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DIGEST OF ARTICLES -- QST, April, 1993
Following are digests of articles printed in the April, 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:An Introduction to Amateur Television - Part 1 (75)
TA2:Fighting Antenna Corrosion (123)
TA3:A Multimode Phasing Exciter for 1 to 500 MHz. (171)
TA4:A Remotely Controlled Antenna Switch (210)
TA5:A Two-Element Duoband Beam (249)
PRODUCT REVIEWS (PR)
PR1:AEA DSP-2232 Multimode Communications Processor (294)
PR2:The ICOM IC-R7100 HF/VHF/UHf Communications Receiver (337)
PR3:Terlyn Outbacker JR-8 HF Mobile Antenna (364)
HINTS AND KINKS (HK)
HK1:Positive and Negative Keyer Keying, Simply (401)
HK2:Low HW-8 Power Output (416)
TECHNICAL CORRESPONDENCE (TC)
TC1:Sporadic-E Causes (433)
TC2:More on Measuring SSB/CW Receiver Sensitivity (451)
LAB NOTES (LN)
LN1: Emergency Power (474)
FEEDBACK (FB)
FB1:QST January, 1993, pp. 34-35 "High Performance, Single-Signal (491)
Direct Conversion Receivers"
NEW HAM COMPANION (NHC)
NHC1:7 dB. for 7 Bucks (510)
NHC2:Scanning the VHF Aviation Band (547)
NHC3:Confessions of a Conversation Hunter (562)
NHC4:Rockets and Radio (571)
NHC5:The Doctor is IN (591)
RADIO TIPS (RT)
RT1:What's Happening on the 2-Meter Band? (613)
RT2:What Type of Feed Line Should I Use? (623)
RT3:The Monoband HF Dipole Antenna (634)
GENERAL INTEREST ARTICLES (GI)
GI1:Don't Get Blown Away by Your Mobile Rig (645)
GI2:Big LEOs (656)
GI3:Visiting Amateurs in the Far East (690)
GI4:Five Meters or Bust (709)
GI5:Transmitter Hunting: Tracking Down the Fun - Part 1 (717)
------------------------------------------------------------------------
TECHNICAL ARTICLES (TA)
Title>TA1:An Introduction to Amateur Television - Part 1
Author>Taggart, Ralph E. - WB8DQT
Source>QST Apr 1993, pp. 19-23
Abstract>First installment of 3, describing amateur television. This
one covers current activities, bands in use, and how to receive and view
local transmissions.
Digest>This is the first of a projected three articles regarding amateur
television (ATV). It should not to be confused with slow-scan TV
(SSTV), which is more akin to facsimile. Part 1 is a description of
present amateur activities in television transmission and reception, the
bands that are currently being used, and an outline of how one might be
able to watch and listen to what is being done now in the local area.
There are three major TV formats in use in the world: the one we use in
North America, known as NTSC, PAL, and SECAM. The last two are in use
in Europe and other countries throughout the world. The PAL system was
developed in Germany and SECAM in France. Which system is used in what
countries is, in most cases, determined by what company got the contract
to put the first broadcasting system in use. Amateurs almost invariably
use the same TV system that is broadcast in their country so as to be
able to use television sets bought in local stores.
Most ATV operation is in the 70 cm. band, which is the lowest frequency
band in which ATV is authorized by the FCC. Some work is done on higher
bands, but 70 cm. seems to show the best transmitting conditions.
In more than 40 states and around the world there are ATV repeaters.
Most use receive and transmit frequencies in the same 70 cm. band.
The distance over which a reliable TV signal can be transmitted for a
given amount of radiated power is substantially shorter than is the case
with audio. The reason is that the bandwidth occupied by a TV signal,
operating in real time, is about 4.5 MHz., more than 300 times as broad!
