Following are digests of articles printed in the January, 1995 issue of
QST. Such digests are being prepared for each issue of QST, and posted
It is hoped that other hams will volunteer to post similar digests of
the other ham technical publications such as QEX, CQ, 73, COMMUNICATIONS
QUARTERLY, RTTY JOURNAL, et al. Especially desirable would be digests
of publications in other countries, such as the RSGB RADIO COMMUNICA-
TIONS and ham magazines in Europe, Japan, Australia, and other countries
around the world. We English speakers would especially enjoy them if
they were translated into our language, but they would also be valuable
additions to the world's knowledge if they were posted in the language
of origin. Who knows? Some bi-lingual ham somewhere might translate
them into English and re-post them.
Worldwide communications are getting better and better. The time has
come to make the world's ham press available to all hams throughout the
The major value of digests is to give readers sufficient information to
decide whether to obtain a copy of the full text. If any U.S. reader
wants a copy of an article in QST, please inquire of other hams in your
own neighborhood. Many have collections of back issues. Anyone who is
unsuccessful in finding a fellow ham with a collection should try every
library in the area, especially those at universities and technical
colleges. If all else fails, a copy can be obtained from the ARRL
Technical Department, 225 Main St., Newington, CT 06111-1494 USA for a
fee of $3.00 per copy. Remember, it is both cheaper and quicker to
obtain one locally.
Readers in most other countries can obtain copies from their own
national ham organizations, sometimes translated into their own
COPYRIGHT NOTICE: Copyright to all the following material from QST
Magazine is held by the American Radio Relay League (ARRL), effective on
the date of issue. Permission is granted for redistribution of the
following in its entirety, or in part, provided that this copyright
notice is not removed or altered and that proper attribution is made to
ARRL as publisher of QST, to the authors of the original articles, and
to W. E. "Van" Van Horne, W8UOF, author of this compilation.
TABLE OF CONTENTS
(line number in parentheses - counting from CUT HERE line)
TECHNICAL ARTICLES (TA)
TA1:The WB2 "REMote" Link 66
TA2:Putting Your Uniden HR-2510 on VHF and UHF 107
TA3:A Look at NVIS Techniques 156
TA4:Getting the Most Out of Your T-Network Antenna Tuner 190
PRODUCT REVIEW (PR)
PR1:QST Compares: 2-Meter FM Mobile Transceivers 288
PR2:GAP Challenger DX-VIII Vertical Antennas 453
PR3:Free Software 552
TECHNICAL CORRESPONDENCE (TC)
TC1:A Vertical Monopole With Elevated Feed - A Full-Length Radiator 595
HINTS & KINKS (HK)
HK1:Easier Adjustment for the Two-Band Coil-Loaded Antenna 667
HK2:Storing Coaxial Cable 697
HK3:Use Red Etch-Resist Pens, Not Black 713
FB1:"The Null Steerer Revisited" QST Jul 94 728
NEW HAM COMPANION (NHC)
NHC1:Gateways: Amateur Radio Meets the Internet 748
NHC2:Quick and Easy CW With Your PC 781
NHC3:The Doctor is IN 812
NHC4:Packet on the High Iron 824
NHC5:A Five-Element Quad Antenna for 2 Meters 839
GENERAL INTEREST ARTICLES (GI)
GI1:Call Sign License Plates 869
GI2:The Hiram Percy Maxim 125th Birthday Celebration 888
GI3:Ham Radio Bill is Now Law 904
GI4:A Call Sign Cap 929
GI5:The Meaning of OMIK 940
GI6:The Considerate Operator's Frequency Guide 959
TECHNICAL ARTICLES (TA)
Title>TA1:The WB2 "REMote" Link
Author>Millner, James - WB2REM
Source>QST Jan 95, pp. 29-34
Abstract>Construction of a remote operating system that will control a
Kenwood TS-440 at a distant site, using control signals on 222- or
440-MHz. and received audio on 2-meters. No computer is necessary.
Digest>WB2REM developed and built a remote operation control system some
15 years ago. With it, he operates his Kenwood TS-440 at a remote
location by sending control signals and audio to and from his operating
position via VHF/UHF radio. The system does NOT require a computer at
either end of the link. It needs only a controller interface that can
be built for a total cost of less than $150, using readily available
The overall system does require an HF transceiver similar to the TS-440
that is equipped for remote control. In addition, the operating site
requires a UHF transmitter (uplink) and a VHF receiver (downlink). FCC
regulations require control signals to be transmitted above 222.25 MHz.,
so either 222- or 440-MHz. can be used for the uplink, and 144-MHz. is
convenient for the downlink. The remote station requires a UHF/VHF
duplex transceiver equipped with fast diode T/R switching. The author
uses a dual-band HT for the control end of the link, and actually works
DX while operating mobile on his bicycle! His UHF and VHF signals pass
through a repeater as he pedals around the town.
