Cub Daddy

I'm wondering if anyone out there has had this particular problem.

My Son and I have been flying at a rural airfield, just a dirt strip, for the last few years. On two seperate occassions - we totally lost control of our plans, approx. 50-75' above the ground. After checking the batteries and radio equipment, all seemed to operate allright. No dead batteries, all servos working, all control surfaces still working. It was as if someone had turned our radios off till the planes were on the ground, then back on again.

Has anyone ever experienced this type of problem???
Suggesstions???
We have not returned to the field since.

rcmodelr

POSSIBLY... When I lived in MN, I flew from an airfield which had an electrical transformer sub-station about 1/10 mile away with a microwave transmitter to send electrical usage data to the electric companies main office.

The microwave would transmit for about 30 seconds about every 20 minutes.

After losing several planes, we met up with one of the electric company employees who maintained the equipment at that sub-station, and also flew R/C.

When he started flying at our site, one day, he brought out the electric companies frequency scanner, and found that although the microwave was a directional transmitter transmitting AWAY from our site, every time the microwave at the substation would transmit, it was also transmitting NON-directional radio waves scattered throughout the 72 Mhz band and that was what was causing our radio interference.

If the substation radio hit us, it was as if we had turned off the transmitter most of the time, but occassionally with seemingly random control surface movements. If the aircraft was high enough at the time, after the 15 - 30 second microwave transmission ended, we again had full control.

And the closer to any surrounding powerlines the aircraft was, the more likely our aircraft was to get hit by the interference.

Cub Daddy

Thanks rcmodelr !! After I read your post, I remembered that their is a Microwave tower about 1/2 mile from the airfield. There is some power lines about a 1/4 mile from the airfield in the same direction as the tower. What (if anything) can I do to overcome this problem? I am trying to locate a new flying site at this time. Maybe one a little closer to home.

smokingcrater

Remember many direction antennas also have a lobe directly off the rear, so it can be just as bad if it is pointed 180 degrees away.

I had a similar problem recently, and found a bad battery connector. Taped it securly and has been fine ever since. (Probably got VERY lucky that it would only glitch for a second or so, and then come back...)

coro

Check all your connections for a good locking connection. Take then appart (pull the wirws gently from the clips at the ends of all servos amd batteries). Check to see that evert wite (three) connects into its copper housing firmly. I have seen first hand the interfearance of an arcing connection. Basically a spark emits its own electrical field when it arcs.

IVCRASH

My Feedback: (-1)

I've had problems in the past with police cars transmitting close by. We had a police firing range around the mountain and they would drive by with their CB's on. They shot down quite a few planes before we asked them to turn their radios off before coming near the field. This was about 15 yrs ago so the narrow band probably took care of the problem but don't know for sure.

mugenkidd

My Feedback: (94)

I fly at a club in Central Oklahoma, and we have banned channels 20-24 from our club because they get a lot of interference from our local TV channels.

Cub Daddy

I can understand about the Freq. problems. Right nowI'm looking for a better flying field.
Cub Daddy

phayd

Could the FCC be contacted as they are transmitting on our frequencies?

Cub Daddy

I'm not sure. Does anyone know the answer to that?

mugenkidd

My Feedback: (94)

From my understanding they are not on the exact frequency but they are close enough to cause problems. And I am sure that the FCC would rule in favor of the larger TV stations as oppossed to the R/C guys.

Cub Daddy

Hmmm! Yea - Sounds about Right! Guess we'll just have to live with it!

phayd

Here is the part of the FCC that would know.

http://www.fcc.gov/eb/tpsd/

I would suggest a complaint to them would be in order. Stress that their violation of our radio frequencies is a hazard, as it renders our 9000 RPM propeller completely uncontrollable. Also, after they are found to be in violation, you can go to small claims and recover the value of downed airplanes, provided that the statute of limitations has not expired.

I would also call the AMA, as they can help with these situations.

Cub Daddy

EXCELLENT!!!
Who would we contact at AMA? Another question - When it comes right down to it, just how would we prove that their equipment caused the problem?

patternfly

Cub Daddy, first try to get hold of frequency scanner and monitor the site, see if the transmitter spreads signals within the 72MHz band. Good Luck!

phayd

Really, you just need to report that there is interference in the area, it is the FCC's responsibility to determine the problem.

As for the AMA, I would call the general number and ask them who you should contact.

Cub Daddy

Thanks PATTERNFLY and PHAYD;
I'll do both!