Digest of Articles - QST Mar 94 (Long - 53k)

Digest of Articles - QST Mar 94 (Long - 53k)

Post by W. E. Van Hor » Wed, 13 Jul 1994 23:49:32

DIGEST OF ARTICLES - QST March, 1994

Following are digests of articles printed in the March, 1994 issue of
QST.  Such digests are being prepared for each issue of QST, and posted
periodically.  Subsequent issues will be posted one per week until they
"catch up" to the current date in mid-1994, thereafter monthly.

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
world!

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
languages.

-------------------------------CUT HERE---------------------------------

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:A Lead-Acid Battery Charger                                       74
TA2:The Pfeiffer Quad Antenna System                                 116
TA3:Using a VU Meter for Phone-Patch Adjustment                      222
TA4:On Center-Fed Multiband Dipoles                                  273
TA5:Under the Hood IV: Inductors                                     332

PRODUCT REVIEW (PR)

PR1:QST Compares: Dual-Band Hand-Held FM Transceivers                363
PR2:Trimble Scout GPS Hand-held Global Positioning System Receiver   544

HINTS AND KINKS (HK)

HK1:Cleaning Up the Beep Tone in the TEN-TEC Omni V Transceiver      598
HK2:Simple Audio Attenuator Solves TNC Overload Problems             613
HK3:Stopping Bug and Paddle Skids                                    634
HK4:Is That Hardware Stainless?                                      642

TECHNICAL CORRESPONDENCE (TC)

TC1:Maximum Bandwidth Monopole Antennas                              660
TC2:Toroidal-Core Color Codes                                        708

LAB NOTES (LN)

LN1:TVI, CATVI, and VCRI                                             732

NEW HAM COMPANION (NHC)

NHC1:Worked All Palm Beach                                           769
NHC2:Getting Started on the Magic Band                               800
NHC3:The Doctor is IN                                                825
NHC4:PACSATs from an Apartment                                       838
NHC5:Plug into PacTOR                                                853
NHC6:An Over-the-Dash H-T Mount                                      864

RADIO TIPS (RT)

RT1:Activity Nights                                                  893
RT2:Operating on the Road                                            930

GENERAL INTEREST ARTICLES (GI)

GI1:Amateur Radio Direction Finding in China                         954
GI2:Radio Gear of Yesteryear                                         971
GI3:A New Outlook on Ham Radio                                      1008
GI4:Being an Elmer                                                  1023
GI5:Anatomy of a 10-GHz Record                                      1037
GI6:Cellular Radio and the Modern Amateur                           1052
GI7:Wally and Mike: Changing Times                                  1071
------------------------------------------------------------------------

TECHNICAL ARTICLES (TA)

Title>TA1:A Lead-Acid Battery Charger
Author>Spencer, Ben C. - G4YNM
Source>QST Mar 94, pp. 25-27
Abstract>Construction of a charger for sealed lead-acid batteries.  Its
circuitry assures safe charging and automatic shut-off when full charge
is reached.

Digest>This article describes the construction of a charger,
specifically designed to charge the sealed lead-acid batteries of the
type used in burglar alarms, older portable telephones, and other kinds
of equipment.  Often they are found for sale in hamfest flea-markets.

Charging such batteries requires that the charging voltage must not
exceed 2.45 volts per cell, the maximum charge rate must not exceed
15-percent of the battery's ampere-hour rating, and the battery must not
be overcharged.  The circuitry of this charger is designed to assure
that all three limits will not be exceeded.

A schematic diagram is included in the article.  The circuit shows a
transformer that operates from 120-volt a.c., with an 18-volt secondary.
A voltage regulator drops the output to 1.2- to 14.75-volts.  The
sensing circuit illuminates a green LED to show when the charger is
switched on and ready to charge or charging current is flowing.  When a
partially-discharged battery is attached to the charging terminals, the
red light goes out and a green light comes on, indicating charging.

When the battery reaches 90-percent of full charge, the green light goes
off, the red light again comes on, the output voltage drops to a low
level, and current stops flowing.  Protective diodes prevent reverse
current flow.  Two different charging rates, 1-amp and 3-amps, are
provided and selected by a two-position switch, labeled "Standard" and
"Rapid".

A PC-board, etched and drilled for this project, is available from FAR
Circuits, 18N640 Field Court, Dundee, IL 60118-9269 for a price of
$6.00, including USA shipping.   A template is available from the ARRL
for an SASE.  Address the request for Spencer Battery-Charger Template
to the Technical Department Secretary, ARRL, 225 Main St., Newington, CT
06111.
                               _________

Title>TA2:The Pfeiffer Quad-Antenna System
Author>Pfeiffer, Andy - K1KLO
Source>QST Mar 94, pp. 28-31
Abstract>Construction and performance of miniaturized quad beam antennas
comprised of two shortened elements made of wire using linear loading.
The size of each element is reduced 45% from that of a full-size quad in
one type antenna described, and 58% in the second type.  Performance of
either is reported equivalent to that of a full-size quad.

Digest>Mr. Pfeiffer has developed miniaturized quad antennas using
linear loading techniques.  He has settled on two configurations which
he calls the "Maltese Quad" and the "Maltese Double-Cross Quad".

The Maltese Cross is the familiar one that was used as identification by
the German air force in World War I.  The arms of the cross get broader
at their ends, so that it looks somewhat like a square with slots cut
out from each corner toward the center.

