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Follow-up-To:rec.radio.amateur.misc
Approved:rec-radio-info@ve6mgs.ampr.ab.ca
Digest of Articles -- QST, May, 1993
Following are digests of articles printed in the May, 1993 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:Home-Brewing a 10 GHz. SSB/CW Transverter - Part 1 (75)
TA2:Single-Conversion Microwave SSB/CW Transceivers (140)
TA3:Build the HANDI-Finder! (203)
TA4:Add Tracking Side-Tone to Your ICOM IC-765 Transceiver (246)
TA5:An Introduction to Amateur Television - Part 2 (284)
PRODUCT REVIEWS (PR)
PR1:HAL Communications PCI-4000 Clover-II Controller (324)
PR2:AlphaLab TriField Meter (386)
HINTS AND KINKS (HK)
HK1:Build a Quick PVC-Supported Quad for About $50 (421)
HK2:Installing a Huskier 160-M Fixed Capacitor in the Ten-Tec (447)
Titan Amplifier
HK3:Putting Variometry to Work in Matching Networks (464)
HK4:When Antennas Should NOT Be Resonant (484)
TECHNICAL CORRESPONDENCE (TC)
TC1:Expanded Range DC and AC Voltmeters (505)
FEEDBACK (FB)
FB1:QST Apr 1993 Product Reviews (530)
FB2:QST Nov 1992 "Dipoles Above Real Earth" (547)
NEW HAM COMPANION (NHC)
NHC1:And the Most Popular Frequency is... (572)
NHC2:Do You Need an Audio Filter? (603)
NHC3:The Doctor is IN (612)
NHC4:A Disguised Flagpole Antenna (626)
NHC5:VHF/UHF Contesting (634)
RADIO TIPS (RT)
RT1:What Is AMTOR? (653)
RT2:Lightning! (660)
RT3:The Ionosphere (672)
RT4:Working the World on 10-Meters (681)
RT5:Is Amateur Radio Safe? (694)
GENERAL INTEREST ARTICLES (GI)
GI1:Festing (Notes of a Hamologist) (710)
GI2:PHASE 3D - A Satellite for All -- Part 1 (723)
GI3 Inspiration N2OVA (779)
GI4:Transmitter Hunting: Tracking Down the Fun (797)
------------------------------------------------------------------------
TECHNICAL ARTICLES (TA)
Title>TA1:Home-Brewing a 10 GHz. SSB/CW Transverter - Part 1
Author>Lau, Zack - KH6CP
Source>QST May 1993, pp. 21-28
Abstract>First of a 2-part construction article describing a 10 GHz.
transverter. It utilizes only readily-available parts but to build it
requires the builder to have had some experience with VHF/UHF gear and
to have access to certain test equipment.
Digest>The author has built a 10 GHz. transverter which, when used in
tandem with a 2-meter transceiver, will receive and transmit on
"X-band", or 10 GHz. One notable thing about this project is that it
uses readily available components, nothing exotic or available only from
military surplus.
He has built the transverter as a series of building blocks, each
connected with the next through plug connectors and coax jumpers. Thus,
each block can be tested independently, or changed in future upgrades.
In this first instalment, Mr. Lau supplies wiring diagrams, parts lists
including recommended sources, and construction details for the local
oscillator building blocks.
Near the beginning of the article, he addresses a question that all
interested readers must answer for themselves: "Do I have the VHF/UHF
construction experience and the test equipment required to handle this
project?" It is his opinion that the construction details are not that
difficult and he suggests two commonly-available ham publications that
give sufficient background information to allow the average
construction-minded ham to build the equipment. But the rub comes in
tuning the amplifiers, mixer, and filters. He states that it should be
possible to accomplish the task with equipment reasonably available to
hams, but optimizing the circuits is much easier if one has access to
relatively sophisticated bench instrumentation, including a spectrum
analyzer.
In a side-bar with the article, Rus Healy, NJ2L, senior assistant
technical editor, recommends that anyone who has not had the experience
of building a lower-frequency transverter should do so before
undertaking the X-band project.
