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The HAM Radio Operator's Antenna Handbook
by Buck Rogers (66 years as K4ABT) HAM
= Helping All Mankind
*LOOP Antennashave less electrostatic noise in your
receiver.
* LOOP Antennas provide additional gain
over conventional wire type antennas
*
LOOP Antennas perform especially well
over poor conducting earth like sand and lossy
soils.
Many HAMs
will tell you about a great antenna that is one
of the better performing wire antenna's and one of the best kept secrets
in HAM Radio. It is called, the Full Wave LOOP Antenna. There are several factors to
consider when choosing your wire gauge and type. BUX COMM uses number 14
AWG, silver-flashed-copper, made up of 41 strands, covered with Sky-Blue
PVC. The (41) multi-strands provide an added (tensile) strength. Because
the wire size, most often referenced by HAM radio articles, is:
High-Tensile Strength 14 AWG, we have chosen it as the preferred size for
our Full Wave, 80 thru 10 meters, LOOP antenna wire size.
The BUXCOMM
LOOPAntenna
requires 70'by 70' of real-estate.
We calculate the length of the Full Wave
Loop Antenna for the lowest band to be used. This formula is as accurate
as you find for any "loop antenna" on the HF bands. In the construction
of our BUX COMM antennas, we use a special, high grade, and High tensile
strength wire, with 41 strands of silver flashed, copper covered with an
esthetically blended sky-blue IR resistant PVC covering. Our sky-blue
covering will not affect the RF transmission in any way.
BUXCOMM HF loop antenna are installed and
supported in one of two ways, "fixed and floating." We use the “floating”
method of support for three (3) corners. The three far corner insulators
are already on the loop when you receive the assembled antenna. One corner
insulator is moved to the right corner, another is slid along the loop to
the far corner (and diagonal away from the feed point),
another insulator is set to the left corner position,
thus "floating" the three (3) corner support insulator(s).
When building the feed point, we employ a different type, "fixed"
insulator. This insulator also supports the 2:1 ratio BALUN. The main
purpose for floating insulators at the three non-fed corners is to enable
the wire to move freely through the insulator, thus providing the best
support when the horizontal loop is supported by tall poles or swaying
trees.
A touch of
Class, the
J-POLE
By Glynn E. "Buck" Rogers Sr
(65 years as K4ABT)
Between the articles by the late Lew McCoy
W1ICP and myself,
the J-POLE, Windom, and ZEPP should be around "forever."
My Hardware J-Poles from 1969
The J-POLE has been around since the early days of HAM Radio, and is a direct descendant of the "ZEPP." Like the ZEPP, the J-POLE is a spin-off,
or a modified WINDOM for VHF. One of the first articles I wrote about the J-Pole was in HRC magazine in 1958. Since 1958, I've written several j-pole
articles in other HAM Radio publications.
Here, my references are to the early, 1923 (version) Windom (Article by Loren G. Windom September 1929, QST magazine) . If you look at the feed of the
early Windom that was fed with a single wire, you may soon see the similarity between the Windom, ZEPP, and the J-Pole.
For now, let's look at some of the features of our J-Pole, whether for; 140-150 mHz, or 430-450 mHz
the J-Pole is easy to erect
the J-Pole needs no radials
the J-Pole has low angle radiation
the J-POLE has greater bandwidth.
the J-Pole has greater immunity to terrestrial noise
the J-Pole is great for local nets or distant repeaters
the J-Pole has more gain than most Ground Planes
the J-Pole is more durable than most Ground Planes
the J-Pole meets most "stealth" antenna restriction agreements
the J-Pole has less static-charge noise, and static-charge build-up.
In the mid-fifties, and early sixties, ridged copper was difficult to find, and even if we were fortunate
enough to locate ridged copper, the cost was prohibitive. Most of our VHF (don't even think about UHF)
operating was AM (for the late model HAM, "Amplitude Modulation"), and on two meters, operating was
centered around 144 MHz. We either opt'd for a bamboo spreader cubical quad, or folded "zepp," as we
called it in those days (now-a-days, called a "J-Pole.")
Another variation to this antenna construction was to use electrical thin-wall conduit or "EMT." EMT actually
means "electrical metallic thin-wall" but somehow early acronyms had a way of getting turned around, or inverted,
. . . or perverted.. hi.
Using metal EMT instead of copper, we learned to use the brazing rods and torch to fabricate our "folded (zepp) Jay."
In any case, we were able to make the J-Pole happen. For VHF, the J-Pole became the antenna of choice,
just as the Windom took its place as the antenna of choice for the lower (HF) bands. As a matter of interest,
look close at both the J-pole and the Windom, and you might find a close resemblance and maybe even some
relationships in the off-center method used to feed each of them.
I've heard of J-poles stacked, collinearized, and some with weird fitted, 1955 Ford fender-skirts. Depending on
who's telling the story, they might have more gain than a yagi on a helicopter at 1200 feet, or they won't reach a hand-held
across the backyard. I try to make it a personal point to stay out of these CB University fences. You can put a "mini-skirt"
on it, you can even place a "tutu" on the J-Pole, but the truth is, it remains a Jpole.
As a personal observation throughout my 64 years as a HAM; Mistakes, Experience, and Knowledge has given
this ole HAM the Wisdomto know the difference. Don't try to build a Windom for two meters,and for
heavens sake, DO NOT attempt building a J-Pole for seventy-five (75) meters.As they say, "do the math;"
Just the long, vertical section of a 75 meter J-pole would near 200 feet.
TO THE POINT OF OUR SUBJECT:
I've had many requests for a ready-made J-pole design that will enable the Amateur Radio user to print the image
from a web page and go directly to the construction table and build a J-Pole antenna for their HAM Radio station.
On this page you will find many illustrations I've drawn to help you understand the manner in which a J Pole is built.
Fabrication can sometimes be a problem for the apartment dweller, or the HAM with limited facilities for this kind
of project.
Let's look first at FIGURE 1a; This is the overview and profile of the
J-Pole we will be working with. There are two different bands we will be
building the J-Pole antennas for. NO, we will not build a two band antenna
on one mast. I've been there, done that.. and it is an exercise in futility.
For openers, I would like to show you that all J-poles are not created equal.
By that statement; I mean, we will modify our construction techniques a bit
and apply a variation to the theme. Notice in the exploded view
at FIGURE 1b, I've deviated from the usual RF feedtechnique that we normally
use to attach our coaxial cable to the J-pole.
Where we usually attach the shield and center conductor to the tuning stub and the
driven element with aero-seal (hose) clamps, here we've made a slight change
in the design by exchanging the elbow for a tee. Below the short (1/4 wave tuning stub)
section, we (carefully) soldered an SO-239 (Chassi-mount) coax (female) connector.
But notice that we must first attach a piece of number 12 or 14 insulated, copper
wire to the SO-239. The length of this wire depends on the spacing between the stub
and (Fig 1A "D")long section of our antenna.
If the antenna is for six meters, the wire length will need to be about, 10 to 12 inches long.
If our antenna is for two meters, the wire length will be less than 8 inches overall.
