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Re: Snow on telly, help needed !



Tesla List wrote:
> 
> Original Poster: "R.E.Burnett" <R.E.Burnett-at-newcastle.ac.uk>
> 
> I was operating my 2kW Tesla coil a couple of weeks ago,  when someone
> in my street complained about snow on their television screen.  The
> person who complained lives 5 houses along from me,  and said that it
> was affecting all of the televisions in the street !  My coil produces
> 2 to 3 foot arcs and works great otherwise.
> 
> I have Searched the Tesla List Archives and have tried many things
> but the problem still persists.  This annoys me since I have read
> posts from people who claim to operate their coils in rooms next to
> TV's without any interference.
> 
> My coil is operated in a garage that is around 20 feet from my house,
> and is fed by two-core cable from the house (LIVE & NEUTRAL).  When
> powered up,  several horizontal lines of white dots appear on my TV
> in the house.  They are not really bright but enough to be a problem.
> 
> I thought that this must be due to noise being conducted from the TC
> back through the LIVE and NEUTRAL wires into the house,  so I took the
> following precautions:-
> 
> 1.  I have installed a two-stage RFI filter at the TC end of the mains
>     cable. This filter is run in reverse and has its earth (CASE)
>     terminal connected directly to the RF ground rods. I have also
>     fitted a VARISTOR from LIVE to NEUTRAL.  The filter is connected
>     "back-to-front".
> 
> 2.  I have installed a single-stage RFI filter at the power socket end
>     of the mains cable (in the house.)  The Earth terminal of this is
>     connected to the earth pin of the plug. The filter is connected
>     "back-to-front".
> 
> 3.  I have changed my RF ground from one 2 foot copper pipe,  to three
>     2 foot copper pipes connected together by 10mm˛ earthing cable.
>     Seperate earth cables run from the secondary, the transformer and
>     the filter,  back to the group of ground rods.
> 
> Wall        FILTER 1                 FILTER 2      HV
> socket       -----                    -----     TRANSFMR
>    E--------!E    !   Supply cable   !     !      ----
>             !     !                  !     !     !    !
>  L   N------!N   N!--------/ /-------!N   N!-----!    !--> To RQ-gap
>  !          !     !  20ft of 2 core  !     !     !    !    and rest
>   ----------!L   L!-------/ /--------!L E L!-----!    !--> of the TC.
>              -----                    -----       ----
>                                         !          !
>                                         !          !         (-T-)
>                                         !          !           #
>                                         !          !           #
>                                         !          !           # TC
>                                         !          !           # sec.
>                                         !          !           #
>                                         !          !           #
>                                         !          !         !--
>                             ------------!          !         !
>                            !   --------------------!         !
>                            !  !   ---------------------------!
>                            \  !  /
>                             \ ! /
>                              \!/     Common RF ground
>                            -------   3x 2ft copper pipes
>                            !  !  !   in watered soil.
>                            !  !  !
>                            !  !  !
>                            !  !  !
>                            !  !  !
>                            !  !  !
> 
> My thinking behind the 3 seperate earhing cables was that the heavy RF
> current from the TC-sec would be carried directly to the ground rods.
> The transformer and filter earths would then both use seperate cables
> to avoid picking up the RF from the secondary ground.
> 
> The only thing I could not try was a full Faraday cage because the
> garage is full of shelves and things.  It is not practical.
> 
> None of these measures have been successful,  and since the TC is
> clearly audible outside, I cannot operate it at all without complaints.
> 
> I have some questions:-
> 
> 1. Can I realistically hope to run a 2kW RQ-gap TC in a domestic garage
>    without causing ANY snow on neighbours televisions ?
> 
> 2. If so,  what am I doing wrong ?
> 
> 3. Is my ground sufficient and wired correctly.
> 
> 3. Is some filtering on the HV side of the transformer likely to help ?
> 
> Please help me !  I am a qualified electrical engineer with a working
> knowledge of RFI and EMC,  but I am confused by this.  Computers etc.
> operating in the house are not affected,  although TV's in houses 150ft
> away have snow.  If this cannot be solved I have no other option but
> to pack up.
> 
>                                         Cheers,
> 
>                                                 Richard Burnett.
> 
>                              (Making some TVI in sunny Newcastle.)
Richard,
Try running your coil late at night (1:00 to 2:00am),I've been running
my 18,000 watt coil here in burbank Ca. for the past 8 years and had no
complaints, get to know your neighbours, try working around there tv
schedule...they have to sleep sometime. Also don't advertise that you
have a broad band transmitter (T.C.)...good luck.
Bill
-- 
"Mind Over Matter"