Conceptually, the transverter is easy enough to understand. On the
receiver side, the 10 MHz. signal from the antenna goes through a
pre-amplifier, a band-pass filter, and into a mixer where it is
heterodyned against a local oscillator signal and converted to 144 MHz.
output. On the transmitter side, the r.f. output from the 2-meter rig
goes to a mixer where it, also, beats against the local oscillator
signal which converts it up to 10 GHz. From the output of the mixer,
the signal goes through a band-pass filter, an amplifier, an optional
second band-pass filter, and out to the antenna.
The "local oscillator" is actually made up of a crystal oscillator at
106.499 MHz., followed by a series of multipliers, each of which is a
separate building block and contains multiple band-pass and low-pass
filters with sufficient amplification to overcome the insertion losses.
The first building block contains the crystal oscillator and the 6:1
multiplier. The output of that block is a spectrally-pure 639 MHz.
signal. Following is a quadrupler block, the output of which is 2.556
GHz. The last block within the local oscillator chain is another
quadrupler with a 10.224 GHz. output frequency.
In next month's issue will be the second, and final, installment. It
will describe the preamplifer, mixer, and power amplifier to complete
the project.
_________
Title>TA2:Single-Conversiion Microwave SSB/CW Transceivers
Author>Campbell, Rick - KK7B
Source>QST May 1993, pp. 21-28
Abstract>Construction details for a microwave transceiver using receiver
and transmitter building blocks described in previous articles, plus
other components. The transceiver can be built to operate on any band
from 432 through 5760 MHz. On the receiver side, the design uses a
crystal-controlled converter to feed an i.f. system at 144 MHz.; that
system is, itself, a direct-conversion single-signal receiver. The
transmitter side is a phasing-type SSB or CW transmitter.
Digest>This is another article by Mr. Campbell who described the "R2"
and "T2" PC-board building blocks in his QST articles in the issues of
January and April, 1993. This article describes a microwave transceiver
that uses them, plus a number of other building blocks, to make a
microwave transceiver.
The first block is a "no-tune transverter" designed to be used outdoors
at the antenna, utilizing a circuit board available from Down East
Microwave Company, Troy, Maine. For this article he used one made for
the 903 MHz. band; similar ones can be obtained from the same source for
use on bands from 432 through 5760 MHz. In all cases, the units convert
the received microwave signals to the 144 MHz. band, and the 144 MHz.
transmitter signals to the microwave band.
Inside the shack, Mr. Campbell's system uses a direct-conversion
transceiver with 144 MHz. input and output. The block diagram of the
2-meter transceiver shows, on the receive side, an optional i.f. (144
MHz.) preamp feeding into the r.f. input on the R2 board. A variable-
frequency 144 MHz. oscillator output passes through a splitter with
one-half of the output going through a 90-degree phase-shift network to
the "I" and "Q" inputs of the R2 board. The output of the receiver goes
to a headphone jack, or directly to a speaker.
On the transmit side, the other half of the oscillator output passes
through a similar 90-degree phase-shift network to the "I" and "Q"
inputs of the T2 board. The transmitter is actuated by either a key or
a microphone, for CW or SSB operation. Its output goes directly to the
output terminal.
The remainder of the article is primarily devoted to the design details
of two alternate "local oscillator" modules. The first of these is a
crystal controlled VXO circuit utilizing a 20.6 MHz. crystal. The
output of the oscillator is made a square wave, rich in odd-harmonics.
Following the output are two cascaded 144 MHz. band-pass filters that
select the seventh harmonic. The tuning capacitor in the VXO circuit
allows frequency to be varied, providing a 50 KHz. operating range at
144 MHz.
The other local oscillator circuit that the author describes is a
"premixed VFO". By this, he means that an HF oscillator, in this case
with a range of 13.0 to 13.12 MHz., is mixed with a 131 MHz. crystal
oscillator to provide the 144 output. The circuitry used in this module
is conventional.
The author's final comment is: "This article describes one of my
favorite applications for the R2 and T2 boards....With the basic
transmitter and receiver circuitry contained on a pair of small
printed-circuit boards, the possibilities for custom-built radios are
limited only by our imaginations."
_________
Title>TA3:Build the HANDI-Finder!
Author>Leskovec, Bob - K8DTS
Source>QST May 1993, pp. 35-38
Abstract>How to build a very simple hand-held direction finder.
