Radio interference

[mr.micro.2u]

Hi guy’s, i am having some problems with dead spots and jittering steering when using my cars on my new track in my shed. I have a large corrigated iron shed and was wondering if there is anything i can do to reduce this problem. My transmitters are AM and it appears that the closer they get to the iron the more erratic they operate. Has anyone had this problem? What can I do ? Will lining the walls with plaster help?
Any help would be appreciated.
Paul

[HACHI-RYOKU]

Here’s a test you can do. It may or may not work. Touch the antenna to the metal wall and then try to control it. Sometimes this helps. If it does work, you could connect a wire to the wall and the antenna while your racing. Sounds strange, I know, but it could be easier than plastering a wall. You could also try changing the frequency, but sense it sounds like you’re running more than one car, I would assume you’ve at least tried two frequencies.

As far as plaster, in theory it would help. Insulating metal reduces the metals ability to recieve a signal. So, if you covered the wall with plaster, it would let more of the signal go to the car. The problem is that that’s alot of metal and covering it may not solve the problem completely. Covering the wall with rubber could be an option if you want to get crazy with it. Not sure where to start when it comes to covering a wall with rubber though. Is there anything else that is close by that may be interfering with transmitions? Power line right above the shed? Tons of electronics in the shed?

A few other things you could try; Bending the antenna on the car at different angles. Standing at different positions in the shed. Checking the car’s antenna conection to the PCB of the car. Changing the car’s antenna to something else like a solid piece of copper wire (gold wire might be an option too. Not completely sure on that one. The basic idea would be to use a metal that could pic up the signal better than the iron.). If the shed’ds not that big, you could tear it down and put a wooden one up instead.

Not sure which one of these ideas would work the best. Transmition problems can be very unique sometimes.

[betty.k]

what cars are you running, iwavers? if so it might not be a reception issue, it could be a crappy servo pot.
another thing to check is that the capacitors are soldered properly to the motor.

if all that fails try soldering an electrolytic capacitor across the battery terminals (min 300uf):8ball:

[mr.micro.2u]

Sorry I should have been a bit more specific, there are 2 definite dead spots in my shed. if i stop any of my cars (mini t/iwaver or either transmitters jrxr2/futaba2pl) in these areas of about 1 square meter, they do not respond to any signal until i move the transmitter up or down or forward or backward say 200 mm or so. My question really is if is there anything i can do to reduce the effect the corrigated iron is having on my signals. I dont know if painting, covering with plaster or modifying the cars will help.

[trash]

Normally this is the kind of thing you would expect with multipath problems and higher frequencies. But RC cars all opperate bellow 100MHz, so multipath only occurs over large distances, generally not inside a shed.

A good example of multipath is if you’re listening to an FM radio station that is weak or you have a crook antenna, as you pull up at a set of traffic lights the signal seems to fade in and out as you move forward about every 1.5 metres. This is because the signal is coming from two directions (because of reflections etc) and when they both arrive at your antenna out of phase, they cancel out. Thought I do not think this is your problem.
What it does sound like is the metalic wall is in the near field of the antenna of the car. It is either de-tuning it or decoupling it. Hence touching the wall with the TX antenna uses the wall as the TX antenna.

The way to make sure that at least the receive antenna isn’t being detuned is to place a 10pf capacitor in series with it, if there isn’t already one there.
If it is 100pf or so, then reduce it. 47,33,22,10pf are a good choice. The smaller the capactiance, the greater the decoupling but at the risk of attenuating more signal.

[ken_wyleung]

Do you try FM RC on your track?
If you really want to do something on your car, connect a long cable from PCB as an antenna, like the 1:10; it can be help.

Good Luck….:)

[betty.k]

wow, trash!!:smiley10: good to hear from you man!

in tribute here’s my most refered to ausmicro thread, about aerials:smiley2: :8ball:
http://www.ausmicro.com/forum/showthread.php?t=9478&highlight=aerial+length

[klims]

i seem to have a similar problem. out of the box i could hear my mr02 steering servo jittering and i seems to go crazy at a particular spot in my hallway (where the bathroom is). any suggestions?

[trash]

I’m about, I only get to log in occasionally these days. I work away from home lot. Just got back from HK, checked out the latest in toys while I was there. RC helicoptersare all the rage. They range from dirt cheap $5 single channel models, through to the the big autogro electrics for about $350.
A whole range of micro planes for $20-$40, some realy nice models with all kinds of combinations. Picked up a micro outboard motor boat for $8. It’s not fast, or proportional steering, but it won’t be long before somebody soops up the little bit motor on them. I even saw a very cool WIG/ekranoplane. But it was too big for me to carry back and I didn’t have enough time to post it.

[Admin]

[JoeOvercoat]

Iron nails in wooden floors (and probably iron rebar in concrete floors) have enough of a magnetic field to interfere with the radio signal. I found that antennas from power2drift on eBay improved reception enough to overcome most of my interference problems from nails in wooden floors.

[Author]

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