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

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

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)

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?

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

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 -

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.

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 -

On 8/2/2011 8:24 AM, 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?


An interesting observation. You'd have to go look at the history of
that article in the code to find out why. It's not impossible that they
were following standard commercial installation practice/recommendations
back in the day, and it was "acceptable power loss" related. (the wire
sizing for AC branch circuits is based on tolerating a 2% voltage drop,
not overheating of the conductor)

On 7/31/2011 3:09 PM, John S wrote:
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

Free at the library, and at various sites for California Title 24.
http://rrdocs.nfpa.org/rrserver/brow...tricalCode2010

And the sections on antennas are widely quoted. I don't think cost of a
copy of the code is why hams don't follow it.

here you go:
II Receiving Equipment - Antenna Systems
Article 810.16 Size of Wire-Strung Antenna -Receiving Station
(A) Size of Antenna Conductors. Outdoor antenna conductors for
receiving stations shall be of a size not less than given in Table 810.16(A)
Table 810.16(A) Size of Receiving Station Outdoor Antenna Conductors
Minimum size of Conductors (AWG) where Maximum Open Span Length is:
Less than 11m 11m to 45m Over 45m
Al Alloy, hard
drawn copper 19 14 12

Cu Clad Steel,
Bronze, other high
strength matl 20 17 14

Or
III Amateur Transmitting and Receiving Stations - Antenna Systems
less than 45 m over 45 m
Hard drawn copper AWG 14 AWG 10
CCS, bronze, etc. AWG 14 AWG 12