More triggered gap testing

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Original poster: "J. B. Weazle McCreath by way of Terry Fritz <twftesla-at-qwest-dot-net>" <weazle-at-hurontel.on.ca>


Hello Terry & others,

Some of you may recall my post on Saturday of the experiments I've
been conducting with the triggered gap configuration Terry and Marc
have come up with.

I did some more testing last night and thought I'd share my findings
with the list for comments.  As I mentioned in my first post, I was
wondering if the 400 Watt load resistor was an overkill, so that was
the first test I did.

Using some heating elements I liberated from an electric furnace in
various series and parallel configurations, I determined that in my
setup the best results where obtained with a 150 Watt load.  Going
to 400 Watts as Terry is using gave me very eratic firing of the GM
HEIC, with a usable mechanical range of perhaps 20 degrees on the 
dimmer's control knob.  I get about a 90 degree mechanical range as
usable with 150 Watts of loading.

After settling on the 150 Watt dummy load, I tried a wide range of
capacitor values from as low as 0.74 uF. up to a high of 4.5 uF. and
found that a 3 uF. motor run cap gave the best results.  I'd be very
interested in knowing why I'm finding I need such a smaller value of
a resistance for the dummy load than Terry is using.  By the way, my
load resistor is connected directly across the dimmer output, while
the ignition coil/capacitor are connected after the second filter.

For the record, my setup is composed of the following:

two Corcom dual-stage filters, one before and one after the dimmer
a Leviton 600 Watt dimmer
a "dummy load" resistor of 103.5 ohm (three furnace elements)
a GM high energy ignition coil
a doorknob coupling cap, 500 pF. -at- 30 KV.

The HV lead from the doorknob cap connects to the centre electrode
of my RQ/TCBOR 7 electrode static gap.  The ground is connected to
the "created centre tap" of my radar transformer secondary as per
Bert Hickman's suggested method.


73, Weazle, VE3EAR/VE3WZL

Listening: 147.030+ and 442.075+
E-mail:    weazle-at-hurontel.on.ca
           or ve3ear-at-rac.ca
Web site:  www.hurontel.on.ca/~weazle