W6SDO.COM SAN DIEGO, CALIFORNIA USA
K4KIO HEX BEAM
The last antenna that has been installed on
my city lot is a K4KIO wide band hex beam.
It has 6 band coverage from 20 to 6 meters
and is said to handle full power on all bands.
Installation of this antenna was completed
May 30, 2012.
The antenna is attached at one corner of a
two story children’s play structure in our
back yard. The twenty meter wire on the
top of the hex beam "basket" is at about
24 feet above ground, as it is initially
The antenna mast is designed to tilt over at
the base using a gin pole and a hand
cranked Harbor Freight winch to perform
the raising and lowering chores. This
concept has worked very well for the
fiberglass flagpole that supports the off
center fed Windom and 160 meter
inverted L antennas.
A 100 foot length of coaxial cable (1318FX
double shielded low loss foam core) drops
down the mast and runs to the common
ground stake. Here it passes through an
Alpha-Delta 2 KW lightning surge protector
before proceeding on up to the shack.
Following some testing at this 24 foot
height, the antenna will be raised to a final
height with the 20 meter top wire of the hex
beam "basket" at about 40 feet above the
ground. I do not want the final height of the
antenna too be high because, from the
computer models that I have seen, these
antennas tend to develop a strong high
angle lobe in addition to the horizontal lobe
as they get higher than 35 feet or so. My
thought is that this might to leads to wasted
transmitter power as well as an increased
amount of multi-path fade on some
The Hex beam was assembled in my side
yard using a saw horse with a short PVC
post attached as the base. The instructions
provided by K4KIO for assembly of the
beam are very well written and were easy
I ordered two ferrite cores kits from K4KIO.
These were placed over the coaxial cable
at the point where it is connected to the
antenna. The number of cores used was
double the recommended number to make
sure that the any common mode currents
will be minimized.
Adding these cores both minimizes the
common mode current on the cable and
reduces the effect of the transmission line
on the radiation pattern. It is particularly
important that any RF floating around in
my second story shack is minimized.
Incidentally, it would be useful if K4KIO
would sell cores with a larger inside
diameter so that they would slide over the
RG-8 coaxial cable connector. I'd be very
happy to spend a little more money for
cores with a larger inside diameter and
gain the convenience of not having to cut
and re-terminate the cable.
I also had some difficulty getting the bow
out of the fiberglass arms when connecting
the short cord according to the instructions
that were provided with the antenna.
Although this is just a visual problem that
does not effect performance, I was able to
straighten out the struts by adding two
additional hose clamps and cable clips.
This allows the location of the short cord
to be adjusted along the length of the
fiberglass strut, independently of the 15
meter element location.
Overall, the materials provided with the
beam were excellent. I especially like the
168 strand flex weave wire that is used for
the elements as it is very flexible and does
not have any unsightly kinks remaining
after it is installed.
The SWR was measured across each of
the six bands while the hex beam was
resting on the test stand in the side yard.
A MFJ-269 SWR analyzer was used to
make these measurements. The SWR
measured was similar in shape, but was
somewhat higher, than the data shown on
the K4KIO web site and was typically
shifted a little lower in frequency. The full
limit power was also applied on each
band for a few minutes to insure that the
antenna was ready to go.
In addition, while the hex beam was still in
this location on top of the saw horse that
was used as a building stand (about 5
feet above the ground in the side yard)
contacts were made on 17 and 20 meters
with several states across the US plus
Hawaii, Germany, Nicaragua and Japan.
This has increased my expectations for
the hex beam once it is raised to it's final
Next, some very preliminary test were
performed on the 17 meter band.
This band was chosen for the preliminary
testing since I have four antennas to
choose from on the 17 meter band. The
antennas that I can now select include this
hex beam, an inverted V off center feed
Windom (a long wire at this frequency)
with good omni-directional characteristics
due to the inverted V construction), my
vertical dipole (to which I have added the
17 meter band - more on this later) and a
two wavelength loop antenna. Each has its
own advantages and disadvantages and
the shoot out between them has been very
interesting. The four antennas can be set
up to use the four antenna selector switch
buttons on the front of the Alpha amplifier
which makes A-B-C-D testing very easy
and a lot of fun!
The initial 17 meter observations are:
1. The hex beam is always quiet and has
the strongest signal in both transmit and
receive mode even though it is only 24 feet
above the ground.
2. The loop has an equally quiet noise
level but delivers signal strengths that are
about 6 db less than the hex beam.