Digest>This construction article gives full details for building a
simple hand-held direction finder for use in "Fox-Hunting". It can be
used in conjunction with an HT for locating AM or FM transmitters over
the frequency range of 45 to 470 MHz. The unit is completely built on a
printed-circuit board. It uses only about a dozen components, one of
which is an IC. The antenna is a "bow-tie" made of stiff wire that is
supported by screws on the PC board. A handle attaches to the board at
the center of the "bow-tie", completing the unit.
In operation, the circuit rapidly switches its input from one side of
the "bow-tie" to the other at an audio rate. When the transmitter to be
found is in line with (i.e. in the same plane of) the antenna, one side
of the antenna is closer to it than is the other. It receives the signal
a tiny fraction of a second earlier than does the other side. This
causes a difference in the phase between the two sides, the result of
which is phase-modulation that creates an audio tone in the receiver.
The tone is determined by the switching frequency.
If the antenna is rotated so that the transmitter is in a line
perpendicular to the antenna plane (i.e. "face-on"), then the signal
reaches both sides simultaneously and there is no phase-shift, hence no
audio tone. This causes a sharp null in that direction, indicating the
direction of the antenna. Note that it is the audio tone that is
nulled, not the carrier. It is much easier to detect a null in the
audio than a null in the carrier, hence the sensitivity of this unit is
excellent. Of course, the null is bi-directional and the ambiguity must
be eliminated by triangulation, which usually means that the hunter must
move laterally to determine which direction is the true one.
A kit is available containing all the parts necessary except connectors,
battery, and the wire antennas. It can be obtained for $27.95 from
North Olmstead Amateur Radio Depot, 29462 Lorain Rd., North Olmstead, OH
44070. A PC board template package can be obtained from the ARRL
Technical Department Secretary, 225 Main St., Newington, CT 06111 for a
business-size SASE. Address it to Leskovec HANDI-Finder Template.
_________
Title>TA4:Add Tracking Side-Tone to Your ICOM IC-765 Transceiver
Author>Mraz, Michael A. - N6MZ
Source>QST May 1993, pp. 39-42
Abstract>Modifications to an ICOM transceiver to allow CW operators to
adjust the sidetone pitch to any desired value while the receiver
automatically adjusts the received signal to the same pitch.
Digest>In the ICOM IC-765, the sidetone oscillator is fixed at 700 Hz.
To adjust the transmitter to the same frequency as a received signal, it
is necessary to tune the received signal to zero beat with the sidetone
pitch, which requires the operator to listen to the received station
always as a 700 Hz. tone. But many CW operators find that tone, or any
fixed tone, unpleasant and want to adjust it.
The author has designed and built a circuit which generates a side-tone
that tracks the receiving pitch within 1 or 2 Hertz. This article gives
full construction details.
The system that Mr. Mraz designed uses an integrated-circuit function
generator to generate an audio tone that tracks the setting on the front
panel "CW Pitch" adjusting knob. That knob adjusts a potentiometer
which, in turn, causes a varying voltage that can be accessed on the
main receiver board. However, the relationship between the knob
position and the pitch frequency is non-linear! Consequently, he had to
add circuitry to cause an equal and opposite non-linearity in his
sidetone generator so that the two tones would precisely track.
The author gives detailed instructions concerning how to perform the
necessary "surgery" on the ICOM circuit board. He cautions any would-be
follower that, if their transceivers are still in warranty, these
modifications would void it.
A kit of parts, including etched and drilled circuit board, for building
the unit is available for $49.00, plus $2.00 shipping within the USA
from LTA, P.O. Box 77, New Bedford, PA 16140.
_________
Title>TA5:An Introduction to Amateur Television - Part 2
Author>Taggart, Ralph E. - WB8DQT
Source>QST May 1993, pp. 43-46
Abstract>A description of the various equipment necessary or desirable
to become active in ATV.
Digest>This is the second installment of this description of amateur
television (ATV) activities. In this article, the author describes
equipment available and other details required in getting started on the
air. What he calls an "entry level" ATV setup comprises a TV camera, an
ATV 70-cm. transceiver, a TV camera, microphone, an optional power
amplifier, and an antenna.