The HF rig is tuned across the band using the UP/DOWN scan controls of
the TS-440. There must be a means of verifying the frequency on which
the transceiver is operating, and also the remote transmitter must
identify itself every ten minutes. WB2REM uses a voice-board accessory
available from Kenwood which, on demand, announces the operating
frequency in words. Identification can be conveniently done with an
automatic CW identifier, such as the one described by Bunn: "A CW
`Stamp' Identifier" in QST Oct 94.
Included with the article is a complete wiring diagram and parts list.
PC-boards for duplicating the system are available from the author for
the price of $16.50, including domestic shipping.
Title>TA2:Putting Your Uniden HR-2510 on VHF and UHF
Author>Fagas, Chris - WB2VVV
Source>QST Jan 95, pp. 35-38
Abstract>Describes simple modifications to adapt the Uniden HR-2510
10-meter transceiver for use with a transverter to transmit and receive
on VHF, UHF or Microwave bands.
Digest>As amateur activity spreads to more and more UHF and Microwave
bands, many hams find that the most convenient and affordable means of
joining the activity on a new band is to use a transverter. This
converts the output of an HF transceiver to the higher band and the
received signal down to the HF band.
For use at the home QTH, the transverters are usually used in
conjunction with the station HF rig. But in many cases, it is more
convenient to have a small and more portable transceiver dedicated to
working with the transverters. The Uniden HR-2510 is a single-band
transceiver designed for use on 10-meters. It is effective and
relatively inexpensive, so WB2VVV made some simple modifications to the
rig to optimize its performance with transverters.
The first modification provides adjustable control of the output power
so as not to over-drive the transverter. A fixed resistor in the driver
stage ahead of the final amplifier is replaced with an adjustable pot.
Next, a separate connection for receiver input is provided, bypassing
the built-in transmitter low-pass filter and T/R switch. To provide for
remote transmit/receive switching, a transistor-activated relay is added
inside the cabinet.
Finally, Mr. Fagas devised a way to reprogram the microprocessor so as
to allow the transceiver to transmit and receive over a 4.0-MHz. band
from 26- to 30-MHz. He does not provide the details for doing this in
the article for fear that it might be misused by non-amateurs. Instead,
he offers to provide the details to any amateur upon receipt of a SASE
including a copy of the writer's amateur radio license.
In a side bar with the article, Zack Lau - KH6CP/1 of the ARRL
Laboratory staff, reports that the HR-2510 tested in their laboratory
showed spurious signal transmissions too high by at least 14-dB. to
allow it to drive a transverter directly. He provides the schematic for
a filter that will reduce these spurs by some 30-dB., thereby
eliminating the problem.
With these simple modifications, the HR-2510 becomes an excellent
transceiver for this use.
Title>TA3:A Look at NVIS Techniques
Author>Farmer, Ed - AA6ZM
Source>QST Jan 95, pp. 39-42
Abstract>Obtaining blanket coverage of a limited geographic area through
the use of near vertical incidence skywave (NVIS) techniques.
Digest>Although much ham attention is directed toward working DX, some
activities depend upon reliable communication over a relatively limited
distance. Examples are emergency operations and traffic nets. Such
solid regional coverage, without gaps, is provided by "near-vertical-
incidence-skywave" (NVIS) techniques.
The essence of such operation is to operate on a frequency low enough
that radio energy directed vertically upward will reflect from the
ionosphere, then use an antenna that directs most of the energy upward.
The highest frequency at which a wave aimed straight up returns to earth
is called the critical frequency. For blanket coverage by skywave
propagation, it is necessary to transmit below that frequency, but not
so low that excessive loss of signal occurs due to atmospheric
absorption. The critical frequency can be calculated by computer
programs like MINIPROP.
Depending upon the time of day, time of year, and the state of solar
activity, this usually dictates a choice of 40-, 80-, or 160-meters.
Optimum antenna installations include horizontal dipoles or
inverted-vees at heights from 0.1- to 0.3-wavelengths.
For operating on 160-meters, even 0.1-wavelength height represents
relatively high towers. An alternative useful in some instances is a
miniature loop antenna mounted in a vertical plane close to the ground.
Title>TA4:Getting the Most Out of Your T-Network Antenna Tuner
Author>Griffith, Andrew S. - W4ULD
Source>QST Jan 95, pp. 44-47
Abstract>Describes T-network antenna tuners and shows how excessive
power loss can result from certain combinations of antenna and
frequency. Advises how to tune for optimum efficiency.
Digest>A conventional T-Network antenna tuner uses two variable
capacitors connected in series and one variable inductor connected from
the junction between the capacitors to ground. The center conductor of
the coax is connected to the respective capacitors at the input and
output; the shield is grounded. This article analyzes a typical example
of such a tuner in which the two capacitors can be adjusted from 20- to
240-pF. and the inductor between 0.1- and 35-uH.
This network can successfully match resistive loads of 10- to 3,000-ohms
to a 50-ohm transmitter output over the range of 160- through 15-meters.
On the 10- and 12-meter bands, the impedance range narrows to about
10-to 1500-ohms because the two capacitors cannot be adjusted lower than
20-pF. When the antenna load also contains reactance, the stated
matching range narrows, but very few cases will be encountered in which
the antennas cannot be matched to a 50-ohm transmitter.
