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. As time permits, I will
be glad to scan articles for you. All copyrights (if any) are hereby acknowledged.
As with most
hobby and how-to magazines, QST has had a long-running monthly column featuring handy tips
from readers and sometimes from the column editor's (currently Steve Sant Andrea) own
experiences. It has taken various names over the years such as "Gimmicks and Gadgets" and now
"Hints & Kinks." This installment from the December 1966 QST presents a short introduction to
a VHF 'Lazy-H' antenna for mounting in the attic (outdoor restrictions were common even half a
century ago). It is of simple construction using lamp cord in the configuration and element
lengths given - still useful in 2013.
V.H.F. Lazy-H Antenna
Gimmicks and Gadgets
An Attic Array for Cliff Dwellers
an indoor antenna to perform satisfactorily is not always easy. Certain sacrifices will result
from any attempt to install an indoor antenna. Yet, by taking advantage of broadband antennas
and effecting the best possible impedance match to them, worthwhile results can be secured from
an "attic special."
The 2-meter Lazy H described in this article is an old standby which
should bring back a few nostalgic memories to 10- and 20-meter operators who have dabbled with
combinations such as this. The entire system, including 40 feet of 300-ohm ribbon line, cost the
author less than two dollars. It took about 45 minutes to cut the wire to length, tack the system
to the attic wall, and adjust the matching transformer for an s.w.r. of 1:1. At optimum efficiency
this antenna theoretically should be capable of a maximum gain (bidirectional) of about 5.9 decibels.
The overall efficiency will be governed by the placement of the array with respect to house wiring,
water pipes, gutters and downspouts. The antenna should be kept as far away from such things as
possible, to lessen the chance of pattern distortion, detuning effects, and absorption of the
Of any number of simple indoor antennas tried for operation on 6 and 2 meters,
the Lazy-H has been superior to all others used.Making The Antenna
A 10-foot length of a.c. zip cord was used for the W1CER Lazy-H. The cord was split at one
end and the two conductors were pulled apart, making two 10-foot lengths of insulated wire. Each
wire was pruned to a length of 115.5 inches and pinned to the attic wall in the configuration
shown in Fig. 1, so that their center sections B-B, crossed. A piece of cardboard, 3 1/2 inches
square, was used as a spacer at the point where the two are transposed, permitting uniform spacing
to be maintained between the phasing line. The insulation was stripped from the wires at the points
marked X, permitting the matching transformer to be soldered into place. The matching transformer
was fashioned from a 20-inch length of 450-ohm open-wire line.Tuneup
is used at the author's station for coupling the v.h.f. equipment
to the 300-ohm transmission lines which feed the antennas. Initial tests were made by terminating
the transmission line with a 300-ohm noninductive resistor and applying a few watts of transmitter
output power to the line through an s.w.r. bridge. The Transmatch was adjusted for a 1:1 s.w.r.
reading and the dial settings were noted on paper. Next, the terminating resistor was removed
and that end of the feed line was tapped along T1
, experimentally, until a 1:1 match
was obtained at the same setting of the Transmatch controls that gave a 1:1 match with the 300-ohm
termination. The dimensions given in Fig. 1 should be well within the "ball park" and should provide
a close match at 145 Mc. The matching transformer should be adjusted for your favorite portion
of the band. Frequency excursions to other parts of the band will be possible, but the s.w.r.
will rise somewhat as you depart from the part of the band to which T1
has been tuned.
The Transmatch will permit matching the transmitter to the line and will disguise the slight mismatch
at "off" frequencies, enabling the transmitter to load up normally. If coax line is preferred,
a balun transformer1
can be attached to T1
in place of the 300-ohm transmission
line after the system has been tuned as just described. This will permit the use of 75-ohm coaxial
line, if desired.Performance
Since the Lazy-H is a bidirectional
array, it should be oriented for maximum radiation in your favorite direction. In the author's
case, north-south directivity was desired so the array was tacked to the south wall of the attic.
Although maximum radiation is at right angles to the plane of the antenna, some side response
exists, making it possible to work in all directions but with reduced efficiency off the ends
of the antenna.
Fig. 1 - Dimensions for the 2-meter
Lazy-H antenna. Make certain that the
center sections, B, are transposed as shown.
During an hour of casual listening with an SR-42 transceiver, several W2 stations in New
York and New Jersey were copied Q5 while using the Lazy-H. Stations as far north as Massachusetts
were also received well above the noise level of the receiver. Many of the stations heard were
more than 100 miles away, offering proof that the antenna was performing satisfactorily.
An antenna of this type should deliver comparable performance on 6 meters, provided careful
attention is given to the dimensions and to the matching. Complete data covering antennas of this
variety is given in the ARRL Antenna Book,
Chapter 4. An outdoor version of the Lazy-H
could be fashioned by mounting the elements on 1 X 1-inch lumber support arms. It would then be
possible to rotate the array, and greater efficiency should be possible since the antenna would
then be out in the clear. - W1CER1 The Radio Amateur's
V.H.F. Manual, pp. 188-189. Posted 3/16/2013