I am careful when I (Benz-O-Matic torch) solder the SO-239 to the copper tee, since
I don't want to heat the SO-239 to the point the solder on the wire melts and I have to
begin the process again.
Shown above ↑ are our direct feed J-Poles.
BUX VBALUN should be installed at the antenna feed point, or
where the coax or feed-line attaches to the J-Pole antenna. BUX
BALUNs are used to connect balanced antennas to unbalanced
transmission lines, such as coax cable. Their primary purpose
is to prevent antenna (RF) currents from flowing down the
outside of the cable. Another function of the BUX BALUN41 is to
match the impedance of an unbalanced coax to the balanced feed
point of a balanced input antenna(s). BUX BALUNS may also be
used as “line isolators” anywhere along the cable to prevent the
destructive influence of induced RF currents (VSWR). BUX 1:1
BALUNs are current BALUNs. They consist of several large,
number 73, ferrite type 44 cores.
BUX COMM, 142 to 150 MHz; Fiberglass J pol For low terrestrial
noise, use fiberglass elements. For optimum performance and gain, feed with
BUX COMM "VBALUN." Courtesy HRC Antenna
Newsletter (c)
BUX COMM, 435 to 450 MHz; Fiberglass J pol For low terrestrial
noise, use fiberglass elements. For optimum performance and gain, feed with
BUX COMM "VBALUN." Courtesy HRC Antenna
Newsletter (c)
Two & Six Meter Beam Construction
Four element, two meter beam, elements can be tubular
aluminum, solid aluminum, or for low terrestrial noise, use fiberglass
elements. This beam may be installed vertical, or horizontal. For
optimum performance and gain, feed with BUX COMM
"VBALUN." Courtesy HRC Antenna Newsletter
(c)
Four element, six meter beam, elements can be
tubular aluminum, solid aluminum, or for less terrestrial noise, use
fiberglass elements. This beam may be installed vertical, or
horizontal. Courtesy HRC Antenna Newsletter
(c)
An old
theory, a new design
By
G. E.
"Buck"
Rogers Sr;
(66+ years as K4ABT)
Home of the original WINDOM Our Favorite Multi-Band Antenna.
The number "1" HAM station, field-day, and contesting,
wire type antenna in the world today. The
BUXCOMM model 802134 Windom is an antenna that enables
operation, 80 through 6 meters, without an antenna tuner.
As a matter of interest, we use the Windom BUXCOMM model 802134
into two (146 MHz) meters as well.
VHF was fun, but most of our enjoyment was on HF;
September 1949, I was exhausted from climbing poles and trees to
move, remove, add, or change my single-band HF antenna's.
The secret to it all, was to
remember and change the plug-in "tank-coil" to match the
antenna band. My ole 807 rig was home-brew, that I had
built on an old Atwater-Kent radio chassis. I had wound the
tank-coils on phenolic, plug-in coil forms (No, it was NOT a
pi-section, tank-circuit, it was a real, sure enough,
link coupled output, no less).
I won't forget the day and all
the jumping up and down by some SWLs who were listening on
another band. I had my 80 meter (3735 kc, now called kHz)
crystal plugged into my homebrew rig, with the antenna
connected and away I went to make some serious early morning
CW contacts on 80 meters.
CAVEATE: The night before, I had been operating 40 meters.
This morning, I wanted to make some 80 meter contacts....
BUT, and However, I forgot to change the "plug-in" tank
coil from the 40 meter plug-in, to the 80 meter coil.
By forgetting to change the 40
meter plug-in coil to the 80 meter coil, I had doubled in
the final.... and the 3735 rock, had put my RF signal output
on 7470 kHz.
YES! you bet I got a
letter... matter-of-fact, I received a "Show-Cause"
notice from the FCC monitoring station at Powder Springs,
Georgia, and furthermore, I received a letter from an OO in
Delaware. Never again, did I forget to switch the plug-in
tank coil when I changed bands... moreover, I made sure the
crystal I was using was for the band I was operating on. To
help me remember, I made an entry into my log book of each
band change, and a check-mark to indicate that I had indeed
changed the tank-coil to correspond with the crystal
frequency. Yes Leroy, there really is more than
one reason or purpose for using a log book.
Antenna tuners were few and far
between. This being the case, it's a good thing the more
up-to-date transmitter's used Pi-Section output tuning. Yes,
I wrote, "transmitter's;" Transceivers
were unheard of in those days..... In those younger years
of my HAM radio hobby, I had used single band dipoles and
doublets for almost every HF Amateur band. I had tried
long-wires, doublets, dipoles, and Zepps, but again,
operation was restricted or limited to single band
operation, maybe two bands at most; That is, until I got a
world war II surplus rig, from Buckners Army Surplus depot
in Anniston, Alabama. The BC-348 receiver was great, but it
only covered 2 Mc (now called MHz). through 18 Mc (A/LA
MHz). About the same coverage with the MOPA BC-191
transmitter, (2 Mc to 18 Mc) (al,et MegaCycle(s)).
In those days, we could buy surplus gear "by the pound"
because most of it was dynamotor powered, or operated from
400 cycle (er..uh, Hertz) mains. I removed the dynamotor
from the BC-348, and built a 115 V powered supply, and with
a mercury vapor, "80 rectifier tube." And the BC-191
transmitter, I built a pole-pig power supply, using a couple
of 866 mercury vapor rectifiers.
Enter; THE WINDOM:
Call it what you like, OCF, OCFD, or the name for which it
is named... its namesake is Windom. The Windom was, is, and
will be the number one antenna in the world for many years
to come. The Windom was first designed in 1923. It was fed
by a single wire (coaxial cable was not around in those
days), The designer William Litell Everitt (his photo is
shown elsewhere on this page), brought it to the world in
1923, and later wrote a brief about it in 1926.
A detailed
article by Loren G Windom, W8GZ written in the September,
1929 issue of QST Magazine. The Windom gained its fame
then and many times through the following years. I had heard of the
"Windom" and read a few articles about the Windom, but most
of my thoughts were ... ho-hum.. just another off dipole fed
a bit off-center.
Then one fall evening in 1949,
at a meeting of the GARC in the old "Sea Scouts" club house
near the Coosa River in Gadsden, Alabama; I listened as
some of my "Elmer's" discussed the Windom all-band HF
antenna. It was when Jack Kennamer, (W4YPC) (SK),
mentioned using one (Windom) antenna on all HF bands....
without an antenna tuner...! my ears went directional !
That last phrase caught my
undivided attention. "all HF bands, ..etc" What ! A
multi-band HF antenna? Surely I had been blessed.
To think that I could hang a
Windom, and no longer have to climb the poles and trees to
hang another (single band) HF antenna was great news to me.
To be able to use it without an antenna tuner was
icing-on-the-cake. For a kid without extra funds, an
antenna tuner was a luxury that I could not afford. Even my
first transmitter was a single 807 rig I homebrewed on an
old Atwater-Kent radio chassis, my grand-father had given
me.
In those days (1945-1949), a
BALUN was unheard of. My Elmer's described, a means of
connecting the coax to the off-center fed antenna using a
lossy, nine (9) turn coil of the coax feed-line at the feed
point. This coil of feedline coax formed a "de-coupling"
loop. The de-coupling loop provided a crude means of
matching the feed coax to the antenna, and at the same time,
it would reduce the "re-radiation" (RF currents) along the
outside (shield) of the feeder coax. Later I began to learn
about something called a "BALUN."
