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Surprising source of radio interference

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Old 09-30-2011, 11:04 AM
  #26
ScottMcM
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Default RE: Surprising source of radio interference

......and one more thing. The sensor wire doesn't run across the magneto, as I stated in my original post. It is, however, very near the magneto when it is attached to the engine.
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Old 09-30-2011, 01:57 PM
  #27
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Quote:
ORIGINAL: ScottMcM

......and one more thing. The sensor wire doesn't run across the magneto, as I stated in my original post. It is, however, very near the magneto when it is attached to the engine.
Do as Andy suggested. Check to make sure the temp sensor does not have an intermittant short to the engine.
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Old 09-30-2011, 02:03 PM
  #28
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Quote:
ORIGINAL: Flypaper 2

Both planes I mentioned above flew fine prior to and after the problems were solved, with no more glitches, so there were no servo problems.
The only thing you have proved is the servos work OK when they are not in an interference environment.
Try this: Turn on your receiver without the transmitter. Then run the engine with a non resistor plug.
If your servos glitch you will know you have servo problems. With the transmitter off your receiver will be in fail safe and not putting out any pulses.
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Old 09-30-2011, 02:41 PM
  #29
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Default RE: Surprising source of radio interference

If it is near the magneto and it is unshielded wire you can get induced voltage in any wire. Moving magnetic field + wire = generator.
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Old 09-30-2011, 03:19 PM
  #30
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Default RE: Surprising source of radio interference


Quote:
ORIGINAL: dirtybird


Quote:
ORIGINAL: ScottMcM

......and one more thing. The sensor wire doesn't run across the magneto, as I stated in my original post. It is, however, very near the magneto when it is attached to the engine.
Do as Andy suggested. Check to make sure the temp sensor does not have an intermittant short to the engine.
Will do. I plan to spend the weekend getting to the bottom of this.
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Old 09-30-2011, 05:54 PM
  #31
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Default RE: Surprising source of radio interference

I'm not here to argue. Just stating a couple of problems and the proper fixes. They're both working fine.
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Old 09-30-2011, 08:37 PM
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Default RE: Surprising source of radio interference

On the heat sensor(thermocouple) ,,, are you getting funny temp readings? (sure sounds like a grounding issue)


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Old 09-30-2011, 09:29 PM
  #33
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Quote:
ORIGINAL: JL1

If it is near the magneto and it is unshielded wire you can get induced voltage in any wire. Moving magnetic field + wire = generator.
Correct. But if that causes the servos to move there is something seriously wrong with the installation. The wire would have to be shorted to the servo pulse line.
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Old 09-30-2011, 09:34 PM
  #34
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Quote:
ORIGINAL: Flypaper 2

I'm not here to argue. Just stating a couple of problems and the proper fixes. They're both working fine.
Its not my purpose to argue either. I am trying to help you.
You think you have fixed your problem but the odds are that you haven't and at some later time it might just bite you.
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Old 10-01-2011, 01:06 AM
  #35
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Default RE: Surprising source of radio interference

Quote:
ORIGINAL: Bill Vargas

On the heat sensor(thermocouple) ,,, are you getting funny temp readings? (sure sounds like a grounding issue)


BV
No, the readings appear just like the readings on my Seagull Yak, which never gives any trouble....hmmmm...the only difference in the two is that one is electronic ignition, and the other is magneto....strange..
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Old 10-01-2011, 06:20 AM
  #36
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Default RE: Surprising source of radio interference

Scott, I would try some snap on ferrite cores from Radio Shack or electronic stores on that lead coming from the engine. In most RF issues those will help to eliminate the RF issue at hand. Do a search on the web,,, they come in all different shapes and wire sizes too, etc.


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Old 10-01-2011, 07:42 AM
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Default RE: Surprising source of radio interference


Quote:
ORIGINAL: Bill Vargas

Scott, I would try some snap on ferrite cores from Radio Shack or electronic stores on that lead coming from the engine. In most RF issues those will help to eliminate the RF issue at hand. Do a search on the web,,, they come in all different shapes and wire sizes too, etc.