It should be noted that this typical T-network is a kind of high-pass
filter and, as such, will not attenuate harmonics. Since modern
commercial transmitters and amplifiers must meet rigid spurious-emission
standards, harmonic suppression in the antenna tuner is no longer
A T-network can be adjusted in an infinite number of ways to make a
particular impedance transformation; therefore, any one of the three
components can be made fixed and the other two adjusted. If a tapped
coil is used for the inductor, it must be treated as the fixed element
and the capacitors adjusted to match. But if the inductor is the roller
type, a different method of tuning can be used.
Although a wide variety of different settings can perform the impedance
transformation, the power efficiency will vary accordingly. The amount
of power lost can, in certain circumstances, become a severe limitation.
The article contains graphs relating loss vs. load resistance. They
show that the loss rises as the load resistance is reduced. They also
show that losses tend to rise exponentially as the frequency becomes
lower. On 160-meters, losses of as much as 20-percent of input power
can be expected using the components as indicated in this example.
In general, it can be said that the larger the output capacitor becomes,
the lower the loss. Also, the higher the antenna resistance, the lower
the loss in the tuner. For use on the lowest frequency bands, an output
capacitor of 1000-pF., or greater, is advisable. Also, if a balun is
used after the tuner, in order to feed the antenna via an open-wire
line, use a 1:1 balun instead of 4:1.
In spite of all the measures that can be taken to maximize the
efficiency of the tuner, on 160-meters it may not be possible to lower
the loss below 0.2- or 0.3-dB. Even that small loss represents
5-percent, or more, power dissipation in the tuner itself. To avoid
destructive heating of the components, it may be necessary to reduce the
The author describes the proper methods of tuning roller-inductor- and
tapped-inductors-tuners, as follows. For roller inductors that can be
finely adjusted, first set the output capacitor to maximum and the input
capacitor to half scale. Adjust the inductor for a dip in the indicated
SWR, which may initially be barely detectable. Slightly increase or
decrease the input capacitance and readjust the inductor for a dip.
If the new SWR reading is lower than it was initially, continue
adjusting the capacitor in the same direction, readjusting the inductor
to minimum SWR with each change, until reaching the point where further
adjustments make no further improvement. If instead of initially going
down, the SWR goes up with the incremental adjustment, reverse direction
of the capacitor moves. If the minimum SWR that can be attained is
greater than 1:1, make a slight reduction of the output capacitor, and
repeat the previous steps. Optimum adjustment is reached when any
change causes the SWR to rise.
For tapped-inductor tuners, start by setting both capacitors to
mid-scale, select an inductance switch position and rotate the output
capacitor through its range to seek a dip in the SWR indication. If no
dip is apparent, set the inductance switch to another position, and
repeat. When a dip appears, adjust the input capacitor for minimum SWR.
Make a slight adjustment in the output capacitor, one direction or the
other, then re-dip by adjusting the input capacitor. If that drops the
SWR, continue in the same direction; otherwise, reverse the direction of
In some cases, an SWR dip can be obtained with different inductance
settings. Choose the setting that allows the use of the largest value
of output capacitance.
PRODUCT REVIEW (PR)
Conductor: Mark Wilson - AA2Z
Title>PR1:QST Compares: 2-Meter FM Mobile Transceivers
Author>Ford, Steve - WB8IMY
Source>QST Jan 95, pp. 70-76
Abstract>Review of 8 2-meter transceivers designed for mobile use.
Included are radios from Alinco, Azden, ICom, Kenwood, Standard, and
Digest>This review covers 8 currently-available transceivers especially
designed for mobile use. They are:
All of these are very small packages designed for mounting in, or under,
the dashboard of a vehicle and many, if not all, of the controls are on
the microphone. All units reviewed offer output power of 50-watts,
switchable in 2 or 3 steps down to as low as 3- to 10-watts. All offer
CTCSS encoders as standard equipment, and CTCSS decoders as optional
equipment, except for the Standard C-1208DA which makes it standard.
All offer memory channels and scanning.
The DR-130T is the simplest and easiest to operate of the units
reviewed. It omits some of the "bells and whistles" that other units
include, but concentrates on those features most often used. It also
has the lowest selling price, $309, of all those reviewed.
The unit offers either 5- or 50-watt output operation. Some reviewers
found that it became quite warm during 50-watt operation, but this
should not be a problem if special attention is given to assuring
sufficient air circulation across the rear-mounted heat sink.
The unit actually tunes over the frequency range of 136- to 174-MHz.
This includes part of the aviation band, but since it is sensitive only
to FM and aviation traffic is AM, this is of little use.
Reviewers comments were uniformly favorable except for complaints about
the manual, which is considered inadequate.
The PCS-7000H is the only radio in the group that offers a 2-year
warranty. Its ample heat sink allows it to run cool, even during long
conversations at the 50-watt level.
Receiver coverage extends all the way from 118- to 174-MHz., thus
including the aviation band from 118- to 136-MHz. When the receiver is
tuned to that band, it automatically switches to AM reception.
