"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

Stainless steel mig welding wire.
Any reason why this won't work as a wire antenna?
Very strong, fairly cheap, but doesn't like kinks.

'I personally think Ray Davies wrote some very good songs.'

http://en.wikipedia.org/wiki/Ray_Davies

wrote in :

Stainless steel mig welding wire.
Any reason why this won't work as a wire antenna?
Very strong, fairly cheap, but doesn't like kinks.

It is small diameter, high resistivity material. If it is magnetic, even
worse.

I depends on its length, and the current flowing.

The article http://vk1od.net/antenna/conductors/loss.htm includes an
example of 316 SS MIG wire.

It is great for stealth antennas, actually doubly so, because not only is
it hard to see, it is hard to hear.


Owen

On 8/2/2011 3:14 AM, wrote:
Stainless steel mig welding wire. Any reason why this won't work as a
wire antenna? Very strong, fairly cheap, but doesn't like kinks.
'I personally think Ray Davies wrote some very good songs.'

http://en.wikipedia.org/wiki/Ray_Davies



SS is a terrible conductor?

I've seen copper clad MIG wire

The real issue is either you're putting that antenna up for the ages, in
which case the NEC (aka NFPA 70) rules are a good sizing guideline; or,
you're putting it up expecting it to fall down sooner or later, in which
case you might as use whatever wire is convenient. For a lot of folks,
buying a 500 foot spool of solid AWG14 wire at the hardware store is a
good compromise.

The real issue is paying attention to "what happens when the wire
breaks" so that you don't wind up inadvertently connecting the 14.4kV MV
distribution line to your hand via the feedline and rig.

On 1 Aug,
Owen Duffy wrote:

"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.

At one time I was working JA from yhe UK using a long wire (about 40m) of 30
swg and 100w. It didn't blow down. however it was only up for a week as a
stealth ant. currently my long wire is 1mm enameled wire, to be less
vu=isibly intrusive (and at current copper prices cheaper) than the
recommended 14 swg (12 awg).

This replaces one which failed a couple of years ago constructed with
thin insulated 5A lighting flex not much more than bell wire that had been up
nearly 30 years.

It's better using a non optimal stealth ant than none at all!

--
BD
Change lycos to yahoo to reply

wrote in message ...
On 1 Aug,
This replaces one which failed a couple of years ago constructed with
thin insulated 5A lighting flex not much more than bell wire that had been
up
nearly 30 years.

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

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?????

No, I don't want to try it. I'm hoping somebody knows. Exciting story even
better.

"Sal"

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

On 8/2/2011 12:24 PM, Sal wrote:
wrote in message ...
On 1 Aug,
This replaces one which failed a couple of years ago constructed with
thin insulated 5A lighting flex not much more than bell wire that had been
up
nearly 30 years.

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

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?????

No, I don't want to try it. I'm hoping somebody knows. Exciting story even
better.

"Sal"



Fusing current is remarkably high for small conductors in free air, even
for 100% duty cycle.

AWG30 (0.01" diameter) = about 10 Amps (Preece equation)

Scales as 1.5 power..
so, going to AWG 20 (.0316") - about 50 amps..

Considering an inverted V dipole with feedpoint Z of 50 ohms, at 1kW,
the current is about 5 amps...

So running that legal limit amp with a brick on the key to your AWG30
stealth antenna won't melt it. (it probably will get pretty warm.. and
corona at the ends might be spectacular)

"Jim Lux" wrote in message
...

Fusing current is remarkably high for small conductors in free air, even
for 100% duty cycle.

AWG30 (0.01" diameter) = about 10 Amps (Preece equation)

Scales as 1.5 power..
so, going to AWG 20 (.0316") - about 50 amps..

Considering an inverted V dipole with feedpoint Z of 50 ohms, at 1kW, the
current is about 5 amps...

So running that legal limit amp with a brick on the key to your AWG30
stealth antenna won't melt it. (it probably will get pretty warm.. and
corona at the ends might be spectacular)


Thank you very much. It's exactly what I was wondering about.

"Sal"

"Owen Duffy" wrote in message
...
"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".

LOL

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.

I'm in a 1960s neighborhood. If anybody bitches about
antennas (nothing, yet), I will invite their attention to the old-fashioned
utility poles & wires that decorate (?) the streets. A few blocks out and a
few years later, they undergrounded the utilities.

Sal