is a story of one Ham's experience in determining how the performance
of his Yagi antenna compared to his identically configured (number of
elements, height off of the ground, etc.) cubical quad antenna. His
location was a farm field in Tennessee, back in the mid 1960s, so there
was really not much in the way of obstacles to perturb signals arriving
at one antenna versus the other, except of course when the direction
of operation happened to have the antennas in line with each other.
Both antennas were tuned for optimal performance at 14.22 MHz,
which is in the high frequency (HF) band.
October 1966 QST
of Contents]These articles are scanned and OCRed from old editions of the
ARRL's QST magazine. Here is a list of the
QST articles I have already posted. All copyrights are hereby acknowledged.
See all available
vintage QST articles.
Yagi vs. Quad
An artist's sketch of the spacious antenna site of W4RBZ. The beams
are mounted 80 feet above the ground on telephone poles spaced 150
Establishing Antenna Superiority Through Reception Reports
By Robert E. Fitz, W4RBZ
After more than 30 years of
hamming from a series of temporary and semi-permanent locations, my
first act upon retirement from the Air Force was to settle at a permanent
location on a small farm in Tennessee and install a pair of the biggest
telephone poles I could acquire.
The many discussions I had
on the ham bands regarding the Yagi beam vs. the cubical quad led me
to conclude that the ideal sport would be the on-the-air comparison
of the two; I wanted to know exactly which antenna I should keep as
the ultimate. These QSOs concerning the Yagi and the quad did not convince
me that either one of them was vastly superior to the other. A big percentage
of the quad men seemed only to be comparing their quad against tribanders
or small beams that had been used in the past.
It seems to be
pretty well established that at the lower heights a quad has a definite
edge over the Yagi. However, I was curious to know how the two antennas
would compare when both were placed at a relatively high elevation.
The merits of Yagis and quads have been expounded through the years,
with it being a matter of opinion which antenna is the superior
of the two. W4RBZ was fortunate to have enough time and real estate
to erect both antennas and make on-the-air comparisons. Here's what
he found out.
A 20-meter 4-elemen t commercial monoband beam was installed on one
of the previously-mentioned poles. This antenna worked better than any
antenna I had ever used before at any location. About two months later
I installed a 4-element quad, using the fiberglass arms and aluminum
spiders available on the market. A coax switch was mounted on the station
control panel to permit instantaneous switching from one antenna to
the other for a rapid cross check.
At the time this article
is being written, I have used the two antennas for about three months
and have checked both antennas with over a hundred stations. Most of
the stations that I asked to give a comparative report were foreign;
a definite effort was made to concentrate on the long-haul boys.
Any good engineer or analyst could point out a number of weaknesses
in my system of comparison. This I will concede. I have only the standard
test equipment available to the average ham; I don't have the capabilities
for installing model antennas or conducting elaborate laboratory tests.
My only motive was to determine whether a good commercial beam performed
as well as, the same as, or better than a typical cubical quad installed
at the same height at the same location by a ham of average ability
with ordinary facilities and equipment.
First of all, a short
description of the antennas is in order. The Yagi has a 36-foot boom
and was adjusted strictly in accordance with the directions given by
the manufacturer. The quad is mounted on a 30-foot boom in a diamond
configuration and was originally installed using the dimensions given
in a previous QST article1 and in use by a number of hams.
Both antennas were peaked to a fundamental frequency of 14,220 kc.
Each antenna is on a separate telephone pole and the boom of each is
mounted exactly 80 feet above ground. The Yagi is about 30 feet closer
to the shack, and is nearer to the highway and power lines; however,
the quad is closer to some tall trees about 50 feet high. Both antennas
are raised and lowered by similar elevator-cage hoisting arrangements.
This photograph shows some of the details of the quad and Yagi antennas.
As mentioned earlier, the quad was originally installed using
those element dimensions that seem to be most commonly employed. During
the firs two weeks of testing there was practically no difference between
the antennas. Then the quad was lowered and completely retuned for maximum
forward gain. This seemed to give the quad an edge on some contacts.
After the quad had been in use in this condition for about three
weeks, one of the old antenna experts from the West Coast suggested
that my quad still might not be peaked for maximum performance and suggested
that I try his dimensions. This I did. The quad performance fell off
noticeably. For the next 25 or 30 checks almost every station giving
a comparison reported either that there was no noticeable difference
between the antennas or that the Yagi had the edge. This was most noticeable
on the long-haul contacts. Previously, VU2CK had reported on several
occasions that the quad had about a one S unit advantage; after this
change, Karnik reported that there was no noticeable difference between
antennas. The same was true with several 9M2, 9M6 and VK9 stations.