The "street price" is $335.
The IC-281H is not only a 2-meter FM transceiver, it is also a 70-cm.
receiver. This means that it can be used as one end of a full-duplex
cross-band operation if the other station can simultaneously transmit
on 70-cm. and receive on 2-meters.
Unfortunately, the low end of the 70-cm. reception is 440-MHz. That
means that the satellite sub-band is out of reach. Otherwise, it could
be used to operate packet at 9600-bits/s to work Oscars 22, 23, or 25 on
packet as well as Oscar 27 on FM voice.
The reviewers discovered that the radio can be modified to extend the
receiver coverage down to 430-MHz. and also to extend the 2-meter
coverage to 118-MHz. However, it requires very extensive modification,
including disassembly and unsoldering a surface-mount component, a
function that most hams would hesitate to undertake.
The TM-241A provides complete receiver coverage from 118- to 174-MHz.
and both AM and FM operation, so can be used to monitor the entire
aviation band when not operating on the ham band. Transmitter power can
be switched to 5-, 10-, or 50-watts.
The reviewers unanimously praised overall performance and found the
multifunction microphone especially well designed for mobile operation.
A late development is that the TM-241A has been accepted for military
use (i.e. MIL-SPEC) rated. This means that it meets the severe
endurance requirements set by the military.
Typical selling price is $335.
This transceiver is loaded with "bells and whistles"; some reviewers
feel too many. Most required several days to learn all of the various
features, the selection of which requires figuring out the multiple
functions on each control button.
One unusual feature is a built-in recorder that will digitize and record
16-seconds of incoming audio.
This unit is not only a 2-meter transceiver, it also is a full-band
receiver on 70-cm. This allows full-duplex crossband links if the other
station has a 70-cm. transceiver with 2-meter receive capacity, such as
the Kenwood TM-451A.
The broad bandwidth for 70-cm. reception makes it easy to operate packet
up to 9600-bits/s and work the Oscars 22, 23 and 25, which transmit
between 435- and 437-MHz. while listening on 2-meters. The rig provides
a 6-pin mini-DIN jack to connect to a packet TNC.
The average selling price of the TM-251A is $399.
The C-1208DA has all controls on the microphone so that the rig can be
mounted under the seat of a vehicle, or otherwise hidden from view.
When leaving the vehicle, users can take the microphones with them.
The downside is that the buttons are necessarily tiny and reviewers
found it somewhat awkward to operate. The digital display is difficult
to read in sunlight; it is necessary to hold it at a particular angle.
Of all the radios tested, this has the widest receiver coverage. It
tunes from 100- to 200-MHz., 250- to 520-MHz., and 800- to 1000-MHz.!
It can be used, as is, to work Oscar 27 satellite on FM voice (2-meters
uplink, 70-cm. downlink). It also has 9600-bit/s packet ability, so
could be used with Oscars 22, 23, and 25.
Street purchase price is $430.
The FT-2200 provides DTMF paging and also CTCSS encoding. It comes with
a detailed, well-written manual and reviewers found it easy to use. The
one criticism concerns a multi-function key which must be pressed and
held for a varying amount of time, depending upon what function is
desired. If the button is held too long, the operation that it
activates is the wrong one!
Receiver coverage extends from 110- to 180-MHz. and automatically
switches to AM when tuning the aviation band. Although the unit could
be used as a packet transceiver, it does not have a separate TNC jack
nor does it support 9600-bits/s packet.
Purchase price is $370.
The FT-2500M is exceptionally rugged. In fact, it was the first radio
in this group to be accepted under MIL-SPEC rating for use by the
military. The front panel is very well designed with only essential
controls visible. Less-used controls are behind a drop-down panel. The
accompanying manual received uniform praise from reviewers as uniquely
straightforward and reader-friendly.
The FT-2500M works well on 1200-bit/s packet. With an internal
modification, it can be made to operate at 9600-bits/s, but the
modification should only be attempted by those experienced in working
with surface-mount components.
Purchase price is $350.
Title>PR2:GAP Challenger DX-VIII Vertical Antenna
Author>Kennamer, Bill - K5FUV
Source>QST Jan 95, pp. 76-77
Abstract>Description and operating test results with the Gap Challenger.
An attempt is made to analyze the principles of operation, without
Digest>One of the more interesting antennas to be introduced in the last
several years has been the GAP Challenger DX-VIII. It is a vertical
designed for ground mounting, with an overall height of approximately
32-feet (9.75-m.). It is made of aluminum tubing. In the center, the
tubing is cut in two pieces and an insulator is inserted, forming a gap
between the two. It is this that forms the name of the company.
When it is erected, the manufacturer recommends that three 25-foot
(7.6-meter) long radial wires be attached to the bottom of the antenna
GAP recommends that the coax feedline be at least 65-feet long
(20-meters). Using its single feedline, it resonates on all bands in
the LF, HF and VHF parts of the amateur radio spectrum except for the
30- and 17-meter bands.
On 80-meters, the manufacturer claims an operating bandwidth of 130-KHz.
between 2:1 SWR points. The customer must specify in which portion of
that band the resonant frequency should be. On all other bands, the SWR
is rated better than 2:1 over the entire width.
