Re: webpage

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

Original poster: "Dr. Duncan Cadd by way of Terry Fritz <twftesla-at-uswest-dot-net>" <dunckx-at-freeuk-dot-com>

Hi Jim!

Date: 11 January 2001 05:56
Subject: Re: webpage


>Original poster: "Jim Lux by way of Terry Fritz
<twftesla-at-uswest-dot-net>" <jimlux-at-earthlink-dot-net>
>


Thanks for the interesting info!

<snip>

>It's also important to remember that 50 ohms is a
compromise impedance
>between most efficient  power transmission and lowest loss.
There is
>nothing sacred about 50 ohms.


Absolutely - if you want to go lower, parallel two 50 ohm
lines for 25 ohm, or higher you can stick 'em in series for
100 ohms!  You can even vary the connections to get balanced
instead of unbalanced if you're really picky for that big
bipolar coil ;-)  I've seen this done by fellow hams - I
know there are diagrams in the RSGBs publications and I
assume that there are in those of the ARRL. Just don't ask
for any ASCII art renderings, please!  But you do need to
consider the load/line impedance when calculating the tank
and link - particularly the link - reactances as this fixes
the loaded Q.

>In the TC area, you might want to choose a low impedance to
keep the
>voltages low. (E = sqrt (P*R))


That was one of my main motivators for doing this experiment
and providing the tuning is right (grin, smoked some 2250Vdc
mica caps due to mistuning!) the volts are indeed relatively
friendly.  I aim eventually to be able to stick a 3A
thermocouple ammeter in the line to help indicate the best
power transfer - I have one sitting waiting, once I'm sure
I'm not going to toast it.  I expect it'll be a month or
three before I'm completely confident with this - it's a
steep learning curve, despite having played with valves for
a while the spark transmitter seems to have quirks of its
own.  But then that's why I got into this game :-)

Dunckx
G0UTY