The quad was again retuned for maximum forward gain, and tests
I will only cite my experience with the
Yagi and quad installation. In general, there was practically no difference
in signal strengths on the short-haul contacts, and there was seldom
any difference on medium-haul contacts to stations in Europe, Africa
and the mid-Pacific. However, on the very-long-haul contacts to the
Far East, Asia and the South Pacific, the quad had a fairly consistent
2-3-db. edge. On only a few occasions was there a big difference in
reported signal strengths; this seemed to work both ways, with the quad
being given a 2-3-S- unit advantage in a few instances and the Yagi
given the same advantage in a few others.
On a number of checks,
inconsistencies in the reports indicated that the different angles of
radiation of the two antennas had pronounced effects. For example, on
one occasion a JA, DU and YK6 were worked in quick succession. The JA
contact gave the quad the edge, the DU reported the stronger signal
from the Yagi and the VK6 reported no difference in signal strengths.
Instances of this nature occurred frequently.
I learned early
in the game that, under ordinary conditions of QSB and QRM, one switch-over
between antennas did not give a valid comparison; the signals from the
two antennas were generally so close in strength that several checks
in quick succession were necessary for the other station to be able
to give a fair evaluation.
While my quad seemed to have an edge
on long-haul contacts, there were still times, under the varying condition
of propagation, that the Yagi put out a stronger signal. The type of
antenna in use at the" receive" end was definitely a factor. Shown below
is a summary of my last 100 reports, the results of which are typical
of my experience over the past three months. The quad was tuned for
maximum forward gain for these checks.
of note is that there was never any reported difference on long-path
contacts. This could be checked on only about a half dozen occasions,
but no one reported any difference between antennas on the few long-path
There are several factors, other than signal strengths
at the" receive" end of the circuit, that must be given consideration
in any final selection of the better of the two antennas. Even when
tuned for maximum forward gain, my quad has a better front-to-back ratio:
received signals were generally weaker off the back of the quad. The
Yagi has stronger side lobes; a number of times, after checks with long-haul
stations, a W station quartering off the side would break in to tell
me that the Yagi appeared to be stronger during the test. This was also
noticeable in reception. I also noted that during periods of heavy rain
the quad had considerably less precipitation static.
other hand, the Yagi is much stronger structurally and mechanically.
The Yagi was comparatively easy to assemble and raise. Constructing
and installing a 4-element quad is like trying to handle a crowd of
romantic octopuses. During periods of high winds the Yagi seems much
more stable and less inclined to shake itself apart or to tear the telephone
pole out by the roots.
During the tests I had lightning strike.
At the time of the stroke, both antenna were grounded at the station
through a Waters Protax coaxial switch.2 The Yagi, with its
grounded boom, suffered no damage. The quad driven element was burned
and cut in two and a small amount of damage was done in the station.
In summary, after three months of playing with the two antennas,
I have found that neither is overwhelmingly superior to the other. I
know I have two good antennas since they both perform well at my location.
For the average U.S. contact or during QSOs of 2000-6000 miles, my antennas
seem to run about neck and neck. The quad has demonstrated to me an
advantage on the long-haul contacts that makes a difference in pile
ups; however, this was not true in every instance. I have also learned
that the quad must be carefully tuned at the actual site of operation
to acquire this advantage.
I still have a lot of playing to
do. I am now trying to figure out some easy way of tying the two antennas
together and possibly feeding them in phase to see what happens; to
date I have come up with no simple system of phasing two antennas 150
feet apart and at the same height. I would welcome any ideas on this
I also have a V beam aimed east and west. While I did
learn that this antenna outperformed a tribander, I haven't yet gotten
around to comparing it with my quad or Yagi on 20 meters. I also want
to compare a Yagi "Christmas tree" against a triband quad; this I intend
to do during the next few months.
I'm still not sure which antenna
I will finally keep. Only when someone notices an ad in the back of
QST listing an antenna for sale will it become obvious which antenna
I have selected as the best for my particular station. However, I'll
probably wind up keeping the antenna that succeeds in riding out the
Tennessee summer thunderstorm season!
Bergren, "The Multielement Quad," QST, May, 1963.
Protax switches are not designed to protect equipment
from a direct lightning stroke - Editor.