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Re: Case ground.

At 10:25 PM 1/13/97 -0700, you wrote:
>> Subject: Re: Case ground.
>
>Subscriber: bert.hickman-at-aquila-dot-com Mon Jan 13 22:10:02 1997
>Date: Mon, 13 Jan 1997 19:18:44 -0800
>From: Bert Hickman <bert.hickman-at-aquila-dot-com>
>To: tesla-at-pupman-dot-com
>Subject: Re: Case ground.
>
>Tesla List wrote:
>> 
>> Subscriber: knardell-at-mailhost.accesscom-dot-net Sun Jan 12 22:17:48 1997
>> Date: Sun, 12 Jan 1997 17:05:44 -0600
>> From: Kevin <knardell-at-mailhost.accesscom-dot-net>
>> To: tesla-at-pupman-dot-com
>> Subject: Re: Case ground.
>> 
>> >Daniel,
>> >
>> >There are a few reasons to tie the case to at least the RF ground:
>> >
>> >Since large Electrostatic fields are present betweent the toroid and its
>> >surroundings, the primary needs to have a path to ground to prevent
>> >electrostatic induction from inducing high ES voltages (to ground) on
>> >the entire primary. Grounding the neon case "bleeds" this off.
>> >
>> >A pair of safety gaps should be used from each neon HV leg to the case
>> >ground (and RF ground). This serves two purposes: it reduces overvolting
>> >the neon's outputs, AND it provides a low-impedance path the the RF
>> >ground in case you take a "hit" from the toroid to the primary. This
>> >protects EACH leg, and prevents an RF flashover that otherwise would
>> >find ground through your neon's secondary to the 120 VAC side... not a
>> >good thing!
>> >
>> >There's a belief that grounding the case reduced RFI, but I'm not aware
>> >of any actual before-after measurements. The first two above should be
>> >reason enough...
>> >
>> >Safe coilin' to you!
>> >
>> >-- Bert --
>> >
>> >
>> >
>> Bert,
>> 
>> I again am having trouble with noise, I was showing my neighbor a new laser
>> I just got and he said he could hear my coil running LOUD over his phone
>> conversation. I have filters inline now, what else can I do? I put some
>> chokes on the HV outputs of my neon and the coil stoped sparking. Why?? I
>> also have a excelent rf ground, would this be a good time to pull the Neon
>> case to the RF gound? My filter system is well grounded (The case) to the
>> house ground as recomended by manufacturer. Any tips or hints, a faraday
>> cage is out the question, I now have a coil, 2 lasers (Very big) and my
>> other electronic junk in my play room, no room, money, or time to construct
>> a cage.
>> 
>> Anything I overlook?
>> 
>> Thanks in advance!
>> 
>>                                        Regards,
>>                                             Kevin Nardelle
>> 
>>    ********************************************
>>    * T   E   S   L   A      C   O   I   L   S *
>>    ********************************************
>> Kevin Nardelle   knardell-at-accesscom-dot-net
>> My main web page IS UP all TESLA
>> related with lotsa pictures and links.
>> http://www.icorp-dot-net/users/kev/tesla
>> http://www.accesscom-dot-net/nardell
>> Non related sites I have
>> The Louisiana Swamps Online (Under construction)
>> http://www.icorp-dot-net/users/kev
>> **********************************************
>
>Kevin,
>
>Tesla coils generate interference in many ways. Electric sparks, in
>general, generate RF noise by "exciting" the small wiring inductances
>and capacitances in your HV primary circuit. This causes the primary
>wiring to "ring" at higher (VHF) frequencies. Streamers and (especially)
>ground arcs also radiate at higher frequencies. Finally the coil
>itself radiates RF across a rather broad spectrum - the lousier the
>primary "Q", the broader the range around your center frequency. 

It is very lousy, the only perfect part of my entire setup is the secondary
and RF ground for it, and my 12KV 120MA Neon. Everything else is certainly
very lousy. I am working on it, little at a time when the neighbors are not
home.

>
>The 120V EMI filters you've added will only help reduce interference
>that's being conducted back into your power mains through the wires. 
>They won't stop radiated high-frequency noise. It sounds like your
>neighbor may be picking up radiated noise on his phone. Is his phone a
>regular (hard-wired) or portable? Portable phones, being radio
>tranceivers, are typically much more sensitive to radiated Tesla Coil
>noise.
>
He has a regular hard wired type, cheapo.


>You can reduce noise radiation somewhat by making all of the high
>voltage and primary/capacitor interconnection wiring as short as
>possible, by minimizing the length of wire connecting your coil to
>your RF ground, and using a solid RF ground (multiple groundrods). Tie
>your transformer case to the RF ground as well. If you're still running
>with the cap across the transformer, this may also increase the noise
>you're radiating. Anywhere you've got a pair of balanced
>current-carrying wires, like those going to the primary, run them close
>together and in parallel to reduce their ability to act as individual
>antennas. 
>
I did just that, infact I am talking with a very nice person, and I find
everybody on this list very nice and ready to help but we email regularly
and I find it is working out well. He told me to shorten the LONG (geezz
12-15 Foot) primary wires, focus on the RQ cylinder gap, and get some good
RFI dealyopies to filter line noise going into the ac feed.

Things are comming together with everyones help.


>Operating your coil at times when your neighbors will be unlikely to be
>using the phone or watching TV will also minimize your neighbor's
>aggravation. Try to get him interested in the hobby (maybe as your lab
>assistant) :^) Keeping your neighbors happy is essential for you to
>continue successful coiling! If the above these measures are still not
>good enough, then other steps can include constructing and running the
>coil in a room surrounded by grounded aluminum siding, metal
>screen/sheet, firing the coil in a more remote location (perhaps off a
>portable generator), or looking for another, quieter hobby - like maybe 
>pyrotechnics?. :^). Unfortunately, a Faraday cage is the only way to
>truly contain radiated RF. 
>
I realize this but if I can get it off the phone and out his computer
speakers he will be very happy as will I.
I have nowhere to relocate to, I am sure it it boils down to it I will have
to shut down or maybe build a very small coil inside a bird cage.



>Using high voltage chokes may reduce coil output somewhat by impeding
>the tank cap charging process. However, they shouldn't prevent the coil
>from operating unless you're running with very wide gaps and were just
>barely firing the gaps prior to adding the chokes. Although chokes will
>help protect your neons from internal breakdown, they won't do much to
>reduce
>radiated HF noise. 

Good, I tried them and the coil put out nothing however they were built for
a laser. I will keep to the basics right now.

>
>Any other ideas, particularly from the Hams out there??
>
>Safe coiling to you!
>
>-- Bert --
>
>

                                       Regards,
                                            Kevin Nardelle

   ********************************************
   * T   E   S   L   A      C   O   I   L   S *
   ********************************************
Kevin Nardelle   knardell-at-accesscom-dot-net
My main web page IS UP all TESLA
related with lotsa pictures and links.
http://www.icorp-dot-net/users/kev/tesla
http://www.accesscom-dot-net/nardell
Non related sites I have
The Louisiana Swamps Online (Under construction)
http://www.icorp-dot-net/users/kev
**********************************************