Space Miser 80m - available again!
 

Dear all,

I have had permission from Roger Harrison VK2ZRH, the copyright holder of
the 1987 article, to place a copy of the article describing the James
Taylor W2OZH "Space Miser 80m" antenna on my web site.

http://www.pcug.org.au/~prellis/amat...miser-80m.html

Enjoy this modest-sized 80m antenna well suited for city apartment living.

Peter
VK1KEP

Interesting. I can't read the small writing thus the question
He is using coax presumably for the braid to rediate.
I suppose there is some benefit to connecting to its inside???
But the main point I question is the usefullnes of brading to radiate versus
a hardline exterior thus introducing high loss. other than to obtain a nice
looking SWR contour.
Regards
Art


"ELLIS" wrote in message
...
Dear all,

I have had permission from Roger Harrison VK2ZRH, the copyright holder of
the 1987 article, to place a copy of the article describing the James
Taylor W2OZH "Space Miser 80m" antenna on my web site.

http://www.pcug.org.au/~prellis/amat...miser-80m.html

Enjoy this modest-sized 80m antenna well suited for city apartment living.

Peter
VK1KEP

He is using coax presumably for the braid to rediate. I suppose there is some
benefit to connecting to its inside???

Hi Art, I think the braid is connected to the inner conductor in an attempt
to reduce I^2*R losses. In small loops, that is a problem. As far as
increasing radiation, it should have the same effect as changing from a smaller
diameter wire to a larger one. You get less loss, but does the inside of the
smaller wire radiate less than the inside of the larger wire?
One thing that caught my eye was the use of 300 ohm line for the capacitor.
The high voltage high Q cap. is another problem with small loops.


73 Gary N4AST

Well I thought that braided wire was not good to use.
I have heard that braiding for instance must not be used for a grounding
wire presumably because of poor electrical connections where the wires
cross..
Cheers
Art


"JGBOYLES" wrote in message
...
He is using coax presumably for the braid to rediate. I suppose there is
some
benefit to connecting to its inside???

Hi Art, I think the braid is connected to the inner conductor in an
attempt
to reduce I^2*R losses. In small loops, that is a problem. As far as
increasing radiation, it should have the same effect as changing from a
smaller
diameter wire to a larger one. You get less loss, but does the inside of
the
smaller wire radiate less than the inside of the larger wire?
One thing that caught my eye was the use of 300 ohm line for the
capacitor.
The high voltage high Q cap. is another problem with small loops.


73 Gary N4AST

Art,

If this is so, then why is flat braided strapping almost universally used
for grounding straps in vehicles and on industrial installations inside
factories such as production lines or heavy machinery.

I think that the poor electrical contact probably is only a risk if the
braid is exposed to the elements at the points of connection, otherwise it
is OK. Even this can probably be offset by good material choice.

In this instance I would have thought that the choice of braid had more to
do with skin effects, and attempting to get the advantages of extra diameter
without the weight of tubing.

I too like the capacitor, an ingenious solution.

Alec Wood
Interested in Amateur Radio?
Take a look at www.ukradioamateur.org

" Art Unwin KB9MZ" wrote in message
news:5YlPb.93528$sv6.361439@attbi_s52...
Well I thought that braided wire was not good to use.
I have heard that braiding for instance must not be used for a grounding
wire presumably because of poor electrical connections where the wires
cross..
Cheers
Art


"JGBOYLES" wrote in message
...
He is using coax presumably for the braid to rediate. I suppose there
is
some
benefit to connecting to its inside???

Hi Art, I think the braid is connected to the inner conductor in an
attempt
to reduce I^2*R losses. In small loops, that is a problem. As far as
increasing radiation, it should have the same effect as changing from a
smaller
diameter wire to a larger one. You get less loss, but does the inside
of
the
smaller wire radiate less than the inside of the larger wire?
One thing that caught my eye was the use of 300 ohm line for the
capacitor.
The high voltage high Q cap. is another problem with small loops.


73 Gary N4AST