I am getting back to the HF bands after some 20 years 'rest'. What is the
best type of wire to use for long wire antennas? The wire will be under some
tension to keep it above some local trees!

-----------------------------------------
You have hobbies. I have hobbies.
Chances are I have one that you don't.
I'll leave it up to you to decide!
http://www.flightsimulatorandhobbies.com/
-----------------------------------------

"Best" has a number of different definitions depending on the particular
situation. If you want wire that'll never stretch or break and will take
a lot of tension, Copperweld is hard to beat. It's springy and a
nuisance to work with, though.

Roy Lewallen, W7EL

JERD wrote:
I am getting back to the HF bands after some 20 years 'rest'. What is the
best type of wire to use for long wire antennas? The wire will be under some
tension to keep it above some local trees!

-----------------------------------------
You have hobbies. I have hobbies.
Chances are I have one that you don't.
I'll leave it up to you to decide!
http://www.flightsimulatorandhobbies.com/
-----------------------------------------

Since '70, I've had good luck with stranded hard-drawn copper for up to
lambda/2 dipole on 80m (no experience with longer spans). The latest stuff
I've been using is 12ga (268 strand) hard-drawn for a single wire 80m dipole
and now a cage dipole for 80m using 14ga from Davis RF
(http://www.davisrf.com/). They also offer porcelain compression
insulators, so a broken insulator won't bring your antenna down (and leave
the end of the wire dangling in the trees). Nice folks to deal with, too.
Bryan WA7PRC

Roy Lewallen wrote:
"Best" has a number of different definitions depending on the particular
situation. If you want wire that'll never stretch or break and will take
a lot of tension, Copperweld is hard to beat. It's springy and a
nuisance to work with, though.

Roy Lewallen, W7EL

JERD wrote:
I am getting back to the HF bands after some 20 years 'rest'. What is
the
best type of wire to use for long wire antennas? The wire will be under
some
tension to keep it above some local trees!

Roy Lewallen wrote:
"Best" has a number of different definitions depending on the particular
situation. If you want wire that'll never stretch or break and will take
a lot of tension, Copperweld is hard to beat. It's springy and a
nuisance to work with, though.

In this day of high copper prices, my two favorite antenna wires are
free wire and cheap wire. We had a fellow near here who, until the past
year or so, was selling 500' spools of insulated #14 or #12 for five or
six bucks per spool. I ran better than ten spools for my 80 and 160m
inverted L's and stocked up for inverted vee wire.

A less expensive alternative might be the hardened aluminum fence wire
in the larger diameters, allowing for some means of preventing the
corrosion from copper to aluminum at the feedpoint.

Dave Heil K8MN

Bob Miller wrote:
Also, I've used the 500' spools at Lowe's Home Improvement; they're in
the $30 or $40 range now, I believe.

Good grief - last time I bought some for radials
they were half that price.
--
73, Cecil http://www.w5dxp.com

"JERD" wrote in
:

I am getting back to the HF bands after some 20 years 'rest'. What is
the best type of wire to use for long wire antennas? The wire will be
under some tension to keep it above some local trees!


You might find the article 'Sufficient sag for wire antenna spans for
wind survival' at http://www.vk1od.net/rigging/sag.htm of interest. You
might wonder why annealed copper in almost any form (enamelled, or PVC
insulated, especially PVC insulated) is so popular.

I endorse Roy's support for Copperweld, but you will not find it readily
available in Oz. There are a few suppliers of HDC (ATN and Discount
Cables come to mind). Stainless steel (2mm dia) is used in some of the
commercial antennas (eg Bushcomm), but you need to consider whether the
additional loss is an issue for the specific antenna.

BTW, MIG wire (copper plated steel wire) is not Copperweld, Copperweld
has a substantial copper thickness (eg 30%, depending on the grade) which
is chosen to be at least several skin depths in thickess so that the RF
resistance is similar to copper, but the strength comes largely from the
copper core. Hams promoting 0.8mm MIG wire (as they do here) are on the
wrong track, it is a grossly inferior product, you are much better off
with galvanised fence wire than MIG wire.

Speaking of which, heavy galvanised steel fence wire (say 1.6mm for
shorter spans) is not all that poor, but beware of newer fence wires
which have thinner zinc, or worse the polymer coated wires with have an
extremely thin layer of ZAl covered by the polymer coating. Though any of
these are going to be better than rusty MIG wire.

Owen

Owen Duffy wrote:
"JERD" wrote in
:


I am getting back to the HF bands after some 20 years 'rest'. What is
the best type of wire to use for long wire antennas? The wire will be
under some tension to keep it above some local trees!



