[RFI] New 857, won't TX on 20m - RFI in truck meters and dial lights (kd4e)
xxw0qe at comcast.net
Sun Sep 14 13:59:04 EDT 2008
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,
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.
> 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.
> RFI mailing list
> RFI at contesting.com
More information about the RFI