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Old August 3rd 11, 12:33 AM posted to rec.radio.amateur.antenna
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Default Using speaker wire for a dipole

On 8/2/2011 11:24, John S wrote:
On 8/1/2011 7:52 PM, Jim Lux wrote:
On 7/31/2011 3:26 PM, Owen Duffy wrote:
John 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.


You refer to the "continuously enclosed metallic shield", I suspect.


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.


That is precisely why. (ice loads, too)


NFPA (according to what you posted) requires heavier gauge wire for
transmitting than for receiving. Transmitting makes the wire weigh more?


No but it does make it more dangerous to persons and things on which it
might fall if it breaks.
--
Tom Horne, W3TDH

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Old August 3rd 11, 12:38 AM posted to rec.radio.amateur.antenna
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Default Using speaker wire for a dipole

On Tue, 2 Aug 2011 12:24:10 -0700, "Sal" wrote:

This got me thinking. (Dangerous, yes, but I occasionally risk it.)


It is supposed to be a license requirment.

Since a normal dipole has current max near the center, is there more
localized heating (I-squared-R) nearer the feed point? Seems like it ought
to be. Can you overheat a small wire and make it fail there by melting?????


Yup. The amount of current that would do that is called the "Fuse
Current" which can be dramatically large. Example, wirewrap wire's
fuse current is slightly more than 10 Amps.

73's
Richard Clark, KB7QHC
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Old August 3rd 11, 12:42 AM posted to rec.radio.amateur.antenna
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Default Using speaker wire for a dipole

On 8/1/2011 20:42, Jim Lux wrote:
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.


The National Electric Code limits the use of Temporary installations to
power and lighting conductors.

"ARTICLE 527 Temporary Installations
527.1 Scope.
The provisions of this article apply to temporary electrical power and
lighting installations." Copyright 2002 the National Fire Protection
Association.

--
Tom Horne, W3TDH
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Old August 3rd 11, 12:46 AM posted to rec.radio.amateur.antenna
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Default Using speaker wire for a dipole

On 7/31/2011 23:51, Irv Finkleman wrote:
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.




Because it disrupts the normal flow of the conversation.







Why is top posting on use net considered discourteous?

--
Tom Horne, W3TDH
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Old August 3rd 11, 01:16 AM posted to rec.radio.amateur.antenna
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Default Using speaker wire for a dipole



"Tom Horne" wrote in message ...

On 7/31/2011 16:32, KD2AIP wrote:
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.


Be aware that the National Electric Code (NEC); that is enforced as law
in many jurisdictions; forbids the use of wire that small for aerials of
radio stations. The NEC specifically requires that size fourteen
American Wire Gauge be the minimum size that is used.

snip
-
And of course, there are hams out there who consider the NEC, as applied to
antennas on their own property, to be an irrelevant government overreach.

Naturally, that is not my opinion




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Old August 3rd 11, 04:11 AM posted to rec.radio.amateur.antenna
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Default Using speaker wire for a dipole

On 8/2/2011 7:33 PM, Tom Horne wrote:

No but it does make it more dangerous to persons and things on which it
might fall if it breaks.


Come on, Guys!

While it's a great idea to follow every official code and
reccomendation, and that no one in their "right mind" would ever
consider anything less than the lowest gauge copperweld wire for their
antenna, the original question is answerable by "Yes, you can make a
serviceable antenna out of speaker wire."

Will it stay up as long as a Copperweld antenna held in place by1/4 inch
thick 100 percent nylon rope?

No it won't.

But it will work. Surprisingly well, in fact.

Let the new guys learn, and throw up antennas that work. As they have to
put up a new one every so often, they will eventually learn about more
long lasting antennas, as well as ones that might have a better pattern,
and other effects that bear on performance.

But the idea that hams are responsible for restrictive covenents (in
reality, Cable television is more responsible for antenna covenants than
anything else) or that the choice of speaker wire is going to
electrocute the neighbors is doing a disservice to the new guys and gals.

I can say this with some conviction because I was one of those noobs
once, and nearly didn't even get on HF because with all the input, I
gave up on putting up an antenna because nothing was good enough. I
didn't have enough space, I didn't have enough height. There just wasn't
any use in getting on the low bands. I needed a separate antenna for
every band because ladder line was awful and traps were bad and every
other option was awful except for some idealized correct antenna, coax
fed, at the proper height.

