance of the servo tester will be different from the receiver.
Agreed 100%. But the conclusion is the same; Resistor plugs is a good insurance, don't you think?

I have two planes with zenoah engines; Silicone spark boots, resistor plugs. No problems.
Old 02-22-2013, 07:07 AM
  #28  
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Default RE: 2.4 ghz interference: It can happen!

AVa8tor: Dumb Question but do u have all the latest Updates to the Hitec Aurora 9 and the Optima 9 twin antenna receiver? Including the one that helps RF Rejection from Ignation engines?
Old 02-22-2013, 09:58 AM
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Default RE: 2.4 ghz interference: It can happen!


ORIGINAL: kwik


ORIGINAL: dirtybird

You need to perform more tests to determine that 2.4 was actually interfered with. Remove the servo connections and monitor the servo outputs with an oscilloscope. I see you are in AZ. If you don't have an oscilloscope meet me somewhere and we can use mine.
I strongly suspect the interference was coupled directly into the servo leads and interfered with the drive pulse.
Another way to test it but not as good is to remove the servo from the receiver and drive it from a servo tester. If you still have the problem you will know it is not coming from the receiver. This is not a sure test though because you don't have a full system and the output impedance of the servo tester will be different from the receiver.
Agreed 100%. But the conclusion is the same; Resistor plugs is a good insurance, don't you think?

I have two planes with zenoah engines; Silicone spark boots, resistor plugs. No problems.
Hey kwik,

I think you are right. I need to check with my friend about his Brison 2.4ci. He changed the plug and might not have bought the right one. The resistor adds a delay in the leading and trailing edge of the hv spark pulse reducing the harmonics energy that causes interference.
Old 02-22-2013, 10:11 AM
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av8tor1977
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Default RE: 2.4 ghz interference: It can happen!

ORIGINAL: HoundDog

AVa8tor: Dumb Question but do u have all the latest Updates to the Hitec Aurora 9 and the Optima 9 twin antenna receiver? Including the one that helps RF Rejection from Ignation engines?
Hi,

Yep, transmitter, module, and receiver(s) all updated just last week.

Side note: I also have telemetry on this plane. I was worried for a moment while I was trouble shooting it that maybe the two wires going from the sensor station back to the receiver were carrying RF interference to the rx, but as I said, properly closing up that spark plug cap cured all glitching. Someone mentioned that maybe the glitching was happening when I was actually moving the controls. No. The elevators, ailerons, rudder, and sometimes throttle were moving all over the place with me not touching a thing. The elevators of course have dual servos, and they would often go to the extremes of their travel, in opposite directions!! This was with the transmitter in full power, flying mode; not range check mode. Now, everything checks out perfect, even during a standard range check with the transmitter "range check" mode in use.

Thanks,
AV8TOR
Old 02-22-2013, 04:22 PM
  #31  
Killer_Matt
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Default RE: 2.4 ghz interference: It can happen!

This is my take on your problem; the RF noise is not creating interference at 2.4 GHZ and then causing the servos to move. If you had interference at 2.4 and it interfered with the radio it might cause some data packets to get corrupted but it would not cause corruption of the packets in such a way as to cause the receiver to move the servo, packets have checksums etc.. The receiver would just throw away the corrupt packets and wait for good ones. If all packets were getting corrupted then the servos would just sit there or the radio would detect no good packets and go into failsafe.All that said it’s likely the RF interference is being picked up on the wires going to and from the servos, if the interference couples into the ground power or signal wires it can cause the servos to nuts. Make sure these wires are kept away from RF sources etc. these wires are not immune to RF interference!


Matt
Old 02-22-2013, 11:29 PM
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av8tor1977
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Default RE: 2.4 ghz interference: It can happen!

I tend to agree. However, the end result is the same; a crashed plane if it should happen in flight, or for some reason go undetected before flight, such as someone forgetting to do a range check before a flying session, or believing the web experts that say 2.4 is immune to interference and doing a substandard install of their equipment as a result.

The technicalities in this case are probably less important than the end result; which is RF interference affecting some portion of the system making the aircraft unsafe to fly. The 2.4 ghz system may be immune to some types of interference, but if other types can enter through servo wires, etc., then the only thing we have really gained with the 2.4 system is the ability to throw our frequency flags away.... (I'm just kidding; I know there are other interference advantages with 2.4.)

AV8TOR
Old 02-23-2013, 06:01 AM
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Default RE: 2.4 ghz interference: It can happen!


ORIGINAL: av8tor1977

I tend to agree. However, the end result is the same; a crashed plane if it should happen in flight, or for some reason go undetected before flight, such as someone forgetting to do a range check before a flying session, or believing the web experts that say 2.4 is immune to interference and doing a substandard install of their equipment as a result.

