Re: Topband: spark gap construction ideas for 160m tower

[Tim Duffy]

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
cellular operators use for lightning protection. Easy and very
straightforward.

73
Tim K3LR

-Original Message-
From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of
donro...@hiwaay.net
Sent: Monday, October 7, 2019 9:49 PM
To: topband@contesting.com
Subject: Re: Topband: spark gap construction ideas for 160m tower

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 typically pure distilled water,  but if the water runs  
down a galvanized tower, all bets are off.Make a rain shield out  
of a plastic Coke or Pepsi bottle  and replace a couple of times a  
year as you inspect all of your connections.

Don ( still doing Broadcast AMs after all these years ) W4DNR



Quoting Jim Thomson :

>> ##  Place  a plastic  cover  above  any  outdoor spark  gap.   Any
> bugs  will  be  fried.
>
> Jim   VE7RF

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Re: Topband: spark gap construction ideas for 160m tower

[donroden]

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 typically pure distilled water,  but if the water runs  
down a galvanized tower, all bets are off.Make a rain shield out  
of a plastic Coke or Pepsi bottle  and replace a couple of times a  
year as you inspect all of your connections.


Don ( still doing Broadcast AMs after all these years ) W4DNR



Quoting Jim Thomson :


##  Place  a plastic  cover  above  any  outdoor spark  gap.   Any

bugs  will  be  fried.

Jim   VE7RF


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Re: Topband: spark gap construction ideas for 160m tower

[Rob Atkinson]

>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 v. breakdown.  keep in mind the articles were for broadcast with a
variety of feedpoint voltages.  But for 160 m., there's nothing wrong
with looking to medium wave broadcast for ideas to take away.

73

Rob
K5UJ
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Re: 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 
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
https://www.kintronic.com/shop/tower-ball-gap/

<73
http://www.contesting.com/_topband - Topband Reflector


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Topband: spark gap construction ideas for 160m tower

[Jim Thomson]

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
https://www.kintronic.com/shop/tower-ball-gap/

<73
http://www.contesting.com/_topband - Topband Reflector

Re: Topband: spark gap construction ideas for 160m tower

[Paul Christensen]

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:

https://www.rossengineeringcorp.com/products/isolation/toroids-spheres-corona-nuts.html

Paul, W9AC

-Original Message-
From: Topband  On Behalf Of GEORGE WALLNER
Sent: Monday, October 7, 2019 9:10 AM
To: Jeff Blaine ; topband 
Subject: Re: Topband: spark gap construction ideas for 160m tower

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.  Looking for ideas.
>
> Making the spark gap is simple.  What has me asking for ideas is the weather 
> element - we have a lot of snow, ice, rain here and a spark gap needs to keep 
> that stuff off.  But put a little cover over it, right?  Well, yes but if the 
> cover is not fully enclosed, then you have wasps and spiders making nests 
> there.  If it's enclosed, then you have condensation and ants.
>
> I like the idea of W8JI's two balls close to each other - the surface area is 
> large so accumulated pitting won't change the spacing and thus the BDV much.  
> And the water will drain off away from the contact points.  But what does a 
> guy make that out of if he does not have a set of brass balls in his junkbox.
>
> 73/jeff/ac0c
> alpha-charlie-zero-charlie
> www.ac0c.com <http://www.ac0c.com> 
>
>
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Re: Topband: spark gap construction ideas for 160m tower

[GEORGE WALLNER]

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.  Looking for ideas.

Making the spark gap is simple.  What has me asking for ideas is the weather 
element - we have a lot of snow, ice, rain here and a spark gap needs to keep 
that stuff off.  But put a little cover over it, right?  Well, yes but if the 
cover is not fully enclosed, then you have wasps and spiders making nests 
there.  If it's enclosed, then you have condensation and ants.

I like the idea of W8JI's two balls close to each other - the surface area is 
large so accumulated pitting won't change the spacing and thus the BDV much.  
And the water will drain off away from the contact points.  But what does a guy 
make that out of if he does not have a set of brass balls in his junkbox.

73/jeff/ac0c
alpha-charlie-zero-charlie
www.ac0c.com  



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Re: Topband: spark gap construction ideas for 160m tower

[Rob Atkinson]

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
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Re: Topband: spark gap construction ideas for 160m tower

[Lloyd - N9LB]

See:  
https://www.qrz.com/DB/w9gl
( scroll down to 3rd picture )

Copper float balls available at any hardware, home improvement or plumbing 
supply store.