The equipment that he describes is manufactured by three companies, AEA,
PC Electronics, and Wyman Research. AEA is a well-known supplier of a
broad line of amateur gear, whereas the other two are small
proprietorships, each run by a veteran of ATV activities. The last two
companies both supply crystal controlled transceivers with power outputs
from 1 to as much as 15 watts PEP. Their video output signals are
double-sideband amplitude-modulated (AM).
AEA's latest transceiver produces signals very similar to commercial
broadcasting standards. It uses "vestigial sideband (VSB)" AM
transmission. This means that the signal is a combination of a
single-sideband with a carrier.
Most ATV operators use home-style camcorders for their TV cameras, and
home-style TV sets for reception. All of the transceivers described
produce video outputs switchable to channels 2, 3, or 4 for viewing. In
amateur TV, as well as in commercial TV, the audio is transmitted by FM
on a sub-carrier which is 4.5 megahertz above, (or both above and below,
in the case of AM video) so that it can be reproduced on a standard
home-TV set.
------------------------------------------------------------------------
PRODUCT REVIEWS
conductor: James W. Healy, NJ2L
_________
Title>PR1:HAL Communications PCI-4000 Clover-II Data Controller
Author>Ford, Steve - WB8IMY
Source>QST May 1993, pp. 71-73
Abstract>Review of a plug-in computer board made by HAL Communications
that acts as a data controller for Clover-II communications. A
description of the Clover-II protocol is included.
Digest>Clover is a new digital mode for HF communications. It was
developed by Ray Petit, W7GHM, working with HAL Communications Company.
That company is producing the PCI-4000 for use in an IBM-compatible
computer with an 80286 CPU, or later, to control a radio transceiver in
the Clover Mode.
Clover provides much improved data communications in the noisy
environment of HF radio, but occupies only 500 Hz. of band-width. It
uses four audio tones, each of which is phase- and/or amplitude-
modulated in one of 10 schemes. The format with the highest data rate
uses 16-phase, 4-amplitude modulation (16P4A), to transmit at a rate of
approximately 750 bits/second. Other formats are more robust in
resisting noise and fading, but result in slower throughput. There are
ten different formats, in all.
Clover's most interesting feature is its adaptive operating. Under
varying conditions of propagation and noise, it adapts the power level,
and also the modulation scheme, to obtain the maximum throughput of
data. Faced with an increase of error rate or dropouts in the data, it
automatically raises the power output or changes the modulation format,
or both. When conditions improve, it reverses the sequence.
Clover uses the "Reed-Solomon" coding system which provides
forward-error-correcting (FEC). Each block of transmitted text contains
"check-bytes" which are used to correct many errors without requiring
repeats of the data blocks concerned. This is a major step beyond the
older digital modes, AMTOR and PACTOR, which verify the successful
reception of data blocks but cannot correct them; they can only ask for
repeats.
The reviewer found the PCI-4000 easy to install. He used it with a
Kenwood TS-820S and found the results were "surprisingly good". On the
air, tuning of the signals is very critical. If the transceivers at the
two ends of the link differ in frequency by as much as 15 Hz., the link
breaks! Consequently, Clover provides a screen display that includes a
frequency indicator. It shows the difference between the two signals in
Herz at all times. The display also shows a "Receive/ Transmit Status
Table". This continuously reports the modulation format in use,
signal-to-noise ratio, tuning error, phase dispersion, error-correction
capacity, and transmitter power at both ends of the link!
Mr. Ford found one weakness in Clover; that is its "Listen" mode does
not perform as well as does AMTOR and PACTOR. That is, it does not
receive well when "listening in" to a QSO between two other stations.
HAL Communications is reportedly trying to improve it.
In summary, the reviewer calls the Clover system: "Undoubtedly the most
efficient HF digital communications mode yet devised for amateur radio."
However, its price is of the order of three or four times the cost of
AMTOR and PACTOR. Consequently, it will probably be used primarily for
handling large quantities of data transfer on HF bands, such as
main-line packet forwarding.
_________
Title>PR2:AlphaLab TriField Meter
Author>Overbeck, Wayne - N6NB
Source>QST May 1993, pp. 73-74
Abstract>A review of a meter designed to measure a.c. magnetic field
strength. It was found to be subject to errors so severe as to make it
useless in radio work.