Each element of the author's Maltese Quad uses crossed spreaders, in
the conventional quad manner, and wires around the periphery; but at
each tip a closed-end stub is inserted that runs down the spreader
toward the hub.  The two sides of the stub add enough wire that full-wave
resonance is reached with much smaller spreaders than those required by
a full-size, full-wave square.  Whereas a full-size 12-meter antenna
requires spreaders to be 14-feet, 2-inches (4.32-meters), measured
diagonally corner-to-corner, spreaders for the Maltese Quad for the same
band are only 8-feet (2.44-meters), measured in the same manner.

The stubs are supported by what the author calls "yard-arms".  These are
short pieces of rod fastened perpendicular to each spreader, one at the
tip and the other close to the hub.  The outer yard-arm must, of course,
be an insulator and is made of fiberglass-reinforced plastic (frp).  The
inner one acts as a shorting bar that forms the shorted end of the stub.

With the Maltese Double-Cross Quad, the author has used the same idea
once more; instead of two crossed spreaders, he uses four.  The
peripheral wires now form an octagon, rather than a square.  Again, a
stub runs along each spreader with the shorted end not far from the hub
and the open end at the tip of the spreader where the wires are attached
to the adjacent peripheral wires.  Now the reduction in size is even
greater.  For a conventional 20-meter quad driven element, the diagonal
dimension is 25-feet (7.62-meters).  Each diagonal across the Maltese
Double-Cross Quad is only 10-feet, 4-inches (3.15-meters)!

The article contains a dimensioned drawing labeled as follows:
        S - Spreader length from hub to tip
        L - Each segment of the peripheral wire, from spreader tip to
            spreader tip, less the width of the stub
        X - The length of the stub
        Y - 1/2 the width of the stub
        Z - The distance from the center of the hub to the shorting bar,
            or closed end, of the stub.

Dimensions for the 12-meter Maltese Quad are:
        S = 48-inches (1.22-meters)
        L = 61-inches (1.55-meters)
        X = 36-inches (0.91-meters)
        Y = 5-1/2-inches (14.0-cm.)
        Z = 12-inches (30.5-cm.)

Dimensions for the 20-meter Maltese Double-Cross Quad are:
        S = 62-inches (1.57-meters)
        L = 42-1/2-inches (1.08-meters)
        X = 47-1/8-inches (1.12-meters)
        Y = 3-inches (7.6-cm.)
        Z = 15-inches (38.1-cm.)

Mr. Pfeiffer recommends that each element be roughly tuned by itself. To
tune the reflector, he used formulas found in the CUBICAL QUAD HANDBOOK,
by W. Orr, published by Radio Publications, Inc.  It contains the
following formulas for calculating the dimensions of an 2-element
monoband quad, as follows:

        Perimeter, Driven Element:  1000/f
        Perimeter, Reflector Element:  1032/f
        Element Spacing:  118/f

From this, he noted that for any given frequency, the reflector in a
conventional quad must be 3.2-percent longer than the driven element. If
the driven element resonates, standing alone, at a particular frequency,
the reflector must resonate at 96.90-percent of that frequency.
Consequently, he tunes the driven element to the target frequency and
the reflector to the frequency correspondingly lower.  After both
elements are mounted, he tunes the array by adjusting the driven element
to establish proper resonance frequency and the reflector to maximize
either forward gain or front-to-back ratio, whichever is desired.

He orients the elements with one corner pointing downward and uses that
corner for his feed point.  The quads are fed using a gamma-match with
the gamma-rod running parallel with, and close to, one wire of the stub.
A copper strap shorting-bar is adjustable along the length of both rod
and stub.  An air-spaced variable capacitor connects between the
feed-line and the gamma-rod.  It and the shorting bar are adjusted
alternately to establish minimum SWR in the conventional manner.

The author has systematically evaluated performance of his antennas in
cooperation with a friend, Joe Belson - K2ANR, whose QTH is within
60-miles (97-kilometers).  K2ANR uses a full-size quad and the two of
them have performed many tests comparing the signal-strengths of their
signals in various directions, distances, and frequencies, at different
times.  They both agree that their signals at remote locations are
essentially equal, even though Mr. Belson's full-size quad is at a
somewhat higher elevation than Mr. Pfeiffer's.
                               _________

Title>TA3:Using a VU Meter for Phone-Patch Adjustment
Author>Lorona, Alfred - W6WQC
Source>QST Mar 94, pp. 32-33
Abstract>Signal level into a phone-patch is critical and should be
adjusted carefully.  Described is the use of a VU Meter to set the gain
properly.

Digest>A phone-patch should be adjusted to deliver a signal into the
telephone line that is strong enough to be easily understood but not
exceeding the maximum allowable signal level. The best way to adjust to
that level is with the use of a VU Meter.

This is a special-purpose meter designed to indicate a reasonably
accurate value for the peaks of a rapidly-varying voice signal.  This
requires careful attention to the meter's ballistics; that is, how
rapidly it responds to changing levels, and how far it overshoots, if at
all.  VU Meters are designed and built for this purpose.  They are
frequently available at hamfest flea-markets and from dealers in
electronic surplus.

A VU Meter must be used with a 3900-ohm series resistor in order to
perform its proper function.  The maximum signal level allowed by the
telephone standard is 1.228-volts RMS with a 1-KHz. sinusoidal signal.
This is equivalent to minus 9-dBm. or about 0.13-milliwatts.

A standard VU Meter cannot be used, by itself, to measure that amount of
signal accurately because it appears so low on the scale that the
accuracy is not good.  The signal should be amplified by 13-dB. in order
to drive the meter upscale into its high-accuracy range.

The article contains a schematic diagram of an op-amp to provide the
proper amount of amplification, using a commonly available 741, or
similar, op-amp IC.  With this amplifier, the VU Meter will indicate
0-dBm. when the signal is actually the desired minus 9-dBm.