An old theory; A new design:
In 1958 I read more papers by
Gillette Guanella which referenced a “current” type
BALUN. then I came across Thomas O’Meara’s papers,
“Analysis and Synthesis with the ‘Complete’ Equivalent
Circuit for the Wide-Band Transformer.” This is when I made
some changes to the design of the Windom antenna. In 1970,
I met Lew McCoy W1ICP (SK). We talked about the Windom
antenna and how we were building them. Lew had some ideas
that I felt had enough merit to give them a try… I made the
changes and… !! walla, almost like magic, Lew's current type
BALUN design gave us the bandwidth that we needed to
make the WINDOM into an eight (8) band, plus antenna (even
adding some VHF bands).
Installation Information
The ideal height for the Windom
is 30 to 40 feet. It affords the Windom a low signal
take-off angle, creating a greater coverage area. As an
inverted Vee, at 30 to 40 feet elevation, an angle of
approximately 110 to 120 degrees at the feed-point, makes
the BUXCOMM Windom ideal for use as an “Inverted V.”
For use as an inverted V, erect
the BUXCOMM Windom antenna at 35 feet above ground, with
each leg tapering to approximately 8 to 10 feet above
ground. Support the ends out of reach of human or animals.
With the ends having a fall
from the apex of 60 degrees from horizontal the distance
between ends (or real-estate required), is approximately
118 feet. As a safety precaution, be sure the ends
are at least 8 feet or more above ground.
Where possible, route the coax
cable to the shack by running it away from the antenna at a
90 degree angle. Length of the coax is not critical, but
remember, shorter is always better.
If the question ever prods your
brain...; "Which end of the Windom should I elevate
highest?"... Here is where common sense comes into play.
ALWAYS, and in never question the common-sense answer;
ALWAYS whenever possible, the longest end.
Here's why.......... In the
late forties, I raised my first Windom, and in doing so, I
had our old farm-barn on one end at about 15 ft, and on the
other, I had to use a 30 ft Martin Gourd (Home for Martin's
(birds that chased bigger birds away).. kept the hawks away
from our hen-house)), it was the highest point, so I opt'd
to use it to attach the short element of my Windom. This
allowed the feed-point to be nearest my ham shack.
WRONG, not the best
decision....
Having learned a valuable
lesson, since then, I have always used the center conductor
of the coax or the positive (HOT (+)) post of my 4 to 1 and
5:1 BALUNs to feed the longest element of my Windom(s).
Since we began building and selling Windoms in 1959, we've
built and sold more than 95,000 Windoms worldwide; All have
been assembled and tested with the long-leg affixed to the
"hot" post of the BALUN, and the recommendation "when
possible," allow the long-element be at the greater height.
Use good quality 50 ohm coaxial
cable such as: RG8X, RG8, or RG213.
It does not matter whose
BALUN you use; Ours, (BUXCOMM MasterMatch series) or
others; PLEASE, Please seal all terminals and appendages in
or out of the
BALUN with Coax-Seal CS 104. It does not matter whose
BALUN you use, NO ONE makes a
BALUN that is impervious to driving Rain.... sooner or
later, it will fail because of moisture ingress. If you
don't wish to seal all the
BALUN terminals, then drill a 1/8 inch "weep" hole in
the bottom of the
BALUN.
Pay close attention to what I'm about to say. This is very
a very important point that other wire-type antenna
manufacturers won't tell you.
* Impedance at the feed point of the Windom (or any
wire type antenna) decreases at resonance as the height
above ground decreases ! or to say it
vice-versa.... and still have the same meaning or result:
* Impedance at the feed point of the Windom (or
any wire type antenna) increases at resonance as the height
above ground increases !
Having made this statement, I should clarify how we arrived
at this axiom.
Here in the BUXCOMM lab and our antenna farm, we made many
tests with the Windom at various heights above ground.
After many, and I mean "many" trials with the Windom at
various heights above terra-firma, we found optimum
performance at thirty-three (33') feet above ground while
using a 4:1 BALUN at the feed point.
When we raised
the BUXCOMM Windom above 40 feet (to 45') we found the
feed-point impedance at 75 meters rose to 266 ohms. To make
our Windom appear at a more constant feed-point impedance,
and at the same operating frequency, we made a change in the
BALUN ratio from 4:1, to 5:1. With our 5:1 BALUN (model
MM51), the impedance at resonance remained fairly constant
when our Windom was 45+ feet above ground.
As we increased the height above ground to between 55 and 70
feet, we found the impedance at the feed point had risen to
almost 300 ohms (actually 294 ohms MOL). To maintain a
well-matched BALUN to feed-point equivalent, we changed the
5:1 BALUN to a (BUXCOMM MM61) 6:1 BALUN.
When in
doubt, use the following rule-of-thumb to
match/balance your Windom and BALUN;
Antenna
height above ground:
20 to 40 feet (optimum performance) use Windom with 4:1
BALUN, 50>200 ohm (BUXCOMM model
MM41) 40 to 55 feet, use Windom with 5:1
BALUN, 50>250
ohm (BUXCOMM model MM51) 55 to * 70 feet, use
Windom with 6:1
BALUN, 50>300
ohm (BUXCOMM model MM61) * No test results
available above 70 feet
BucK4ABT
Today we have toroid cores and
BALUN devices that provide a more efficient means of
coupling RF energy to the antenna (reducing the VSWR,
"standing-waves"), while performing better impedance
matching. In the drawing shown above, I've drawn the exact
dimensions of the Windom I built in 1949. The only
differences in my Windom of 1949 and today are:
1) the material the insulators
are made of, and 2) I've substituted a 4 to 1 BALUN for the
(lossy) 9 turn, 8 inch diameter, decoupling loop. 3) added
coaxial cable feed via the 4:1 BALUN.
As I soon learned, this is one
of the best and least expensive HF multi-band antennas ever
made. It appears as an off-centre-fed (OCF) dipole. This
off-center fed design is actually the way the first Windom
antennas were designed. The short side of this story is:
the early Windom's were fed with a single wire (non-coaxial)
which allowed the RF to radiate freely inside and outside
the HAM shack.
Using an open-wire feeder from
the transmitter to the antenna was somewhat dangerous when
running power levels above 50 watts. This is in difference
to today's rules regarding RF radiation exposure, so to
prevent this radiation by the feeder wire, we have adopted
the use of coaxial cable to feed the Windom antenna. In
order to do so, we had to move a bit further away from
center than the designer of the Windom had.
Instead of using a 330 ohm feed
point on the Windom (approximately 14% offset from center of
the antenna and with the Windom more than 50 feet above
ground), we found a more suitable feed point that was closer
to 33 percent off-center. This point comes closer to being a
233 ohm feed-point, and since we adapted the Windom for coax
feed, we now use a 1 to 4 (MM41) current BALUN when our
Windom is 25 to 35 feet above ground, and a 1 to 5 (MM51)
current BALUN when our Windom is 40 to 55 feet above
ground. (remember,
the feed point impedance increases as we increase its height
above ground).