A 3-foot (1-m.) long piece of plastic pipe is supplied with the antenna
to be used as a base. The antenna, itself, is shipped disassembled.
Included is a very thorough manual. The reviewer found that it is easy
to assemble in 1-1/2 hours, or less, using the supplied nut-driver as
the only tool.
The manufacturer has not published a theoretical analysis of the
operation of the DX-VIII, but it is clearly "a vertical monopole with
elevated feed", as described by Belrose in Technical Correspondence in
this issue of QST. A side-bar with the Product Review contains a
summary of an article from the December, 1991 issue of RADIO
COMMUNICATION (published by the Radio Society of Great Britain), by
Peter Hart, G3SJX which partially analyzes its operation, as follows.
The coax feedline leads through a hole in the outer wall at the lower
end of the antenna, making no connection to the tubing at that point. It
extends upward, through the gap, to the top of the antenna where it is
terminated by a large value capacitor connected between the center
conductor and the shield of the cable. The shield is also connected to
the top of the antenna tubing. At the gap insulator, the outer shield
of the cable is cut without damaging either the inner conductor or the
dielectric. The shield on the lower part of the cable is attached to the
lower piece of the tubing.
In addition, three stubs are shunted across the gap. They are made of
pieces of small diameter tubing spaced away from the main antenna tubing
with spacers of various lengths. One of the stubs extends upward from
the gap, the other two downward.
The series stub formed by the coax inside the upper portion of the
tubing is 1/4-wavelength long on 80-meters. It converts the large value
of the end capacitor to inductive reactance which then acts as
end-loading to resonate the upper portion as an 80-meter monopole. On
other bands, it and the other stubs work in ways that are "not clear"
to G3SJX, to resonate the antenna.
The reviewer had available, for comparitive tests, dipoles for 10-, 15-
and 20-meters at heights between 20- and 30-feet (6- to 9-m.), an old
Electrospace HV-3 vertical with 8 30-foot (9-m.) radials, and also a
Cushcraft R-7 multiband vertical. The HV-3 is 31-feet (9.5-m.) high and
operates as a top-loaded shortened monopole on 80-meters, a full-size
quarter-wave on 40-meters, and a 5/8-wave on 20-meters.
On 80-meters, the operating bandwidth was found to be appreciably wider
than specified: the antenna resonated at 3850-KHz. and showed SWR 1.6:1
at 3950, 1.4:1 at 3750. With comparative tests, the reviewer found the
signal strength using the GAP to be about 2 S-units poorer than the old
HV-3. On 40-meters, the GAP performed equally with the HV-3 and
outperformed the R-7 by about 1 S-unit. On 20-meters, the HV-3 and the
horizontal dipole both gave signals about 1 S-unit better than the GAP.
On 20-meters, the GAP and the R-7 delivered about equal performance, 1
S-unit below that of the HV-3 and the dipole.
On 15-meters, the GAP and the R-7 were equal, more than 2 S-units poorer
then the dipole at 30-foot (9-m.) height. On 12-meters, the horizontal
dipole was 2 S-units better and the R-7 about 1 S-unit better than the
GAP. On 10-meters, performance of the GAP was much poorer than any of
the other antennas.
The reviewer did not try the GAP on 6-meters, but did on 2-meters. On
that band, contacts were made but no comparison antenna was available.
He was surprised to find that he could successfully operate the GAP on
30-meters by using an antenna tuner, although the manufacturer does not
rate it for use on that band.
In summary, the reviewer feels that the GAP antenna does an effective
job on all bands where it is active, with the possible exception of
Source>QST Jan 95, p. 47
Abstract>Software, free for the asking, makes many calculations of
interest to hams.
Digest>(This is a short "New Products" announcement, not a full
Product Review, but it deserves inclusion in this Digest).
George "Murph" Murphy - VE3ERP, has released a new version of HAMCALC
software, which is a collection of computer programs of value to anyone
who experiments and designs in radio. Best of all, it is free for the
asking; one can download it from the ARRL BBS at (203) 666-0578, or via
The list of functions that can be performed by the various programs is
enormous. It includes such items as design of air-core inductors,
filters, antenna traps, attenuator pads, parabolic antennas, regulated
power supplies, series and parallel components, telescoping aluminum
tubing, great-circle paths, impedance-matching networks,
transmission-line losses, sag in wire antennas, and on, and on, ....
The programs are all user-friendly and menu-driven. On-screen
instructions are included for most functions.
The entire package can be downloaded from the ARRL telephone Bulletin
Board at (203) 666-0578, or via Internet, by ftp from a number of
sources including oak.oakland.edu. For those without modem access via
telephone, the author will provide the programs by mail. Contact him at
the following address:
George Murphy - VE3RP
77 McKenzie Street
Orillia, ON L3V 6A6
TECHNICAL CORRESPONDENCE (TC)
Conductor: Paul Pagel - N1FB
Associate Tech. Editor
Title>TC1:A Vertical Monopole With Elevated Feed - A Full-Length
Author>Belrose, John S. (Jack) - VE2CV
Source>QST Jan 95, pp. 78-79
Abstract>When a vertical monopole is fed at a point 1/3 of the way up
its height, it emits low-angle radiation over a much wider range of
bands than one fed at the base. This article describes the details.
