Air as an insulator ...


Jerry N9AVY
 

I seriously doubt this theory.  Where I once lived just outside Chicago,  Had an 4BTV with radials mounted on roof of house.  Spring storms came around and I ran to basement to disconnect antenna while lightning was all around.  After antenna was disconnected and coax was hanging 6 feet above basement floor, I watched a big, blue arc go from coax to basement floor. 

Doubt that air is a good insulator.

Jerry  N9AVY


Kevin Lemon
 

Good. Then I can pull the coax out of my ears.


On Fri, Jan 8, 2016 at 11:54 AM, Jerry n9avy@... [070]
<070@...> wrote:
 

I seriously doubt this theory.  Where I once lived just outside Chicago,  Had an 4BTV with radials mounted on roof of house.  Spring storms came around and I ran to basement to disconnect antenna while lightning was all around.  After antenna was disconnected and coax was hanging 6 feet above basement floor, I watched a big, blue arc go from coax to basement floor. 

Doubt that air is a good insulator.

Jerry  N9AVY


Kevin Lemon
 

On a more serious note, I recall buying a 1921-02 arrestor for one of my B727s or DC9s back in the day. Pretty healthy looking device. Planes get hit often, wonder if I can find one.


On Fri, Jan 8, 2016 at 11:54 AM, Jerry n9avy@... [070]
<070@...> wrote:
 

I seriously doubt this theory.  Where I once lived just outside Chicago,  Had an 4BTV with radials mounted on roof of house.  Spring storms came around and I ran to basement to disconnect antenna while lightning was all around.  After antenna was disconnected and coax was hanging 6 feet above basement floor, I watched a big, blue arc go from coax to basement floor. 

Doubt that air is a good insulator.

Jerry  N9AVY


 

Jerry,

What you saw happened one time...in your basement and could never be recreated...anywhere else...at any time...and you’re dealing with huge, massive voltage, and there are no constants.

Air is the best insulator there is.

Put a lot of air between the voltage terminus and ground and see. Is 6’ a lot? Apparently not when you consider the unknown and unmeasured voltage of lightening.

Concrete is also an insulator. Not a very good insulator, but none the less it insulates to a point. Google “Ufer Ground” and see how concrete is used in construction for grounding...and I mean HUGE buildings!

Milt.

N6MG

 

 

 

From: 070@... [mailto:070@...]
Sent: Friday, January 8, 2016 9:54 AM
To: yahoogroups <070@...>
Subject: [070] Air as an insulator ...

 

 

I seriously doubt this theory.  Where I once lived just outside Chicago,  Had an 4BTV with radials mounted on roof of house.  Spring storms came around and I ran to basement to disconnect antenna while lightning was all around.  After antenna was disconnected and coax was hanging 6 feet above basement floor, I watched a big, blue arc go from coax to basement floor. 

 

Doubt that air is a good insulator.

 

Jerry  N9AVY


Jerry N9AVY
 

Had a couple of Pyrex insulators rated at something like 5 KW and were about 8 inches long.   Unfortunately, they disappeared from my parents garage many years ago.  The 2 little thieves hit every garage in town and only stole radio stuff.  They're probably dead or still in jail... Oh yeah, they worked at Knight Kit when I was there back in 60's ...shipping dept. and had been putting labels on stuff to send to their friends/fences.  They both got fired !

Jerry  N9AVY




From: "Kevin Lemon k0mci@... [070]" <070@...>
To: "070@..." <070@...>
Sent: Friday, January 8, 2016 12:00 PM
Subject: Re: [070] Air as an insulator ...

 
On a more serious note, I recall buying a 1921-02 arrestor for one of my B727s or DC9s back in the day. Pretty healthy looking device. Planes get hit often, wonder if I can find one.


 
I seriously doubt this theory.  Where I once lived just outside Chicago,  Had an 4BTV with radials mounted on roof of house.  Spring storms came around and I ran to basement to disconnect antenna while lightning was all around.  After antenna was disconnected and coax was hanging 6 feet above basement floor, I watched a big, blue arc go from coax to basement floor. 

Doubt that air is a good insulator.

Jerry  N9AVY



Kevin Lemon
 

This topic has me on a mission. Not only am I pondering the sourcing of aircraft arrestors, now I am also wondering if I can find a good 522-1501-00 Collins HF transceiver. 
I'm sure they're out there. 

On Fri, Jan 8, 2016 at 12:23 PM, Jerry n9avy@... [070]
<070@...> wrote:
 

Had a couple of Pyrex insulators rated at something like 5 KW and were about 8 inches long.   Unfortunately, they disappeared from my parents garage many years ago.  The 2 little thieves hit every garage in town and only stole radio stuff.  They're probably dead or still in jail... Oh yeah, they worked at Knight Kit when I was there back in 60's ...shipping dept. and had been putting labels on stuff to send to their friends/fences.  They both got fired !

