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Old July 31st 11, 09:32 PM posted to rec.radio.amateur.antenna
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Default Using speaker wire for a dipole

Anyone have experience making a dipole from 18 gauge speaker wire? I
have a whole lot of it lying around the house, and was wondering if I
could put it to some good use.

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Old July 31st 11, 11:09 PM posted to rec.radio.amateur.antenna
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Default Using speaker wire for a dipole

On 7/31/2011 4:02 PM, Owen Duffy wrote:

Owen

PS: hams universally ignore the guidance of NFPA 70 which makes
recommendation on conductors for antennas.


Maybe because NFPA 70 costs $150 US?

John
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Old July 31st 11, 11:26 PM posted to rec.radio.amateur.antenna
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Default Using speaker wire for a dipole

John S wrote in :


Maybe because NFPA 70 costs $150 US?


Yes, standards are expensive things and it is a frustration when
researching.

Anyway, NFPA makes recommendation on the wires for ham antennas
specifically, and it may be binding in some places.

I suspect the reason for ignoring it is that the advice is unaccepable
to most hams.

That said, it does seem over the top in some areas, and is hardly
comprehensive in its thinking. For example, the prescription for
feedlines seems to not be aware of the existence and use of coax.

I guess it is these gaps that give critics the basis for arguing against
the whole thing.

Anyway, in respect of antenna wires, it does not 'permit' annealled
copper or other low strength materials, and it 'requires' a minimum
conductor diameter of #14 for up to 150' span.

They may have had in mind the risk to persons and property where low
strength conductor are broken in high wind and make contact with power
lines.

Owen
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Old August 1st 11, 02:07 AM posted to rec.radio.amateur.antenna
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Default Using speaker wire for a dipole



"KD2AIP" wrote in message
...

Anyone have experience making a dipole from 18 gauge speaker wire? I
have a whole lot of it lying around the house, and was wondering if I
could put it to some good use.

-
Should work fine with the caveats of added weight from the insulation, etc.

Some years ago, there was a QST article written by a ham who built a 20
meter quad using insulated wire. He found that it changed the expected
resonance, IIRC downward. So you may have to play with the length a little
more than expected from the calculated lengths.



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Old August 1st 11, 04:51 AM posted to rec.radio.amateur.antenna
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Default Using speaker wire for a dipole

This topic is likely to spur a lot of discussion. For a while two of us
were using zip cord
which in itself is frequently used as speaker wire.

Mine was strung across and somewhat around the back yard to I could work 75m
and up with a tuner.
George, VE6VA surprised me when I noticed he had a feedling going out of his
shack -- it was cloth covered line cord! Both of us had lots of fun on the
bands.
I should add that my transmission line and both halves of the dipole were
made
from one piece of line cord/speaker wire -- I just brought the end of the
transmission
line into a plastic wire-tie, and fed the lines around the yard, using a
couple
tree branches and a small pole on the garage. The other dipole half was
just
long enough to reach the front of the house where it was then suspended
by a small lilac bush and a tall fir tree. End insulators were just bits of
scrap plastic and both ends were suspended with a long string of short
and medium pieces tied together! From experience I think that I can
generalize that you matter how much nylon line a ham buys, in time
it degenerates into a wide assortment of randomly short lengths, none
of which alone can serve any purpose!

After 50 plus years of hamming fun, I have come to the conclusion that
anything with a little metal in it will serve as an antenna if you hook it
up in the right manner. It has truly surprised me over the years just
how little antenna I had, and how far it was getting out.

Some antenna's will work better than others, and eventually every
ham, whose expectations eventually approch infinity will want to try
a 'better antenna'. Aside from collecting materials, and it doesn't
take much to make a dipole, once you know where you can string
your wires, it's easy to try a variety of antennas. In the long run
you will probably find that a half wave dipole will do the best,
and if you can drop the ends, changing it into an inverted-Vee
you will have near omnidirectional operation on the higher bands.

