Step 1. PVC Painting
The antenna is made from three 10 foot sections of readily
available PVC tubing in three diameter sizes: Top Section = 1 inch,
Middle Section = 1 inches, and Bottom Section = 2 inches. To make
this antenna environmentally & stealth friendly, the three PVC
sections were spray-painted green by suspending each 10 foot section
from two pieces of nylon rope between two branches of a convenient
backyard tree. Brown paint would work just as well.
Figures 1 and 2 show a PVC section before and after painting. All
three 10 foot sections were allowed to thoroughly dry before
proceeding (see Figure 3).
Figure 1. PVC Before
Figure 2. PVC After
Figure 3. Painted PVC Pipes
Step 2. Bottom Section: Coax, Antenna and Ground
Refer to figures 4 and 5
below for the following:
The bottom 2 inch PVC section is
prepared for both ground and coax connections by drilling the
necessary mounting holes. A PVC cap is placed on the bottom of the 2
inch diameter PVC tube, and then, using a felt-tip marker, a circle
is drawn around the PVC just above the border between the bottom cap
and PVC section. This "marker" ensures that subsequent drilled holes
will clear the bottom PVC cap.
Coax Connection: The PVC cap is then
removed, and then holes are drilled for the SO-239 connector and 4
attachment screws. The SO-239 hole is centered about 2 inches above
the marker (see Figure 4).
Bottom Antenna Binding Post: One 1/8
inch hole is drilled for the antenna binding post, placed 2 inches
above the marker. A red binding post was used for the antenna
Ground Binding Posts: Two 1/8 inch
holes are drilled for the ground posts, each placed 1 inches above
the marker. Black binding posts were used for ground connections.
Summary: The 3 binding post holes
(i.e., 1 antenna + 2 ground) are placed equidistant from each other
around the PVC section. The antenna post and ground posts are
staggered by about inch to avoid any possibility of shorting (see
Figure 4. SO-239 Connector
Figure 5. Binding Posts & Internal Wiring
Step 3. Wiring: Coax Connector and Antenna Post
One end of a 4 inch piece of #14 wire is soldered to the center
connector of the SO-239. The other end is then soldered to either a
spade or ring lug. The wire is then pushed through the prepared
SO-239 hole in the 2 inch PVC tube, and the SO-239 connector secured
to the PVC tube using only 3 of the 4 mounting holes. The free end
of the insulated wire is connected to the inner section of the red
antenna post using the spade or ring lug. After securing the antenna
post a binding nut, the connection can be soldered (see Figure 5).
Step 4. Wiring: Coax Connector and Ground Post
A 6 inch section of #14 insulated wire is soldered (or crimped)
to spade lugs on both ends.
One end is connected on the outside of the PVC to the remaining
SO-239 screw and secured to the PVC. The other end of the #14 wire
is connected to the closest black ground binding post on the outside
of the PVC.
Inside the PVC, another piece of #14 wire is attached between the
2 ground binding posts.
This essentially connects both ground binding posts and the coax
base together. Check to be sure the antenna and ground connections
inside the PVC are clean and not touching each other. Braided coax,
such as RG-58, can also be used instead of the #14 wire for ground
post connections. At this point, the SO-239 and all binding posts
should be tightened and secured.
For extra strength and protection, the binding posts can also be
glued to the PVC, both inside and outside (see Figure 5)
Step 5. PVC Mast Preparation and Assembly
The Top, Middle, and Bottom sections are assembled using a
high-tech solution: duct tape. I actually used Gorilla Tape10 for
wrapping because it uses two layers of adhesive and two layers of
fabric backing to make it much stronger than standard duct tape.
First, the 1 inch diameter PVC tubing is shortened from 10 feet
to 7 feet 6 inches by cutting off 2 feet 6 inches from one end. Duct
tape is then wrapped around the tubes as follows:
For the Top Section (1 inch diameter tube) = Two wrappings. First
wrap = 2 inches from bottom of tube. Second wrap = from 9 to 11
inches from the bottom of the tube (see Figure 6).
For the Middle Section (1 in diameter tube) = Two wrappings.
First wrap = 2 inches from bottom of tube. Second wrap = from 22 to
24 inches from the bottom of the tube (see Figure 6).
Figure 6. Wrapped With Duct Tape
The 3 PVC sections are then telescoped together. When assembled,
the Middle Section will extend 24 inches into the Bottom Section,
and the Top Section will extend 11 inches into the Middle Section.
Its important to use enough duct tape to ensure a good fit between
the PVC sections.