Digest>Mr. Belrose, an ARRL Technical Advisor, makes the point that a
grounded vertical antenna with an elevated feed makes a better
multi-band DX antenna than does one of the same height with base feed.
A drawing accompanying the letter illustrates what is meant by an
elevated feed. It shows a typical amateur tower of height "H" which is
broken into two pieces, insulated from each other, at a point 1/3 of the
way up from the bottom.
A 50-ohm coax feedline runs to the base of the tower where it passes
through a 4:1 transmission-line unbalanced-to-unbalanced transformer.
The ground side of the transformer output is attached to the base of the
tower, as also are at least 3 radials cut to a quarter wavelength for
each band to be utilized. The "hot" side goes to a 1/4-inch (6-mm.)
diameter copper or aluminum tube that runs up the inside of the tower,
insulated from it, through the gap between the lower 1/3 and the upper
2/3 of the tower, and is connected to the lower end of the latter. Thus
the lower section acts as a transmission line, with characteristic
impedance near 200-ohms, feeding the upper 2/3 of the tower as a "thick"
The resulting antenna will give good performance over a much broader
frequency range than will a ground-mounted vertical. The radiation
pattern of a ground-mounted monopole shows a main lobe that concentrates
most of the energy at low elevation angles when the height is less than
5/8-wavelength. When it is greater than that, however, the low-angle
lobe breaks up and much of the radiation is emitted at high angles where
it is largely wasted.
Elevating the feed point to approximately 1/3 of the total height
prevents the breakup of the low angle lobe until the height is well over
a full wavelength. Consequently, the monopole with elevated feed will
deliver acceptable performance over a 5:1 frequency range (antenna
electrical heights of 0.2- to 1-wavelength).
To illustrate the difference in radiation patterns between the two
monopoles, vertical patterns for each were generated by computer using
NEC-2 software. The antenna modeled was a tower 12-meters (40-feet)
high with 4 insulated and resonant radials mounted 1-meter above
average ground. The one with elevated feed was broken at the 4-meter
level. Patterns were calculated for each band from 10- to 30-meters.
The 30-meter pattern (where the monopole is less than a half wavelength)
shows practically no difference between the antennas. Both radiate in a
main lobe at low angles. At 20-meters, the patterns show a decided
difference; the ground-based antenna now shows substantial radiation
above 60-degrees elevation.
For each band up to 15-meters, the elevated-fed antenna continues to
show a single lobe at low angles as the ground-based one radiates more
and more power in a high-angle lobe as its low-angle lobe shrinks. At
12-meters, the elevated-fed one also shows a high-angle lobe that is
beginning to steal energy from the low-angle lobe. At 10-meters (where
the antenna height is substantially greater than a full wavelength) the
elevated-feed no longer gives much benefit. Both antennas show
high-angle lobes that are at least 5-dB. stronger than the low-angle
HINTS AND KINKS (HK)
Conductor: David Newkirk - WJ1Z
Sr. Asst. Technical Editor
Title>HK1:Easier Adjustment For the 2-Band Coil-Loaded Antenna
Author>Michaels, Charles J. - W7XC
Source>QST Jan 95, p. 43
Abstract>A piece of wire, dangling from each end of a Lattin-type 2-band
antenna, makes adjustments easier.
Digest>Many years ago, William J. Lattin - W4JRW, published in QST a
description of how to make a dipole resonate on two adjacent bands using
only loading coils near the ends of the wire. Recently, W7XC wanted to
modify his 40-meter dipole to cover 80-meters, as well. He had
previously learned that adjusting a Lattin-type dipole to resonance on
both bands takes an annoying amount of cutting and splicing of the
higher-frequency portion of the wire, since it requires adding wire to
the original length, not t***.
To make it easier to adjust, W7XC added 4-foot (1.2-m.) pieces of wire
onto both ends of the 40-meter dipole and left them*** down, not
attached to the end insulator. Then he fastened a 5-foot (1.5-m.)
extension wire from the original end insulator to a second insulator at
each end of the antenna.
The Lattin design calls for loading coils of 100- to 120-uH. at the ends
of the higher frequency dipole. The author finished by soldering each
coil across the original insulator, electrically connecting the
extension wire to the original dipole. Then he was able to tune the
40-meter section by simply t*** the length of the*** wire,
and tune to 80-meters by similarly pruning the extension wires.
Title>HK2:Storing Coaxial Cable
Author>Pagel, Paul - N1FB
Source>QST Jan 95, p. 43
Abstract>Store unused coaxial cable on reels obtained at the hardware
Digest>Long lengths of coax cable can be stored conveniently by using
reels sold for holding garden hose. These are quite sturdy and often
available at discounted prices of the order of $15 or $20.
Alternatively, plastic reels are sold for coiling electrical cord.