BV

You are correct, IMHO

I am an RF guy from WAY back.......and the interference you get from ANY ignition system is Next level bad![:@]

The entire noise floor goes way up on a Spectrum Analyzer to show this…

It will make most anything “Glitch”…..or malfunction.

I like to use these wherever I can in Gas planes…

http://www.jrradios.com/Products/Def...ProdID=JRPA028

Very affordable insurance...

And I would move everything away from the magneto and make sure the entire ignition system is well shielded and there is no shorting out any of the wires…

Make sure plug cap is tight and use resistor plug.

In general I stay away from Magneto’s but by no means is electronic ignition any better……ignition pulses are high energy interference that can even cause damage to sensitive electronics such as telemetry modules or Rx units……

Be careful with the ferrites not to “Mask” the problem……I try to get everything working without them and then use them to help insure low noise levels in the system.


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Old 10-01-2011, 07:53 AM
  #38
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Default RE: Surprising source of radio interference

Of all the replies your the only one who has a viable solution to the problem. Loose cap plugs and non resistor type sparkplugs also are problamatic. It appears that 2.4ghz technology has it share of problems and the only thing it has solved is waiting for the pin. When I started in this hobby I flew ppm FM and experienced all types of RF both internal and external and than came pcm and most if not all issues evaporated. RF was still around but the new designed receivers filtered out must interference. Bottom line is dollars you are willing to spend on electronics and nothing more. Example of this would be in extension leads. Those made of pure cooper wire or a clone made in China which uses tin.
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Old 10-01-2011, 09:27 AM
  #39
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Default RE: Surprising source of radio interference

Are you sure the noise is coming through the 2.4 receiver and not from the servo leads or servo electronics picking up low frequency noise?
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Old 10-01-2011, 10:04 AM
  #40
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Default RE: Surprising source of radio interference

2.4 is much better than 72 for rejecting noise. A buddy and I built a Sea Fury Reno Racer quite a few yrs ago for the big rc jobs to race in Quebec but the race was canceled about a month before the dateline. This one weighed 60 lbs with a Quadra 200cc racing engine. About 20 servos in it all together. Was plagued with servo glitches. Did fly about 3 times but decided it was to dangerous. We gave it to his son to tinker with as he's an avid RCer too. This summer he brought it up for our IMAA do with a 2.4 radio in it. Not a whimper out of it with no other goodies to cancel the noise than the 2.4 radio itself. Great to see it fly again.
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Old 10-01-2011, 11:24 AM
  #41
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Default RE: Surprising source of radio interference

Really, I was involved behind the scenes in Reno racing before 2.4ghz was introduced and they all flew on 72mhz. The only radios that failed were Hitec and I'm not talking about their servos. I'll say it again its all about dollars invested and how your electronics are installed. I mentioned leads in my last post and discovered this due to what I though were malfunctioning elevator servos. Our company built an erial target with a fuselage length of sixteen feet. the length of the elevator servo leads were about ten feet. The problem was traced to a voltage drop because of the long leads. We made our own leads using pure cooper strands. I don't remeber the gauge but it sloved the problem. Most models don't no anything about electronics and there operation and blame the equipment as being the culprit when in reality it's there own stupidity. Nothing is perfect and you usually pay for what you get. Is an O.S. engine the same as an ASP?
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Old 10-01-2011, 11:35 AM
  #42
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Default RE: Surprising source of radio interference

Given a strong enough signal (and a 40kv magneto is just that), ANY receiver can have glitches. It's called swamping.
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Old 10-01-2011, 11:44 AM
  #43
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Default RE: Surprising source of radio interference

Point well made. Output transmitter power is the name of the game. Our company would order FM ppm receivers matched to assigned military frequencies. With these receivers and a linear amplifier powering our modified RC transmitters we never experienced loss of signal or jamming. Remeber our commercial transmitter are rated at .75 watts of output power. The linears we used went from 10W to 50W. You might say we captured the receiver.
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Old 10-01-2011, 11:52 AM
  #44
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Default RE: Surprising source of radio interference


