Given the on going OT flame feast I decided to enliven everyone's day
by posting something actually on topic.

Many, maybe most, or us have a random wire for an antenna.

Many may have wondered what the impedance of that wire might be.

http://www.microwaves101.com/encyclopedia/calwground.cfm

Enter 1 for the Permitivity. While insulation will have a very minor
effect, the air surrounding the antenna will swamp the insulations
contribution.

Wire size can be found at
http://www.tfcbooks.com/referenc/wiresize.htm.

Because most real world wires sag, I pick the highest point and lowest
point
and average them.

Tests with a receiver and a RF noise bridge shows measured values very
close
to the calculated values.

Terry

VERY useful and refreshingly on-topic post! Thank you!


wrote in message
oups.com...
Given the on going OT flame feast I decided to enliven everyone's day
by posting something actually on topic.

Many, maybe most, or us have a random wire for an antenna.

Many may have wondered what the impedance of that wire might be.

http://www.microwaves101.com/encyclopedia/calwground.cfm

Enter 1 for the Permitivity. While insulation will have a very minor
effect, the air surrounding the antenna will swamp the insulations
contribution.

Wire size can be found at
http://www.tfcbooks.com/referenc/wiresize.htm.

Because most real world wires sag, I pick the highest point and lowest
point
and average them.

Tests with a receiver and a RF noise bridge shows measured values very
close
to the calculated values.

Terry

In article .com,
wrote:

Given the on going OT flame feast I decided to enliven everyone's day
by posting something actually on topic.

Many, maybe most, or us have a random wire for an antenna.

Many may have wondered what the impedance of that wire might be.

http://www.microwaves101.com/encyclopedia/calwground.cfm

Enter 1 for the Permitivity. While insulation will have a very minor
effect, the air surrounding the antenna will swamp the insulations
contribution.

Wire size can be found at
http://www.tfcbooks.com/referenc/wiresize.htm.

Because most real world wires sag, I pick the highest point and
lowest point and average them.

Tests with a receiver and a RF noise bridge shows measured values
very close to the calculated values.

Impedance of a wire over ground.

Z= 138 * log (4* height / wire diameter)

--
Telamon
Ventura, California

Is it always the same? What if the ground is dry,or wet? How about the
lenght of the wire,bare wire or covered wire? Laying directly on the
ground or above the ground?
cuhulin

wrote:
Is it always the same? What if the ground is dry,or wet? How about the
lenght of the wire,bare wire or covered wire? Laying directly on the
ground or above the ground?
cuhulin


Laying on the ground?

If:

Z= 138 * log (4* height / wire diameter)

Then, with a wire on the ground having a zero height,

Z= 138 * log (4*zero / wire diameter) =

Z= 138 * log (zero/ wire diameter) =

Z= 138 * log (zero)

darn...let's try:

Z= 138 * log (http://www.cognigencorp.com/nonmem/nm/99jun101996.html)


and there it all falls apart again, much like the antenna, which
obviously also fell apart. It was obviously not strong enough to let
dxAce lynch himself.



mike










mike

I admit I am dumb about such thingys.Like the auld saying goes
though,There is no such thing as a dumb question.
cuhulin,isn't so smart after all

I sure am humble though,,, and I like them cute Canadian Gurrlz. smile
cuhulin