- 73 de Mike N3LI -



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Old August 3rd 11, 04:20 AM posted to rec.radio.amateur.antenna
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Default Using speaker wire for a dipole

On 8/2/2011 7:42 PM, Tom Horne wrote:

"ARTICLE 527 Temporary Installations
527.1 Scope.
The provisions of this article apply to temporary electrical power and
lighting installations." Copyright 2002 the National Fire Protection
Association.


I have found that the safest option is to not ever put up any antenna
whatsoever, Tom. It's just too dangerous, and gives us unneeded exposure.

Can you ensure that an antenna that is installed to the code
specifications, will not fall down?

Will your code spec prevent you from incurring liability if a wire
antenna falls down and electrocutes a neighbor?

The answer to both questions is "no", BTW.

I find that this entire discussion is pretty amazing when compared to
the original question.

As opposed to electrical code and liability admonitions, perhaps a good
answer is:

"Yes, you can make an adequate antenna from speaker wire. There might be
better options, though."

- 73 de Mike N3LI -
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Old August 3rd 11, 11:23 AM posted to rec.radio.amateur.antenna
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Default Using speaker wire for a dipole

On Tue, 02 Aug 2011 23:11:33 -0400, Mike Coslo rearranged some electrons
to say:


But it will work. Surprisingly well, in fact.


My present HF antenna is a piece of 4-conductor ribbon cable, with 60
feet of each outside conductor pulled off to make a 120 foot dipole, the
rest of the cable being used as a feedline to a balun and thence to a
tuner. Is it ideal? No. But it's good enough to work 45 states so far
on 75m, a few dozen DX contacts on 20 and 40m, etc. Plus, it's nearly
invisible against the side of the house.

During field day, I used a homemade doublet fed with 450 ohm ladder line
to the same tuner, remotely mounted in a waterproof box, I was able to
work 15m and 80m on the same antenna, made a few hundred contacts.
Eventually (when the leaves fall) I plan to replace the ribbon cable
dipole with the doublet and the remote tuner on some tall trees in the
backyard.

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Old August 3rd 11, 02:16 PM posted to rec.radio.amateur.antenna
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Default Using speaker wire for a dipole

Very simply, yes, it can be used for making antennas. If it's strong
enough to hold up it's own weight, and that of the feed line without
stretching unreasonably, then it should do fine. What happens if it
stretches? You shorten it. I think I'd try a larger size for 160
meters and maybe 80 meters, but if it can stand the weight and the
weather, why not?
- 'Doc


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Old August 3rd 11, 09:48 PM posted to rec.radio.amateur.antenna
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Default Using speaker wire for a dipole

Hear! Hear!

I would have been off the air forever if this newsgroup had been
my only source of knowledge. I would have been afraid!
What I didn't know about Jx and SWR didn't make any difference -- I was on
the air and really enjoying the hobby! I didn't even know how to solder
then!

Irv VE6BP (first licenced in '58)

"Mike Coslo" wrote in message
...
On 8/2/2011 7:33 PM, Tom Horne wrote:

No but it does make it more dangerous to persons and things on which it
might fall if it breaks.


Come on, Guys!

While it's a great idea to follow every official code and reccomendation,
and that no one in their "right mind" would ever consider anything less
than the lowest gauge copperweld wire for their antenna, the original
question is answerable by "Yes, you can make a serviceable antenna out of
speaker wire."

Will it stay up as long as a Copperweld antenna held in place by1/4 inch
thick 100 percent nylon rope?

No it won't.

But it will work. Surprisingly well, in fact.

Let the new guys learn, and throw up antennas that work. As they have to
put up a new one every so often, they will eventually learn about more
long lasting antennas, as well as ones that might have a better pattern,
and other effects that bear on performance.

But the idea that hams are responsible for restrictive covenents (in
reality, Cable television is more responsible for antenna covenants than
anything else) or that the choice of speaker wire is going to electrocute
the neighbors is doing a disservice to the new guys and gals.

I can say this with some conviction because I was one of those noobs once,
and nearly didn't even get on HF because with all the input, I gave up on
putting up an antenna because nothing was good enough. I didn't have
enough space, I didn't have enough height. There just wasn't any use in
getting on the low bands. I needed a separate antenna for every band
because ladder line was awful and traps were bad and every other option
was awful except for some idealized correct antenna, coax fed, at the
proper height.

- 73 de Mike N3LI -








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