With the offset at one third
(1/3) distance from one end, we find the Windom has a median
impedance of approximately 223 ohms. This impedance is more
practical for using a 4:1 BALUN at the feed-point. In order
to use a 6:1 BALUN and achieve a close impedance match, we
must move the feed-point further away from ground.
With the use of our Windom
antenna, many customers will order the
6:1 BALUN because a friend told them to do so. These
are customers who are sometimes misled by the unknowing.
The 6 to 1 BALUN is OK when employed with the Windom feed
point above or more than 55 feet above ground. HOWEVER, we
no longer use that 14 percent center offset.
We have moved to a more
desirable feed-point (33 %) offset, and use a
4:1 BALUN (20 to 40 ft above ground or a
5:1 BALUN when we have the Windom feed-point 40 to 55
feet above ground. When in doubt, use the
4 to 1 BALUN (BUXCOMM model MM41). In either case, the
4 to 1 and 5 to 1 BALUN's are more efficient than a 6:1
BALUN.
Using a
4:1 or
5:1 BALUN at the feed-point of the Windom antenna, we
can operate without the use of an antenna tuner. The Windom
is an uncomplicated, easy to use, harmonic related antenna.
If we are the owner of an antenna tuner then by all means
use it. Since I run 200 watts (or less) I for one don't
like the idea of placing too many obstacles (antenna tuner)
in line with my antenna, because each transition from one
feed-line, tuner, or other transmission line transformer
simply adds more losses into the equation and thus reduces
this wonderful antenna's high performance.
It could be that many young
hams ignore the multi-band Windom antenna because of its
sheer simplicity and may think it's too good to be true.
Think about it, and while you are doing so, remember, the
more trinkets, and unnecessary inserts that are placed into
the RF path to the antenna are simply "window-dressing" or
gimmicks. These added "gimmicks" become losses to that
extra bit of RF signal that could have made that rare and
needed contact (difference) in a contest pile-up. The
original coax cable fed Windom has proven itself over and
over, to be the number one wire type antenna with the most
versatile and valued performance record in the HF
communications world.
Today, many radio amateurs are
using multiband Windom antennas with more than satisfactory
results. It would not be without reason that Windom antennas
are being employed during IARU HF World Championships,
worldwide DXpeditions! and most of all, by
"high-stake-contests." The complexity of feeding other
dipoles and doublets, the losses in dipoles with traps, and
the esoteric marketing of some other antennas seem to appeal
to them more. In the long haul, they find the Windom is the
best choice for all these applications, uses, and easy band
changing.
Remember the axiom: "When
you have achieved perfection, anything more becomes a point
of diminishing returns." Enough said!
Trust me on the above
paragraph, as I have experimented with every Windom and T2FD
concept or design that can be imagined. Having built and
sold thousands of these two antennas, I've found that It's
difficult to improve on perfection.
All BUXCOMM
160 through 2 meter WINDOMs are factory assembled and
tested.↓
Similar to WINDOMs shown above, These WINDOMs are completely
assembled, ready to connect the coax, and erect. BUXCOMM
Windoms are power rated at 1000 watts SSB and include all
insulators, high-tensile strength, super flexible PVC
covering, Power-Flex, tinned, copper wire, connectors, and
BALUN. Our High-power versions are rated at 2000 watts and
are identified with an "HP" in the model number. See coaxial
cable and related items below. You can be on the air in no
time, with any of our Windoms. BUXCOMM Windoms are the
choice of Hams, World Wide
The Windom can be installed as a Droop-End (see
figure D below) or as a sloper, but in no case,
should the angle be greater than 90 degrees
against itself. To use an angle that folds
against the pattern of the opposite end, or the
feed line of the Windom, could change the
impedance of the feed-point, change the
multi-band features, and most important, destroy
the radiation characteristics of the antenna.
�For
the best performance and reliability, use high-quality
RG-8X, RG8U, or in the case of high power, and VHF, use
RG213.
�Antenna
cable should run as directly as possible from the antenna
BALUN to the transceiver or tuner.
�Avoid
sharp bends in the cable as they can impair performance by
crimping or creating a time domain reflected (TDR) impedance
change.
Antenna Feed-line and Cable Tips:
Outdoor antennas should have for lightning
protection. Use a gas-stop or gap type BUXCOMM
7516 grounding (lightning) block where the antenna cable
enters the house or transceiver/tuner. Run a wire from the
grounding screw or tap, to your station's ground rod BUXCOMM
15929 GROUND ROD
�This
is not only an important safety consideration but also a
National Electrical Code (NEC) requirement
�Outdoor
connections should be protected from exposure to the
elements by applying silicone grease to prevent oxidation.
There is an exception; When the antenna "elements" are made
of twin-lead, and fed with coaxial cable via a
BALUN, then we understand how the ladder-line or
twin-lead can indeed become the radiating element(s). e.g. "Folded
Dipoles,"
JPOLE,
T2FD, and
Compact Dipole, In the case of the
G5RV,
the thirty-three feet of ladder-line or twin-lead (TLT)
should have a twist of one-half turn per foot.
A touch of
Class, The Windom and the J-POLE By Glynn E. "Buck"
Rogers Sr K4ABT
The J-POLE has
been around since the early days of HAM Radio, and is a
direct descendant of the "Windom" Like the Windom or ZEPP,
the J-POLE is a spin-off, or a modified WINDOM for VHF and
UHF. One of the first articles I wrote about the J-Pole was
in HRC magazine in 1958. Since 1958, I've written several
j-pole articles in CQ Magazine and other HAM Radio
publications. Here, my references are to the early, 1923
(version) Windom (Article by Loren G. Windom September 1929,
QST magazine) .
If you look at the feed method for
the early Windom, it was fed with a single wire. You soon
see the similarity between the Windom, ZEPP, and the J-Pole.
Look close at the configuration of the Jpole and the
Windom, and you will understand why in many of my articles
in CQ Magazine and other publications, that I often refer to
the Jpole as a VHF Windom, with the short section folded
back on itself to form the parasitic element. It is for
this reason that I feel these are two of the best antennas
ever designed. Having said this, you will also note that
the Windom (and the Jpole) are powerful antennas that
provide outstanding performance on all bands above the band
for which they are cut or designed for.
The reason
these two antennas perform so well (as Multi-Band antennas;
Windom for HF & lo VHF, Jpole VHF & UHF), is because they
operate at harmonics of the fundamental or lowest frequency
for which they are cut/designed. To add additional feeders
(ladder-line), other than 50 ohm coax or UNUNs is a waste
of RF energy. Only 50 ohm coaxial cable and a BALUN at the
feed-point is all that is necessary. Anything more, add
losses into the equation that cannot be overcome
after-the-fact. See "frequency vs wavelength" and "ham-band,
harmonic relationships" in the following color-coded chart.
From: Richard
Soikkeli Sent: Monday, May 19, 2008 11:35 AM To:
[email protected] Subject: Thanks for your fantastic
Windom antenna!