With the op-amp driving a VU-Meter, and the patch attached to the phone
line, connect the input terminals across the telephone and speak the
following sentences twice into the phone:  "Joe took father's shoe bench
out." and "She was waiting at my lawn."  Adjust the gain until the meter
indicates 0-dB. as the average of the three highest peaks spoken while
those two sentences are read twice. Ignore occasional extreme peaks.
The sentences are selected to contain all of the fundamental sounds of
the English language.

The author recommends that, before anyone attaches a phone-patch to
their telephone line, they should consult the ARRL Handbook regarding
phone-patches, and also obtain a copy of FCC Part 68, from the
Government Printing Office, and read sub-part D.
                               _________

Title>TA4:On Center-Fed Multiband Dipoles
Author>Belrose, John S. - VE2CV and Bouliane, Peter - VE3KLO
Source>QST Mar 94, pp. 34-36
Abstract>Results of a study show that a horizontal dipole fed with tuned
feeders is the most versatile amateur antenna.

Digest>Since the availability of the WARC bands, amateurs now have eight
bands available between 3.5- and 30-MHz. and the use of multi-band
antennas has become even more popular than before.  A simple dipole, fed
with tuned, open-wire feeders is, arguably, the most versatile antenna
of all.  It can be made of any length but, for good performance on the
lowest frequency, i.e. 3.5-MHz., it should not be less than about
100-feet (30-meters) long.  A very popular version is one first
specified by Louis Varney, G5RV.  It is a 102-foot (31-meters) flat-top,
fed with 450- to 600-ohm balanced open-wire line or, in a second
version, with a 34-foot (10.4-meter) open-wire stub fed at the bottom
end with 72-ohm twinlead or coax cable.

In his first published description, G5RV  called the stub a "matching
section", but later decided that he had made a mistake in doing so.
Actually, it acts as a matching section only on the 20-meter band.

The authors have analyzed many variations of center-fed dipoles, both
flat-top and also "inverted vees", with special attention to the G5RV
design.  In addition, they physically tested a G5RV antenna with a
stub, erected as an "inverted vee".

The article contains computer plots of the resistance, the reactance,
and the SWR across the entire frequency range from 3.0- to 30-MHz.  It
shows that the flat-top is naturally resonant at 3.49-, 7.52-, 14.15-,
19.5-, and 24.6-MHz.  The plots show the very wide range of resistance,
reactance, and SWR shown by the antenna at the various frequencies.  The
stub clearly performs no useful function.  They recommend that tuned,
open-wire feeders be used all the way from the antenna tuner, located
at a convenient place, to the center of the antenna.

On the higher frequencies, the antenna becomes more than one
half-wavelength long and the radiation pattern breaks up into multiple
lobes in various directions.  If the wire is horizontal, all of these
lobes are radiated at the same elevation angle; but if the ends droop,
in an "inverted vee" configuration, that is no longer true.  Some lobes
will radiate at relatively low angles and others only at high angles.
Consequently, the authors recommend that, for use on higher frequencies,
it be mounted horizontally.

Their final conclusions are that the center-fed dipole, mounted as high
as possible and as nearly horizontal, fed with tuned feeders, is the
most versatile, as well as one of the simplest, of all multiband
antennas.  However, they also point out that when an antenna is
operating on a frequency at which its length is considerably greater
than a half wavelength, the radiation breaks up into a number of lobes
with nulls at certain azimuth angles.  This means that there are some
directions, on certain bands, in which the radiated signal cannot be
heard!  This, then, is no longer a general-coverage antenna.  They
suggest that, for frequencies higher than 10-MHz., a better
general-coverage multiband antenna is a horizontal loop.
                               _________

Title>TA5:Under the Hood IV: Inductors
Author>Bergeron, Bryan - NU1N
Source>QST Mar 94, pp. 37-40
Abstract>A primer on inductance and inductors.

Digest>This article is an elementary discussion of inductors and
inductance.  The author describes what they are, how they work, what
they do, and the various types that are used in radio.  After inductors,
he leads into transformers.

Accompanying the article are photographs of typical inductors found in
radio apparatus.  Included are r.f. chokes; toroidal cores, with and
without windings; air wound coils; roller inductors; power
transformers; audio transformers; and i.f. transformers.

Mr. Bergeron explains inductive reactance and its effect on electric
current; also parasitic shunt capacitance, internal resistance,
and the concept of Q.

In a side-bar, three types of variable inductors are described: a coil
with a core that can be adjusted in-and-out, a tapped coil with the
taps selected by a multi-position switch, and a roller-inductor.

Finally, the color code used for encapsulated r.f. chokes is explained.
------------------------------------------------------------------------

PRODUCT REVIEW (PR)
        Conductor: Mark Wilson - AA2Z
                   Editor, QST
                               _________

Title>PR1:QST Compares: Dual-Band Hand-Held FM Transceivers
Author>Ford, Steve - WB8IMY
Source>QST Mar 94, pp. 71-76
Abstract>Performance comparisons of five dual-band FM hand-held
transceivers: Alinco DJ-580T, ICOM IC-W21AT, Kenwood TH-78A, Standard
C558A, and Yaesu FT-530.

Digest>For FM operations through repeaters, and for short-range simplex,
the 2-meter band and the 70-cm. band are nearly equally popular.
Dual-band rigs cover both. In this article, Mr. Ford reviews five
models: Alinco DJ-580T, ICOM IC-W21AT, Kenwood TH-78A, Standard C558A,
and Yaesu FT-530.

