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Tune Around! Topics For
Technicians! |
THE KL7JR 5 BAND
PIPE VERTICAL That's 20,
17, 15, 12 and 10 meters!
It is
designed for portability for field days, camping, or permanent
installation, cost, and to achieve at least 1/2 wavelength
on the
WARC bands.
You will not
believe it's performance until you try
it!
Material List: 1 ea 10 foot
3/4 inch EMT conduit
1 ea 10 foot
1/2 inch EMT conduit
1 ea 102 inch
CB whip
3 each hose
clamps
Assorted
bolts, nuts from junk box
Insulating
support for base of antenna (3 inch)
Assorted # 12
wire or plumbers tape for radial ring
4 to 6 or
more radials + - 16 feet long from wire for each
radial
NOTES and BUILDING TIPS: (See
drawing above)
It is assumed that
you will use a good tuner with this antenna and low loss coax with short
runs. Cheap RG-58 types of coax is not recommended. As designed, the swr
will be high on the bands since this is a non-resonante antenna so an
external tuner will be needed. The internal tuner on your radio may
not have enough range to work properly.
Slide 1/2 inch EMT pipe into 3/4
inch EMT pipe 18 inches
Drill and bolt or pin above
sections together. (Assure that you have good electrical and mechanical
connections between all sections)
Hose clamp the CB whip on the
outside surface of the 1/2 inch EMT section assuring that it overlaps 12
inches with the 1/2 EMT for a total length of all 3 sections for a
total of 26 feet top to bottom.
Use some form of insulator on the
base to isolate the antenna from ground.
Build your ground and radial ring
from about 12 inches of wire and lay around the base of the
antenna.
Atttach the radials, as many as
you can lay out.
Attach the center conductor of
your coax to the base of the antenna and the shield to the ground ring
where radials are attached.
Raise antenna (See Antenna Raiser
Project) and support....you may need to guy it with rope if
windy.
March,
2011 "I wanted to thank you for your article about the 5 band pipe vertical that I found by accident on hamuniverse.com. I have just returned to the radio after a very long absence and have been making do with a short dipole on the roof (CCRs). While it has been good for casual things, it really lacks for DXing and contests, which are both things I want to pursue more seriously in the future. A week ago I decided to try to make a vertical that I could "sneak up" in my backyard for contests like this weekend's ARRL Int'l DX SSB. Yours was the plan I used. Spent a day gathering parts, and another putting it together. Finished it Friday morning, contest started at 5PM Idaho time. My wife helped me lift it onto the quickie mount I made in the backyard. We guyed it because we were expecting a storm Friday night. I set out 10ea 16 foot radials and a couple 32 footers. John, you already know how well it works, but I was taking a gamble... my wife was pretty skeptical about conduit, clamps, a CB whip, and a bunch of wires all over the backyard. But I have to say, the performance was much better than I had hoped. I wasn't able to work the entire contest time so my numbers aren't large by any means, but I ended up with 88QSOs on 4 bands, 11,233 points, and (I think) 28 countries. All continents but Antarctica. What a hoot! 100 watts from Yaesu 450 and an AT-200 tuner. From SW Idaho (not exactly DX paradise hi hi). I wanted you to
know you've added to my enjoyment of the hobby. I'll listen for you
on the
bands.
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