These have outer diameters of about 14-inches (35-cm.) and can hold 50-,
or more, feet of RG-8 cable. They sell for approximately $6.
Title>HK3:Use Red Etch-Resist Pens, Not Black
Author>Covington, Michael A. - N4TMI
Source>QST Jan 95, p. 43
Abstract>Red pens are better than black pens for etch-resist use.
Digest>Red permanent-ink markers make better resist pens than black
ones. Further, the marking is nearly tranparent and it is easy to see
the copper underneath to be sure it is not being etched away. Lumocolor
Permanent Overhead-Projector pens are especially good for this use.
Title>FB1:"The Null Steerer Revisited", QST Jul 94
Author>Michaels, Charlie - W7XC
Source>QST Jan 95, p. 38
Abstract>Correct the schematic diagram in the original article, for
Digest>In Figure 1, the coaxial shield braid is shown grounded, but not
with a lead directly from the cable to the No. 2 terminal on transformer
T1. A short and direct connection is important, so the schematic should
be modified to show a lead directly from the end of the shield nearest
the transformer to the No. 2 transformer terminal.
NEW HAM COMPANION (NHC)
The New Ham Companion is a regular section of QST. It features
articles of primary interest to newcomers to the hobby.
Title>NHC1:Gateways: Amateur Radio Meets the Internet
Author>Ford, Steve - WB8IMY
Source>QST Jan 95, pp. 58-59, 69
Abstract>Connect VHF/UHF packet networks in different cities through
gateways to and from the Internet. TCP/IP protocol must be used.
Digest>Packet operations and bulletin boards are thriving and continuing
to grow all over the country. Links between them, however, can be
tenuous, so messages sent over considerable distances can be delayed, or
even lost. HF packet and satellites help bridge the gaps, but both have
An alternative for long-distance links between packet systems is the
Internet, which is fast, continuously available, and highly reliable. At
least 30 packet/Internet gateways are now in operation in the USA, and
many more will soon become available.
It behooves all packet operators to prepare to take advantage of such
gateways as soon as possible. To do so, it is necessary to convert to
TCP/IP operation. This is the protocol that is universally used on
Internet, and so a TCP/IP message can pass directly from packet-to-
To convert to TCP/IP, an operator needs only NOS software. The TNC must
be capable of operating in KISS mode, but practically all modern ones
Using NOS introduces some complexities and a guide book will go a long
way to ease the conversion. The author recommends "NOSIntro", by Ian
Wade - G3NRW, published by the ARRL.
Title>NHC2:Quick and Easy CW With Your PC
Author>Taggart, Ralph E. - WB8DQT
Source>QST Jan 95, pp. 60-61
Abstract>Construction of a simple interface to connect a computer to a
radio for sending and receiving CW.
Digest>Many CW operators, especially those who have multi-mode
communications processors (MCP) for operating digital modes, like to use
their computer keyboards to replace keyers in forming code, and also for
the computer to decode the received Morse code signal. WB8DQT, in this
article, points out that one does not need an MCP; a simple interface
can be used, instead.
The article presents construction details for a combined receive-
interface circuit and transmitter-keying circuit. The total parts cost
of the combination should be less than $50.
Complete schematic diagrams and parts list are included, as well as
alignment instructions. The unit connects to the computer via the
parallel printer port; only four of the contacts are used. Connections
to and from the radio are only two: audio output from the radio's
headphone jack, and keying input to its keying jack.
An etched and drilled PC-board is available from FAR Circuits, 18N640
Field Court, Dundee, IL 60118, for $6.50 including domestic shipping.
The software required is known as MORSE.EXE, which can be obtained at no
cost from the ARRL telephone bulletin board system, (203) 666-0578, or
from several other sources.
Title>NHC3:The Doctor is IN
Source>QST Jan 95, p. 63
Abstract>Questions and answers of primary interest to newcomers.
Digest>Questions discussed in this issue include: why repeaters operate
with offset frequencies; the possibility of a geostationary amateur
radio satellite; the reason why a multiband dipole might fail to operate
on one band; and possible 40-meter compact beam antennas.
Title>NHC4:Packet on the High Iron
Author>Ford, Steve - WB8IMY
Source>QST Jan 95, pp. 64-66
Abstract>Relates a train trip on which he operated packet, as well as
FM, through the window of his car.
Digest>WB8IMY took a trip on an AMTRACK train from New York City to
Orlando, Florida, almost a 24-hour train ride. During the journey, he
operated 2-meter packet, as well as some FM voice, from his roomette.
He carried with him his 2-meter HT, a Kantronics KPC-3 TNC and a laptop
computer. All along the route, he was able to contact repeaters and
PBBSs through the window of his car.
Title>NHC5:A 5-Element Quad Antenna for 2-Meters
Author>Reynante, Jim - KD6GLF
Source>QST Jan 95, pp. 67-69
Abstract>Construction of a simple and cheap high-gain 2-meter antenna.