All five of the units tested have a number of functions in common.
Among these are: band, memory, and program scan; simultaneous dual-band
receive; automatic power off; crossband repeater function; CTCSS
function; DTMF paging.  All transmit a maximum of 2- or 2.5-watts, using
the standard battery.  All are approximately the same size and four of
the five weigh between 13 and 14.4 ounces, battery included; only the
Yaesu model deviates a bit, weighing 18.5 ounces.

Alinco DJ-580T

This unit has the lowest list price of any of the five: $519.  The
average selling price among several QST advertisers is $409.  The
reviewer found that programming is somewhat difficult and requires
frequent consultation of the instruction manual.  But the manual is
poorly written; its English is poor, and some descriptions are not
complete.

When used as a cross-band repeater, some reviewers found that they had
to use the low-power output setting on 70-cms. to avoid causing
interference on the 2-meter receiver.

The unit offers extended receive coverage, including the upper part of
the aircraft band.  A simple modification, described by the manual,
allows full aircraft band coverage.  The unit offers 20 memory channels
per band, and eight different scanning functions are supplied.  One can
scan both bands simultaneously; scan the memory channels; scan within
preset frequency limits; etc.

Paging and tone-squelch are standard functions.  Also one can be paged
using DTMF tones or subaudible CTCSS tones.

ICOM IC-W21AT

This unit offers all of the standard features plus a couple of special
functions.  One is what their ad writer calls "artificial intelligence"
(AI); a key can be programmed to produce the same effect that otherwise
would require a number of keys to be pressed in sequence.

Another is automatic output control.  When talking through a repeater,
the unit measures the repeater's signal strength and reduces its
transmit power to the minimum required to maintain communications.  The
reviewers found that the feature works well with strong signals but,
with weaker signals, it must be turned off.

A third special feature that most reviewers liked was the "whisper"
function that allows the unit to be held to one's ear and used in full
duplex, like talking on a telephone.

The IC-W21AT provides 35 memory channels per band, and several scanning
modes.  Its 2-meter receive frequency range is broader than the amateur
band, but does not include the aircraft band.  The list price is $623,
which is second highest among the five.   An average selling price among
several QST advertisers is $514.

Kenwood TH-78A

This unit is noted as the one that has the most programmable features.
The negative side of that is that it is correspondingly more difficult
to program, even with the manual.  After using it for two weeks, none of
the reviewers felt that they had mastered the radio.

The operation manual has no index and some of the instructions are not
clear.  A summary "Minute Manual" is also available, and helps partially
to overcome the problem.

Aside from the programming, the unit is reportedly easy to use.  The
scanning functions are notably flexible.  When it is switched to a
particular repeater frequency, the unit automatically selects the
correct offset frequency.  When programming the frequency of a
particular repeater, one can add the call sign, or any other 6-character
label, into the memory to remind the operator which repeater it is.

The TH-78A provides a DTSS system for remote access and also paging.
When it is actuated, by sending the correct DTSS code and glancing at
the display, one can not only hear the audio but also see who is paging.
An automatic timer will shut down the unit if it transmits continuously
for more than ten minutes.

In summary, the reviewers call the unit "an exceptional radio for hams
who need its full-featured paging capability and other programmable
functions".  The list price is $599.  Typical average selling price is
$449.

Standard C558A

The reviewers commented about this unit's extremely solid "feel", but
most commented that the LCD display is small and difficult to read.  The
frequency digits are large enough, but certain other display items, such
as the offset indicator, are almost microscopic.  Even the edge lighting
does not help very much in dim light.

This unit, like others reviewed, also received criticism for the
difficulty in programming, but operation was found to be easy after the
radio was programmed.

The C558A comes with 20 frequency memories per band, but it can be
expanded to 100 per band!  The frequency scanning, also, is quite
versatile and includes simultaneous 2-meter/70-cm. scan of the full
bandwidth.

This unit's crossband repeater function was rated the best performer
among all five.  Some receiver desensitization was noted during repeater
operation.

DTMF tones can be used for paging this unit, and also the squelch can be
set to remain closed until it hears a particular subaudible tone,
without requiring a page.  A unique feature is a 15-dB. receive
attenuator that can be used in an environment (such as a hamfest!) where
a lot of H-Ts are in use.

In summary, the reviewers recommend the Standard C558A as a good
performer in all respects except for the LED display.  Its list price is
the highest of the five, at $689.  The average selling price is also the
highest: $529.

Yaesu FT-530

This Yaesu unit is unique among the five in that it drew praise, not
criticism, for its ease of programming.  Several reviewers even said
that they were able to program basic functions without use of the
manual!  But the manual is rated as excellent, written in conversational
English.  In addition, the ergonomic design is excellent and the display
is fully readable in "all" lighting conditions.

It provides 41 memory channels per band.  DTMF paging and coded squelch
is used.  It can even be programmed to acknowledge automatically.
Another programmable function is a clock/alarm system that switches on
at a preset time.

A battery saver function is provided that reduces power output in
response to the received signal strength from a repeater.  Also, the
status of the battery charge can be checked from the LED display if one
pushes the proper buttons.

Several items are included that would be useful for mobile operation of
the H-T from an automobile.  Among them is an optional remote
mike/speaker that contains an LED display of both frequency and signal
strength.  Also, a VOX circuit is provided in the radio.

The 2-meter receive frequency range is 130- to 170-MHz., which provides
a portion of the aircraft band.  To listen to aircraft requires a manual
actuation of the AM button.

