My quarter wavelength vertical tower (driven element in my vertical
parasitic array - see last 3 editions of the ON4UN low band DXing book) has
a shorted quarter wavelength of coax connected to the feedpoint. That keeps
the vertical at ground potential for lightning, etc. This is one method
If you gap a pair of spheres graphite, brass, or stainless
steel... typically the thickness of a credit card for a 1/4 wave
broadcast tower at 1KW carrier / 4KW peak; unless you shield the gap,
water WILL bridge the gap either side-by-side or stacked vertically.
Rain drops are
>Curious as why non resistor spark plugs aren't on the list of choices. Easy to
>gap. Pt-Pt electrodes last forever (100k miles). There was a ham mounting two
>on a Cu plate for ladder line, but that was many years ago. <
That can work but the other construction methods offer a wider range
of
Curious as why non resistor spark plugs aren't on the list of choices.
Easy to gap. Pt-Pt electrodes last forever (100k miles). There was a
ham mounting two on a Cu plate for ladder line, but that was many years ago.
Grant KZ1W
On 10/7/2019 2:21 PM, Jim Thomson wrote:
Date: Sun, 6 Oct 2019
Date: Sun, 6 Oct 2019 19:08:17 -0500
From: Rob Atkinson
To: topband@contesting.com
Subject: Re: Topband: spark gap construction ideas for 160m tower
https://www.radioworld.com/tech-and-gear/understanding-arc-gaps-for-am-systems
https://www.thebdr.net/articles/steel/twrs/LimitingStatic.pdf
Here's a DIY article from Jeff Welton at Nautel:
http://support.nautel.com/tips-n-tricks/how-to-make-roll-your-own-carbon-ball-gaps/
The carbon spheres that Jeff mentions are made by Ross Engineering. Not sure
of the cost, but may be worth considering:
Jeff,
I use stainless steel acorn nuts on the ends of matching screws. Not a
complete ball, but the facing surfaces are rounded.
George,
AA7JV
On Sun, 6 Oct 2019 13:27:58 -0500
Jeff Blaine wrote:
I need to add a spark gap of some sort onto my full-size 160m insulated-base
tower.