Dear
Buck, Thank you so much for your patient
technical help and the Buxcomm Quality windom
antenna. 2 weeks ago down came the 102' G5RV and
up went the
802134 BUXCOMM Windom.
Now I
am filling the log book with countries I rarely
could even hear before, much less work, even with
500w CW. I have "busted" some pile ups with a first
or second call and got real 599 rpts from DX over
8000 miles away. The low noise factor and gain
does the trick. Also, I don't have RF into my son's
computer speakers any more and I'm sure the
neighbors are happier.
I am
advising our Field Day team to ditch the g5rv's as
they don't compare at all as you told me would be
the case. I only wish I had heard about BUXCOMM
Windom's sooner and had more fun working DX over the
years. I just installed a 2nd windom for my jr.
high ham station. Now its time to break out the QRP
rig and see what it will do too. I will be ordering
more parts soon.
73
and thanks again, Rick AE6RS
To manage both
CW and Phone portions of the HF bands with the Windom, some
"pruning" of the elements L1 & L2 can be made. Pruning
(reducing) the length of L1 & L2 may cause an increase in
VSWR at the lower ends of the band(s). Always remember to
make the cuts proportional to each element. If you remove 12
inches (1 ft) from L1, remove only six (6) inches from
L2.... If you remove 2 feet from L1, remove one (1) foot
from L2. Do not remove more than 3 feet total (L1=2 ft, L2=1
ft)
The Windom
above is cut for the CW portions of the HF bands.
For the
technical minded Windom builder, we opt for the
4:1
BALUN because it is; more efficient, and weighs less.
Another nice feature we found using our Rhode & Swartz
Antenna Systems Analyzer, the Windom exhibits similar
feed-point impedance across the bands from 75 through 6
meters.
A word to the
wise.... NEVER make any angle of the Windom (or any flat-top
antenna) more than 90 degrees. Ends can hang down, from a
horizontal plane, but do not allow the angle to be tighter
than 90 degrees e.g. 75, 45, degrees etc. A Windom may also
be installed as an Inverted Vee, as long as the Apex (Point
where BALUN feeds the Windom) is not sharper than 90
degrees. The Windom is suitable for mounting as an inverted
V, supported between two masts, tower, or trees. The Windom
wire elements must not come in contact with limbs,
vegetation or metal objects. In practice, try to keep both
ends (wire elements) of the Windom three (3) or more feet
away from any limbs, vegetation or metal objects.
The
BUXCOMM Windom can be purchased in several different
band or lengths. The number of bands covered is determined
by the length.
Since writing
this article several decades ago for a major HAM radio
magazine, I've received tons of mail (and eMail) asking for
more information, especially with regards to my 160 meter
version;
The
BUXCOMM model 166260 Windom antenna is a horizontal wire,
multi-band antenna intended for use without an antenna tuner
on 160, 80, 40, 30, 24, 20, 17, 15, 10, 6, abd 2 meters.
The WARC bands of 30, 17, 15, and 12 meters by using an
antenna tuner. The antenna wire is made of 61 strands of
silver flashed wire and covered with non-metallic,
super-flexible PVC insulation. Each end of the BUXCOM Windom’s
have end insulators made of high tensile strength TyNYTE.
The Center insulator is also Tynyte, and is fed by customer’s
choice of either a
4:1
or 6:1 BUXCOMM MasterMatch BALUN transmission line
transformers. The BALUN feed is attached near the one-third
offset point according to the feed-point required by the
BALUN ratio (200 ohms/4:1, 250 ohms/5:1,or 300 ohms/6:1). By
using a different feed-point for 4:1 BALUNS, a slight
increase in antenna efficiency is realized when using the
MM51 (243 ohm) feed which results good VSWR on all
referenced HAM bands. The antenna is suitable for mounting
as a dipole, supported between two masts, tower, or trees.
The Windom wire elements should not come into
contact with any limbs or other vegetation. Here's why;
The sky-blue
insulation on the wire elements of our Windom antennas
provide esthetic blending with the environmental
surroundings, added tensile strength, and most important, it
prevents oxidation of the wire. Oxidation can wreak havoc
after a few years exposure to the elements.
A
few new HAMS do not understand why we advise against
allowing the wire elements (although insulated) to come in
contact with metal objects, tree limbs, and similar
vegetation. Here, insulation does not prevent
"proximity influence (added capacitance), and RF absorption"
by nearby vegetation, be it limbs, or metallic objects. The
same thing happens when the "sap" is up in the limbs, as
happens when the antenna elements come in contact with, or
near metal objects; stray capacitance, both inductive and
capacitive will surely detune a well engineered antenna
The
BUXCOMM Windom’s may also be installed as an "inverted
Vee".
Do not exceed 90 degrees when
erecting the
Windom Antenna as an "inverted Vee". Specifications:
Frequency range: 1.8
– 2.0 MHz 3.5
– 4.0 MHz 6.8
– 7.4 MHz 13.9
– 14.7 MHz 27.8
– 29.8 MHz 49.5
– 54.0 MHz Feed-point
Impedance 50 ohms VSWR <2.0:1 Horizontal Polarization (If
suspended as an Inverted Vee, do not exceed 90 degrees)
Maximum power 1000 Watts SSB, 600 W AM/CW, Wire Length
model 166260 = 260ft. WARC bands of 30, 17, 15, and 12
meters by using an antenna tuner. Now-a-days, I see a lot of
knock-offs of the windom, they even try to change the name
or use acronyms and try and relate it to the dipole. The
Windom is still a
Windom, regardless of what they call it. As with the
"apple." The apple is still an "apple" regardless of what
other name they try to give it!
Having said that: Here then is
"the rest of the story."
First of all, we'll address the
formula, and how to determine the length(s) of each section,
using the same old formula that I used in 1949. One third
plus two thirds will not work. Use the formula below, as
is: Do not be concerned with the off-set of the feed point,
as this formula takes into consideration, the correct
off-set for feeding the (BUXCOMM) Windom.
Long element = 468, divided
by the frequency, then multiply by .69 (= Feet) Thus
468 divided by a frequency of 3.7 Mhz., = 126.4, multiplied
by, 0.69 = 87.3 feet
Short element = 468, divided
by the frequency, then multiply by .37 (= Feet) Thus 468
divided by a frequency of 3.7 Mhz., = 126.4, multiplied by
0.37 = 46.7 feet
To find the total/overall
length of the Windom, add 87.3 feet and 46.7 feet =
134 feet.
The "Windom
Antenna" was described by Loren G. Windom in QST
magazine, September 1929. Pages 19 through 22. It is named
after its inventor/designer (See Photo below).
BUCKnote:Top Left; The transmitter shown
is the Central Electronics model 20A Multi-phase transmitter
It was a Phasing type side-band (slicer). It ran a pair of
6AG7 (metal tubes) which were used in the output as a class
AB1 linear amplifyer. Later, Collins crystal lattice
filters were added to suppress one of the sidebands to make
the CE 20A into a "single" sideband transmitter.
Lower-left; beneath the phasing exciter is a Collins RF
power amplifier, Center is the NationalHRO-50
with its tuning units (3) sitting atop a Precision
Electronics receive Pre-Selector. In the early fifties, the
HRO was one of a few receivers that had a BFO stable enough
to inject some Beat-Frequency (local carrier) and receive
DSB or SSB.