PVC Sections - Overlap
The next step in PVC assembly is to further secure the "joints"
with a bolt and nut. The lower joint (between the Middle and Bottom
sections) is secured by drilling a inch hole through both PVC
sections about 12 inches from the top of the 2 inch diameter Top PVC
section, and using a 3 inch bolt, nut, and washer to fasten the
The middle joint (between the Middle and Top sections) is secured
by drilling a similar hole, about 6 inches down from the top of the
1 inch diameter Middle PVC section, and using a 2 inch bolt, nut,
and washer to secure the joint.
Top Antenna Binding Post
(Shown above) Similar
to the Bottom antenna post previously mentioned, a Top antenna post
is prepared by drilling a 1/8 inch hole one inch from the top of the
Top PVC section. A red-capped binding post is attached to it, using
a nut and glued to secure it. The helically wound antenna wire will
be connected to this post, which will also be the antenna
to-capacitance hat attachment point.
Step 6. Helically Winding The PVC
With the sections assembled
and fortified, the antenna is ready to be helically wrapped with
wire. As previously mentioned, experimentation with HWVs has shown
that a half wavelength of wire is often needed for quarter wave
resonance, assuming the turns are evenly spaced. At a desired
resonance frequency of 1.825 MHz, 256 feet 5 inches of wire is
required for a 160 meter vertical, using the formula 468/freq. For
this first version of the antenna, I chose #22 insulated wire for
the antenna I had a good supply sitting in the garage.
Using our kitchen table, which measures 5 feet long and a coffee
can with 2 large screws protruding from sides at the top and bottom
180 deg apart (to keep the wire from falling off the can as it was
being wound), my XYL "unwound" the wire from the supply spool, while
I wound it onto the coffee can. 50 times across the kitchen table =
250 feet + an additional 6 feet 5 inches did it. The wire was cut,
adding a few extra inches for experimentation, but keeping the 256
feet 5 inch point marked.
Figure 9. Wire Wrapping
Wrapping begins by first attaching the antenna wire to the Bottom
Antenna Binding Post of the 2 inch PVC section using a spade or ring
solder lug. The wire is then wound from bottom to top, being careful
to keep the "winding pitch" as consistent as possible, and avoiding
the bolts near the two PVC joints. A spacing of about inch seemed to
work well. Wire wrapping is not a difficult step, but does require a
bit of patience. Its best not to rush this part of the project. Duct
tape is helpful here every few feet to keep the windings secure (see
Figure 9). In a later version of this antenna, I hot-glued the
antenna wire to the PVC for even better protection.
The end of the wire at the top of the antenna is then soldered to
a spade or ring tongue and attached to the Top Antenna Binding Post
with the red cap at the top of the 1" PVC section.
Option For Portability: Its possible to make the antenna portable
by cutting the antenna wire at the two PVC joints. Then, after
removing wire insulation, alligator or "quick disconnect" clips are
attached to the antenna wire ends. The antenna can then be pulled
apart, moved, re-telescoped together, and the full antenna wire
length restored by simply connecting the antenna clips together.
Step 7. Top Cap Preparation: Capacitance Hat
There are several designs for a suitable HWV capacitance hat to
provide capacity termination and reduce noise. At first, I chose the
"circular hat" design described by Jack Swinden (W5JCK), where six
12 inch brass rods are spaced equally around a PVC cap, and soldered
together.2 However, I eventually settled on a simpler "square hat"
design using two 36 inch brass rods spaced 90 degrees apart, and
connected together with #14 gauge copper wire.9
Either of these methods work well. The "square hat" design is
The square hat construction begins by drilling four 1/8 inch hole
90 degrees apart in the 1 inch PVC cap, about 1 inch from the
bottom. An additional 1/8 inch hole is drilled next to one of these
holes. The brass rods are inserted into the cap, forming an "X". A
pair of pliers is helpful here, as it will be a snug fit, which is
what you want.