The technicalities in this case are probably less important than the end result; which is RF interference affecting some portion of the system making the aircraft unsafe to fly. The 2.4 ghz system may be immune to some types of interference, but if other types can enter through servo wires, etc., then the only thing we have really gained with the 2.4 system is the ability to throw our frequency flags away.... (I'm just kidding; I know there are other interference advantages with 2.4.)

AV8TOR
Ever since 2.4 Sprectrum type radios have become so prevelent I have seen more planes just crash for no apperant reason ... many more times than ever with 72 Mhz. I truley believed it to be one particualar brand of radio, Using a Non-Hopping form of spread spectrum. Now that they have converted to a Hopping system and replaced some of a certian series of DSM2 receivers You see less of the just fly into the ground for no reason type of crashes. Have seen a Multi copter and a fix plane, just fly off to never never land within the last 2 weeks. Never to be seen again. The Multi Copter had a Return To Home GPS System on it and it just flew away. Who's knows why ... Just My recent Observations ...
Old 02-23-2013, 06:56 AM
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Default RE: 2.4 ghz interference: It can happen!


ORIGINAL: HoundDog


ORIGINAL: av8tor1977

I tend to agree. However, the end result is the same; a crashed plane if it should happen in flight, or for some reason go undetected before flight, such as someone forgetting to do a range check before a flying session, or believing the web experts that say 2.4 is immune to interference and doing a substandard install of their equipment as a result.

The technicalities in this case are probably less important than the end result; which is RF interference affecting some portion of the system making the aircraft unsafe to fly. The 2.4 ghz system may be immune to some types of interference, but if other types can enter through servo wires, etc., then the only thing we have really gained with the 2.4 system is the ability to throw our frequency flags away.... (I'm just kidding; I know there are other interference advantages with 2.4.)

AV8TOR
Ever since 2.4 Sprectrum type radios have become so prevelent I have seen more planes just crash for no apperant reason ... many more times than ever with 72 Mhz. I truley believed it to be one particualar brand of radio, Using a Non-Hopping form of spread spectrum. Now that they have converted to a Hopping system and replaced some of a certian series of DSM2 receivers You see less of the just fly into the ground for no reason type of crashes. Have seen a Multi copter and a fix plane, just fly off to never never land within the last 2 weeks. Never to be seen again. The Multi Copter had a Return To Home GPS System on it and it just flew away. Who's knows why ... Just My recent Observations ...
In the days of of 72 you had to build your aircraft. The flier/builder was generally more knowledgeable than todays flier.
Today anyone that has a few spare bucks can have a hot p-51.
There are also many more fliers than there use to be.
Some of the high dollar airplanes you see at EVA are operated by fliers that have no understanding of what goes on inside their aircraft. They are just operators. Good fliers but still just operators.
They will have no knowledge of what would have happened and blame it on the radio.
I was flying at the EVA field on 2.4 and suddenly the airplane went uncontrollable and crashed.
It had hit an unseen dust devil. How do I know? Another flier hit the same dust devil but was able to get his A/C down and the radio of mine has worked flawlessly ever since. Thats just incident that you would be tempted to blame the radio.

Old 02-23-2013, 07:24 AM
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Default RE: 2.4 ghz interference: It can happen!

Like I said a year ago for no reason at all they just dive into the ground ... and I mean it happens to very experienced Pilots and Instructors and my self ... I know a the differance between a hit and complete loss of control. I've had it happen both on 72 and 2.4. Granted it can be for many many differant reasond BUT!
Old 02-23-2013, 09:27 AM
  #36  
dirtybird
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Default RE: 2.4 ghz interference: It can happen!

There are many reasons 2.4 CAN fail. How are the batteries? What kind and what capacity?
Are you running thru a regulator?
Are you using heavy duty wires thru the switch? What are your switches?
How is your receiver orientated in your aircraft?
Are you flying in the vicinity of a large mass of metal that could cause reflections?
What is the sun spot activity? A large flare can wipe out communications.
I am sure there are more. Its tempting to blame the radio.
2.4 was developed with spread spectrum technology to be highly resistant to any kind of interference but there are plenty of other ways it can fail
Old 02-23-2013, 10:37 AM
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av8tor1977
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Default RE: 2.4 ghz interference: It can happen!

On a lighter note....

I once lived at a small rural airport in south eastern Arizona. The area was really strange radio-wise. I had lots of problems getting my Satellite TV system locked on and working, GPS systems took forever to lock in, etc., etc. This happened before I got 2.4 ghz equipment:

Where I flew my models, there was one distinct spot on the base leg of the landing pattern where for just an instant, the throttle would rev up all by itself. No other glitches, just a quick blip of the throttle. My friends and I laughed about it. It was always right at that same spot, and it happened with nearly all my planes. (Play the Twilight Zone music here....)

AV8TOR

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