The Swiss Quad Antenna at ZS6PP
September 1967 QST
design for a "Swiss Quad" antenna appeared in the September 1967 edition
of QST magazine. One of its touted strong points is not needing spreaders
or a boom. I am not an antenna design guy, so I can't comment on its
usefulness. No gain measurement was provided by the author. The article
states that the antenna had not yet enjoyed widespread adaptation in
the U.S. at the time of the writing. A Google search for Swiss Quad
antennas turns up a handful of modern examples:
LU7MGP. I could not locate an example of a computer-generated gain
plot (radiation pattern) for the Swiss Quad, so if you know where one
exists, please let me know so I can post a hyperlink. Maybe you own
a copy of EZNEC
and can model it? BTW, the drawings are very well done a la patent artwork.
September 1967 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 (if any) are hereby acknowledged.
The Swiss Quad Antenna at ZS6PP
Rotatable Antenna with Phased Elements
By E.P. Towers, ZS6PP
This antenna, designed originally by HB9CV, has not yet received
widespread attention in the Western Hemisphere. Measurements made by
the designer indicate that its performance is superior to the conventional
two-element quad, while the structure is much simpler and sturdier.
In a worldwide survey of 60 DX-minded hams,1 the majority
rated the quad as the "Number One" antenna. However, as we all know,
this antenna is more difficult to construct and erect than a conventional
Yagi beam. It is for this reason, presumably, that it is not in such
general use as its reputation would lead us to expect.
conducting extensive experiments, HB9CV was so successful in simplifying
the construction and design of the quad that he filed a patent application
in 1960 for an entirely new concept of this antenna, and named it the
"Swiss Quad."2 Since then, the design of this antenna has
been treated in additional articles by others.3 Reference
to this previous material is recommended for full information.
In constructing a Swiss Quad for 20 meters, the author found that
he had to modify and adapt details suggested by these articles. In response
to requests from other hams around the world for information on his
design, these notes from his own experience and that of others who have
constructed similar antennas are presented. Due acknowledgment is made
here to the inventor and to the authors of earlier articles.
Refer to the sketch of Fig. 1 for a general idea of what the Swiss Quad
looks like. It differs from the conventional quad electrically in that
both elements are driven - with a phase difference of 180 degrees. Construction
is simplified by making the horizontal members of aluminum tubing sufficiently
rigid to support the weight of the vertical members, which are made
of wire, thereby eliminating the customary spreaders. Additionally,
the horizontal members are bent in such a manner as to provide the desired
element spacing without the need for a boom.
The author's antenna
is fed with coax line and gamma match, as shown in Fig. 2.
The vertical members are 230 inches long for 14,250 kc.
Thus the supporting mast must be about 20 feet long, plus sufficient
length at the bottom for mounting in a rotator socket or tower bearing.
It may also be desirable to add rigidity to the antenna by extending
the mast 2 or 3 feet above the top horizontal members so that the outer
ends of these members can be guyed to the mast with nylon cord. In any
event, it will usually be necessary to splice sections of tubing together
to obtain the necessary mast length. A method of splicing that the author
found satisfactory is illustrated in the sketch of Fig. 3. Sections
of 2-inch 10-gauge dural tubing were used for the mast. Further strength
can be added by applying a self-guying or truss system to the mast.
However, the author did not consider this necessary.
The horizontal members are fastened to the mast at the
cross-over points by means of two brackets (one for the top set, and
one for the bottom set). The brackets are made up of three pieces of
aluminum or steel angle, as shown in Fig. 4. An alternative that would
avoid welding would be to use wider angle stock which would provide
space for attaching the element-supporting angles individually to the
mast with U bolts and serrated yokes. If this method is used, care must
be taken to make sure that the two angle pieces are oriented at exact
right angles to each other. (The welded arrangement assures this automatically.)
The antenna elements must be insulated from the brackets. To accomplish
this, the author cut sections of flexible 1-inch polyethylene pipe to
lengths slightly longer than the bracket. The pipe was then slit lengthwise
so that it could be spread and forced over the 7/8-inch aluminum tubing
of the elements. The angles should be notched as shown to allow the
clamps (gear-type, stainless steel) to secure the elements firmly. The
top bracket can be mounted permanently on the mast before assembling
the antenna. Mounting of the bottom bracket should be postponed until
The sketch of Fig. 5 shows the dimensions
of the horizontal antenna members used by the author for 14,250 kc.