In summary, the Yaesu FT-530 got excellent reviews for easy operating
and convenient features.  The only reservations expressed were that some
reviewers felt that the audio output from the speaker is a bit weak for
noisy environments.  The list price is $569 and the average selling
price is $439.

The editor's summary notes that all the rigs reviewed were found to be
quality products.  Performance of the radios on alkaline batteries was
superior in every transceiver tested.  With the advent of rechargeable
alkalines, the optional battery cases deserve consideration.

A negative factor common to all five manufacturers was a lack of any
caution in the manual regarding crossband repeaters and links.  It is
absolutely necessary, before establishing a crossband repeater, that
great care be taken to see that the repeater frequency selected is
not in use for some other service.  Simply listening and finding it
temporarily unused is no indication that it is, in fact, a free
frequency.  One should consult the ARRL Repeater Directory and check
carefully before attempting repeater operation!  Also look at the band
plans in the front of the book and make sure that the frequency planned
is designated for FM operation.  Finally, a check should be made with
the local or regional coordinators.
                               _________

Title>PR2:Trimble Scout GPS Hand-Held Global Positioning Receiver
Author>Wilson, Mark - AA2Z
Source>QST Mar 94, p. 77, 81.
Abstract>Description of the U.S. Global Positioning System (GPS) and the
Trimble Scout receiver for automatically determining exact position
anywhere on earth via the GPS.

Digest>The Global Positioning System (GPS) was established by the
Department of Defense to allow American military personnel to determine
their exact location anywhere on the face of the earth at any time.  It
operates from a number of satellites in orbit, several of which are
always within reach of every point on the planet.  Recently, the
technology has been released for commercial use and the Trimble Scout is
one of the latest products made available to consumers.

It is a hand-held device, slightly larger than a scientific calculator,
with an LCD display and eight push-buttons on its face.  On command, it
will display one's precise location in a number of ways: degrees,
minutes, and seconds of latitude and longitude; degrees, minutes and
hundredths of minutes of latitude and longitude; 6-character Maidenhead
grid locators; and a number of other systems designed to be used certain
kinds of maps.  One can save a location to memory in one coordinate
system and later view it in any of the others.

When power is first turned on, the Scout scans for satellite signals and
locks on as many as it can find in two minutes.  Almost always, it will
have little difficulty finding as many as six.  Three are required to
calculate position in two dimensions.  With four, the unit also displays
altitude above sea level.

After the satellites are accessed, commands are selected from menus
shown on the LCD display.  Six menus are available: Location,
Navigation, Library, Setup, Route, and Advanced.  In the Route mode, one
can enter the location of a particular destination and the Scout will
calculate its distance and bearing.  Also, one can specify any number of
intermediate way points and the unit will show the progress being made
toward each as the trip progresses.

The Scout will perform many other functions, including some not
connected directly with navigation.  For example, it will calculate the
azimuth and elevation of the moon and other celestial objects at any
time.

The manufacturer's list price of the Scout is $795.  Accessories
available include an external antenna, d.c. power cord, and other items
for a list price of $225.
------------------------------------------------------------------------

HINTS AND KINKS
        Conductor: David Newkirk - WJ1Z
                   Sr. Asst. Technical Editor
                               _________

Title>HK1:Cleaning Up the Beep Tone In the Ten-Tec OMNI V Transceiver
Author>Perras, Henry J. - K1ZDI
Source>QST Mar 94, p. 78
Abstract>A circuit that creates a clean "whistle" tone.

Digest>The keypad beep in the OMNI V is a two-KHz. raspy tone that is
not "clean".  Mr. Perras has designed and built a 2-KHz. bandpass filter
using a dual op-amp that generates a clean "whistle".

Schematics are included showing the circuit of the filter, and also
where the connection points are located on the OMNI V logic board for
the filter leads to be soldered in place.
                               _________

Title>HK2:Simple Audio Attenuator Solves TNC Overload Problems
Author>Booth, Lionel S. - N5LB
Source>QST Mar 94, p. 79
Abstract>A modified connector containing a 20-dB. attenuator is used
between the receiver and TNC to eliminate problem of excessive audio
signal level input in a packet setup.

Digest>When input signals from the author's Drake R-4 receiver are
adjusted to the low level required by the Kamtronics KAM TNC, the volume
is too low for listening.  His solution was a 600-ohm pi-section
attenuator inserted between the receiver and the KAM input.

It uses three resistors: 3,000-ohms in series with the hot wire of the
audio coax; and two of 750-ohms each, connected between the hot wire and
the shield, one ahead of, and the other after, the series resistor.  It
provides 20-dB. attenuation.  He built the attenuator inside a piece of
copper tubing with a phono plug on one end and a female phono jack on
the other.
                               _________

Title>HK3:Stopping Bug and Paddle Skids
Author>Moretti, Michael - WB2SRL
Source>QST Mar 94, p. 79
Abstract>Suction cups from the hardware store, attached underneath a
bug or paddle, stop skidding.
                               _________

Title>HK4:Is That Hardware Stainless?
Author>Mandeville, Bob - N1EDM
Source>QST Mar 94, p. 79
Abstract>Determine whether hardware is stainless steel by using a
magnet.

Digest>The author suggests that one can easily check the hardware in the
junkbox to determine whether or not it is stainless steel by using a
magnet.  He states that stainless steel is not magnetic, whereas most
hardware is made of carbon steel that is strongly attracted to magnets.
------------------------------------------------------------------------

TECHNICAL CORRESPONDENCE (TC)
        Conductor: Paul Pagel - N1FB
                   Assoc. Technical Editor
                               _________

Title>TC1:Maximum Bandwidth Monopole Antennas
Author>Formato, Richard A. - K1POO
Source>QST Mar 94, pp. 80-81
Abstract>A discussion of bandwidth of vertical monopoles of varying
diameter.  Relatively broad bandwidths can be achieved with large
diameter conductors.  Large diameter conductors can be simulated by
multi-wire "cage" antennas.

