Topband: spark gap construction ideas for 160m tower

[Grant Saviers]

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 19:08:17 -0500
> From: Rob Atkinson <ranchorobbo at gmail.com>
> To: topband at contesting.com
> Subject: Re: Topband: spark gap construction ideas for 160m tower
> 
> <There are a number of ways of making a ball gap.  but more important
> <is arriving at the correct spacing for the gap.
> <The way rain is handled is usually by positioning the balls one above
> <the other so a water bridge doesn't form between the balls.
> 
> <Read this by Mark Persons:
> https://www.radioworld.com/tech-and-gear/understanding-arc-gaps-for-am-systems
> <Here's another treatment:
> https://www.thebdr.net/articles/steel/twrs/LimitingStatic.pdf
> <Kintronic sells them
> https://www.kintronic.com/shop/tower-ball-gap/
> 
> <73
> <Rob
> <K5UJ
> 
> ##  a  simple  1 megohm  resistor  across  the  base  will  drain  static buildup.
> A  35-100 uh  coil  across  the  base  will  also  drain static  buildup.
> Neither  of  the  above  will  work  with  a direct  lightning hit  to  top of
> tower.   A  buddy used a helical hairpin   across  the  base of  his   100  ft
> tall   160m   vertical....  suspended  between  2  trees...with  T  loading capacity hats.
> Helical  hairpin  also  DC  grounds  the  vert.
> 
> ##  I  built a simple adjustable  spark  gap  like  Mark  Persons describes
> in  the  1st url  above.   I used  .25-20  brass  machine  screws...and
> also mating  brass  lock  nuts...and  also  brass  acorn nuts..with  their
> domed  heads.   IF the  acorn  nuts  get  fried,  replaced real  easy.
> 
> ##  My  hb  spark  gap  is  not  for a vertical  though.  Its  wired  across
> a  4 H Dahl,  127  lb  choke...  that  I  picked  up across  town.   Its
> a  C-L-C  filter  network for a B+  supply.   The C-L-C network  is  in
> series  with  the  B+...  after  the  FWB  assy.   The  choke  itself is isolated
> from  the  chassis.   The  spark  gap  is  just a safety precaution....  and  gapped
> for  like  300  volts.
> 
> ##  Identical  adjustable  spark  gaps  are  wired across the  vac  load  caps
> on  the hb linear amps.   Gapped  for a breakdown  thats   way less  than  the
> hi  pot  test  rating  of  the  vac  load  cap.   But  higher than a  max 2.5:1  swr  across
> the  vac  load  cap... which  is a PI  net..so  at a 50  ohm  point.   Amps kick  offline
> with a 2:1  swr.
> 
> ##  Place  a plastic  cover  above  any  outdoor spark  gap.   Any  bugs  will  be  fried.
> 
> Jim   VE7RF
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