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DX7+DS821's=Geiger counter

Old 09-27-2010, 12:26 PM
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dan4466
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Default DX7+DS821's=Geiger counter

I have a DX 7 w/5 DS821's mounted in a Seagull Spacewalker 1.20 with a small gasser. I just put the plane together and am using a AR7000. Whenever I get the radio within 10-12 inches from the servos they sounds like a geiger counter going off. The servos never move at all like normal interference, just the sound. I have tried everything from different Rx, switch and so on. I even discounted the whole gas system. I then just pulled servos out and plugged them in with 2 different AR7000's and they still do it. This radio doesn't do this on two other gas planes. I have plenty of seperation with radio gear. These servos are used ones I bought and am wondering if there is something that the previous owner could of done to them. I have used 821's in other plane with the DX7 w/o problems. I am wondering if this is something they do when the radio is that close and I haven't noticed it before. Get the radio a foot away and it stops right away. Also, if I push the range check button on back of radio, it stops. It range checks good. I also tried a 4.8V batt instead of the 6V just to be sure. Thanks for any help!
Old 09-27-2010, 01:44 PM
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chunkyplunker
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Default RE: DX7+DS821's=Geiger counter

I have the same thing happen with a Christen Eagle I fly. It never has had any effect on my aircraft during flight. I have always just written it off to interference from the transmitter with the circuitry in the servos.
It didn't seem to effect when I used a 72mhz transmitter.
Old 09-27-2010, 02:12 PM
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Default RE: DX7+DS821's=Geiger counter


ORIGINAL: chunkyplunker

It didn't seem to effect when I used a 72mhz transmitter.
I even tried a 72mhz myself with the servos and they didnt do it either.
Old 09-27-2010, 03:06 PM
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Rafael23cc
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Default RE: DX7+DS821's=Geiger counter


ORIGINAL: dan4466

....Whenever I get the radio within 10-12 inches from the servos they sounds like a geiger counter going off....
Any radiation type of communications is going to have some sort of effect on it's receiving part of the system when the receiver is EXTREMELY close to the transmitter. Case in point, your experience..... If the system passes the range check, what does it matter what it does when it is 10 inches away? Do you fly that close?


I have seen a nasty burn on a soldier's hand because he was holding on to an antenna on top of a vehicle when somebody pressed the button to transmit. I know that power levels are vastly different, but it illustrates my point of EXTREMELY close when talking about transmitters.

Rafael


Old 09-27-2010, 03:27 PM
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chunkyplunker
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Default RE: DX7+DS821's=Geiger counter

I know what you are saying Rafael. As a communications specialist in the military it was hard to get some people to accept the idea that an antenna could do that. To demonstrate we used to set up an old AM transmitter that transmitted around 1KW with a long wire antenna 10ft off the ground during winter, and show the soldiers the melted snow under the antenna. Most got the idea after that.
Old 09-27-2010, 03:57 PM
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Default RE: DX7+DS821's=Geiger counter

We used to cook hot dogs on the IFF whiskers of a radar antenna

As for the RF swamping it doesn't surprise me, I wouldn't worry about it.

What I would do is find better servos for a 120 size gasser.
Old 09-27-2010, 04:04 PM
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Default RE: DX7+DS821's=Geiger counter


ORIGINAL: BarracudaHockey

What I would do is find better servos for a 120 size gasser.
Yes, I know that, I'm not a newbie. Since I was only gonna put a flight or two on it they'll do till I get some 645's for next year.

Thanks, guys. I just wanted somemore input before I flew it.
Old 09-27-2010, 04:48 PM
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Default RE: DX7+DS821's=Geiger counter


ORIGINAL: BarracudaHockey

We used to cook hot dogs on the IFF whiskers of a radar antenna

As for the RF swamping it doesn't surprise me, I wouldn't worry about it.

What I would do is find better servos for a 120 size gasser.

Hey that sounds cool. and a good idea.[8D]

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