Antennas, discussed here have impedance, Jx+something or other, specific
lengths,
and so many rules that your life as a ham will make you miserable
when you dare approach the shack. Throw an arrow into the
air (throw an antenna into the air), suspend it here and there, and
then see if it works. If it does, Great! -- If it doesn't -- well, try
something else. Chances are you will have so much fun that
you postpone tidying up the knots, but some of those things
stay up for ever until their age approaches that of a typical
old fogie antenna fussy, Smith chart interpreter, know-it-
all hams, like most of us here

Antennas are funny people!

Get the wire up, have a ball!

Irv
VE6BP, Calgary

Political correctness is a doctrine, fostered by a delusional, illogical
minority, and rapidly promoted by an unscrupulous mainstream media, which
holds forth the proposition that it is entirely possible to pick up a piece
of poop by the clean end.


"KD2AIP" wrote in message
...
Anyone have experience making a dipole from 18 gauge speaker wire? I
have a whole lot of it lying around the house, and was wondering if I
could put it to some good use.



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Old August 1st 11, 06:06 AM posted to rec.radio.amateur.antenna
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Default Using speaker wire for a dipole


"KD2AIP" wrote in message
...
Anyone have experience making a dipole from 18 gauge speaker wire? I
have a whole lot of it lying around the house, and was wondering if I
could put it to some good use.


My favored gauges are 12 and 14. I took a dipole I modeled in EZNEC
(Evaluation Version) and changed from 12 gauge to 18 gauge. The behavior of
the antenna changed dramatically.

No, I'm kidding. EZNEC showed insignificant shifts in VSWR and gain at
optimum takeoff angle. You apparently face only mechanical issues. If the
wire parts when you pull it up, you'll need to connect it to a stout span
line.

I have two 20m dipoles hanging, one with a span line and one free-hanging.
They were both temporary ... last year.

"Sal"
Champion Procrastinator


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Old August 1st 11, 06:58 AM posted to rec.radio.amateur.antenna
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Default Using speaker wire for a dipole

"Irv Finkleman" wrote in
:

....
I should add that my transmission line and both halves of the dipole
were made
from one piece of line cord/speaker wire


Yes, I freely admit that I was a sucker who implemented that type of
antenna system on the advice of mentors.

Since learning those j thingies that you deride, I have come to learn
enough to quantify the sacrifice in performance.

Yes, it 'works', whatever that means!

One way to make sure newbies never challenge you is to lead them down
the same misdirected paths as yourself in the hope that they never catch
up.

Whilst there are those who glibly recite that "any antenna is better
than no antenna at all", it is also true that you might work stations on
any antenna, just you will work more on a better antenna.

I know that dumbing down the hobby is the fashionable trend, deride
those who see ham radio as an essentially techical exploit as the new
age ham is embarking on a social experience, just the connectivity is
several orders of magnitude below those of most social network
appliances. Whilst cutting edge hams are breaking DX records with things
like WSPR at 0.5bps, kids are socialising on mobile phones at greater
than 10Mbps.

When you take the passion for understanding the technology out of ham
radio, it just doesn't compete.

Owen
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Old August 1st 11, 07:02 AM posted to rec.radio.amateur.antenna
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Default Using speaker wire for a dipole

"Sal" wrote in :

I have two 20m dipoles hanging, one with a span line and one
free-hanging. They were both temporary ... last year.


Sal, there would be those who would chide you that such an antenna
obviously wasn't big enough... in the sense that "if it didn't blow down
last season, it wasn't big enough".

And we wonder why so many housing block have restictive covenants that are
not ham friendly. We might just have bought that on ourselves to some
extent.

Owen
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Old August 2nd 11, 01:42 AM posted to rec.radio.amateur.antenna
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Default Using speaker wire for a dipole

On 7/31/2011 2:02 PM, Owen Duffy wrote:


PS: hams universally ignore the guidance of NFPA 70 which makes
recommendation on conductors for antennas.


Are you saying the electrical code is sort of like the pirate code? more
guidelines than actual requirements?

I think the way that hams can rationalize it is that most wire antennas
(particularly those made with fine wire) are, by their nature,
"temporary installations". The finer the wire, the more temporary.


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