Depending on the type of plastic, physical length of insulated wire will
be
shorter by about 5% for the same resonant frequency vs. bare wire.
Otherwise it will work.

Isn't that true just for VHF and higher frequencies due to the velocity
factor??? I'm fairly certain that doesn't apply for HF.

Jerry
--
Jerry Bransford
To email, remove 'me' from my email address
KC6TAY, PP-ASEL
See the Geezer Jeep at
http://members.cox.net/jerrypb/

"Yuri Blanarovich" wrote in message
...

Jerry,
It applies to any frequency. I don't know if I would
agree with the 5%, but there is a 'shortening' affect if
the conductor is insulated. Is it going to make any real
difference on HF? Nope...
'Doc

"'Doc" wrote in message
it going to make any real
difference on HF? Nope...

Exactly.

Jerry
--
Jerry Bransford
To email, remove 'me' from my email address
KC6TAY, PP-ASEL
See the Geezer Jeep at
http://members.cox.net/jerrypb/

.Is
it going to make any real
difference on HF? Nope...

Exactly.

Jerry


YES, it makes real difference in calculating the proper length. If you are
making, let's say quad for 10m and used EZNEC to calculate the dimensions using
bare wire and then used insulated, you would end up exactly in the middle of CB
band. Nope? Exactly! What?

Is that "any real difference on HF"? Yep, to me is. Using #12 insulated house
copper wire makes exactly 5% difference.

If you do not care where the antenna resonates, than NOPE.
If you care to maintaing performance, pattern, impedance, SWR, than YEP!

If you are making long wire antenna or Beverage, than length and shortening
factor does not matter. But if antenna dimensions are critical then it DOES
matter. As far as performance of insulated wire as a radiator of RF, the effect
is negligible.

Yuri, K3BU

"Yuri Blanarovich" wrote in message
...
.Is
it going to make any real
difference on HF? Nope...

Exactly.

Jerry


YES, it makes real difference in calculating the proper length. If you are
making, let's say quad for 10m and used EZNEC to calculate the dimensions
using
bare wire and then used insulated, you would end up exactly in the middle
of CB
band. Nope? Exactly! What?

Is that "any real difference on HF"? Yep, to me is. Using #12 insulated
house
copper wire makes exactly 5% difference.

If you do not care where the antenna resonates, than NOPE.
If you care to maintaing performance, pattern, impedance, SWR, than YEP!

If you are making long wire antenna or Beverage, than length and
shortening
factor does not matter. But if antenna dimensions are critical then it
DOES
matter. As far as performance of insulated wire as a radiator of RF, the
effect
is negligible.

Yuri, K3BU

Yuri:

You are answering a question that was not asked. Your answer is excellent if
the question we Is it necessary, when calculating element length, to
consider the type of wire used?

If you calculate based on insulated wire and then build it out of bare wire,
it ain't going to work well either.

Assuming one calculates for whatever radiating thingy one is using, it makes
little difference whether that thingy is bare or insulated.

Paul AB0SI

On Wed, 10 Dec 2003 03:05:05 GMT, "
wrote:



Yuri:

You are answering a question that was not asked. Your answer is excellent if
the question we Is it necessary, when calculating element length, to
consider the type of wire used?

If you calculate based on insulated wire and then build it out of bare wire,
it ain't going to work well either.

Assuming one calculates for whatever radiating thingy one is using, it makes
little difference whether that thingy is bare or insulated.

Paul AB0SI


As I understand it, the formulas are based on bare wire, so if you use
insulated, you should take into account a little shortening. That was
the only point being made, I believe.

Bob
k5qwg

As I understand it, the formulas are based on bare wire, so if you use
insulated, you should take into account a little shortening. That was
the only point being made, I believe.

You do want to make it about 5% shorter if you use insulated wire...I built my
full wave 80 meter loop out of 13 gauge copper clad steel wire with a
polyethylene insulator...and it turned out to be too long...I wouldn't figure
the 5% in the equation, you can always trim the extra off.

Steve
kb8viv

Yuri:

You are answering a question that was not asked. Your answer is excellent if
the question we Is it necessary, when calculating element length, to
consider the type of wire used?

If you calculate based on insulated wire and then build it out of bare wire,
it ain't going to work well either.

Assuming one calculates for whatever radiating thingy one is using, it makes
little difference whether that thingy is bare or insulated.

Paul AB0SI

The question was:
"What are pros and cons of using insulated twisted pair wire for wire
antenna projects? (its what I have handy) Comments invited."

Lacking more specific question (didn't say white kind of "wire antenna
projects" resonant or random length), I pointed out "cons" - the effect of
insulation on calculation and modeling the antenna's physical length vs.
electrical. 5% shortening from insulation makes difference if you end up in 10m
ham band or 11m CB band, that is 1.4 MHz difference and that IS significant.

Inquirer can decide for himself if it is important for his case (making
resonant antennas) or not (non resonant, long wire antennas).

If I offended anybody's insulation, then I am sorry :-)

Yuri, K3BU

Yuri,
The reason I can't agree with the 5% thing is that I haven't
measured it, not that the number is correct or not. There is
a difference in length when using insulated/noninsulated wire,
I just can't say exactly what that difference is.
Since any calculation is only going to be approximate
(depending
on how/where the antenna is mounted) trimming is almost always
going
to be required. Since that 'tweaking' would take care of the
difference in insulated/noninsulated wire, I just haven't
bothered
about figuring it. If you have, then good, I don't have a
problem
with that...
'Doc

One who Art calls Doctor writes:

The reason I can't agree with the 5% thing is that I haven't
measured it, not that the number is correct or not. There is
a difference in length when using insulated/noninsulated wire,
I just can't say exactly what that difference is.


I described what it is exactly as I measured it using #12 wire on a 10m 3
element quad. Calculated it with (cheap) EZNEC, I put it up, it ended up smack
in CB band. Calculated the offset, for the red insulation I was using (helps to
emit red hot electrons :-) it was 5%. Adjusted the length and bingo, right
where I wanted it.

Expensive EZNEC using NEC4 can include insulation in calculations and provides
more accurate results and it can be used to show the exact, more-less
difference due to plastic coated wires (according to Roy d'Eznec).

So if you didn't measure it yet, everyone is going to call me a liar? :-)
Maybe I should start taking bets? Haven't you guys learned to put a little
trust in my 45 years of haming, beating contest records and generaly honest and
being mostly right?


Yuri