Digest>In this letter, Mr. Formato discusses the operating bandwidth of
quarter-wave monopole antennas operating against ground planes.  He
shows that the useful bandwidth is a function of the diameter of the
antenna conductor, itself.  He defines the operating bandwidth as the
frequency band between SWRs of 2.5:1.  This width is much broader for
"fat" antenna conductors, that is with diameters an appreciable fraction
of the wavelength, than with thin wire.

He further defines the diameter of the antenna as D, the length of a
quarter-wave in free space as L, and F(0) the frequency at which the
antenna is a physical quarter wavelength.  Note that, using these
definitions, F(0) is not the resonant point of the antenna; resonance
occurs at a few percent lower than F(0).

He shows that with an antenna fed with 50-ohm cable, (1) maximum
bandwidth occurs when the ratio of monopole length to diameter (L/D) is
5:1.  (2) That bandwidth is approximately 50 percent of F(0).  (3) The
frequency of minimum SWR is about 1.3 percent less than F(0). (4)
Approximately two-thirds of the bandwidth is above F(0) and one-third
below it.  (5) The SWR minimum is a near perfect 1.009:1.

Such an antenna with dimensions of 4.35 meters (14.27-feet) long and 87
centimeters (2.85-feet) in diameter would cover 13.92 MHz. to 22.57
MHz., including the entire 20-, 17- and 15-meter bands!  For such an
antenna to perform precisely as calculated, the ground plane would have
to be infinite.  But, with 16 or more radials a half-wavelength or more
long at the lowest frequency, the results would be comparable.

For those to whom a 2.5 SWR is uncomfortably high, the graphs shown with
the letter indicate that the bandwidth between 1.5 SWR points is about
plus and minus 10 percent around F(0).  Hence, at 20-meters, the
bandwidth would be 2.8 MHz.!

It is not necessary that the antenna conductor, itself, be solid.  A
"cage" of wires spaced the appropriate distance apart will behave nearly
as well as solid metal.  At least 8 wires should be used, preferably
more.
                               _________

Title>TC2:Toroidal-Core Color Codes
Author>Czuhajewski, Michael A. - WA8MCQ
Source>QST Mar 94, p. 81
Abstract>Description of several different color codes used by various
manufacturers of toroidal cores.

Digest>The author points out the disconcerting fact that there is no
industry-wide color code for powdered-iron and ferrite core materials.
Some manufacturers, such as Micrometals, Arnold Engineering, and others,
have color codes of their own, some of which duplicate those of other
manufacturers is some, but not all, materials.

If one finds a core that is red, it MAY be powdered-iron with a
permeability of 10, but it also MIGHT be a ferrite core of permeability
850, 1800, or 10,000!  Be suspicious of any colored core if the
manufacturer is not positively known.
------------------------------------------------------------------------

LAB NOTES (LN)
        Conductor: Steve Ford - WB8IMY
                   Asst. Technical Editor
                               _________

Title>LN1:TVI, CATVI, and VCRI
Author>Hare, Ed - KA1CV
Source>QST Mar 94, pp. 82-83
Abstract>Advice on how to eliminate interference from amateur radio
transmissions on TV, cable TV, and VCRs.

Digest>This is in the form of a fictitious conversation between Ed Hare,
ARRL Lab Supervisor, and Joe Hamm, a ham who is having trouble with RFI.
Mr. Hare explains the use of a low-pass filter on the output of an
amateur transmitter.  Next, he explains TV overload from a transmitter's
fundamental signal and recommends installation of a high-pass filter at
the TV set.  Then, the use of a common-mode ***on the antenna lead to
the TV set.

Finally, he discusses the problem of the amateur's 2-meter signal
leaking into a cable-TV cable and interfering with Channel 18, which is
at 144.0- or 145.25-MHz., depending on the cable company.  The cable
company is responsible for eliminating leakage into their cable.  FCC
regulations require that the carrier-to-noise ratio must be at least
40-dB. and the carrier-to-coherent disturbances ratio 47-dB. at the
customer's location.  But any pickup in the customer's TV set, itself,
is nobody's responsibility except the customer's!

If the ham is confident that the transmitter is "clean", and the cable
company's cable is within specifications, then it is between the
neighbor and the manufacturer of his TV set.  For good neighborly
relations, the ham should do whatever s/he can to help the neighbor
overcome the problem.
------------------------------------------------------------------------

NEW HAM COMPANION (NHC)

        The New Ham Companion is a regular monthly section in QST that
concentrates on articles of primary interest to newcomers to ham radio.
                               _________

Title>NHC1:Worked All Palm Beach
Author>Penn, Morton - WA2STA
Source>QST Mar 94, p. 60
Abstract>A contest sponsored by a local radio club encourages more ham
activity by newcomers.

Digest>The West Palm Beach, Florida, Amateur Radio Club faced the
challenge that many clubs see; that is that many new technician and
novice licensees were becoming members but not getting on the air as
much as they could.  In order to encourage more active participation by
newcomers, the club decided to conduct activities that will draw them
in.