Spreading the same amount of power over that much more spectrum width
reduces the signal level by some 25 dB. But at these frequencies,
multi-element beam antennas are easy and inexpensive to build, so it is
possible to pick up as many as 15 dB. gain compared with that of a
quarter-wave whip antenna. Hence, if one can work a given station on FM
audio with an HT running from 1 to 10 watts output, it will probably be
possible to work over the same distance with ATV, using a high-gain
antenna and from 10 to 100 watts output.
The next installment of this series will discuss the details of an
operating an ATV station.
_________
Title>TA2:Fighting Antenna Corrosion
Author>Roleson, Scott - KC7CJ
Source>QST Apr 1993, pp. 24-26
Abstract>The causes of antenna corrosion and how to minimize it.
Digest>Weather-caused antenna corrosion occurs primarily when two
different metals such as aluminum and copper come in contact with each
other. When the antenna gets wet from rain, all the elements necessary
for galvanic corrosion are present. The word "galvanic" implies that an
electro-chemical process is at work. In fact, it is the same process
that explains how a battery works.
All metals form a "galvanic series" based on the voltage that each
develops (in relation to a platinum electrode) when it is immersed in an
electrolyte such as rainwater. At one end of the series, the "anodic"
end, are, in order, magnesium, zinc, and aluminum. At the other end,
the "cathodic" end, are gold, silver, nickel (passive), and copper.
Thus aluminum and copper are far apart on the scale and there is a
relatively large voltage that develops between them.
The electric potential causes the water molecules (H2O) to break down;
the oxygen atom combines with an atom of the aluminum forming
aluminum-oxide, and two electrons combine with the hydrogen ions that
were left from the breakdown of the water molecule to form a molecule of
hydrogen gas (H2). The aluminum oxide is an insulator and, before long,
the former low-resistance electrical contact between the copper and
aluminum becomes a high resistance joint.
There are two ways to overcome such corrosion problems. First, the part
of the copper that touches the aluminum should be covered with solder
("tinned"). Then the connection should use a star-type lock-washer on
the screw that compresses the joint, and it should be secured with
stainless-steel hardware. The lock-washer will cut through any oxide,
or other insulating coating, to insure good conductivity.
Second, the overall joint should be covered with a waterproof compound,
and that, in turn, wrapped with a weatherproof covering. Stainless steel
and solder are not far from aluminum in the galvanic series, so do not
generate much voltage that would promote a chemical reaction, and
preventing water from getting into the joint will prevent any corrosion
at all.
There are a number of corrosion-fighting compounds on the market that
both enhance conductivity of a metal-to-metal joint, and also waterproof
it.
_________
Title>TA3:A Multimode Phasing Exciter for 1 to 500 MHz.
Author>Campbell, Rick - KK7B
Source>QST Apr 1993, pp. 27-31
Abstract>Construction of a relatively high-performance but simple CW/SSB
transmitter, a companion to the single-signal direct-conversion receiver
in January, 1993 QST.
Digest>The author of this article is the same person who wrote the
article in the January, 1993 QST describing a single-signal
direct-conversion receiver. In this month's article, he is describing a
companion transmitter that can be used in CW or SSB modes.
He omits a description of the two local oscillators which, presumably,
will be the same ones used in the receiver. The only frequency-specific
components in this transmitter are the ones that form a low-pass filter
at the output; he gives a table of values for the inductors and
capacitors involved, so that the unit can be built for the 7, 28, 50,
144, 222, or 432 MHz. bands.
The transmitter generates a single-sideband signal using the same
phasing method that the author used to provide single-signal reception
in the earlier receiver article. In fact, the whole circuitry is very
similar to that of the receiver.
The r.f. output is limited to 3 milliwatts and so, in almost all cases,
it will be used to drive a power amplifier. Aside from the final
amplifier and the local oscillators, a complete wiring diagram and parts
specifications are included.
Etched, plated, and drilled p.c. boards are available from Applied Radio
Science, P.O. Box 225, Houghton, MI 49931 for $10.00 each, postpaid.