-Original Message-
From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Jeff Blaine
Sent: Sunday, October 06, 2019 1:28 PM
To: topband 
Subject: Topband: spark gap construction ideas for 160m tower

I need to add a spark gap of some sort onto my full-size 160m insulated-base 
tower.  Looking for ideas.

Making the spark gap is simple.  What has me asking for ideas is the weather 
element - we have a lot of snow, ice, rain here and a spark gap needs to keep 
that stuff off.  But put a little cover over it, right? Well, yes but if the 
cover is not fully enclosed, then you have wasps and spiders making nests 
there.  If it's enclosed, then you have condensation and ants.

I like the idea of W8JI's two balls close to each other - the surface area is 
large so accumulated pitting won't change the spacing and thus the BDV much.  
And the water will drain off away from the contact points.  But what does a guy 
make that out of if he does not have a set of brass balls in his junkbox.

73/jeff/ac0c
alpha-charlie-zero-charlie
www.ac0c.com


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Re: Topband: spark gap construction ideas for 160m tower

[donovanf]

Just purchase them, they're not expensive. For example: 


www.antiquelampsupply.com/3-8-dia-brass-ball-tap-6-32f.html?gclid=EAIaIQobChMI_auMy7GI5QIVho7ICh2C4wEvEAQYAyABEgJFGPD_BwE
 


73 
Frank 
W3LPL 

- Original Message -

From: "Jeff Blaine"  
To: "topband"  
Sent: Sunday, October 6, 2019 6:27:58 PM 
Subject: Topband: spark gap construction ideas for 160m tower 

I need to add a spark gap of some sort onto my full-size 160m 
insulated-base tower. Looking for ideas. 

Making the spark gap is simple. What has me asking for ideas is the 
weather element - we have a lot of snow, ice, rain here and a spark gap 
needs to keep that stuff off. But put a little cover over it, right? 
Well, yes but if the cover is not fully enclosed, then you have wasps 
and spiders making nests there. If it's enclosed, then you have 
condensation and ants. 

I like the idea of W8JI's two balls close to each other - the surface 
area is large so accumulated pitting won't change the spacing and thus 
the BDV much. And the water will drain off away from the contact 
points. But what does a guy make that out of if he does not have a set 
of brass balls in his junkbox. 

73/jeff/ac0c 
alpha-charlie-zero-charlie 
www.ac0c.com 


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Re: Topband: spark gap construction ideas for 160m tower

[Wes]

Spark has been prohibited since 1934. :-)

On 10/6/2019 11:27 AM, Jeff Blaine wrote:
I need to add a spark gap of some sort onto my full-size 160m insulated-base 
tower.  Looking for ideas.


Making the spark gap is simple.  What has me asking for ideas is the weather 
element - we have a lot of snow, ice, rain here and a spark gap needs to keep 
that stuff off.  But put a little cover over it, right?  Well, yes but if the 
cover is not fully enclosed, then you have wasps and spiders making nests 
there.  If it's enclosed, then you have condensation and ants.


I like the idea of W8JI's two balls close to each other - the surface area is 
large so accumulated pitting won't change the spacing and thus the BDV much.  
And the water will drain off away from the contact points.  But what does a 
guy make that out of if he does not have a set of brass balls in his junkbox.


73/jeff/ac0c
alpha-charlie-zero-charlie
www.ac0c.com


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Re: Topband: spark gap construction ideas for 160m tower

[JAYB1943]

Hi Jeff – try toilet tank float balls..I think I have still seen them around 
in Copper ...73 jay NY2NY 
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Topband: spark gap construction ideas for 160m tower

[Jeff Blaine]

I need to add a spark gap of some sort onto my full-size 160m 
insulated-base tower.  Looking for ideas.


Making the spark gap is simple.  What has me asking for ideas is the 
weather element - we have a lot of snow, ice, rain here and a spark gap 
needs to keep that stuff off.  But put a little cover over it, right?  
Well, yes but if the cover is not fully enclosed, then you have wasps 
and spiders making nests there.  If it's enclosed, then you have 
condensation and ants.


I like the idea of W8JI's two balls close to each other - the surface 
area is large so accumulated pitting won't change the spacing and thus 
the BDV much.  And the water will drain off away from the contact 
points.  But what does a guy make that out of if he does not have a set 
of brass balls in his junkbox.


73/jeff/ac0c
alpha-charlie-zero-charlie
www.ac0c.com


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