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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"