Digest>The TriField Meter is designed to measure electromagnetic field
strength in view of the widespread furor over purported health effects
of low-level a.c. fields. It supposedly measures magnetic and electric
fields separately and also has a built-in r.f. probe to detect field
strength at frequencies of from 50 MHz. to 3 GHz.
The reviewer found that, in the magnetic field modes, the meter gave
readings that were consistently too high. The well-written instruction
sheet accompanying the meter explains why: although its readings at 60
Hz. are supposed to be accurate, readings are a function of frequency
and higher frequencies will give higher readings. But there is no way
to measure the frequency of the field that the user is measuring, so it
is not possible even to estimate how much in error the measurements are!
The reviewer's final conclusion was that "...its readings are almost
certain to be misleading, creating a false sense of security or - more
likely - causing undue alarm. It is not hard to envision groups of
concerned citizens armed with these meters patrolling their
neighborhoods in search of "radiation" - and finding hazards behind
every bush!"
------------------------------------------------------------------------
HINTS AND KINKS
conductor: David Newkirk, WJ1Z
Sr. Asst. Technical Editor
_________
Title>HK1:Build a Quick PVC-Supported Quad for About $50
Author>Evans, Clark J. - WA4DLL
Source>QST May 1993, p. 75
Abstract>Construction details for a square loop antenna.
Digest>This short item includes a dimensioned drawing and construction
details for a square loop antenna, which the author calls a
"single-element quad". The spreaders, each 28 feet long, are made of
1-inch PVC pipe stiffened with dowel sticks along their entire lengths.
The dowel sticks are 4-feet long. Eight of them are required to
reinforce each of the two spreaders since they are overlapped 3-inches
at the splice between adjacent sticks. They are attached to the PVC
pipe by nylon-tape wraps about every two feet.
The bottom leg of the square is horizontal. It is broken at the center
with an insulator. Coax feedline is attached at that point. In order
to keep the weight of the feedline from causing the lower leg to droop,
the author reinforces the spreaders with a 17-foot 8-inch length of 3/4"
by 3/4" molding between spreader ends.
The author reports that he operates the antenna on 80, 20, 15, and 10
meters through the use of an antenna tuner. As for performance, he
reports: "My DX has increased 10-fold".
_________
Title>HK2:Installing a Huskier 160-M Fixed Capacitor in the Ten-Tec Titan
Author>Lynch, Joe - N6CL
Source>QST May 1993, pp. 75-76
Abstract>Step-by-step instructions for replacing a blown capacitor in
the Titan amplifier, manufactured by Ten-Tec.
Digest>Mr. Lynch reports that, when operating his Ten-Tec Titan amplifier, the
160-meter fixed capacitor in the plate tank circuit blew out, and its
identical replacement also blew out. He replaced it the second time
with a capacitor obtained from Ten-Tec that is rated at three times
higher working voltage than the originals (15 Kv. vs. 5 Kv.) Since the
replacement capacitor is larger than the originals, he had to make a
modification to the amplifier to mount it. He gives complete
instructions of how to do this, and illustrates it with a photograph.
_________
Title>HK3:Putting Variometry to Work in Matching Networks
Author>Zavarella, Art - W1KK
Source>QST May 1993, p. 76
Abstract>Using a variometer (variable inductor) in ham gear.
Digest>A variometer is an inductor in two parts, one of which can be
moved relative to the other. When the two parts are perfectly in line,
the turns of wire in the moveable part add to the turns in the other to
form a coil with turns count equal to the sum of the two. If the
moveable portion is turned by a full 180-degrees, however, then the
field created by its turns subtracts from that of the fixed part,
reducing the net inductance. Intermediate positions give intermediate
inductances. Thus it becomes a continuously variable inductor without
coil taps or moveable contacts.
Mr. Zavarella shows photographs of antenna tuners that he has built
using variometers.
_________
Title>HK4:When Antennas Should NOT Be Resonant
Author>Aitken, Hugh - W1PN
Source>QST May 1993, p. 76
Abstract>If the ends are not plugged, tubular Yagi elements resonate
acoustically in the wind.
Digest>The writer reports that he erected a new tri-band Yagi antenna
but failed to put the plastic end-caps on the elements. Now, when the
wind blows the open-ended tubing resonates in the manner of organ pipes!
The sounds are very annoying to his family, as well as neighbors.
