bonasa-u

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Have a Sullivan onboard glow driver, model M060. I'm using an airtronic trans/receiver on the 31 channel. Despite mounting the receiver 8 to 9 inches away from the driver electronics, my servos go haywire when the plane is only about 60 ft away. The interference stops immediately if I turn the driver off. Don't know what to do, the technician at Sullivan is "leaving" and they have no immediate replacements. I'm wondering if going to the 2.4 G system using a RDS 8000 transmitter/receiver setup with the same airtronic servos will solve the problem. Anyone experience this issue?

ArcticCatRider

My Feedback: (6)

Does this happen when the motor is running or off?

Any kind of loose connection that has opportunity to "gap" will create RF noise. Glow drivers (and I'm not familiar with the type you're using) don't typically have a great connection to the "center electrode." The ones I have used have a decent amount of slop and interference can sometimes be noticed while removing them.

bonasa-u

My Feedback: (1)

Connections should be tight. Doesn't matter if engine is running or not. Driver "kicks in" when throttle stick is set for low speed/idle, irregardless of whether the moter is actually running or not, and gives me the problem.Incidentally, it's a saito 82a 4 stroke (I notice your membership!)

ArcticCatRider

My Feedback: (6)

Wow. A true case of RF energy coming from your set up. Is the glow driver battery near the engine? If it were me, before trying a different radio set up, I would try different lengths of wire for the hot and the ground going to the engine. If that is unsuccessful I would try to shield the antenna...or the wires for the glow driver.

You might find RF shielding fabric or weave at an electronics store, or strip a section of Coax cable and use the shielding from that.

bonasa-u

My Feedback: (1)

Interesting thoughts. I've already ordered a Airtronic RDS 8000. If that doesn't work will try altering the wires/shielding. Wanted exponential/dual servo capability anyway, besides the added security. The glow driver battery is right next to the driver switch, and both are close to the engine. Why do you ask?

acdii

Going to 2.4 should help eliminate RF interference.   It has much better filtering than the FM does.

ArcticCatRider

My Feedback: (6)

I was just curious to see how spread out all the components are in the fuse. You might be able to get away with a shielding a portion of the fuse...almost like an RF firewall. The 2.4 system's wavelength and modulation is so different than the traditional radios that it will likely negate the interference.

In any event, it is still a solvable problem with a 72 Mhz system..be it AM, FM, or PCM...spark ignition set ups and on board glow drivers have been around a longer time than spread spectrum systems.

acdii

Dats true! It is also an art form to build RF shielding in something like a RC plane.    Trouble is, when you think you have it solved. A violent maneuver can upset the shielding and your back to square one if you are lucky. 

bonasa-u

My Feedback: (1)

Wrote to Sullivan Products..... I’m using the onboard glow driver M060. It works excellent close range, but at about 60 ft out my servos all get jittery and unresponsive to input unless I turn the driver off. This was when my receiver was 2 ½ inches from the driver switch. I moved it 9 in away, and it does work better, with the servos getting ‘jittery’ now at about 350 ft (transmitter fully charged/antennae up/receiver antennae unobstructed,etc.) That obviously still is not enough distance to safely fly the plane. I’m wondering if this can be solved. One thing I was wondering would be, would going to the 2.4 G band using a airtronic RDS8000 transmitter work, as opposed to the airtronic channel 31 transmitter I am now using…or would that make things worse. Or, (less costly perhaps), is there a way to shield the driver from the receiver? Very frustrated. I do see advertisements for drivers that give off minimal RF interference and wonder if I should just call it quits with the Sullivan and try one of those. Please give me your thoughts on how to do the least rebuilding to get this to work. Thanks so much in advance.

Sullivan products responded .... Well honestly RF interference in R/C planes is one of those "systemic" things. That is to say that usually it is caused by some combination of things in the system and triggered by a specific part. In this case the glow driver is producing some signal that is radiating and causing interference in your radio. Unfortunately it is usually not direct. The operating frequencies of the parts used in the glow driver are WAY different than what the receivers use, for obvious reasons. I'm talking by several decimal places. What can happen though is that those radio signals get propagated through your plane by the glow driver wires or through conductors like your landing gear picking up and re radiating at different frequencies. When this happens edge or corner waves can be produced that resonate at frequencies different than the originating frequency. Remember that any conductor acts as an antenna, both receiving and transmitting and some can inadvertently do a surprisingly good job of it without intending to. Anyway, with patience and experimentation you can probably knock it down alltgether or at least to something manageable. Trying things like grounding different metal parts of the plane to the glow driver battery or moving the driver or even changing it's orientation or putting some heavy foil around it and grounding that to the battery all may help. Unfortunately if the wires are the radiating source that is causing the problems then you would need to go to shielded wires like the gassers use for ignition. That is no fun though. So my advice would be to play around with it as much as you want but if it does not work out or you are not 100% confident that the problem is solved, take it back to your retailer and ask for a refund. If the shop gives you any trouble contact us and we will explain and support the return. It is not worth wrecking a plane over. Just keep in mind that there is no reason to say that our MO60 Drivers are "Noisy" or "Cause interference". We have over 7500 in service and have had 3 people contact us in the past 4 years since they were released saying they were experiencing this type of problem. One solved it by changing channels or radio, I forget which, and one put in a servo isolation system because he was having other interference issues anyway and one returned it. Above all fly safe and Kudos to you for doing your range checks properly!


I answered....Thanks for the advice. I’m currently waiting for a 2.4 G transmitter to be delivered, thought I’d give that a try first. But if it doesn’t work, I was wondering how does one ‘ground’ a 4-cell battery pack? I’ve two packs, one for the receiver/servos that has a standard airtronic connector from the battery which does have/includes a ground wire, besides the +/- connections, that powers/grounds the receiver. I do notice that the two receivers connections to the glow driver switch does include ground wires to it. However, the other 4 cell pack that powers the glow driver came with a micro dean connector that plugs in to the micro dean driver switch wire. As you probably know it has no ground wire, just the +/- connections. Are you suggesting I somehow ‘ground’ that battery to the glow driver switch, and/or other metal components, and if so, how do I do that? It seems to me that somehow I would have to open the pack, somewhere(where?) solder a ground wire on to it, then open up the glow driver switch and solder that new ground wire to(where specifically) to it, besides the other metal components (perhaps my metal landing struts, motor, shielding foil?). Thanks again!

Sullivan...All battery packs only have two connections + and -. The negative is what is considered ground. When talking about grounding things it just means electrically connecting them to the negative terminal of the battery. I am not sure what the third connection is on some of the packs you are referencing. This may be related to internal circuits of the pack but can't say for sure without knowing more about them. Sorry for any confusion.

I answered...I feel kind of silly now, of course the black should be ground. I have seen the third wire occasionally referred to as a “signal’ wire. Guess it carries further servo instructions. Anyway, great news. The transmitter arrived today and I’ve had the time to install and test it. On the 2.4 G frequency there was no interference, even with the receiver about 1100 ft away. Will test further but is looking good as I hadn’t even spaced the antennae wires properly and their final position will even be further from the glow driver than the initial test. I’m sure the problem is solved. Thanks again for your time. It sure is nice to hear that 4 stroke saito lazily idle so low with the driver.

bonasa-u

My Feedback: (1)

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