Digest>KD6GLF found himself a bit too far from the local repeater to
provide reliable communications with an omnidirectional antenna. His
solution was to design and build a 5-element quad antenna. His design
is very simple and inexpensive. It is completely described in this
The mast and boom are both made of 2 x 2 inch (50 x 50 mm.) lumber. The
spreaders for the quad elements are made of 5/8-inch (15.6-mm.) diameter
dowel sticks, about 30-inches (76-cm.) long. The elements are made of
No. 10 copper wire.
A plot of the SWR across the 2-meter band is included. It shows a
minimum of about 1.4:1 at mid-band, 1.8:1 at the low end and 2.0:1 at
the high end of the band. The antenna provides gain of about 11 dBi.
The author reports that he has no difficulty accessing repeaters up to
50-miles (83-km.) away using only his HT with power output of 1.5-watt.
He cannot even hear those repeaters when he uses his quarter-wave
ground-plane antenna, although it is mounted 10-feet (3-m.) higher than
GENERAL INTEREST ARTICLES (GI)
Title>GI1:Call Sign License Plates
Author>Ludkiewicz, Mike - W1DGJ
Source>QST Jan 95, pp. 23-25
Abstract>Collecting auto license plates bearing ham radio calls.
Digest>W1DGJ enjoys the hobby of ham radio in two ways: by operating
his amateur station, and by collecting ham radio license plates from the
In this article, he gives a short history of states offering auto
license plates bearing amateur radio call signs. Apparently, the first
state to do so was Michigan, in 1939. By the 1950s, almost every state
did, and they continue to this day.
Accompanying the article are illustrations of a few plates from various
states, as well as one from a foreign country.
Title>GI2:The Hiram Percy Maxim 125th Birthday Memorial Celebration
Author>Cain, James D. - K1TN
Source>QST Jan 95, pp. 26-28
Abstract>A QSO Party to celebrate the 125th birthday of Hiram Percy
Digest>In early September, 1994, an ARRL QSO Party was held in
celebration of the 125th anniversary of the birth of Hiram Percy Maxim,
ARRL's founder. Participants could apply for a certificate; more than
5000 of which were issued.
The event will be repeated in September, 1995. Details will be
Title>GI3:The Ham Radio Bill is Now Law
Author>Mansfield, Steve - N1MZA
Source>QST Jan 95, pp. 48-49
Abstract>The Ham Radio Bill passed Congress and was signed by the
president. It is now Public Law 103-408.
Digest>After trying for several years, the ARRL succeeded in persuading
the United States Congress to pass a joint resolution acknowledging that
radio amateurs provide valuable help during all kinds of emergencies.
It expresses the "sense of Congress" that all government agencies should
encourage the use of new technologies in the amateur service. It also
recommends that authorities throughout the nation should make
"reasonable accommodations" for amateur radio operation from private
homes, automobiles, and in public places.
The resolution was signed by President Clinton October 22, 1994. It
thereupon became Public Law 103-408.
Although this law requires no specific action by any government agency
or personnel, it can be of help in negotiations with any authority at
any level of government that might be acting, or planning to act, in
ways that might impede lawful amateur activities.
Title>GI4:A Call Sign Cap
Author>McCarthy, George - W6SUN
Source>QST Jan 95, pp. 50-51
Abstract>Caps and hats displaying call letters.
Digest>Many hams wear caps or hats of varying descriptions bearing their
call letters emblazoned on them. In this article, Mr. McCarthy relates
some of his experiences while wearing his.
Title>GI5:The Meaning of OMIK
Author>Cain, James D. - K1TN
Source>QST Jan 95, pp. 52-55
Abstract>Describes OMIK, an organization formed by African-American hams
but open to all.
Digest>OMIK is a national ham radio organization made up primarily of
African-Americans. The organization has more than 2500 members and has
been active for more than 40-years. It prides itself on its
informality, and carries on many worthwhile activities.
In the early days, the organization grew largely in response to the
discrimination the members received from racial bigots in other
organizations. OMIK is open to membership for anyone "interested in
applied electronics", not necessarily licensed hams, and certainly
without regard to race.
Title>GI6:The Considerate Operator's Frequency Guide
Source>QST Jan 95, p. 86
Abstract>A recommended frequency plan for the HF bands.
Digest>Following is a frequency plan for each of the HF amateur bands.
It is offered as a "gentlemen's agreement" for orderly division of the
assigned amateur bands to minimize interference. It does not have the
force of law; other than under the provisions of FCC rules, no frequency
is assigned for the exclusive use of any station, or for specific modes
1.800-1.830 CW, RTTY and other narrowband modes
1.830-1.840 CW, RTTY and other narrowband modes, intercontinental
1.840-1.850 CW, SSB, SSTV and other wideband modes, intercontinental
1.850-2.000 CW, phone, SSTV and other wideband modes
3.590 RTTY DX
3.790-3.800 DX Window
3.885 AM calling frequency
7.040 RTTY DX
7.290 AM calling frequency
14.100 NCDXF beacons
14.286 AM calling frequency
29.300-29.510 Satellite downlinks
29.520-29.580 Repeater inputs
29.600 FM simplex
29.620-29.680 Repeater outputs