They created a contest, limited to novice, technician, and
technician-plus amateurs, whether or not they were club members.  The
Worked All Palm Beach contest was the result.  The object was to work as
many stations as possible in Palm Beach County.  Only five frequencies
were authorized for contest contacts: 28.150 (CW), 28.400 (SSB), 144.105
(CW), 144.205 (SSB), and 146.55(FM) MHz.  All contacts had to be
Simplex, no repeaters allowed.  Each station had to exchange signal
report, its municipality, and a contact number.

Requiring all contacts to be on single frequencies, thereby insuring
pileups and QRM, was done deliberately.  The intent was to give the
newcomers experience in operating under congested conditions.

The net result was highly successful and caused increased participation
by numbers of newcomers.
                                _________

Title>NHC2:Getting Started on the Magic Band
Author>Neubeck, Ken - WB2AMU
Source>QST Mar 94, pp. 61-63
Abstract>How to get started on the 6-Meter band.

Digest>The 6-meter band, (50-54 MHz.), is called the "Magic Band" by
many hams who use it, but others call it the "Forgotten Band" because of
its lack of usage.  One of the most exciting aspects of 6-meter
operations is the frequent availability of Sporadic-E propagation.  It
is intermittent, almost unpredictable, most exciting when it occurs, and
is independent of the sunspot cycle.

Sporadic-E is caused by ion clouds that form in the E-layer of the
ionosphere.  They occur most commonly in the summer months, but
occasional openings occur during all seasons.  When the clouds are
present, they act as super-efficient reflectors of radio signals and
long-distance QSOs are possible with very low power and modest antennas.

In addition to distance communications, 6-meters is also an excellent
local band.  With 50-watts and a modest antenna, the author suggests
that contacts over a 100-mile radius are very reliable.
                               _________

Title>NHC3:The Doctor is IN
Author>Various
Source>QST Mar 94, p. 64
Abstract>Questions and answers of interest to newcomers.

Digest>This month's column answers questions about: interference caused
by transmitter harmonics, and what to do about them; the balun in an
antenna tuner that heats up during transmissions; a glossary of ham
jargon; and incidental transmission of music from an autopatch when the
caller is put on "hold".
                               _________

Title>NHC4:PACSATs From an Apartment!
Author>Schliemann, Dieter K. - KX4Y/ZS6BBH
Source>QST Mar 94, pp. 65-66, 69
Abstract>Operating via satellites from a temporary location using indoor
Yagi antennas.

Digest>The author is a satellite enthusiast and operated two
yagi-antennas on a common boom, for 2-meters and 70-cms., to work
PACSATs.  Recently, at a temporary location, he set them up in an unused
bedroom.  He was very gratified to find that the setup worked fine and
he was successful in working Oscars 22, 23, and 25 with his indoor
setup.
                               _________

Title>NHC5:Plug Into PacTOR
Author>Gold, Jeff - AC4HF
Source>QST Mar 94, pp. 67-69
Abstract>The advantages of PacTOR mode.

Digest>In this article, Mr. Gold explains what PacTOR is, what equipment
is necessary to operate in the PacTOR mode, what its advantages are, and
the fun he has had with it.
                               _________

Title>NHC6:An Over-the-Dash H-T Mount
Author>Leyson, Herbert - AA7XP
Source>QST Mar 94, p. 70
Abstract>A simple mounting bracket for using an H-T as a mobile rig.

Digest>This article describes a very simple mounting bracket into which
the author hangs his H-T so that it can be used as a mobile rig while
driving.  It is bent out of coat-hanger wire, and after being formed to
shape, it is covered with plastic tubing slipped over the wire.  It is
a square-ended "U-shape" with hooks at the top end that hook into
the air vents that direct defroster air onto the windshield.  From the
vents, the wires extend across the shelf above the dashboard, and bend
down over the dashboard for 2- or 3-inches (50- or 75-mm.) to the
square end of the "U".  The belt clip on the H-T hooks over the
bottom of the "U", and the unit hangs vertically in front of the
dashboard.

The author states that the transceiver is secure in its
mount as its own weight holds it in place, but he can instantly remove
it when he leaves the car.
------------------------------------------------------------------------

RADIO TIPS (RT)

These are short items, scattered among the articles in the NEW HAM
COMPANION section.
                               _________

Title>RT1:Activity Nights
Author>Owen, Mike - W9IP
Source>QST Mar 94, p. 63
Abstract>Regularly scheduled "activity nights" to encourage CW and SSB
activity on VHF/UHF.

Digest>Often, on the VHF/UHF bands, it is not easy to have a QSO.  In
order to encourage more CW and SSB activity on those bands, so-called
Activity Nights have been agreed on in various parts of the country.
The author lists a table of frequency, day, and time of Activity Nights
that have been established somewhere, but does not state where that is.
They should be taken as representative, not necessarily everywhere.
Each operator should check with others in the area to determine what, if
any, times have been set aside in that manner.  The examples he lists
are:
        Band                 Day and Time
        50-MHz.               Sunday, 6:00 pm
        144                   Monday, 7:00 pm
        222                   Tuesday, 8:00 pm
        420                   Thursday, 9:00 pm
        902                   Friday, 9:00 pm
        1296                  Thursday, 10:00 pm

The author also cautions that most operators will make initial contacts
on the established calling frequencies, then QSY to other frequencies
for ragchewing.  Calling frequencies are:
        Band                 Frequency
        50-MHz.               50.125 SSB
        144                   144.100, 144.110 CW
                              144.200 SSB
        222                   222.1 SSB/CW
        432                   432.1 SSB/CW
        902                   903.1 SSB
        1296                  1296.1 SSB/CW
                               _________

Title>RT2:Operating on the Road
Author>Ford, Steve - WB8IMY
Source>QST Mar 94, p. 70
Abstract>Safety rules for mobile operating.

