Re: TVI (was snow on telly results)

Hi Dale,

	I work in the basment in a house with steel siding.  Television is all by
coaxial cable and the AC is very well grounded by local codes.  The coil
system is grounded to underground water pipes within 10 feet in the
basement.  I use RFI filters wherever I can stuff them.  I run important
stuff off separate grounds.  I run computers, digital scopes, stereo, VCR,
etc. very close by and the EMI seems to be almost zero.  Only the actual
voltage fields seem to be a problem when static electricity starts to
collect on things when I get too close.

	Some work suggests that heavy short connections in the primary circuit
have much less EMI than cluttered long wiring and poor connections.  

	Also, if the arcs are hitting grounded targets there may be much more RFI
than if they simply go to air or hit something that is pretty resistive.
Of course, if they hit the AC wiring somehow...

	Have you determined if the EMI is transmitted or coming through the AC
wiring.  That would be an important clue?  If it is in the AC, better
grounds and RFI filters may be needed.  If it is transmitted, good heavy RF
wiring may be needed.  Perhaps a rotary gap would have much less noise than
the multigap types??

	My area has not used TV antennas for 20 years now so I can hardly remember
how all that worked :-)).  If the antenna grounds are picking up noise that
may also be a problem.  The soil in your area may also be a factor.

BTW - This is not at all "taboo".  We just my not know what is going on

	For what its worth...


At 12:21 PM 1/19/99 -0000, you wrote:
>Hi all on the list,
>                      I had no response to the question below.
>It was intended as a serious question on a serious issue.
>I hope no-one took offense to it.  In the absence of any info from US
>coilers (or any other countries), I am still wondering why we seem to get so
>many TVI problems from coiling here in the UK, that US coilers dont seem to
>I know of at least 4 guys local to me who had to give up because of TVI, so
>it may also be the reason why there are so few coilers in the UK!
>I hope this is not a "taboo" subject on the list.
>Any thoughts anybody has on the subject would be very much appreciated.
>       Best wishes to all coilers,   Martin Dale   TCBON
>>As to why our American friends seem to get away without major TVI >problems
>>I'm not sure.
>>More space between houses maybe., cable TV., lower TV channel >frequencies?
>>Whatever it is, there sure 'aint any difference between UK RF and good old
>>American RF!
>>Any of you guys over there prepared to comment (please)?
>>Best regards everyone,    Martin Dale,  TCBON   (also G6ABU!)