Next, a 6 inch piece of #14 insulated wire is stripped on one
end, and soldered to a spade or ring lug on the other end. The
stripped end is slipped through the remaining 1/8 inch hole and
wrapped securely around the "X" junction of the two brass rods
inside the PVC cap, where everything is securely soldered (see
Figure 10). The brass rods are tied together externally by
connecting them together with #14 gauge bare copper wire in two
places: the tips of the rods and also midway between the rod ends
the and PVC cap. The bare copper wire is soldered to the brass rod
at all 8 intersections, to complete the "square hat" (see Figure
Figure 10. Inside Top PVC
Figure 11. Completed Square
Finally, the PVC cap is attached to the Top Section of the
antenna, and the capacitance wire secured to the Top Antenna Binding
Post using the spade or ring lug. For maximum result, its important
to have a good electrical connection between the antenna wire and
Step 9. Bottom Cap Preparation
The bottom cap is used to support and protect the antenna. A inch
hole was drilled in the center of a piece of scrap plywood (about
one foot square). Another inch hole was drilled in the bottom of the
2 inch PVC cap. The threaded aluminum rod was trimmed to 12
inches,and run through the bottom PVC cap, and then through the
plywood (see Figure 12 below). Nuts and washers were attached on the
threaded rod inside the cap and also on the other side of the
plywood. When tightened, only 2 inches of rod was left inside the
cap, to ensure that the antenna and ground wiring in the bottom
section of the mast would not be disturbed (see Step 2). About 10
inches of threaded rod was left sticking out from the bottom of the
plywood (see Figure 13). The plywood base serves as a stabilizing
platform to ease final installation of the vertical. By gently
standing on it and pushing, you can easily drive the 10 inches of
threaded rod into the ground.
Figure 12. Bottom Cap on Plywood
Figures 13. Showing Threaded Rod and bottom cap
Step 9. Erecting The Antenna
After the PVC sections were bolted together, and completely wire
wrapped, the capacitance hat was attached to the top of the antenna,
including the capacitance wire-to-antenna binding post connection.
The antenna is now ready for final installation (see Figure 14). The
bottom 2 inch PVC cap/plywood base was set in the ground at its
mounting location. Bracing the bottom against the ground, the
antenna was carried to the PVC cap/plywood base and carefully set
into the PVC cap. One person can carry & mount the antenna but
its a bit easier with two folks (see Figure 14 below).
Figure 14. Ready To Erect
Figure 15. Installed and Neighbor Friendly
My QTH required bracing the mast to my back fence and securing it
at the 6 foot point with nylon rope. To keep the vertical,
"vertical", a section of nylon rope was also attached at 12 feet
using a convenient tree limb and the rope secured at ground level.
Final guying/bracing will depend upon your antenna placement.
Radial Wires: This antenna does require some
ground radials. Of course, use as many as your QTH allows. I
started with four 1/4 wavelength ground radials cut for 160 meters
and have expanded that number now to eight, using #16 stranded
insulated wire. Spade lugs are soldered to ground radials which are
then attached to one of the two ground posts. Because of the
geometry of my property, my radials cover only a 180 degree arc but
they work pretty well.
Initial Readings: After attaching a 6
foot piece of 50-Ohm coax, an MFJ 249B antenna analyzer showed
resonance close to 1.790 MHz. The antenna wire was adjusted at the
bottom to bring the resonance closer to 1.830 MHz. Running 500 watts
through this antenna without a tuner showed a 50 KHz bandwidth, with
<2:1 SWR. With a tuner, the antenna can be adjusted anywhere from
1.800 to 1.900 MHz with an SWR under 2:1.
Version 3.0 - Update
After a few months of use, I took down the antenna and decided to
fortify the antenna wire by hot gluing it to the PVC. While on the
ground again, the entire antenna was re-wrapped using 4-conductor
#18 wire stranded wire I had a good supply sitting in the garage. At
each end of the antenna the ends of the 4-conductor wire were
twisted and soldered together before wrapping and attaching to the
Top and Bottom antenna binding posts. I also added two elevated
radials around the fence line
Although I have not done any side-by-side comparisons, this
updated version of the antenna appears to "hear" better, and
feedback on the air tells me that I have a somewhat stronger signal.
However it is not necessary to use 4-conductor wire with this
antenna. A single conductor works just fine, and is easier to wrap
around the PVC tubing.
So how does this Helically Wound Vertical for 160 meters perform?
From the West coast,its a solid performer throughout the North
America. I have worked all 50 states, Canada, and Mexico during the
last year with it, almost all confirmed via LoTW. I was awarded
First Place, Single Operator, Low Power for the Santa Clara Valley
section in the 2007 ARRL 160 Meter contest. In the 2009 CQWW 160
Meter contest, I worked 46 states and 7 countries using 600 watts in
just a few hours of operating. For DX, with limited operating time,
I have worked 30 countries. Overall, this antenna plays well to the
Far East, South Pacific, Eastern Russia, Caribbean and Central/South
America. Europe is the most difficult region to reach from my
location, but thats generally true for most West coast stations.
Am I the loudest signal on the band? No. Can I compete in pileups
with folks having better antennas or higher power? No. But am I
having fun on Topband using a homebrew antenna that generates
memorable QSOs. You bet!