Digest>Operating on the road is great fun.  To be sure that it is also
safe, abide by the following rules:
        Do not operate your radio when traffic is heavy.
        When making an autopatch call, find a place to stop.  Don't dial
             while driving.
        When talking on a repeater, pause to listen at the beginning of
             each transmission to listen for breakers.
        Use Simplex frequencies for ragchewing; leave the repeater for
             other uses.
        Do not use headphones!
        When you leave your car, take the radio with you.
        Use an outside antenna.  "*** ducks" inside the car are poor
             substitutes.
------------------------------------------------------------------------

GENERAL INTEREST ARTICLES (GI)
                               _________

Title>GI1:Amateur Radio Direction Finding in China
Author>Baldwin, Richard - W1RU
Source>QST Mar 94, pp. 22-24
Abstract>Description of an international RDF competition held in China.

Digest>The author recounts his experiences visiting an international
radio direction-finding competition that was held in China, near a
section of the Great Wall.

The contest was limited to two hours and ten minutes, and all movement
was on foot.  Competing required both radio acumen and also physical
stamina!  Teams came from all over the East Asia/Pacific Rim area, and
one team came all the way from Bulgaria.  The competition was apparently
a great success, and a good time was had by all participants.
                               _________

Title>GI2:Radio Gear of Yesteryear
Author>Shrader, Bob - W6BNB
SourceQST Mar 94, pp. 41-43, 57
Abstract>Basic description of spark and arc transmitters.

Digest>In this article, the author describes the kinds of equipment and
radio signals that were transmitted and received in the days before
continuous-wave (CW) signals and vacuum tubes.  Every ham has heard of
spark transmitters, but the author points out that there were three
types of transmitters used before vacuum tubes.  One was spark, one was
arc, and the third was high-frequency alternators.

Spark transmitters generated highly damped waves created when a very
high voltage was applied across a narrow air gap and a spark leaped
across it.  The spark caused a pulse of current that flowed through the
primary of a "oscillation transformer" that, connected to the antenna,
formed a resonant circuit.  The pulse e***d that circuit to form an
oscillatory current that was highly damped by the loss of power due to
radiation from the antenna.

An arc transmitter differed from a spark transmitter in that the arc
e***d the oscillatory antenna circuit continuously rather than
intermittently.  Hence it caused a continuous wave, but not one with the
spectral purity that later was generated by vacuum tubes and given the
name "continuous wave", or CW.

The third type of non-electronic transmitters was the high-frequency
alternator transmitter.  Everyone is aware that electric power is
generated by 60-Hertz alternators.  By building machinery with multiple
poles and turning them at very high rotational speeds, it is possible to
generate pure sine waves mechanically at frequencies up to nearly 100
KHz.!  Some of the most powerful transmitters ever built generated pure
RF signals in this manner.
                               _________

Title>GI3:A New Outlook on Ham Radio
Author>Kirkendoll, John - N0KJT
Source>QST Mar 94, pp. 44-48
Abstract>How a blind ham became interested in radio and overcame the
problems he faced.

Digest>The author of this article is blind, and this is the story of how
he became interested in ham radio.  He received a great deal of help
from his "Elmers", experienced hams.  Now that he has overcome every
hurdle on the way to the top in ham radio, and holds an Extra-class
license, he is devoting much of his time to acting as an "Elmer" for
others.
                               _________

Title>GI4:Being an "Elmer"
Author>Young, Phillip - WD0CFJ
Source>QST Mar 94, pp. 44-47
Abstract>Personal satisfaction from helping newcomers get started in
radio.

Digest>Because of the close connection between this article and the
preceding one, it is formatted as if it were a series of side-bars with
the Kirkendoll article, above.  The author, Mr. Young, acted as the
"Elmer" for John Kirkendoll as well as others.  He has received great
personal satisfaction from his experiences.
                               _________

Title>GI5:Anatomy of a 10-GHz. Record
Author>Swedblom, Chuck - WA6EXV and Lee, Phil - W6HCC
Source>QST Mar 94, pp. 48-49
Abstract>How a QSO of more than 500-miles was made on 10-GHz.

Digest>On July 18, 1993, two-way exchanges were made on 10-GHz. between
Mt. Ashland in southern Oregon, and Mt. Pinos in southern California,
not far from Santa Barbara.  The distance was 537.3 miles (865-Kms.).

Contributing to the final success was the presence of other hams on
other peaks strung out in a line of mountain-tops between the two end
points.
                               _________

Title>GI6:Cellular Radio and the Modern Amateur
Author>Stone, Norman - WG1C
Source>QST Mar 94, pp. 50-55
Abstract>Basic description of cellular radio as it is, and of probable
future developments.

Digest>This article begins with a comprehensive review of cellular radio
as it now exists in the United States and other developed countries.
In any city of any size in the USA, today, a person can drive anywhere
with a phone in the car and talk continuously to another telephone
located anywhere.

The author makes clear that the present cellular system is only a
beginning.  He states cogently: "The developed countries are rapidly
moving toward a*** Tracy wrist-radio for everyone.  It will
communicate via satellite, or other means, anywhere in the world."
                               _________

GI7:Title>Wally and Mike: Changing Times
Author>Kearman, Jim - KR1S
Source>QST Mar 94, pp. 56-57
Abstract>History of changes in ham radio over the last 40 years.

Digest>This is a fictional conversation between an experienced ham and a
newcomer.  The old timer is explaining the state of ham radio 40 years
ago, and the impact that each new development had on the hobby.

------------------------------------------------------------------------