You might find the article 'Sufficient sag for wire antenna spans for
wind survival' at http://www.vk1od.net/rigging/sag.htm of interest. You
might wonder why annealed copper in almost any form (enamelled, or PVC
insulated, especially PVC insulated) is so popular.

I endorse Roy's support for Copperweld, but you will not find it readily
available in Oz. There are a few suppliers of HDC (ATN and Discount
Cables come to mind). Stainless steel (2mm dia) is used in some of the
commercial antennas (eg Bushcomm), but you need to consider whether the
additional loss is an issue for the specific antenna.

BTW, MIG wire (copper plated steel wire) is not Copperweld, Copperweld
has a substantial copper thickness (eg 30%, depending on the grade) which
is chosen to be at least several skin depths in thickess so that the RF
resistance is similar to copper, but the strength comes largely from the
copper core.

I think you mean the strength comes from the steel core?

FWIW, when they say 30%, that means that the wire has 30% of the
conductivity of the same diameter copper wire, not that it is 30%
copper. You have to look in the mfrs tables to see what the cladding
thickness is.


Odd that there aren't suppliers in Australia.. Maybe because there isn't
an existing telegraph/telephone cable infrastructure in rural areas? In
the U.S., there were and still are millions of miles of the stuff
installed before carrier telephony, coax, optical fibers, etc became
common. And, it's still used for MV power distribution, much of which
is still above ground.

Jim Lux wrote in
:

Owen Duffy wrote:
....
thickess so that the RF resistance is similar to copper, but the
strength comes largely from the copper core.

I think you mean the strength comes from the steel core?


Yes, thanks Jim.

FWIW, when they say 30%, that means that the wire has 30% of the
conductivity of the same diameter copper wire, not that it is 30%
copper. You have to look in the mfrs tables to see what the cladding
thickness is.

Yes, IIRC it is rated on its 60Hz resistance as a competitor to HDC
aerial power applications.

Odd that there aren't suppliers in Australia.. Maybe because there
isn't an existing telegraph/telephone cable infrastructure in rural
areas? In the U.S., there were and still are millions of miles of the
stuff installed before carrier telephony, coax, optical fibers, etc
became common. And, it's still used for MV power distribution, much
of which is still above ground.

Yes, pity that. Remember that we had a monopolistic telecomms market
until ~1995. I did scavenge a littel copper clad steel (3.2mm) on one
occasion, but most aerial phone cables were HDC.

My article mentions an aluminium clad HT steel fencewire which looks
interesting for antennas, but it does bring the issue of corrosion
resistance connection to aluminium. Unfortunately, this wire is only
available in 1km rolls.

It turns out that HDC is probably the best available wire in Oz (JERD is
a VK5), but gal fencewire or stainless steel are eminently suited to
lossy antennas like TTFD etc.

I do remember Roy discussing the resistivity of rust, but I don't recall
figures... does anyone have any figures for the resistivity of the rust
coating on a rusted steel wire? I guess its permeability is also relevant
to RF resistance.

Owen

Owen Duffy wrote:
. . .
I do remember Roy discussing the resistivity of rust, but I don't recall
figures... does anyone have any figures for the resistivity of the rust
coating on a rusted steel wire? I guess its permeability is also relevant
to RF resistance.

No, I don't believe I've mentioned rust, although I've commented on
copper and silver salts a couple of times. I wouldn't try to guess what
the resistivity of rust might be, since it would surely vary a great
deal with the amount of hydration.

A highly resistive coating won't add appreciable loss, nor will a highly
conductive one. There's an in-between range which will. But keep in mind
that the skin depth is inversely proportional to the square root of the
conductivity, so a thick coating with twice the DC resistivity will
increase the RF resistivity only by a factor of about 1.4.

The real problem with thinly plated steel wire is that if and when the
coating corrodes off -- or if it's too thin to begin with -- the current
ends up flowing in the steel itself. Steel is terribly lossy stuff at RF
chiefly because of its permeability, not that its conductivity is all
that hot to begin with. Skin depth is inversely proportional to the
square root of permeability, so a steel with permeability of 100 has
1/10 the skin depth it otherwise would, resulting in 10 times the RF
resistance. If you consider half wavelength antennas at various
frequencies all made from the same size wire, you find that the loss
gets worse as frequency decreases. So it's often more of a problem on
the lower frequency bands.

Some stainless steels are magnetic and some aren't. Magnetic ones are
much lossier at RF for the same reason as ordinary steel.

Roy Lewallen, W7EL

The 'best' wire for long antennas is whatever you happen to have
the most of that will support it's own weight. After that, it's more
a matter of what color insulation you think is nice. And after that,
it's whatever you can convince yourself that you can afford. Have
several pieces of different wire size/type? If they will support
their weight, splice the @#$ things! Paint it all pink. Pink works
very well for antennas.
- 'Doc