There are some obvious improvements that can be made to increase
overall on-the-air performance with this type of antenna. They
include, among others:
-Installing more ground radials in a full 360 degree pattern
-Using a remote tuner at the antenna feedpoint to reduce coax
-Running legal-limit power
-Adding beverage antennas for improved reception
A Helically Wound Vertical is not "the" perfect antenna for 160
meters, but for a small lot, or where CC&R's are strictly
enforced, this easy-to-build vertical is a good alternative to an
inverted-L or dipole. During the last year, I have helped other hams
around the country get on the air with this HWV design for 160
This unsolicited comment from Armand Sun, K6IP, is typical of the
feedback I've received:
12 "I finally put up the HWV antenna and I'm happy to report that
it works FB. Mine has two feed options: ladder-line or coax. I'm
currently feeding with ladder-line and one elevated radial from
leftover wire on the spool and the results are excellent! It takes a
KW from 1.8 - 1.9 MHz. I painted mine olive drab with black #14 wire
so it's pretty stealthy. I would imagine brown would be good too.
Sometimes the traditional designs just don't blend well with the
existing antenna farm. A Helically Wound Vertical is a good option
for small lots or for those with antenna restrictions. Thanks for
the design. It was fun to build and just what I needed for a Topband
So, no more excuses for Armand -- or Me. Now how about you?
John Miller, K6MM
Published in QST, June 2009, pages 32-36.
1G. Ellingson, WA0WHE. "A Helically Wound Vertical Antenna For
The 75-Meter Band," QST, Jan1972, page 32.
3J. Moraski, "The Rubber Duckie 160 Meter Antenna", HF Antenna
Book, published by CQ Magazine, edited by Bill Orr, W6SAI, 1996, p.
4F. Lee, G3YCC. "A Practical Antenna for 160 Metres"
5A. Wells, G4ERZ. http://topband.blog.cz/0612/a-practical-antenna-for-160m-by-alan-g4erz
6P. Sidwell, M0VEY. http://uk.groups.yahoo.com/group/topband-helical/
7 The ARRL Antenna Book, 21st Edition, 2007, p. 6-38.
8R. J. Edwards, G4FGQ. (a) "Model and Predict Helically Wound
August 2, 1997; (b) "Very Short, Helically Wound, Monopole
May 19, 2006
9 I am especially grateful to Jon Sims, N7ON, for sharing his
ideas and experiences with me. J. Sims, N7ON Personal
communications, January 2006.
10 Gorilla Tape.
11 A downloadable
construction manual is posted on my website here:
12A. Sun, K6IP. Email communication, January 29, 2009. Quoted
Home Depot or Lowes
10' length, 2" diameter schedule 40
10' length, 1-1/2" diameter schedule 40 PVC
10' length, 1"
diameter schedule 40 PVC,
1" diameter PVC end cap,
diameter PVC end cap,
1/4" x 3 1/4" threaded bolt, nut, washer
1/4" x 2 3/4" threaded bolt, nut, washer
1/4" x 1 foot
threaded aluminum rod,
3 foot length brass rods (2
4 1/4" diameter nuts, 4 1/4" diameter washers,
Rust-Oleum PVC Spray Paint (dark green or brown)
2 packets, multipurpose posts,
1 packet, crimp-on spade or
1 packet, alligator clips
500 foot roll insulated stranded wire (you can use 14, 16, or 18
Roll of your favorite ground wire for radials (insulated or
Duct tape or Gorilla tape (2" wide)
SO-239 chassis mount coax socket + mounting screws/nuts
Soldering iron, solder, glue/glue gun, hacksaw, drill, 1/8" drill
bit, 1/4" drill bit, felt-tip marker
Biographical Sketch of author:
John Miller, K6MM
John Miller, K6MM, is the President of the Northern California
Contest Club, which sponsors the California QSO Party every October.
He was first licensed in 1958 as WV2BQJ in Syracuse, NY. His first
station was a Heathkit DX-40 and Hallicrafters SX-99 receiver, with
an end-fed long wire. He has also held callsigns in Ohio(WB8CHZ),
Pennsylvania (WA3VTM), and California (WA6OMA, KE6MI).
John recently retired after careers in research, marketing, and
sales in the pharmaceutical, medical diagnostics, and human
resources industry. He holds BS and MS degrees from Syracuse
University, an MBA from Pepperdine University and a PhD in chemistry
from Case Western Reserve University. John worked his way through
college as a keyboard player in a rock and roll band. His hobbies
today, in addition to his three grandchildren, include the radio
sport of contesting, experimenting with antennas, and exploring the
back roads of the Bay Area on his Harley. His personal website is at
http://www.k6mm.com. You can reach
John at 6349 Slida Drive, San Jose, CA 95129 or at k6mm at arrl.net.