He recommends that others be more careful and seal the ends of all
tubing with caps or plugs.
------------------------------------------------------------------------
TECHNICAL CORRESPONDENCE
conductor: Paul Pagel, N1FB
Associate Technical Editor
_________
Title>TC1:Expanded-Range DC and AC Voltmeters
Author>Grebenkemper, John - KI6WX
Source>QST May 1993, pp. 77-78
Abstract>Construction of expanded-range a.c. and d.c. voltmeters.
Digest>The writer provides wiring diagrams and parts lists for
contructing either a d.c. or an a.c. voltmeter with an expanded range,
more properly termed a "suppressed-zero" meter scale. In other words,
instead of reading from 0 to 15-volts, the meter reads from 11- to
15-volts, providing better resolution and accuracy over the operating
range.
The meters can be accurately calibrated at both ends of the scale with a
trim potentiometer to adjust each end.
Parts kits are available from FAR Circuits, 18N640 Field Ct., Dundee, IL
60118-9269. A PC-board and meter-face template package is available
from ARRL Technical Department Secretary, 225 Main St., Newington, CT
06111 for a business-size SASE. Address the request to the
"Grebenkemper DC and AC Expanded-Range Voltmeter Template".
------------------------------------------------------------------------
FEEDBACK (FB)
Title>FB1:QST Apr 1993 Product Reviews
Author>Ford, Steve - WB8IMY and Jeff Bauer -WA1MBK
Source>QST May 1993, pp. 74
Abstract>Errors in Product Reviews in QST April, 1993.
Digest>In the April, 1993 Product Review of the AEA DSP-2232, pp. 65-66,
the list price should be $999, not $899. Also the Doppler-shift
correction feature has not yet been enabled.
In the same issue's Product Review of the Outbacker antenna, p. 70,the
model reviewed was the Perth model, not the JR8. The Perth has a main
shaft of 4-foot length with 3-foot whip, whereas the JR8 is 4-feet
overall. On 75 meters, the Perth resonates down to 3.6 MHz., as
reported, but the JR-8 resonates only between 3.9 and 4.0 MHz.
_________
Title>FB2:Dipoles Above Real Earth
Author>Michaels, Charlie - W7XC
Source>QST May 1993, p. 78
Abstract>Errors in Technical Correspondence item, page 68, QST Nov 1992.
Also, Feedback in QST Feb 1993 regarding this same item wrongly changed
Equation 1.
Digest>Equations 3-5 of the Michaels letter titled: "Dipoles Above Real
Earth" in Technical Correspondence, QST Nov 1992 contained errors.
Corrections can be obtained from ARRL's Technical Department Secretary
for an SASE. Ask for the Michaels Dipoles Corrections Template.
Also, in QST Feb 1993 Feedback, Michaels advised that an error had been
made in Equation 1 of the same 1992 letter. He now states that that was
incorrect; Equation 1 as originally published in 1992 is correct.
------------------------------------------------------------------------
NEW HAM COMPANION
This section is devoted to articles and short features of special
interest to newcomers to the ham radio hobby.
_________
Title>NHC1:And the Most Popular Frequency is...
Author>Mabey, Jay - NU0X
Source>QST May 1993, pp. 60-61
Abstract>A study of frequency distribution of repeaters on the 144 and
430 MHz. bands.
Digest>This summarizes the number of repeaters on each frequency in the
2-meter and 70-centimeter bands throughout the United States and Canada.
At last count, there were 6110 2-meter repeaters and 5059 70-centimeter
repeaters!
Certain frequencies are much more popular than others. There are 156
repeaters on the single frequency 146.940 MHz. On the 70-centimeter
band, things are more spread out. The most popular frequency on that
band, 444.500 MHz., has only 23 repeaters.
The article also gives data on the number of "continuous tone-coded
squelch systems" (CTCSS). These are systems that require a continuous
audio tone to be transmitted by any transceiver that is accessing it.
In some cases, they are used to prevent access by anyone other than a
small group of members. In other cases, the tone signal required is
openly published. On the 2-meter band, there are a total of 694
repeaters using CTCSS, 11 percent of the total. On the 70-centimeter
band, there are 1131, or 22 percent.