3. The OCF inverted V has a noise level
that is 2 to 3 db higher than the hex beam
and produces signal levels that vary
between equal and 4 db lower.
4. The vertical dipole usually has a 3 to 6
db higher noise level, compared to the hex
beam, and produces signal levels that are
typically 3 to 6 db less than the hex beam.
It does better on transmitting than it does
on receiving due to the higher noise level
when it is used for receiving.
Another bicycle riding buddy of mine,
Mert AF6RF, has his hex beam mounted
on the top of a crank up tower that he built
from an aluminum extension ladder.
Last revised December 10, 2012
The gin pole that is used to raise and lower
the antenna mast is made from a 12 foot
length of 4 x 4 inch pressure treated wood.
This gin pole is attached to the corner of the
grand-children's two story play structure
using bolts fabricated from 1/2 inch
A slot was cut into the top of the gin pole
and a 3 inch diameter pulley was installed.
A steel cover plate from an old 3 1/2 x 3 1/2
inch electrical box has been attached to the
top of the gin pole to keep the cable from
jumping off the top of the pole in the event
that the cable becomes slack for any
The initial antenna mast is made from an
18 foot long length of 2 inch heavy wall steel
electrical conduit pipe. This mast pivots at
the base using a 0.5 inch bolt that connects
it to the bottom of the gin pole. The mast is
self supporting and requires no guy wires
which might distort the radiation pattern. A
3/16 inch galvanized cable is routed from
the hand cranked Harbor Freight winch to
the pulley at the top of the gin pole and then
down to the antenna mast that is to be
raised. For safety, a length of polyethylene
tubing has been slipped over the cable in
order to damp out any potential whipping
should the cable break or become
disconnected while under tension.
The winch is installed on a 4 x 4 post in an
area that is just above and outside of the
play yard. Two bags of post hole concrete
mix were used to securely anchor the post.
The winch makes raising and lowering the
antenna an easy one man job. It takes less
than five minutes to either raise of lower the
Next, the height rotor post tip was set at
about 11 feet above the ground so that the
antenna could be attached.
Finally, the antenna was carried up a ladder
by my friend Arizona and placed onto the
top of the rotor.
With the Yeasu G800DXA rotor and hex
beam antenna installed, the cables were
attached to the mast with UV resistant tie
wraps. The coaxial cable and rotor cable
connectors were covered with weatherproof
tape. The rotor was also tested and
calibrated before raising the antenna.
When it is raised into position, the antenna
mast is secured to the top of the gin pole
with a single 3/8 inch bolt.This adds some
reenforcement to the mast to insure that it
will be fully self supporting.
|INSTALLATION OF THE HEX BEAM
|INITIAL RESULTS USING THE HEX BEAM
After installing the hex beam at this
intermediate height, the SWR is lower
than it was at five feet above the ground,
but not by as much as I expected.
The resulting SWR in the center of each
of the six general class phone bands is
Band 20M 17M 15M 12M 10M 6M
Kenwood 1.6 1.4 1.4 1.5 1.2 1.7
Alpha 2.1 1.7 1.7 2.1 1.4 NA
MFJ-269 1.8 1.5 1.7 1.8 1.4 2.3
The differences in the SWR that is
measured by each of the measuring
devices is probably the result of each
device having a slightly different way of
performing the SWR computation. Never
the less, each shows the SWR minimum
at virtually the same frequency.
These SWR readings are also within the
range that the Alpha amplifier can deliver
full power to the antenna.
When testing of this "low" antenna version
is completed, the short electrical conduit
pipe mast will be replaced with a 33 foot
tall fiberglass flag pole. This fiberglass
pole is five inches in diameter at the base
and will require no guy wires for this
application. This mast will put the base of
the hex beam at about 36 feet above
ground and should provide a substantial
performance improvement while still not
showing too much from the front of the
Since this hex beam has been installed
at a very low height, I can check out the
answers to three very interesting
1. How visible is a hex beam, as seen
from the street view of my lot, if it is
mounted at a very low stealthy height?
2. How good is the performance of hex
beam at this very low height especially
as it compares to my OCF all band
inverted V with a 45 foot apex?
3. How good is the hex beam when it is
compared directly one-on-one with my
radial free, very stealthy and much less
expensive vertical dipole (with both
antennas operating at very similar heights
above ground level)?
A quick walk along the sidewalks at the
front and side of my lot quickly answered
my first question. The hex beam mounted
in the back yard and at this height is
Another KIO hex beam. This one is
mounted on top of the shack of my
bicycle riding buddy, Thomas,
N6TNC. He works stations around the
world with it.