On 29 Dec, 15:09, Brian Kelly wrote:
Denno wrote:
Hi. *I have spool of #12 industrial grade tin coated copper strand
wire that I had planned on building a 40 meter vertical loop with.
While scouring the web, I came across a white paper on wire, tubing
and RF compatibility, and it said that tin-coated copper was "somewhat
inferior", but silver coated or pure copper strand were fine for
antenna use. *Contrary to this, I have read in this Newsgroup that tin
or silver coating is a must-have for good RF radiation.

Any views on tin coated copper strand?

Also, where do you all find Copperweld? *It sounds ideal, but I
haven't been able to find it anywhere.

Thanks!

The guy on the other end of the QSO will never be able to tell the
difference between your signals coming from your bare copper wire
antenna and those coming from your tinned copper wire antenna. Tinned
copper wire is much more corrosion-resistant than any form of bare
copper wire and tinned stranded wire is mechanically much more durable
than any form of solid wire when used as antennas.

http://www.boatus.com/boattech/casey/05.htm

A 40M loop made from your #12 tinned stranded wire should serve you
well for a long time so go for it.

My favorite source for all sorts of "ham wires":

http://thewireman.com/index.shtml

The ultimate antenna wire in my view is his #13 'Toughcoated' tinned
stranded 'Copperweld' P/N 531

w3rv

.

If you have time to wait before you work on your antenna
I expect to put an antenna together with #22 tinned solid wire.
I intend to wind my wire on a small diameter plastic tubing
for a sufficient length to slide onto 3/4 of the circumference
leaving the remaining quarter for the wire to stretch to find
a sweet spot. When I have reached required the 3/4 length I will
then continue the winding back to the starting point so that both
feed ponts are close together.It is required that you cut the wire
at the end of the windings so that you can unwind each wire
end one loop and then fasten the ends with a wire nut.
This loosens the turns just enough to make it easier to slide
of the former and onto the hula hoop. Tho I am confident that
a sweet spot will occur with stretching the windings. It
is usefull to add a plate capacitor in series with the feed wire
which allows you to move freely the wide existing bandwidth of the
helical loop of the antenna. The information given will allow
you to procede with building your own if your time is getting short.
If you cannot get sufficient wire length on the former for the
frequency required then by all means run another wire length
over the previous windings before you slide it over the hula hoop.
Hoops were less than $5 at Wallmart the last time I looked and they
have a insert in the tubing that can be removed for the
assembly operation This method of winding gives multiple resonant
points
way closer than you would find using other methods so the addition
of the capacitor if large enough will allow you to cover the other
bands.
If you are smart you can also stretch the windings at will if you
have the need to get closer to alternate frequencies.
As a side issue it is much better if you use solid wire insulated
wire rathe than stranded as this provides much better outward spring
to the loops and some clearance over the hoola hoop during assembly.
The above will give the same radiation as if the wire was stretched
out
but with a minimum of volume used, tho the take of angle rules still
stands with respect to height. Also note that with the radiation
being concentrated at a relative point basis one should not stand
near the hex loop near field for health reasons.
Best regards and good luck.
Art Unwin KB9MZ...xg