[Lowfer] tonight

Bill Ashlock ashlockw at hotmail.com
Tue Jan 3 23:54:33 EST 2012


Jay,

I'm just beginning to understand the ins and outs of high Q vertical antennas. Loop antennas are much more stable... and safe. Thanks for the URL on Stefan's auto tune setup. I'll take a look. I wonder how that works in a really high Q and in a windy environment to boot?

I was just thinking that the Q of the capacity from ground screen to ground would be an interesting parameter to track with changing soil conditions. Maybe even the capacity variance would be interesting. My LRC meter has a Q readout which does fairly well in capacitor Q determination at 185K. 

BTW, I was experiencing a random total loss of supply current that you may have noticed, and this turned out to be an arc between the start and finish wires inside the coil form. I still can't figure out why I need more inductance right now. I'll remove the loading coil and measure it in the shack when I get back. Everything in that setup can be removed in short order and taken apart for testing - and that appears to be the only way to go for an experimental setup where nothing is known for sure.

Today I noticed that another perimeter wire can be added to the ground screen with spacing equal to the existing web wires and still keep the size within practical moose-snagging limits :) Your high voltage leads me to measure the voltage between ground screen and the ground and see if this turns out to be equal to the total antenna voltage divided down by the capacity divider formed. Should be about 200v.

Bill

> From: jrusgrove at comcast.net
> To: lowfer at mailman.qth.net
> Date: Tue, 3 Jan 2012 22:48:55 -0500
> Subject: Re: [Lowfer] tonight
> 
> Bill
> 
> Thanks for the measurement on antenna current ... always glad to hear the actual matches the 
> calculated. With the elevated ground screen and high antenna Q bet you'll need an auto tune 
> variometer to stay in resonance with varying conditions! Wonder if you've seen Stefan's auto tune 
> setup over on the rsgb list?
> 
> Based on the elevated ground screen tests here at the 100 watt level (137 kHz) and the high voltage 
> encountered on the ground screen (pulled 3/8" arcs) I've gone back to the existing 'on ground' 
> screen ... especially considering that power levels up to a kW are in use here.
> 
> Good luck with the experiment and keep us posted.
> 
> Jay W1VD  WD2XNS  WE2XGR/2
> 
> 
> 
> 
> ----- Original Message ----- 
> From: "Bill Ashlock" <ashlockw at hotmail.com>
> To: <lowfer at mailman.qth.net>
> Sent: Tuesday, January 03, 2012 9:47 PM
> Subject: Re: [Lowfer] tonight
> 
> 
> >
> >
> > Thanks for the "Wm" report Doug. That's only half a watt. For some reason more inductance is 
> > needed than I could get from the loading coil to reach resonance. It was so cold and windy up 
> > there that I couldn't make a change (Back in Andover right now ). At least the ground has 
> > re-frozen up there and the current at resonance is ~.315A. BTW if Jay is seeing this the antenna 
> > current matches the calculated value.
> >
> > Bill
> >
> >> Date: Wed, 4 Jan 2012 01:20:30 +0000
> >> From: kb4oer at gmail.com
> >> To: lowfer at mailman.qth.net
> >> Subject: [Lowfer] tonight
> >>
> >> Already seeing the "WM" graphical ID in the Lowfer "watering hole". Think
> >> I'll stay parked there tonight. Forecast is "lower teens" F here in TN.
> >> G'night all. 0500 comes early.
> >>
> >> D. KB4OER
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