Also, a catalog of kit information is available from the same source for
an SASE. An etching template/parts-overlay package can be obtained from
the ARRL Technical Department Secretary, 225 Main Street, Newington, CT
06111 for an SASE. Address the request to the Campbell T2 Board
Template.
_________
Title>TA4:A Remotely Controlled Antenna Switch
Author>Thompson, Nigel - KG7SG
Source>QST Apr 1993, pp. 32-35
Abstract>Construction of a remotely-controlled antenna switch.
Digest>This article describes an antenna switch that can be mounted
outdoors and controlled automatically by ICOM MF/HF rigs, or manually
with other rigs. It is designed to switch a single feedline coming from
the shack to each of up to seven antennas, one each on 10, 15, 20, 30,
40, 80, and 160 meters.
The author designed this system to work with his ICOM 735 transceiver
which makes a band signal available on a rear-panel multi-pin socket
labeled: ACC2. Four leads connect from the ACC2 socket to the
antenna-switch box: 13.8 v. supply, +8.0 v. reference, ground, and
band-output-signal voltage. The last of these provides a d.c. voltage
that changes in approximately 1.0 volt steps, from 0 to 8 volts to
indicate which band is in use. However, the 18 and 21 MHz. bands are
indicated by the same voltage, as is also true for the 24 and 28 MHz.
bands.
On pin number 1 is a plus 8.0 volt reference voltage. The author
connects a voltage divider between the 8.0 volts and ground with a tap
corresponding to each of the levels indicating the respective bands. On
each tap, he connects one section of an LM339 quad-comparator chip. A
straightforward circuit causes the comparators to "decide" which band is
in use and activate one of seven relays that switches the feedline among
the antennas, and also lights an LED indicating which one is active.
A complete wiring diagram, parts list (with Radio Shack stock numbers),
and photographs of the author's unit, are included. For people who use
transceivers other than ICOMs, a wiring diagram shows a multi-position
switch and voltage divider circuit to allow manual control of the same
system. Most hams would probably opt to use the rotary switch directly
to control the current to the individual relays rather than code and
decode the switch position as an analog voltage level.
_________
Title>TA5:A Two-Element Duoband Beam
Author>Mansheim, John V. - W0JCS
Source>QST Apr 1993, pp. 36-37
Abstract>Construction article for a two-element beam for the 12- and
17-meter bands.
Digest>This is a construction article giving full information and
instructions for building a two-element yagi beam to cover the 12- and
17-meter bands. The design uses a driven element and reflector, each of
which is a classical type of trap-dipole. That is, the traps are
resonant at the middle of the higher frequency band, in this case the
12-meter band. When that band is in use, the impedances of the resonant
traps are so high that they can be considered open-circuits and the
active length of the dipole is resonant on that band. When the lower
frequency is in use, the traps present an inductive reactance which
means that, in tuning, the overall physical lengths of the elements must
be cut somewhat shorter than would be the case if the traps were not
present.
The author relates that he made the duoband beam out of a 12-meter beam
that had been erected previously. He only extended the elements and
inserted the traps; he did not change the separation between the
elements, which is 71-1/2 inches. That dimension represents 0.15
wavelength on 12-meters and about 0.11 wavelength on 17-meters. Both
dimensions are within the ranges recommended by authorities on Yagi
design.
The traps used are commercially available, manufactured by Unadilla
Antenna Manufacturing Company, Andover, MA 01810. They are apparently
designed for mounting on tubular elements as each coil form, itself,
forms an insulator and mechanical support for two pieces of tubing.
Dimensioned drawings and complete parts lists are included, as are
photographs of the final result. The author states that the beam shows
apparent gain of 5 to 6 dB. over his dipoles, front-to-back ratio more
than 10 db., and front-to-side ratio of 25 dB. He states that his total
cost, including the four traps, was less than $100.
