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Reducing Radio Interference


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timmeh
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Joined: 20 Jul 2004
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Location: Victoria


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Can i reduce rf problems with the ibc by using ferit cores on the drive motor leads and using a seperate battery for the reciever

And dose anyone have any more ideas on reduceing rf probs
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Post Thu Aug 26, 2004 6:16 pm 
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Spockie-Tech
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Joined: 31 May 2004
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Location: Melbourne, Australia


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Ferrite cores are supposed to help I have them on a couple of my robots, but without back-to-back testing, its hard to say what makes major improvements and what doesn't.

Based on our limited experience so far, I would say the biggest improvement we have had has been changing to 75Mhz radio's. I dont know if it just moves the radio carrier frequency away from noise sources, or whether the higher frequency means shorter antenna's work better, or quite why, but none of the bots on 75mhz at Marayong had any radio control issues that I know of.

If thats not an option, then you just need to keep working on supressing sources of interference and improving your antenna's until it works, but its a frustrating job without some radio testing gear.. like trying to fix electrical problems without a multimeter.
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Post Thu Aug 26, 2004 6:26 pm 
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timmeh
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Location: Victoria


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I might as well use some ferrit cores anyway they dont weigh much and i have a hand full of them lying around

What typ of antenna do you recomend?
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Post Thu Aug 26, 2004 6:29 pm 
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Spockie-Tech
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I havent found one that works amazingly well for 36mhz yet. The best I know of so far is Team Vertex's idea of using a length of bicycle-style brake cable.

Its cheap, flexible, near unbreakable and can be gradually trimmed (with a damn strong set of cutters Wink) to tune the antenna until you get the best range.
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Post Thu Aug 26, 2004 6:34 pm 
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timmeh
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Joined: 20 Jul 2004
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Location: Victoria


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The typ of brake cable that has the wire round in a spring typ way all the way threw the cable and have your reciever antenna wire run threw it and then wrapped around the end like whet they do on rc cars?
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Post Thu Aug 26, 2004 6:36 pm 
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Spockie-Tech
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thats the stuff..

(p.s. I moved all this radio interference talk to its own thread and out of the IBC thread since its relevasnt to all types of controllers)
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Post Thu Aug 26, 2004 6:41 pm 
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Philip
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Joined: 18 Jun 2004
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Location: Queensland near Brisbane


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http://homepages.which.net/~paul.hills/Radio/Radio.html

Post Thu Aug 26, 2004 7:15 pm 
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timmeh
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Joined: 20 Jul 2004
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Location: Victoria


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I herd chris saying he has servo churping probs.
A wise man onece told me that can be caused by metal contact like links and things bumping against each other or metal movieng about" It can create small signals or something so maybe when chris added more armor something is moveing about?

And brett what length should i start at with my antenna before i start cutting it down to tune it?
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Post Thu Aug 26, 2004 7:22 pm 
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Glen
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Joined: 16 Jun 2004
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well here is what i can report from my observations from today.

you definitely get better radio with an opto isolated IBC and reciever. basically an optoisolator chip that goes between the IBC and radio on the servo cables. basically means there is no physical connection between the two.

running the RX of its own batteries is a definite radio reception bonus.

jake had a pretty gung ho setup where he uses two 9v batteries to power the IBC or something of that nature.

from the looks of things it seems to be working. it doubled the range with my buggered reciever up to like 4-5m and with jakes capacitance hat antennae (i.e piece of copper) he was standing some 20m across the road and still had absolutely fine control.
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Post Sun Aug 29, 2004 9:33 pm 
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Valen
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Joined: 07 Jul 2004
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Location: Sydney


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from my experiments running off RX batt alone dosent help matters much
the noise is radiated along the servo leads, the first and easiest mod is the opto isolation of the servo leads it gave us about 50% boost the first time then after whatever oddness caused our radio range to drop right off after the switchmode mod (to about 5m or less) it braught it back up to 15 or so.
we found that with one lead isolated we could affect range by about 30-40% by putting the "live" servo leads on top of the reciever (no connection)

Post Sun Aug 29, 2004 10:15 pm 
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3Faze



Joined: 26 Jun 2004
Posts: 99
Location: Lincolnshire, UK


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Think this was linked to on the ABBL forum, but I'll put it on again:

Guide notes on interference - Tim Mann from the Stinger Team [/url]

Post Mon Aug 30, 2004 9:00 am 
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Glen
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http://www.radio-electronics.com/info/receivers/index.php

heres some interesting stuff about radios. someday ill understand it heh

http://www.yntdesign.com
http://www.charlesriverrc.org/articles/radio/joelfoner_rcrfi_scanningfaq.htm
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Post Fri Oct 08, 2004 8:37 am 
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