bring a new homebrew antenna
to try out. Then in March 2006 while I was
looking through an issue of QST, I noticed an
MFJ advertisement for their 10 and 12 foot
telescoping whip antennas. Thats when my
wheels started churning. After a few minutes
of doing some calculations and sketches on
paper, I came up with this rugged lightweight
antenna.
After placing the order with MFJ for two
of the MFJ-1954 10 foot whips, I ventured
to my local Home Depot and purchased the
rest of the parts. Surprisingly, this little proj-
ect only took me about an hour to build. The
fun really started several days later when I
received the telescoping whips. The initial
tune-ups with my MFJ antenna analyzer
and Elecraft K2 indicated that this antenna
loads up beautifully on 20, 17, 15, 12 and 10
meters without the need for a tuner. The best
news is that it can be built for around $60.
Travel Friendly
When broken down for transport, this
antenna, minus the mast, consists of two
short 2 foot 7 inch long elements and two
lightweight MFJ whip sections retracted to
a length of 2 feet.
To operate on the 20 and 17 meter bands,
loading coils are used to resonate the sys-
tem, with precise tuning available using the
telescoping whips. In order to operate on the
15, 12 or 10 meter bands, the loading coil is
bypassed and with a short jumper across the
coil terminals the antenna operates as a full
sized unloaded half-wave (
/2) dipole.
How Does It Perform?
Three days after completing my new
A Super Duper Five Band
Portable Antenna
Make camping and travel more fun with this easy to duplicate antenna.
Clarke Cooper, K8BP
antenna, I drove north from my winter resi-
dence in Phoenix to Grand Canyon National
Park for a couple of days of camping.
With this antenna 10 feet in the air and my
Elecraft K2 at 5 W output, I had no trouble
making SSB and CW contacts to all parts of
the US as well as some long haul DX con-
tacts. The DX contacts on that trip included
Asiatic Russia, Australia, Belize, Lithuania,
Italy, Japan and Hawaii on 20, 17 and 15
meters. My location was surrounded by high
mountains to the north, east and west. I was
quite pleased with my latest antennas per-
formance. Even though I found no activity at
all on the 12 and 10 meter bands I still feel
very confident that when they open up, this
antenna will be a winner on these bands as
well. I just cant wait until I start using this
antenna on Pactor to get my e-mail.
Making it Happen
The parts required are listed in Table 1.
Cut the copper and PVC pipe per Table 1 and
Figure 1. Remove burrs from all cut edges
using emery cloth. Assemble all the parts on
a clean surface. At a small sacrifice in weight,
a
5 8
inch by 2 foot dowel can be inserted into
the copper T to provide additional strength.
This is recommended for extended use.
Push two of the copper bushings into the
center T and insert the two CPVC couplings
into the copper bushings as far as possible.
Figure 1 Details of PVC and copper pipe pieces for antenna center. From May 2007 QST © ARRL
Figure 2 Antenna assembly drawing.
Figure 3 Detailed view of inner element
construction.
Table 2
Tools Required
Carpenters saw
Tubing cutter
Electric drill and bits
Emery cloth
Fine le
Hacksaw
Measuring tape
Propane torch
Soldering iron
Table 1
Parts Required to Assemble the
Portable Dipole
Quantity one unless noted.
Alligator clips (4)
Copper pipe,
3 4
× 26 (2)
Copper pipe bushings (made from
3 4
pipe),
3 4
× 1
1 2
(4)
Copper pipe reducer,
3 4
×
1 2
(2)
Copper T,
3 4 CPVC cement
CPVC gold pipe,
3 4
× 2
1 2 Fine thread stainless nuts,
3 8
× 24 (2)
FSC hardwood dowel,
5 8
× 4
Insulated solid 20 gauge wire, 10
MFJ -1954 (10 foot) telescoping whip (2)
Sheet metal screws, #8 ×
3 4
(package)
SXC CPVC couplings,
3 4 Ring terminals, 20 gauge size (6)
Drill four
3 32
inch holes on top of the center
insulated T assembly and secure with four
#8 ×
3 4
inch screws.
Next, insert both
3 4
× 26 inch copper pipe
elements into the CPVC couplings and drill
four
3 32
inch holes. Then secure the four #8 ×
3 4
inch screws as shown in Figures 2 and 3.
Assemble the loading coil forms by
lightly gluing two CPVC couplings to each
end of a
3 4
× 2
1 2
inch CPVC pipe piece using
CPVC cement. Make sure you apply glue
only on the coupling half that will be used
with the
3 4
× 2
1 2
inch CPVC pipe, as the
other end of the couplings will be fastened
later by #8 sheet metal screws. After assem-
bly, wipe any excess glue from the outside of
the form and from the inside of the free end
of both of the coil CPVC couplings.