All four members are made identical. Forty-five degree bends are made
at equal distances from the centers of a 16-foot length of 7/8-inch
18-gauge aluminum tubing which forms the center section. (Borrow a conduit
bender from your local electrician, or have him do the job; otherwise,
the tubing is sure to kink when the bends are made.) The ends are slit
to take extensions of 3/4-inch 16-gauge tubing. The junctions are secured
with stainless-steel gear-type hose clamps. The ends of the extensions
should be flattened and drilled for screws that will be used to fasten
the horizontal members and the vertical wire members together. The extensions
are not added until final assembly.
can be started by laying the mast, with upper bracket attached, across
the tops of a pair of stepladders at least 5 ft. high. Clamp the top
pair of horizontal members not too tightly in the bracket while their
positions are adjusted so that the members cross each other at their
exact centers. Then twist the members in the bracket, if necessary,
so that they lie in the same plane, at right angles to the mast. Clamp
the members firmly in this position while hole centers are marked at
the exact centers, and in the mast bracket, as shown in Fig. 4. Drill
the holes for sheet-metal screws, attach soldering lugs, line up the
members accurately again, and tighten the clamps. Wire the three lugs
together with the shortest possible leads. Do not allow the leads to
touch the bracket at any point. The author found this precaution necessary
to obtain a satisfactory matching adjustment.
The end extensions
can now be added, and the telescoping adjusted to give the widths shown
in Fig. 1. The two extensions in each element should be maintained at
equal length, of course. Give all four ends of the horizontal sections
a slight upward bend to help compensate for the weight of the vertical
The vertical wires can be made of No. 14 copper
wire, or stranded wire of equivalent cross section. No. 8 aluminum TV
ground wire is also suitable. If solid wire is used, stretch the kinks
out, and try to avoid reintroducing them during the assembly. Measure
off the vertical lengths shown in Fig. 1. Mark the wires plainly at
the measured length, then add several inches for adjustment. Attach
the top ends of the wires securely to the ends of the top set of horizontal
members. Then spray all connections with acrylic, or apply other suitable
protection against corrosion, or loosening of the securing bolts.
At the center of the clearest available space, drive a section of
pipe whose inside diameter is slightly larger than the outside diameter
of the mast into the ground. Swing the mast vertically and insert the
bottom end into the pipe. If an extension can be added temporarily to
the mast to bring the lower horizontal members at step ladder height
above ground, so much the better. (It may be necessary to guy the mast
temporarily with rope.)
Temporarily clamp the bottom mounting
bracket to the mast, while the mounting and adjusting procedure described
previously for the upper set of horizontal members is repeated for the
bottom set. Be sure that the longer extensions are on the same side
of the mast as those of the upper set, and that the sets are lined up
as accurately as possible in the same plane. At the conclusion, give
the ends a slight downward bend.
Attach the vertical wires temporarily
to the bottom horizontal set at the measured points. Then slide the
bottom bracket down on the mast until the vertical wires are reasonably
taut, and reclamp the bracket.
The author made
the matching section of 3-conductor plastic-insulated electrician's
house wire, conductors in parallel. The wire was spaced about 1/200
wavelength (about 4 inches for 14 Mc.) from the elements by means of
a series of aluminum clamps spaced at intervals, as shown in Fig. 6.
(In some other instances, it has been necessary to use either wider
or closer spacing to obtain a match.) The insulation was removed from
the wire only at the ends for connection to the adjustable clamps, and
at the center for connection to the feed line. Notice that the matching
taps must be made at equal distances from the cross-over point. The
distances from the taps to the ends of the horizontal members will not
be equal because of the difference in lengths of the reflector and director
The matching taps were set initially about halfway between
the bends and the ends of the horizontal members. A short length of
line terminated in a loop of 2 or 3 turns of wire was connected to the
feed point. Resonance was then checked by coupling a grid-dip oscillator
to the loop. All four lengths of the vertical wires were then adjusted
equally until the g.d.o. showed resonance at the desired center frequency.
The bottom bracket was then repositioned to bring the vertical wires
taut, and the bracket was fastened permanently in place.
line was then connected and the matching taps adjusted for minimum s.w.r.,
keeping the taps at equal distances from the cross-over point. The author
found that there was no change in the s.w.r. when the antenna was elevated
to full height.
Those with tilt-over towers should have no difficulty
in mounting the antenna. Those with fixed towers will probably have
to feed the mast up through the tower, fasten on the top horizontal
members, raise the mast, and then attach the bottom set of horizontal
No attempts were made to establish the
gain of the antenna in respect to a dipole. On receiving, signals can
be heard that just aren't there on a dipole. With the bottom of the
antenna 35 ft. above ground, and an input of 150 watts, performance
on transmitting has been excellent to all points on the globe. Judging
from S-meter readings, the front-to-back ratio appears to be better
than 20 db.
1 Ross, "How DX Kings
Rate Antennas," QST, January, 1964.
2 Baumgartner, "The Swiss
Quad Beam Aerial," R.S.G.B. Bulletin (England), June, 1964.
DL-QTC (Germany), October, 1964. Amateur Radio Bulletin (Australia),
April, 1965. Radio ZS (Republic of South Africa), August, 1965.