Some more Questions on RF Interference and others

To: tesla-at-pupman-dot-com
Subject: Some more Questions on RF Interference and others
From: "Human Buirski" <hbuirski-at-hotmail-dot-com> (by way of Terry Fritz <twftesla-at-uswest-dot-net>)
Date: Sat, 15 May 1999 08:36:53 -0600
Approved: twftesla-at-uswest-dot-net
Delivered-To: fixup-tesla-at-pupman-dot-com-at-fixme

Hi everyone,

Any info on the following will be much appreciated:

1st here is the particulars of my coil.

NST -at- 12KV, 30mA (240V, 50Hz)
Secondary: 4" PVC, 1000 turns 0.5mm wire and a 5" Plexiglass about 1050 
turns 0.5mm wire.
Primary: flat spiral, about 12 turns of 3.15mm wire (enamel coated). I'm 
going to get 1/4" tube today to make a new one.
Cap: 0.02 microfarad, 15KV (got it at a radiaham festival for equivalent of 
about 4.8US$, the show was held on marconi day a few weeks ago, and they had 
two tesla coils (and a lot of other high voltage stuff there, 100KV xray 
machine xfrms etc). They didn't have any special filters etc as far as I 
could see and the building they had it in was right beside a field full of 
radio dishes, didn't hear anyone complain about that :). The two guys who 
presented it worked for a University here in my country and I asked the one 
guy and he said it wasn't illegal.)
RSG: 4 electrodes, about 3100 rpm, type of fan engine.
Toroid: some sponge tube I coated with Al foil.

1) What is the range of the RF Interference of a Tesla coil? I currently 
have no neighbours around me except across the street.
2) Can a faraday cage be made out of the wire used for bird cages? or must 
it be a more fine mesh of wire? Also can the frame be made out of 
wood/plastic?
3)What is the minimum size of a faraday cage for my coil dimensions? Our 
ceiling is 3 meters high.
4) Anyone got plans for building one? Especially one that can be dismantled 
in a few minutes?

5) Our ceiling consists of pressed metal plates (patterns), will that act as 
some kind of block to some of the RFI?

6) I have this circut for a mains filter (got it somewhere on internet, 
can't remember where):

AC in  -----CHOKE--------------------------to NST
                   |   |
                  --  --
                  --  --
                   |   |
                   --------Ground
                   |   |
                  --  --
                  --  --
                   |   |
AC in  -----CHOKE--------------------------to NST

Each choke, 30 turns of 3.15 mm wire on a 1" diameter iron rod (I cut a 
weightlifting rod for it, couldn't find ferrite cores except small toroid 
ones)
Caps: 630V, 220nF each (maybe use bigger caps?)

With this circuit I still get feedback, can this go out of our house wire 
and into the powerbox that distribute to the rest of the neigborhood? I 
don't care about our own radios/TV in the house since I unplug the TV and 
usually only run my coil at odd hours and for short durations.

7) Can I use the lighning protection unit/surge protector/mains filter of my 
pc to filter the mains? Must I connect it in reverse for this?

8) We got suspended wooden floors in our house? Will that make things a bit 
safer in case of a hit from the secondary?

9) How do you convert caps rated in nanoJoule to farads?

Thanx in advance.

Human Buirski
Pretoria
South Africa



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