Re: RF Interference : HELP!!!
In a message dated 96-08-28 02:48:08 EDT, you write:
<< el snippo
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
Any suggestions to curb my stupidity would be most welcome (especially by my
wife who wants to watch TV again!!!).
A couple of comments: You said even when the farady cage is disconnected
from the main RF ground, you get the same results. I am not a farady expert
but I think if you are going to use one, it should be connected to a
separate, isolated ground. The main RF ground on a working medium to high
power Tesla coil gets pumped up quite a bit and isn't a good ground for other
parts of the system. You can probably draw sparks off the ground wire where
it enters the ground.
You said your line ground is connected to the house earth. If by this you
mean the main AC ground on your breaker box, this could be at least part of
the problem. I suggest using a separate ground for all your filters - not
the house ground. It does sound like you have a conducted RF problem. The
coil itself if producing good sparks does not transmit a great deal of RF.
Most problems are caused by allowing the RF to get back into the house
wiring either through the AC mains or the AC ground.