Loren Windom, W8GZ, was first to
reveal the antenna to the radio amateur community by
describing the antenna in the September 1929 issue of QST.
Although it was first built and tested by William Everitt
(see photo), it was by Windom's name that the antenna became
known.
The
Windom antenna is an off-center fed dipole with an
unbalanced coax feedline. In 1937, the Windom was first
described as a compromise multi-band antenna. The antenna
can be employed on most all HAM bands 80, through 10 meters.
What became perhaps the most popular multi-band Windom
design of all, was the Windom antenna, described by the late
first
build and tested by William Everitt (see photo), it was by
Windom's name that the antenna became known. It had the same dimensions as the
multi-band Windom Antenna,
but fitted with a 200
Ω to 50
ohm, (4:1) BALUN at its feed-point and fed with coax.
In recent years, some
operator's are using 300 to 50 ohm, or 6:1 BALUNS. They
base their decision on the simple math that the feed point
is three (30) ohms closer to 300, than 200. In reality and
measured with highly accurate antenna bridges, we have found
the feed point impedance of the Windom to be 233 ohms. The
feed-point of the Windom is 223 ohms nominal, this is a
measured impedance while the
Windom Antenna is suspended at 40 feed above ground.
Has anyone ever heard of "surge-impedance?" In tests, we've
found, there's no significant difference in performance
either way. Therefore, the trade-off is a matter of
personal choice. Mine of course, is the
Windom Antenna with a 4:1 Current BALUN (MM41).
If you plan to run more than 1000 watts SSB into our Windom,
we suggest you request our Windom with the
BD2K41 Current BALUN rated at 2kW SSB.
Beneath the Windom
Selection boxes; are the BALUN selections: The BALUN default
selection is 4:1 If Windom is erected
25 to 50 feet high, use default (4:1) selection.
If Windom is erected 50 to 65 feet high;
Select, 5:1 BALUN If Windom is erected
65 or more feet, Select 6:1 BALUN
1250 Units in Stock
Please Choose:
Windom Model
BALUN, Select type:
Here are some final notes:
In our
BUXCOMM BALUN's, we make it a point to polarize the
posts of our MasterMatch series, identified by a RED or
BLACK dot, or ring on the brass terminal posts. This
provides the user with a benchmark that allows the BLACK
post to be used towards the "cold" side of the antenna and
the RED post is connected to the long, or "hot" side of the
antenna. Some old-timers of my vintage, refer to the cold
side of the antenna as the "parasitic" element.
As a point of
interest, in some installations, the coax feed-line may pass
through the RF field of the antenna, RF current can be
introduced into the feed-line after the balun. In this
situation, a 1:1 Current Choke should be inserted into the
feedline near the feed-point of the antenna.
Loop antennas
have a fairly low impedance when they are built one (1)
wavelength in circumference. The low feedpoint impedance at
harmonic multiples of the resonant frequency as opposed to
dipole antennas, have low feed-point impedances at ODD
multiples of the resonant frequency.
When a
Full-Wave Loop
is operated near resonance on the desired band, a 5 to 1 or
2 to 1 balun works very well, when using 50-ohm coaxial
cable to the radio from the balun, VSWR at resonance will
normally be below 2:1. An external antenna tuner is not
required. If necessary, the transceiver's internal antenna
tuner may be used.
Typical SWR
Plot of full-wave horizontal loop at approximately 40 feet
above average ground using BUXCOMM MM21, 2:1 balun should
exhibit an VSWR at resonance below 1.5:1.
Application
Notes for BUXCOMM BALUN`s
Definitions:
BALUN = Asymmetrical to Symmetrical; UNUN = Asymmetrical
to Asymmetrical
1:1 BALUN: 50
ohms to 50 ohms, or to feed dipoles and similar antennas
with 40 to 75 ohm feed points.
BUXCOMM model MM11
1:2 BALUN: 50
to 100 ohms. This Balun is suitable for feeding Vertical
Antennas, Quads, Loop antennas and Ladder Line antennas.
BUXCOMM model MM12
1:4 BALUN: 50
to 200 ohms. This Balun is suitable for the coupling 50 ohm
coaxial cable to Windom’s,
and off-center-fed antennas.
BUXCOMM model MM41
1:5 BALUN: 50
to 250 ohms; Suitable for coupling 50 ohm coaxial cable to a
Windom’s,
when the Windom is more than 50 above ground.
BUXCOMM model MM51
1:6 BALUN: 50
to 300 ohms. This BALUN is suitable for the adjustment to
asymmetric fed dipoles such as Windom’s,
G5RV, and zepp antennas. The BALUN is fed directly to the
Windom and similar antennas. With double-zepp and G5RV
antennas and use of asymmetrical feeder, the BALUN is
positioned before entry of the cable into a building.
BUXCOMM model MM61
1:9 BALUN: 50
to 450 ohms for coupling Asymmetrical to Symmetrical
feeders.
BUXCOMM model MM91
1:9 UNUN:
asymmetrical to asymmetrical (unbalanced to unbalanced) Long
wire antennas, Ground Plane`s, Verticals, and some types of
"beverage" antennas,.. etc.
BUXCOMM model MM19LW
1:16 UNUN:
Similar to above application; asymmetrical to asymmetrical
(unbalanced to unbalanced) Long wire antennas, Ground
Plane`s, Verticals, and some types of "beverage" antennas,..
etc
HOW TO HANG BUXCOMM BALUNS
An
Improved G5RV Antenna:
The
original G5RV antenna was developed by Louis Varney G5RV for 20 meters.
Although his design was a good one, he used the 450 ohm ladder line as a
feed-line-to-antenna impedance match, and without the use of a BALUN. We
discovered that feeding the 450 ohm ladder-line directly with an antenna
tuner, left us with a shack full of RF…HOT mics, hum, and in some cases, we
had "squeals" from rectified RF getting into the microphone audio path,
within the transceiver, a sure sign of RF-Feedback (base rectification).
To make
the G5RV more "user-friendly" and with less RF exposure within the
HAM-shack, we added an MM11 BALUN at the lower end of the 450 ohm
ladder-line, and from the asymmetrical input of the MM11 BALUN (outside the
HAM shack), we used 50 ohm (low impedance) coax to reach the antenna tuner
inside the HAM shack. We’ve found that this improvement to the G5RV has put
more of our transmitted RF into the elements of the antenna, and made the
antenna virtually noise free and reduced re-radiation as much as 85 percent.
Without
using an external antenna tuner, we’ve found that our transceiver will work
into the 50 ohm coax and the MM11 BALUN with VSWR below 2:1 on the bands the
G5RV is cut for.
By
making the additional BALUN and coax improvement to the original 20 thru 10
meter G5RV, it is now possible to build the G5RV for more bands, and thus
cover lower bands and frequency’s. We now have a means by which we can have
an antenna that fits almost any real-estate configuration, from as little as
27 feet (8.2 m), (20 thru 10 meter bands) to 207 feet (64 m) (160 thru 10
meter bands).
BUXCOMM
now builds G5RV antennas in four (4) versions and lengths. Depending on your
available space, you may choose the size and version to fit your needs and
available real-estate space.
