A Home Brew HF Vertical From Copper Pipe
In my younger days on portable island activating adventures,
I used a homebrew multi-banded quarter-wave vertical antenna that was easy
to assemble and disassemble and didn't take up a lot of space in my canoe.
BILL OF MATERIALS 1- 10' length 1/2" copper pipe (top section)
1- 10' length 3/4 inch copper pipe (base)
1- 3/4" male sweat fitting threaded
1- 3/4" female sweat fitting threaded
1- 3/4" by 1/2" reducing coupling threaded
1- 1/2" male sweat fitting threaded
1- 1/2" female sweat fitting threaded
70' #14 or #16 wire
(ground radials) and various nuts, bolts and clamps from the junk box
Now cut both pipe sections in half and solder the appropriate fittings on. (5 foot sections makes for easy portability)
Total cost around $25.00 and two hours to build.
If you've never soldered copper tubing before, perhaps a little help from someone who has; would be nice.
Pipe lengths plus appropriate tip = band of your choice:
PIPE LENGTHS TIP LENGTH BAND
3 @ 5
2 @ 5 feet 36 inches 18 MHz
2 @ 5 feet 12 inches 21 MHz
2 @ 5 feet none 24 MHz
2 @ 5
The same ground radials
were used on all bands.
I used 5 foot lengths only because it packed well in my truck and canoe. You may want to use shorter or longer lengths depending on your situation (ie- instead of one 5 foot length, perhaps you want to go to a more transportable length of 2 at 30 inches long)
To secure the antenna I built an "H frame" structure from 2"
PVC pipe and used 1" PVC for the riser. The H frame breaks down to two
pieces for transporting.
I used heavy duty alligator clamps for both the center coax and braid connection. Since I operate mainly on 20meters, I cut four lengths of wire at 16.5 feet long (1/4 wavelength formula 234 divided by Freq. in MHz) out of #14 insulated wire.
Then bare one end and tie all four together. I used a 1/4" bolt with a couple nuts and washers as the connector.
The alligator clamp on the coax braid clips easily on the 1/4" nut as does the clamp on the center conductor of the coax to the pipe.
I keep the ground radials permanently attached to the PVC H frame with ty-raps and when transporting, I simply coil the wires and stuff in each PVC leg.
When I'm set up, I simply throw out the radials in each direction. I put as many in the water as I can. I'm sure it helps cut down on the "noise" verticals are known for.
Additional tips and notes:
I highly recommend using a tuner with this antenna since background and ground conditions affect SWR and will differ from set up locations and the 24 and 28 MHz lengths are a bit long "electrically speaking".
You may want to cut tips of the correct lengths for 10 and 12 meters.
Also, very important, do not use a wrench to tighten the pipe sections as it's easy to strip the pipe threads! (I only had to do that once!). Hand tighten the copper pipe sections only.
I can honestly admit this antenna is easy to tune on many bands, is not noisy and works DX! 73 and happy hunting! John Reisenauer Jr., KL7JR/KL7USI