------------------------------------------------------------------------
PRODUCT REVIEWS (PR)
Conductor: James W. Healy - NJ2L
Sr. Asst. Technical Editor
_________
Title>PR1:AEA DSP-2232 Multimode Communications Processor
Author>Ford, Steve - WB8IMY
Source>QST Apr 1993, p. 65.
Abstract>Review of AEA's first communications processor to feature
Digital Signal Processing.
Digest>The DSP-2232 differs fundamentally from the previous digital mode
equipment manufactured by AEA in that it uses digital signal processing
(DSP) modems in software, rather than the hardware of all previous
models. Since it is much easier to change software than hardware, that
means that this new system is very much more versatile and can emulate
almost any modem in software.
This one unit can operate in AX.25 packet (300, 1200, and 2400 bit/sec
AFSK; 1200 and 4800 bit/sec PSK; 9600 bit/sec FSK) Baudot and ASCII
RTTY; AMTOR; CW;NAVTEX; TDM (Time-division multiplex); KISS (for
TCP/IP); and other special applications. In addition, using extra
software not provided with the unit, it can process SSTV and FAX modes.
The second feature differentiating the '2232 from the older AEA units,
like the venerable PK-232, is the fact that it can simultaneously
operate different modes on two different rigs. One channel can monitor
a VHF packet cluster while the other is operating HF AMTOR, for example.
The reviewer reports that the unit's performance on HF and VHF packet is
excellent. It exhibited better noise immunity, especially on HF packet,
than other units that he has used. It also did very well in PSK PACSAT
operation. He transmitted MFSK on the 2-meter FM uplink to the
Fuji-OSCAR 20 and received PSK on the 70-cm. downlink very effectively.
Like the older PK-232, the DSP-2232 includes the SIAM (Signal
Identification and Aquisition Mode) which automatically identifies
unknown digital signals, if it is within the modes that the unit is
programmed to recognize.
In spite of its great versatility, the unit is easy to understand and
operate and comes with a thorough and "user-friendly" operating manual.
Its price is high, but much less than the total cost of the alternate
equipment that would be necessary to perform all of the different
functions that can be performed by this one unit alone.
_________
Title>PR2:The ICOM IC-R7100 HF/VHF/UHF Communications Receiver
Author>Newkirk, David - WJ1Z and Healy, Rus - NJ2L
Source>QST Apr 1993, pp. 67-69
Abstract>Review of ICOM's R7100 receiver. Covers exceptionally wide
frequency range. Designed more for Short Wave Listening (SWL) than
amateur radio use.
Digest>This article reviews a new ICOM receiver that covers the very
broad range from 25 to 2000 MHz. It includes 920 memories, a scanner, a
noise-blanker and selectable automatic frequency control (AFC).
It is a multi-conversion superhet. From 25 to 512 MHz., it uses triple
conversion with i.f.'s at 778.7 MHz., 10.7 MHz., and 455 KHz. Above 512
MHz., it uses quadruple conversion with first i.f. at 266.7 MHz. and the
other three the same as those used below 512 MHz. For tuning the range
from 1025 to 2000 MHz., an internal crystal-controlled converter
converts those frequencies to the basic tuning range of 25 to 1025-MHz.
In spite of its impressive features, the reviewer feels that this
receiver does not meet the requirements of serious ham operation. It is
designed more for the short-wave listener who wants to extend his
listening far beyond the "short waves". Its dynamic range is limited,
its narrowest selectivity is 2.4 KHz. bandwidth, its synthesizer is
noisy, and its tuning resolution is far too coarse for serious CW and
SSB reception.
_________
Title>PR3:Terlyn Outbacker JR-8 HF Mobile Antenna
Author>Bauer, Jeff - WA1MBK
Source>QST Apr 1993, p. 70
Abstract>Reviews an exceptionally rugged multiband mobile antenna.
Digest>The Outbacker is a multiband mobile antenna made in Australia. It
is advertised and noted as being exceptionally rugged. Several
different models are offered; the one reviewed is the 150-watt
4-foot-long model JR-8 for 75 through 10 meters.