Jerry  N9AVY




From: "Kevin Lemon k0mci@... [070]" <070@...>
To: "070@..." <070@...>
Sent: Friday, January 8, 2016 12:00 PM
Subject: Re: [070] Air as an insulator ...

 
On a more serious note, I recall buying a 1921-02 arrestor for one of my B727s or DC9s back in the day. Pretty healthy looking device. Planes get hit often, wonder if I can find one.


 
I seriously doubt this theory.  Where I once lived just outside Chicago,  Had an 4BTV with radials mounted on roof of house.  Spring storms came around and I ran to basement to disconnect antenna while lightning was all around.  After antenna was disconnected and coax was hanging 6 feet above basement floor, I watched a big, blue arc go from coax to basement floor. 

Doubt that air is a good insulator.

Jerry  N9AVY



John Etling
 

You are perfectly making my point spot on… If air is such a great insulator, what will prevent the lightening from jumping a 1” gap of a glass fuse?

 

… I’m just sayin’

 

73 de K3JAE

John Etling

k3jae@...

070 #1820   LONP #321

PODXS 070 – Nobody Special – Just a Member

 

 

 

 

From: Jerry n9avy@... [070] [mailto:070@...]
Sent: Friday, January 08, 2016 11:54
To: yahoogroups <070@...>
Subject: [070] Air as an insulator ...

 

 

I seriously doubt this theory.  Where I once lived just outside Chicago,  Had an 4BTV with radials mounted on roof of house.  Spring storms came around and I ran to basement to disconnect antenna while lightning was all around.  After antenna was disconnected and coax was hanging 6 feet above basement floor, I watched a big, blue arc go from coax to basement floor. 

 

Doubt that air is a good insulator.

 

Jerry  N9AVY


Kevin Lemon
 

On Fri, Jan 8, 2016 at 12:28 PM, 'John Etling' john@... [070]
<070@...> wrote:
 

You are perfectly making my point spot on… If air is such a great insulator, what will prevent the lightening from jumping a 1” gap of a glass fuse?

 

… I’m just sayin’

 

73 de K3JAE

John Etling

k3jae@...

070 #1820   LONP #321

PODXS 070 – Nobody Special – Just a Member

 

 

 

 

From: Jerry n9avy@... [070] [mailto:070@...]
Sent: Friday, January 08, 2016 11:54
To: yahoogroups <070@...>
Subject: [070] Air as an insulator ...

 

 

I seriously doubt this theory.  Where I once lived just outside Chicago,  Had an 4BTV with radials mounted on roof of house.  Spring storms came around and I ran to basement to disconnect antenna while lightning was all around.  After antenna was disconnected and coax was hanging 6 feet above basement floor, I watched a big, blue arc go from coax to basement floor. 

 

Doubt that air is a good insulator.

 

Jerry  N9AVY


Mike Flowers
 

As Milt said – with lightning, all bets are off …

 

From: http://www.aharfield.co.uk/lightning-protection-services/about-lightning

 

There is estimated to be around 2,000 lightning storm active around the global at one time creating over 100 strikes per second. These thunderstorms generate a potential difference of 200,000 to 500,000 volts between the Earth’s surface and the ionosphere, with a fair weather current of about 2×10-12 amperes/meter2.

 

- 73 and good DX de Mike, K6MKF, President - NCDXC

 

From: 070@... [mailto:070@...]
Sent: Friday, January 08, 2016 10:15 AM
To: 070@...
Subject: RE: [070] Air as an insulator ...

 

 

Jerry,

What you saw happened one time...in your basement and could never be recreated...anywhere else...at any time...and you’re dealing with huge, massive voltage, and there are no constants.

Air is the best insulator there is.

Put a lot of air between the voltage terminus and ground and see. Is 6’ a lot? Apparently not when you consider the unknown and unmeasured voltage of lightening.

Concrete is also an insulator. Not a very good insulator, but none the less it insulates to a point. Google “Ufer Ground” and see how concrete is used in construction for grounding...and I mean HUGE buildings!

Milt.

N6MG

 

 

 

From: 070@... [mailto:070@...]
Sent: Friday, January 8, 2016 9:54 AM
To: yahoogroups <070@...>
Subject: [070] Air as an insulator ...

 

 

I seriously doubt this theory.  Where I once lived just outside Chicago,  Had an 4BTV with radials mounted on roof of house.  Spring storms came around and I ran to basement to disconnect antenna while lightning was all around.  After antenna was disconnected and coax was hanging 6 feet above basement floor, I watched a big, blue arc go from coax to basement floor. 

 

Doubt that air is a good insulator.

 

Jerry  N9AVY


 

Mike, the map on the referenced website shows a lot of activity in the center of Africa.

Not where I expected to see that most.

Very interesting...and good reading.

Thanks for sharing that.

Milt.

N6MG

 

From: 070@... [mailto:070@...]
Sent: Friday, January 8, 2016 10:41 AM
To: 070@...
Subject: RE: [070] Air as an insulator ...