Model 80
thru 10 meter band coverage; Overall Length BALUN
Here's more commendation for our BUXCOMM Windom antennas:
From: M33Access Sent: Monday, October 16, 2006 2:55 PM To: [email protected]
Subject: BUXCOMM WINDOM
Hello
I couldn't
resist the opportunity to tell you about your Windom antenna I bought a
couple weeks ago. I have been off the air for a number of years. Probably
close to 15 to be exact. My oldest son got his ham ticket this past summer
and started buggin me to get on the air. That's when I decided to bite the
bullet and get on.
After working
for days trying to make my old "Inverted V" work. I turned to you folks and
your off center fed Windom. Since then I hung the antenna at the 70' mark on
my tower and the long end to about the 55' mark on a tree in the back yard.
My station is simple, I use the Kenwood TS-180s barefoot to the Windom. I
love to work rtty and packet. I am using an ancient AEA Pakratt232.
I have heard DX
that I never heard in my years of being a licensed Ham. I have worked Italy,
England, South Africa and last night I worked a station in Chile. CHILE! Now
that is at the other end of the world! This is so neat, I can't tell you how
much I am loving your antenna. Remember this is barefoot. I have my dad's
SB-230 amp, but it's not hooked up. I don't have the DIN plug for my 180
yet.
If you have
customers asking how your BUX Comm Windom antenna works, give them my call
and I will be happy to meet them on the air.
73, and thanks
again.
Bob WB8UJB
From: Andy
KA3ODJ
Sent: Wednesday,
June 07, 2006 6:49 PM To: [email protected] Subject: 166261W100 Just
wanted to let you know that your 166261W100 antenna here at KA3ODJ is
working like Gang Busters. Purchased the antenna primarily as a 160 Meter
antenna for the Internet Remote Base. The SWR and performance exceeded what
I had expected, I have added it to the selection choices for the other
bands. Can not wait to get the ends up higher, they are only 35" or so right
now. Getting good reports from the users of the Internet Remote Base. No RF
Problems at the coax end either, I also am using one of your Master Match at
the antenna switch. I am running an Icom PW1 and in the past, I've had RFI
issues in the shack resetting the computer, but no more, with this new
BUXCOMM Windom, it's clean as a whistle. Feel free to give your antenna a
try if you like. To operate Remote, You will have to download W4MQs software
to get access. http://wpmq.com. Thanks for a great product at a fair price.
Andy KA3ODJ
Our Windom Measurements
Freq mHz
1.9
3.5
7.1
10.7
14.2
21.4
28.5
SWR
1.8
1.2
1.8
1.55
1.33
2.1
1.25
Impedance
233
218
158
161
280
256
190
Metric Conversion
INCHES
To Millimeters Inches x 25.40 To Centimeters
Inches x 2.54 To Meters Inches x 0.0254 From Millimeters M x 0.03937
From Centimeters C x 0.3937 From Meters M x 39.3701
FEET
To Millimeters Feet x 304.8 To Centimeters Feet x
30.48 To Meters Feet x 0.3048 From Millimeters M x 0.00328 From
Centimeters C x 0.03281 From Meters M x 3.28084 From Centimeters C x
0.01094 From Meters M x 1.0936
YARDS
To Millimeters Yards x 914.4 To Centimeters Yards
x 91.44 To Meters Yards x .9144 From Millimeters M x 1.094 x 10- 3 From
Centimeters C x 0.01094 From Meters M x 1.0936
* Makes the antenna radiation pattern predictable.
* Reduces QRN and TVI to the neighbors.
BUXCOMM BALUNs
should be installed at the antenna feed point, or where the coax or
feed-line attaches to the above ground antenna. BUX BALUNs are used to
connect balanced antennas to unbalanced transmission lines, such as coax
cable. Their primary purpose is to prevent antenna (RF) currents from
flowing down the outside of the cable. Another function of the BUX BALUN41
is to match the impedance of an unbalanced coax to the balanced feed point
of a balanced input antenna(s). BUX Line-Isolator BALUNS may also be
installed anywhere along the cable to prevent the destructive influence of
induced RF currents (VSWR). The best location for the BUXCOMM LISO is
to install it at the output of the transceiver or between the linear and the
coax cable feed line to the BALUN at the antenna.
The illustrations,
drawings, and documentation shown on these pages are for use at the readers
discretion and is NOT a recommendation by BUXCOMM Corporation, its owners,
or employees.
Noise is the enemy of
Packet, Voice, Data, and Digital Communications. In addition to providing
Equipment and Personnel Protection
from lightning, a good ground system will reduce noise in your Packet
Station, or your mountain-top communications site.
G. E. "Buck"
Rogers Sr.
If you follow these Lightning Protection & Grounding procedures
ANTENNAS
AND SUPPORTING STRUCTURES
Metal antenna structures that are anchored into the
ground are inherently self-protected. Some radio systems antennas and
beams may be unlikely to be damaged by direct lightning strokes, but
they should be bonded to metal supporting structures to eliminate
arcing. If the ability of an antenna to withstand direct lightning
strokes is doubtful, Lightning rods atop the tower or supporting
structure, to intercept strokes should be provided where the
transmission pattern permits.
Lightning rods may be attached directly to a metallic supporting
structure and should protrude sufficiently above vulnerable elements to
provide an adequate "cone of protection". Top lighting fixtures may also
be subject to damage if they are not properly shielded. Metallic antenna
towers, either guyed or self-supporting, provide an excellent conducting
path for stroke currents but the footings, base, and guy anchors of such
structures must be properly connected to suitable grounding electrodes.
When wood poles are used to support antennas a lightning rod should be
provided at the top of the pole to intercept strokes. This lightning
rod should have a large size ground wire cadwelded to it and routed to a
good ground system. This will give protection against pole splitting and
possible antenna damage. In a common arrangement, a ground rod is
attached to the pole with one end protruding sufficiently above the top
of the pole to provide a suitable cone of protection. A #6 AWG (or
larger), solid, bare copper, down conductor is connected to the rod and
stapled directly to the pole on the side opposite the coax or
transmission line to the antenna. All pole-top hardware, the antenna,
and any supporting guys should be bonded to this grounding conductor.
At the base of the pole the shields of lines, equipment cabinets, and
any other conducting objects should be bonded to the down lead which
then must be connected to the common area ground system similar to that
shown below.
An overview of how a communications site is grounded.
Your site should not contain an independent ground(s).
ALL grounds should be connected together as shown in the illustration
above. A single point (common) ground is noted by the Master Ground
Bar or MGB, as shown. Ground rods are chemical rod systems that
are used in areas where grounds are hard to achieve.
The drawing above is a "cut-away" that illustrates how the chemical
"L" ground is installed. Chemical ground rods are also available in
straight or "vertical" shaft design.
NOTICE:
When working around electrical
earth or signal grounds, Never intrude, interfere with, or
interrupt, any part of this ground system. Above all, do not
"break" or open your electrical power ground. In no way should
you compromise your electrical service grounds! When in doubt,
call or consult your utility company and a licensed electrician.
