[RFI] New 857, won't TX on 20m - RFI in truck meters and dial lights (kd4e)

[Larry Benko]

I agree with Jim completely but would like to add one thing.

In both war and in troubleshooting the first thing you need to 
understand is the strength of the enemy.  In this case it means at what 
power level do you have problems.  If you can transmit at 50w without 
problems but have problems at 100W then you only need to reduce the 
offending common mode current by 3dB (pretty easy to do) but if you 
begin to have problems at 1W you will need to reduce the offending 
common mode current, or more likely currents, by 20dB (a much much 
harder task).  Just because you experience problems only on 20m only 
means the threshold of the problem is less than 100W on 20m.  You may 
very well "almost" have problems on other bands.

73 and good luck,
Larry, W0QE

Jim Brown wrote:
> This is very bad advice. A major CAUSE of RFI to auto electrical 
> systems is lousy chassis bonding due to excessive emphasis on 
> painting the chassis parts. The body of a vehicle is a big broad 
> mass -- IF all parts are well bonded together. Resonances and RFI 
> occurs when it is NOT well bonded. 
>
> 73,
>
> Jim Brown K9YC
>
> The On Sun, 14 Sep 2008 16:32:01 +0000, Keon wrote:
>
>   
>> I think you have created a ground loop. The thing is, bonding is 
>>     
> good but in bonding you can create resonate length wires and stuff 
> if you bond too much. 
>
>   
>> Worse come to worse, unbond everything and start over. Bond the 
>>     
> doors and hook and check the bands. Then bond a bit more.
>
>   
>> I suspect  if you bonded your exhaust and you are driving a big 
>>     
> truck; that is long enough to resonate on 20 so unbond that first. 
>
>
>
>
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