Drill two vertical holes in both coil
assemblies, all the way through each end
of the CPVC coil form assembly. Insert a
length of 20 gauge wire all the way through
both vertical holes of the coil form. On the
short end, leave enough wire to connect to
a ring terminal later. Carefully wind nine
turns on the form and feed the remaining end
through both holes. Adjust the coil windings
by twisting the coil and pressing on the coils
to remove any slack. When you are satisfied
that the coil windings are tight, leave enough
wire to connect to a ring terminal later. The
completed coil assemblies are shown in
Figure 4.
Insert the remaining
3 4
× 1
1 2
inch copper
bushings into a
3 4
× 1
1 2
inch copper pipe
reducer and carefully solder them together.
Handle with extreme care until these items
have cooled down.
Insert both
3 4
× 24 nuts into the
1 2
inch
ends of the pipe reducer until they are flush
with the ends of the reducer. Carefully solder
the nuts to the copper reducer. After they
have cooled down, insert the
3 4
inch ends
of the reducers into the 20 meter coil form.
Confirm that both coil windings run in the
same direction. Then drill a hole in each
outer section of the CPVC bushing, keeping
both holes symmetrical.
Measure the coil wire tag ends and care-
fully strip off just enough insulation to make
a loop that feeds into the terminals. Confirm
that the center of the terminal is aligned with
the mounting hole. Crimp and solder the
wire connections.
Fasten each coil form to its respective
pipe reducer and secure with a #8 ×
3 4
inch
sheet metal screw. Slide the remaining end
of each loading coil housing onto the end of
each 2
1 2
foot dipole element. Rotate the coil
terminals so they are on top. Secure the coil
assembly to each dipole element with a #8
×
3 4
inch sheet metal screw. Attach the MFJ
-1954 telescoping whips by screwing them
into the end of each coil assembly as shown
in Figure 6.
Attach a length of coax by separating
the center conductor and outer shield and
soldering a ring terminal on each. Secure
each terminal to the outer side screws on
the T assembly. Wind a 6-turn 7 inch diam-
eter coil on the antenna end of the coax and
secure with tape or wire straps. Connect
the coax to the antenna by loosening up the
side screws on each active element insula-
tor. These screws are the ones on the outer
edge of the CPVC coupler next to the ele-
ment. Slide the coax terminals under each
of these screws and retighten the screws. It
doesnt matter which side the coax shield
or center conductor is attached to. After
these connections have been made, take an
ohmmeter and hold one meter lead on the
center T and with the other lead touch both
elements. Both sides should indicate an
open circuit.
If you wish, instead of the coiled coax From May 2007 QST © ARRL
Figure 4 Completed loading coil
assemblies.
Figure 5 One side of the antenna with retracted whip attached.
Table 3
Antenna Tuning Chart Settings and Resulting SWR
Band
Tune Frequency
Max SWR
Coil
Whip Length

(MHz)
20 Meters 14.2
1.4:1
Yes
118
17 Meters 18.11
1.0:1
Yes
78
1 2 15 Meters 21.15
1.1:1
No
99
12 Meters 24.94
1.2:1
No
78
10 Meters 28.8
1.2:1
No
64
Figure 6 Dipole feed connection
toroid balun option shown.
choke, you can use a 1:1 balun such as the
one in Figure 6 that I made with a T200-2
toroid, a couple of feet of enameled wire and
some odds and ends I had in my junk box.
are tripod mounts, improvised railing sup-
ports and many types of telescoping support
poles available from a number of manufac-
turers. I have had good results using a Model
S216 telescoping fiberglass pole manufac-
tured by Hastings. These are available at
electrical supply houses. There are other
similar types sold by a number of Amateur
Radio dealers.
In my usual installation, I have secured a
short piece of CPVC tubing on the top tele-
scoping section. On the other end of this
short piece, I insert it into a CPVC coupling
that is part of the T section on my antenna.
I have also used short pieces of aluminum
tubing fastened together made from old an-
tenna beam elements. Even short pieces of
inexpensive CPVC pipe will do for a 4 to 5
foot mast.
For the base, I often use a folding por-
table flood light base I picked up at a yard
sale. If packing in by foot, I leave the base
at home and use available supports such as
tree stumps to hold up the mast by secur-
ing with a piece of small rope. With this
method, one can set up this antenna within
5 minutes.
One final bit of advice please be care-
ful when setting up your antennas wherever
you are.