Remember, lightning is unpredictable. A direct lightning
strike or a nearby hit/strike can damage your equipment. In
addition; It can cause injury to those near the strike, start
fires, or cause death. Again; When in doubt, call the local
utility company or consult a licensed electrical contractor or
specialist.
For those who want top level
lightning protection, here are a few of the current generation in
lightning protection devices.
A
Secondary
Lightning Protector
Remember the axiom; "An ounce of prevention is worth a pound of
cure." This lightning protector contains a modified spark gap
that provides that ounce of prevention. We offer this device as a
secondary radio protector. Remember, there is no substitute for
a good earth ground, AC line surge, and spike protection.
Remember the axiom; 'An
ounce of prevention is worth a pound of cure.' This
lightning protector contains a modified spark gap that provides
that ounce of prevention. . Remember, there is no substitute for
a good earth ground, AC line surge, and spike protection. Where
lightning is involved, we make no warranties. We offer the 7516
as a secondary lightning protector. Ground wire attached to wire
lug.
Power line Surge & Spike
Suppressor, with three Outlets,
and all three are MOV
protected.
"Don't plug it in without protection !"
Lightning and power surges can permanently
ruin your electronic equipment.� Changes in voltage can cause
lockups and loss of work and data.� This device will protect
your equipment from the threat of bad power. This Surge
Arrestor offers a great value for high-end home and business
equipment applications such as home and office computers,
expensive HAM gear, high-performance stereo equipment,
printers, appliances, televisions and more.
FYI... No inline device will
protect against a powerful, direct lightning hit.
The industry "work-horse" is the model 3710 (and
3730) Ground Tester. I consider my model model 3730 to be
one of the most "user friendly" devices that I have ever used to test an
existing ground system at communications sites.
Digital Ground Resistance Tester Model 4610
(When it comes to making ground measurements and soil resistance
tests, this "magic box" is my first choice!)
Measures from 0 to 1999 ohm
Direct reading bridge
Fall-of-potential method
Autoranging
Measures Ground Resistance (3-point) and soil resistivity
(4-point)
Step voltage tests
Touch potential measurements
Continuity tests on bonding
The model Digital Ground Tester Model 4610 performs accurate ground resistance
measurements (3-point) on single rods or computer grids, and soil resistivity
measurements (4-point). It may also be used for step voltage tests and touch
potential measurements.
The model Model 4610 is autoranging: It will automatically seek out the optimum
measurement range. To use the tester, simply connect the leads, press to
measure, and read. This rugged, easy-to-use tester is ideal for maintenance
crews performing multiple and repetitive tests.
Here are some rules of safety that could
help save your life if lightning threatens.
Stay indoors, and don't venture outside,
unless absolutely necessary.
Stay away from open doors and windows,
fireplaces, radiators, stoves, metal pipes, sinks, and plug-in electrical
appliances.
Don't use plug-in electrical equipment like
hair dryers, electric tooth brushes, or electric razors during the storm.
Don't use the telephone during the storm;
lightning may strike telephone lines outside.
Don't take laundry off the clothesline.
Don't work on fences, telephone or power lines,
pipelines, or structural steel fabrication.
Don't use metal objects like fishing rods and
golf clubs. Golfers wearing cleated shoes are particularly good
lightning-rods.
Don't handle flammable materials in open
containers.
Stop yard work, especially when the mower or
tractor is pulling metal equipment, and dismount. Tractors and other
implements in metallic contact with the ground are sometimes struck by
lightning.
Keep away from water and off small boats.
Stay in your automobile if you are traveling.
Automobiles offer excellent lightning protection.
Seek shelter in buildings. If no buildings are
available, your best protection is a cave, ditch, canyon, or under head-high
clumps of trees in open forest glades.
When there is no shelter, avoid the highest
object in the area. If only isolated trees are nearby, your best protection is
to crouch in the open, keeping twice as far away from isolated trees as the
trees are high.
Avoid hill tops, open spaces, wire fences,
metal clothes lines, exposed sheds, and any electrically conductive elevated
objects.
When you feel an electrical charge; if your
hair stands on end or your skin tingles; lightning may be about to strike you.
Drop to a prone position immediately!
For those who want
lightning protection, here is one of many, lightning protection
device.
An HF Dipole Antenna
specially designed with the Apartment Dweller, RV, & Field-day
operator in mind. Don't be fooled by those over-priced
knock-offs that use a piece of drilled aluminum that breaks in a cold
wind. This is the original, Fixed station, RV,
apartment dweller, and portable dipole from BUX Communications. It is
designed for rapid deployment and effective HF communications where space is
limited. The mounting bracket and hardware are made of high-quality,
hard-drawn, aircraft aluminum, to withstand the elements and maintain a strong
posture in adverse wind and weather conditions.
On a budget,
Mobile in an RV, or live in a space-restricted environment?..
Here's the the solution:Here's an HF horizontal (or vertical) polarized antenna that will
meet those beams "head-on!" When installed on a rotor, this combo
makes a great bi-directional fixed-station antenna. Shown here
with BUX UNUN (ONION) as the decoupling balun (unun) to prevent
reradiating of the coax shield and better match at the antenna feed
point.
When the stations
with the gain and power in their antennas are transmitting in the
horizontal plane, then you should be meeting them in the same
plane. Horizontal signals tend to follow the earths contour, and
are easier to capture using a horizontally polarized antenna.
See the BUX UNUN elsewhere on this
page.
BCC Photo � Photo above; BUX
COMM, "DBLCOMBO", see details
below. BUX COMM � graphics 1998-2004
(c)
By combining a pair (two) of
the single band HF Mobile (loaded)
tunable-tip antennas, you
can have an ideal, single element, (bi-directional) horizontal
dipole.
← At left; is a photo of the BUX
CommCo dipole configuration using a pair of our model BHF20M
mobile antennas, and our model DABRKT "Double Antenna
BRacKeT." The DABRKT will fit up to one and a quarter
inch (1-1/4") diameter mast.
The supporting mast is
attached to the apex of our warehouse. Overall height of my
antenna above ground is only 17 feet. When you see me on 20 meters
(14.070,15 USB) running test on RASCAL interfaces, this is the
antenna I am using.
←
By combining a pair (two) of the
single band HF (VHF) whips at left, you can have an ideal, single
element, horizontal dipole (beam). This type antenna opens the world of
HF and VHF communications for the apartment dweller, RV HAM, field-day
operating, and a variety of other uses and applications. Bracket alone
is $16.95
tuneable-tip antennas allow adjusting for minimum
VSWR.
or see the DBLSPCL; details
below↓
←
When you see me in QSO on 20 meters,
using PSK31, I am using this antenna mount with two of the BHF-20 M
antennas at 17 ft. An FT-817 at 5 watts PEP, worked 50 +
countries.
When installed on a rotor, this combo
makes a great bi-directional fixed-station antenna.
Turning radius, seventeen feet,
(approx).
HF Mobile
(loaded), tunable-tip
antennas
All text and graphics on these
pages are ��™ of G. E. Rogers Sr and BUX COMM Corp 1986 - 2009
All drawings, photos, text, and related
graphics are the property of G E "Buck" Rogers Sr.,
and may not be copied, or reproduced, in any form without the written
permission of the author.
