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Re: RF Interference : HELP!!!



Hi Ed

> The coil I am running is as follows. 
> 
> 8" coil form - 1036 turns (28") #22 enameled wire.
> 11 turn 3/8" copper tubing primary
> 3 - 0.01 (0.03uF total) capacitors - homemade coiled LDPE/flashing
> 4 - 15kV, 30mA (1.8kW) neon sign transformers
> Air quenched cylindrical spark gap.
> 6" x 20" toroid
> Single line filter between the variac and the neon trannies.
> 
> This puts out 5 foot hot white sparks so I think the tuning is pretty good.
> (photo's on the web page soon!)
> 
> Could the RF ground be too feeble for this amount of power?
> 
> Thanks for your input. I will do some line investigations and see if I can
> isolate the source. 
> 
> Graham 
>  >>
>
>Graham,
>
>It sounds like quite an impressive system.  Lots of power.  You still did not
>describe your RF ground.  Where do you have the ground on the line filter
>connected?
>
>Ed Sonderman
>
Thanks, I am very happy with it's performance (except all the interference).

I have buried aluminum flashing (several feet) as well as copper and other
piping. I have not been able to go very deep (<4') as the ground is more
like a river bed than real soil. The boulders are big and plentifull and
digging is VERY hard work. Besides digging up half my yard I don't really
know how to overcome this. I think it is insufficient as an RF Ground.

I did some more tests and now I am even more confused. I have confirmed that
my faraday shield and RF ground is in no way connected to the house earth.
(checked it with the scope and get more line noise with the vacuum
cleaner!!). So I am happy the line filter is working. I have even
disconnected the trannie earth from the line filter earth and placed it on
the RF ground. (RQ suggested this). The line filter ground is connected to
the house earth. I was still getting a strong interference on car radio and
TV and a simple antenna connected to the scope probe. So I removed the
secondary completely from the faraday shield (which is still grounded) I
STILL get the same strong interference. It is no weaker than with the
secondary in place!!! Even if I disconnect the farady shield from the RF
ground it gives the same results.

I can't believe that the radiation can penetrate the shield like it does.
Either I am stupid and am missing a major point or this coil has a mind of
it's own???

Any suggestions to curb my stupidity would be most welcome (especially by my
wife who wants to watch TV again!!!).

Thanks 
Graham