Re: streamer loading effect

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Terry Fritz" <twftesla-at-qwest-dot-net>

Hi Steve,

>Hi Steve,
>
>At 02:34 AM 8/9/2002 -0500, you wrote:
>>Hello all,
>>
>>Tonight i ran my large 1800va TC.  Boy it was great!  unfortunately i didnt 
>>hit the ground with my arcs (well not yet, im about 10" away from that).  My 
>>toroid is at least about 44" above the ground.  Im getting a max of about 
>>56".  Besides rambling about my arc lengths, i noticed a neat little 
>>phenomena.  When the arcs get longer, the tuning get lower!  The difference 
>>in tuning will go from about 10 turns with a low spark gap setting, up to 
>>about 13 turns, as the arcs begin to spew out into the air.  
>
>The stremers are mostly conductive.  I made a wire "test streamer" out of a 
>bunch of lengths of piano wire:
>
>	http://hot-streamer-dot-com/temp/P5120013.jpg
>
>The added wire (streamer) is just like adding top load to the coil.  It 
>lowers the frequency 5-10%.  A "wire" streamer is easy to make and may help 
>with pre-tuning a coil.
>
>Even though I made it and took the picture, I never managed to test it...  I 
>must have gotten something else on my mind...  &:-)  Maybe I'll try this 
>tonight.
>
>I know the "rough average" load is about 1pF per foot of streamer length but 
>this should give a far better number.
>


I tried it tonight.  The secondary is 22.1mH and without a top load it
resonated at 356.6kHz which suggest an capacitance of 9.01pF

When I put the top terminal on, the frequency dropped to 227.3kHz or
22.18pF so the terminal "adds" 13.17pF.

With the wire streamer, the frequency is 190.7kHz or 31.52pF for another
9.34pF which is what the streamer seems to add.

So the frequency dropped 16.1% and the capacitance increased 42% from the
wire streamer load.  That sounds about 2X too high to me compared to a real
streamer case, but those are the results of this test.

Cheers,

	Terry