The author ends the article with a description of the ARRL REPEATER
DIRECTORY, of which he is Editor. He says of it: "It is a complete
directory of repeaters in the USA and Canada from 10 meters through 23
centimeters."
_________
Title>NHC2:Do You Need an Audio Filter?
Author>Gill, Steven J. - KG7YK
Source>QST May 1993, pp. 62-63
Abstract>Mr. Gill describes what audio filters are and how they are
used. He emphasizes their use in CW operations. He also makes mention
of digital signal processing (DSP), but does not discuss it in depth.
_________
Title>NHC3:The Doctor is IN p. 64
Author>Various
Source>QST May 1993 - p. 64
Abstract>Questions and answers on topics of primary interest to
newcomers.
Digest>In this issue, the questions include: 10-10 numbers, r.f.
feedback; the difference between a duplexer and a diplexer; computers
for use in ham stations; the illegality of automatic, unattended station
operations on HF bands; and what to do if electronic equipment gets
water-soaked.
_________
Title>NHC4:A Disguised Flagpole Antenna
Author>Parker, Albert - p. 65
Source>QST May 1993, p. 65
Abstract>A description, with photographs, of a vertical antenna
disguised as an attractive flagpole.
_________
Title>NHC5:VHF/UHF Contesting
Author>Ford, Steve - WB8IMY
Source>QST May 1993, pp. 67-69
Abstract>A description of VHF/UHF contests, what they are, and when
they take place.
Digest>The author encourages newcomers to participate in VHF/UHF
contests and gives hints concerning how to boost one's scores. He also
discusses "grid square" designators and includes a map of the USA with
grids indicated.
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RADIO TIPS (RT)
These are short items, scattered among the articles in the NEW HAM
COMPANION section.
_________
Title>RT1:What Is AMTOR?
Author>Ford, Steve - WB8IMY
Source>QST May 1993, p.61
Abstract>A description of the amateur radio mode: AMTOR - AMateur
Teleprinting Over Radio.
_________
Title>RT2:Lightning!
Author>Ford, Steve - WB8IMY
Source>QST May 1993, p. 63
Abstract>Hams are warned to protect their radio equipment from the
destructive effects of lightning.
Digest>Antennas should have lightning arrestors with low-impedance leads
to ground. All equipment should be protected and, preferably,
disconnected from the antenna and also the power mains, when lightning
conditions occur.
_________
Title>RT3:The Ionosphere
Author>Ford, Steve - WB8IMY
Source>QST May 1993, p. 66
Abstract>A short description of the ionosphere including a diagram of
the atmosphere showing the D, E, F1, and F2 layers. Also discusses the
effects of ionization on radio propagation.
_________
Title>RT4:Working the World on 10-Meters
Author>Ford, Steve - WB8IMY
Source>QST May 1993, p. 69
Abstract>A description of propagation conditions on 10-meters.
Digest>Directed primarily to Novice or Technician class amateurs with HF
priveleges, it describes the 10-meter band as a "real powerhouse". Even
in the present declining phase of the sunspot cycle, exciting
propagation happens unpredictably, and beginners are encouraged to
monitor the band for openings.
_________
Title>RT5:Is Amateur Radio Safe?
Author>Ford, Steve - WB8IMY
Source>QST May 1993
Abstract>Purported hazards of electromagnetic fields, including radio
waves.
Digest>This gives a balanced description of the questions that have been
raised about the possible hazards of electromagnetic fields, including
radio. Some sensible precautions are outlined for amateurs to follow
when working with transmitters.
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GENERAL INTEREST ARTICLES
_________
Title>GI1:Festing (Notes of a Hamologist"
Author>Apteryx, Ann - W1NG/7
Source>QST May 1993
Abstract>Humor.
Digest>This is a humorous article in which the author compares
people-watching at a hamfest with bird-watching. Among the posited
"bird-types" are the purple dealhunter (hunticus bargainicus), the
wandering buynothing (optex non-purchasicus), and the lesser cheapskate
(pricens reducensis).
_________
Title>GI2:PHASE 3D - A Satellite for All -- Part 1
Author>Jansson, Dick - WD4FAB and Tynan, Bill - W3XO
Source>QST May 1993, pp. 49-51
Abstract>A description of amateur satellites launched in the past, their
limitations, and the ground equipment needed to use them; a discussion
of why so few amateurs are doing so; and a description of the proposed
new Phase 3D satellite now being built.