 

 

As Milt said – with lightning, all bets are off …

 

From: http://www.aharfield.co.uk/lightning-protection-services/about-lightning

 

There is estimated to be around 2,000 lightning storm active around the global at one time creating over 100 strikes per second. These thunderstorms generate a potential difference of 200,000 to 500,000 volts between the Earth’s surface and the ionosphere, with a fair weather current of about 2×10-12 amperes/meter2.

 

- 73 and good DX de Mike, K6MKF, President - NCDXC

 

From: 070@... [mailto:070@...]
Sent: Friday, January 08, 2016 10:15 AM
To: 070@...
Subject: RE: [070] Air as an insulator ...

 

 

Jerry,

What you saw happened one time...in your basement and could never be recreated...anywhere else...at any time...and you’re dealing with huge, massive voltage, and there are no constants.

Air is the best insulator there is.

Put a lot of air between the voltage terminus and ground and see. Is 6’ a lot? Apparently not when you consider the unknown and unmeasured voltage of lightening.

Concrete is also an insulator. Not a very good insulator, but none the less it insulates to a point. Google “Ufer Ground” and see how concrete is used in construction for grounding...and I mean HUGE buildings!

Milt.

N6MG

 

 

 

From: 070@... [mailto:070@...]
Sent: Friday, January 8, 2016 9:54 AM
To: yahoogroups <070@...>
Subject: [070] Air as an insulator ...

 

 

I seriously doubt this theory.  Where I once lived just outside Chicago,  Had an 4BTV with radials mounted on roof of house.  Spring storms came around and I ran to basement to disconnect antenna while lightning was all around.  After antenna was disconnected and coax was hanging 6 feet above basement floor, I watched a big, blue arc go from coax to basement floor. 

 

Doubt that air is a good insulator.

 

Jerry  N9AVY


Mike Flowers
 

Yep – lots of heat + humidity = thunderboomers!

 

- 73 and good DX de Mike, K6MKF, President - NCDXC

 

From: 070@... [mailto:070@...]
Sent: Friday, January 08, 2016 10:56 AM
To: 070@...
Subject: RE: [070] Air as an insulator ...

 

 

Mike, the map on the referenced website shows a lot of activity in the center of Africa.

Not where I expected to see that most.

Very interesting...and good reading.

Thanks for sharing that.

Milt.

N6MG

 

From: 070@... [mailto:070@...]
Sent: Friday, January 8, 2016 10:41 AM
To: 070@...
Subject: RE: [070] Air as an insulator ...

 

 

As Milt said – with lightning, all bets are off …

 

From: http://www.aharfield.co.uk/lightning-protection-services/about-lightning

 

There is estimated to be around 2,000 lightning storm active around the global at one time creating over 100 strikes per second. These thunderstorms generate a potential difference of 200,000 to 500,000 volts between the Earth’s surface and the ionosphere, with a fair weather current of about 2×10-12 amperes/meter2.

 

- 73 and good DX de Mike, K6MKF, President - NCDXC

 

From: 070@... [mailto:070@...]
Sent: Friday, January 08, 2016 10:15 AM
To: 070@...
Subject: RE: [070] Air as an insulator ...

 

 

Jerry,

What you saw happened one time...in your basement and could never be recreated...anywhere else...at any time...and you’re dealing with huge, massive voltage, and there are no constants.

Air is the best insulator there is.

Put a lot of air between the voltage terminus and ground and see. Is 6’ a lot? Apparently not when you consider the unknown and unmeasured voltage of lightening.

Concrete is also an insulator. Not a very good insulator, but none the less it insulates to a point. Google “Ufer Ground” and see how concrete is used in construction for grounding...and I mean HUGE buildings!

Milt.

N6MG

 

 

 

From: 070@... [mailto:070@...]
Sent: Friday, January 8, 2016 9:54 AM
To: yahoogroups <070@...>
Subject: [070] Air as an insulator ...

 

 

I seriously doubt this theory.  Where I once lived just outside Chicago,  Had an 4BTV with radials mounted on roof of house.  Spring storms came around and I ran to basement to disconnect antenna while lightning was all around.  After antenna was disconnected and coax was hanging 6 feet above basement floor, I watched a big, blue arc go from coax to basement floor. 

 

Doubt that air is a good insulator.

 

Jerry  N9AVY


David M (AJ4TF)
 

Actually dry air is a pretty good insulator... dielectric strength is about 3 kV / mm
Polyethylene is at least 6 times better.  Diamond is 2 MV / mm!

de AJ4TF


ljl2002@att.net
 

I had a strike in the neighbors yard this last summer about 150 ft from my antennas.  Shredded the oak tree that it hit and the noise was incredible.
Don't think I want to repeat that again.

Joe
KA1PPV  #1482


On Friday, January 8, 2016 6:09 PM, "aj4tf@... [070]" <070@...> wrote:


 
Actually dry air is a pretty good insulator... dielectric strength is about 3 kV / mm
Polyethylene is at least 6 times better.  Diamond is 2 MV / mm!

de AJ4TF