Quote:
ORIGINAL: ChuckA

Are you sure the noise is coming through the 2.4 receiver and not from the servo leads or servo electronics picking up low frequency noise?
Heh....at this point I'm not sure of anything[]....I am learning quite a bit about rf interference though
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Old 10-01-2011, 02:06 PM
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Default RE: Surprising source of radio interference

We could have solved the problems if the race had of been put on, with choke coils, rewiring etc., but after the races were canceled it was a moot point, as the nearest races were at Reno and not worth the drive. Would have made a good show plane but that's about all. The newcomers don't realize how lucky we are with 2.4
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Old 10-01-2011, 02:53 PM
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Default RE: Surprising source of radio interference

Tell that to those who have suffered for "brown outs".
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Old 10-01-2011, 03:34 PM
  #47
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Default RE: Surprising source of radio interference


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ORIGINAL: flycatch

Tell that to those who have suffered for ''brown outs''.
The solution to the Brownout issues involves using batteries with adequate Capacity and Voltage. I have been using 2cell 2500mah LiPo Rx packs with Regulators, or unregulated 2cell LiFe packs and I have never had a Brownout with my Spektrum or JR Rx's.

2.4 is the best thing that has happened to this hobby and I have flown 72Mhz for 33 years.
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Old 10-01-2011, 03:54 PM
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Default RE: Surprising source of radio interference

Tell your story to those who have lost their models to this new technology. I have and still am flying 72mhz but I don' use PPM only pcm dual conversion receivers. In the old days of ppm I experienced a lot of problems and airborne failures so I'm not advocating the continued use of 72mhz. The reality of 2.4ghz is simply cost for the manufacture nothing more. The other advantage is no longer waiting for your frequency to clear. The average modeler is not willing to pay $200 USD for a DC PCM receiver but they will pay $70 USD for a 2.4ghz receiver. I'm staying on 72mhz until it becomes illegal.
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Old 10-01-2011, 04:24 PM
  #49
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Default RE: Surprising source of radio interference

I bought the first DX6 locally when they first came out and never had a brownout. As Rich says"use enough batt power and you wont have trouble". Chucked in planes from overheated ESCs and such,but nothing to blame on the radio. No trouble with the DX7. Had troubles with the DX8 when they first came out with the ensueing teething problems but they have been solved and it's now working great. Been at RC for the last 50 yrs, starting out with escapements. Try one of them for reliability when you your rubber band runs out. Now that's a brown out.
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Old 10-01-2011, 05:04 PM
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ORIGINAL: flycatch

Tell your story to those who have lost their models to this new technology. I have and still am flying 72mhz but I don' use PPM only pcm dual conversion receivers. In the old days of ppm I experienced a lot of problems and airborne failures so I'm not advocating the continued use of 72mhz. The reality of 2.4ghz is simply cost for the manufacture nothing more. The other advantage is no longer waiting for your frequency to clear. The average modeler is not willing to pay $200 USD for a DC PCM receiver but they will pay $70 USD for a 2.4ghz receiver. I'm staying on 72mhz until it becomes illegal.
I do not need to "Tell My Story" to anyone. The facts are available to anyone who cares to look for them. With any new technology there are problems that develop which the manufacturers eventually resolve. Brownouts happen to be one of them. Those who are unaware that there is a solution to that problem or just won't use adequate batteries will still be at risk from Brownouts.

I travel to meets all around New York State, the surrounding states, and Canada. We are not experiencing any significant problems with 2.4. Perhaps our part of the country is immune from the gremlins that affect 2.4 users elsewhere. I am on RCU many times per day as well as occasionally on FG and RCG. I have read many of the threads regarding RC Radios. I am personal friends with some pilots who compete nationally at the highest levels. None of them are turning away from 2.4.

I have spent years tracking down RF problems that glitched 72Mhz radios. For us, 2.4 has made most of that unnecessary, not to mention freedom from ShootDowns and no need for a Frequency Pin.

I am sorry for others who still have issues with 2.4, but we are not seeing any problems here. The only thing keeping anyone from getting rid of 72 altogether is just the cost to convert.
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