Snow / Disconnecting Antenna
 

Hello folks,

I've read for many years of how one should always disconnect the
antenna when it snows. I'm curious, though, as to why snow is
something that would be of particular concern. I guess the concern
over thunderstorms seems straightforward enough...that lightning
strikes, even at some distance away, can result in significant,
potentially damaging static voltages in the antenna. But does/can
atmospheric conditions during a snow result in this same sort of
phenomenon?

As an aside, related or perhaps not, in the areas of the U.S. in which
I've resided, I've only lived through one thunder-snow.

Anyway, just wondering about that.

Junius

Snow / Disconnecting Antenna
 

On 7 Feb 2006 16:21:38 -0800, "junius" wrote:

Hello folks,

I've read for many years of how one should always disconnect the
antenna when it snows. I'm curious, though, as to why snow is
something that would be of particular concern. I guess the concern
over thunderstorms seems straightforward enough...that lightning
strikes, even at some distance away, can result in significant,
potentially damaging static voltages in the antenna. But does/can
atmospheric conditions during a snow result in this same sort of
phenomenon?

As an aside, related or perhaps not, in the areas of the U.S. in which
I've resided, I've only lived through one thunder-snow.

Anyway, just wondering about that.

Junius

Static electricity is caused by the snow hitting the wire. If you use
an unbalanced transformer on your antenna and the low side is
grounded, you're OK. The good radios have an UnUn built-in.

Snow / Disconnecting Antenna
 

In article .com,
"junius" wrote:

Hello folks,

I've read for many years of how one should always disconnect the
antenna when it snows. I'm curious, though, as to why snow is
something that would be of particular concern. I guess the concern
over thunderstorms seems straightforward enough...that lightning
strikes, even at some distance away, can result in significant,
potentially damaging static voltages in the antenna. But does/can
atmospheric conditions during a snow result in this same sort of
phenomenon?

As an aside, related or perhaps not, in the areas of the U.S. in which
I've resided, I've only lived through one thunder-snow.

Anyway, just wondering about that.

Snow flakes can and do carry static charge. This is transferred to the
wire and voltage builds up until discharged.

--
Telamon
Ventura, California

Snow / Disconnecting Antenna
 

Telamon,

Why Do Snow Flakes (Frozen Water) Carry a Static Electrical
Charge and Normal Rain Drops (Liquid Water) Do Not ? ? ?

Could It Be . . .
Shape and Size of the Structures while they are passing through
the Air and the Ease of Moluculer Movement (or lack of same)
within the Structures while they are passing through the Air.

Environmental ESD, Part I: The Atmospheric Electric Circuit
- by - Niels Jonassen "Mr. Static"
http://www.ce-mag.com/archive/02/07/mrstatic.html
An Understanding of the Atmospheric Electric Circuit
provides an insight into the processes underlying ESD events.

Environmental ESD, Part II: Thunderstorms and Lightning Discharges
- by - Niels Jonassen "Mr. Static"
http://www.ce-mag.com/archive/02/09/mrstatic.html
The Properties of ThunderStorms and Lightning Discharges as
related to the Atmospheric Electric Circuit are discussed.

Mr. Static - Index = http://www.ce-mag.com/mrstatic.html
The On-Line Resource for Static-Related Compliance Issues


someone / anyone enlighten me more - i want to know ~ RHF

Snow / Disconnecting Antenna
 

I didn't know snow builds static,untill somebody mentioned it in this
news group.I learn something every day.
cuhulin

Snow / Disconnecting Antenna
 

Telamon - TYVM - Nice Reply - I Give It 5-Stars ~ RHF

Snow / Disconnecting Antenna
 

On 11 Feb 2006 12:22:41 -0800, "junius" wrote:

Thanks for the expanded explanation, Telamon!

So basically, then, one is fine doing shortwave listening during a snow
storm, provided that one is not using an outdoor antenna that is
exposed to the falling snow (or alternatively -as per David's post- if
one has an outdoor antenna which employs an unbalanced transformer and
the low side is grounded).

All antennas should have a path to DC ground. This is my religion,
being a former broadcast engineer on the Gulf Coast. Lots of ground,
lots of MOVs, equals less sleep interrupted by thunderstorms.

Snow / Disconnecting Antenna
 

On Sat, 11 Feb 2006 16:25:23 -0600, wrote:

What part of the Gulf Coast?
cuhulin

Upper Texas.

Snow / Disconnecting Antenna
 

In article . com,
"junius" wrote:

Thanks for the expanded explanation, Telamon!

So basically, then, one is fine doing shortwave listening during a snow
storm, provided that one is not using an outdoor antenna that is
exposed to the falling snow (or alternatively -as per David's post- if
one has an outdoor antenna which employs an unbalanced transformer and
the low side is grounded).

You have two options I can think of to mitigate the static problem.

1. A voltage transformer of some type not a current type.
2. Some type of static discharge unit on the coax lead-in to an outdoor
ground stake.

#1 You can get more signal out of the wire by using the transformer so
this solves two different problems of improving the wire reception
performance and blocking static electricity from reaching the radio
input at the same time.

Technically the amount of static protection provided by two windings in
the transformer is called voltage creep-age. This factor goes up with
distance and the insulative value (voltage breakdown) on the wires used
to make the transformer.

The wire antenna and outside ground stake are connected to the ends of
the primary winding. The coax lead-in shield and center conductors are
connected to the ends of the secondary winding. The coupling between the
windings is magnetic only and with the wire insulation the static
electricity can't cross between them but the signal does magnetically.
The static on the wire goes to the ground stake keeping it at a very low
value, a value far below the insulative value of the transformer wires.

Depending on the wire height above ground and the wire gauge you change
the turns ratio of the windings to accommodate the wires impedance but a
9:1 transformation will do the job in most installations.

#2 This is basically an air gap from center conductor to ground where
the coax shield is directly connect to ground at an outside ground
stake. Usually the device is a kind of tube filled with a gas that
squelches the gap current after the voltage spike so it doesn't stay
permanently shorted. The voltage will rise to the gap value, the tube
will conduct for a period of time sufficient to drain the charge to a
value below the gap value and then the current to ground is stopped.

I favor #1 (blocking) because the transformation of the wire impedance
is useful by itself and 0 volts of the DC static voltage is all that
ever reaches the radio input. #2 (shunting) will allow the DC static
voltage to reach the radio input to the specified gap value of the
static suppresser that is in use and the suppresser supplies no other
benefit by its inclusion in the antenna system.

--
Telamon
Ventura, California

Snow / Disconnecting Antenna
 

Upper Texas? that's where the Atlantic Ocean is.
cuhulin