Digest>The two authors are Vice President of Engineering and President,
respectively, of Radio Amateur Satellite Corporation (AMSAT). In this
article, they discuss the satellites that have been launched over the
past 30 years and the ones that are in orbit now.
They describe the different modes and methods of use that have been
utilized in the past and speculate on why so few amateurs have actually
tried to use them. They conclude that one reason is that many hams
perceive that the technology is too difficult and/or the equipment too
expensive for them to be interested. Another seems to be that many hams
who are active in VHF and UHF are put off by the fact that satellites do
not handle FM.
The authors' rebuttal to the first objection is that the technology of
operating through satellites is no more difficult or more expensive than
other aspects of amateur radio operating. Regarding FM, they point out
that if a satellite were designed for FM repeating, the power
requirement would be prohibitive and the number of stations that could
access the satellite at any one time would be so severely limited as to
make it impractical. They make an adequate case that CW and SSB modes
are necessary in satellite operations.
Next, they discuss the kind of station equipment that is needed to take
full advantage of the current satellites, especially the high-altitude
ones. These, specifically OSCARs 10 and 13, provide nearly world-wide
communications to amateurs throughout the world. They are in orbits in
which the apogee (the point in the orbit that is farthest from earth) is
so high that the satellite appears to move very slowly across the sky
and stays visible for several hours each day. They make it possible for
hams all over the northern hemisphere to communicate with each other.
Finally, they discuss the new Phase 3D satellite that is under
construction at this time. Oscars 10 and 13, the present "high-altitude
birds", are reaching the ends of their operating lives. The Phase 3D
will be the largest and, by far, the most sophisticated one ever
launched. Because of its high-powered transmitters and extra-sensitive
receivers, it will be possible for hams all over the world to access it
using simpler equipment than is required with Oscars 10 and 13.
Furthermore, it will be possible for ground-based repeaters to link with
other repeaters long distances away via the satellite! The result may
be hams communicating with each other over inter-continental distances
using HTs!
Next month, in Part 2 of this article, the authors will discuss design
details of the Phase 3D satellite and its orbit.
_________
Title>GI3:Inspiration: N2OVA
Author>Lorito, Philip - WB2HDY
Source>QST May 1993, pp. 52-55
Abstract>The true story of how a terminally ill boy became a ham in his
final months on earth.
Digest>This is a human-interest story about a young boy who was
suffering from a terminal illness. His strongest wish was to become a
radio ham.
The author, and many other individuals, as well as the FCC, cooperated
to make the boy's dream come true. His name was Jason Longboat, and his
ham call was N2OVA. He received his license in early 1992, and died in
November of that year, but his last months on earth were made distinctly
happier through ham radio.
_________
Title>GI4:Transmitter Hunting: Tracking Down the Fun - Part 2
Author>Moell, Joe - K0OV
Source>QST May 1993, pp. 56-58
Abstract>Second installment of a description of radio direction finding
as a competitive activity.
Digest>In this article, Mr. Moell discusses details of organizing "Fox
Hunts" and also describes different kinds of direction-finding
equipment. In sidebars included with the article, there are discussions
of several different types of RDF instruments that use something other
than beam antennas to indicate bearing. One of these is a "homing set".
The authors state that a homing set uses a pair of vertical antennas and
a control box with a "right-left" indicator such as LEDs. However, they
do not describe the principle of operation.
Another type is the time-difference-of-arrival (TDOA) system. This uses
two antennas that are switched in sequence at an audio rate. It is the
same principle as was discussed in the article: "Build the HANDI-
finder!" by K8DTS in this issue.
The last type system described is doppler systems. These are usually
mounted on vehicles, since they use multiple antennas (typically 4 or 8)
which are rapidly sequenced to simulate a rotating antenna. As the
putative antenna rotates, the received signal shifts up and down at an
audio rate. The receiver detects this as an audio signal, the phase of
which indicates the direction of arrival relative to the heading of the
vehicle, and is often displayed on a CRT. This system is capable of
giving instant display of heading from a short burst of transmitted
signal. However, it is much less sensitive than beam antennas and
cannot be carried on foot.
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