"Highland Ham" wrote in message
...
Michael Coslo wrote:
Highland Ham wrote:
In the US, copper water pipe comes in three grades, K, L and M, in
increasing order of quality/cost. We also have "DWV" copper pipe for
drains
and vents (non-pressure applications, I guess). Same over there?
================
Question : Would any of the above grades of copper pipe affect the RF
radiation characteristics of the antenna ?


The answer depends upon whether you mean an effect that is noticible
or not. ;^)
============================================
My question is directed to the different grades K,L and M ,whether any
particular grade would give better RF radiation performance .
It could be that the grade with the highest copper content gives the best
performance ,although I doubt that it will be measurable.
J-pole antennas I am familiar with are all made of aluminium,but copper is
of course better long term in an outdoor environment and electrical
contacts are reliable following soldering.

Frank GM0CSZ / KN6WH


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I have made emergency VHF antennas from a hunk of 2x4 and two pieces of 3/8"
aluminum grounding wire. Then I get a piece of mini8x (any 50 ohm coax will
do), skin back the insulation until I have enough material to solder an
alligator clip onto the center lead and one onto the equi-distant piece of
shielding. I then drill two 3/8's diameter holes approximately 4" apart in
the hunk of 2x4. Calculate the 1/2 wavelenth of the band you wish to operate
on. Cut a hunk of 3/8" grounding wire to that length, straighten and then
insert it into one of the previously drilled 3/8" holes in the hunk of 2x4.
Cut another hunk of 3/8" aluminum grounding wire to exactly one half the
length of the first piece and then insert it into the remaining hole in the
2x4.

Connect the coax to your VHF rig via the PL-259 that you soldered onto the
end opposite the end with the alligator clips and plug it into your rig.
Clip the alligator clip fastened to the center coax conductor to the longest
piece of 3/8" wire (half wavelength) and the shield connected alligator clip
to the shorter wire protruding from the 2x4. Adjust the height of the two
clips (should be even with one another) for the lowest SWR. Voila! You're on
the air with an instant J-Pole antenna.

All of this can be enclosed in PVC plastic piping for use outdoors.


Ed, NM2K