Although rugged, the two-piece antenna weighs a total of only 1-3/8
pounds. The bottom section is a fiberglass-reinforced-plastic (FRP)
rod, helically wound with a copper-wire radiator, encased in epoxy. The
helix is tapped at eight different points for operation on the different
bands. Bandswitching is done by changing the plugs on a flexible jumper
that is wrapped around the outside of the antenna. The jacks that the
jumpers plug into are oriented downward so that water does not enter
them.
The reviewer deliberately mounted the antenna on the roof of his car and
repeatedly banged it into overhead tree limbs, etc. Finally, the
stainless-steel whip that forms the upper part of the antenna did break
off but only after having been hit many times. The lower portion and
the extra-rugged base were not affected at all. The whip was easily and
quickly replaced.
He reports that he really enjoyed using the Outbacker and, in fact, was
so taken with it that he gave away his other name-brand antenna.
------------------------------------------------------------------------
Hints and Kinks (HK)
Conductor: David Newkirk, WJ1Z
Sr. Asst. Technical Editor
_________
Title>HK1:Positive and Negative Keyer Keying, Simply
Author>Boyars, Art - K3KU
Source>QST Apr 1993, pp. 71-72
Abstract>Circuit description for a keyer able to handle either positive
or negative keying lines.
Digest> Mr. Boyars' hint is a simple circuit that can key either
positive or negative keying lines. It uses two transistors. They
operate in the normal manner when keying negative lines, but when used
to key positive lines they operate in a way not usually considered
normal. Nevertheless the circuit works reliably and well. He discusses
the operation in detail and shows how and why the transistors work.
_________
Title>HK2:Low HW-8 Power Output
Author>Czuhajewski, Michael A. - WA8MCQ
Source>QST Apr 1993, p. 72
Abstract>Correcting a problem of low output in Heath transceivers.
Digest>The writer points out that some Heath HW-8 transceivers deliver
low power output on 80 and 40 meters, caused by an increase of the
permeability of the output network ferrite cores. He explains how to
diagnose this problem and how to correct it.
------------------------------------------------------------------------
TECHNICAL CORRESPONDENCE (TC)
Conductor: Paul Pagel, N1FB
Assoc. Technical Editor
_________
Title>TC1:Sporadic-E Causes
Author>Spokes, G. Neil, Ph.D. - AB4YK
Source>QST Apr 1993, P. 73
Abstract>Hypothesis to explain 5-day periodicity in VHF sporadic-E
propagation.
Digest>The writer comments on a recent observation made by Emil Pocock,
W3EP and Pat Dyer, WA5IYX. They found a 5-day periodicity in VHF
sporadic-E propagation that was maintained over at least a decade. Dr.
Spokes suggests that there are "hitherto undiscovered flowing streams of
particles or gases orbiting around the sun in comet-like trajectories
that intersect the Earth's orbit primarily in the May-August and
November-February time frames." He predicts that researchers may find
other manifestations of the hypothesized particle streams and suggests
ways of testing for their presence.
_________
Title>TC2:More on Measuring SSB/CW Receiver Sensitivity
Author>Zeiller, Thomas W. - KK6ZI
Source>QST Apr 1993, p. 73
Abstract>Debate between Zeiller and Sabin - W0IYH over definition of the
term "excess noise power" and its possible effects in identifying
sources of receiver noise.
Digest>The writer suggests that William Sabin, W0IYH, author of the
article: "Measuring SSB/CW Receiver Sensitivity" in QST, October, 1992
used an incomplete definition of the term "excess noise power", and
proposes that this definition caused some problems in identifying the
source of noise.
Following Mr. Zeiller's letter was a rebuttal and further clarification
by Mr. Sabin.
-----------------------------------------------------------------------
LAB NOTES (LN)
Conductor: Steve Ford, WB8IMY
Asst. Technical Editor
_________
Title>LN1:Emergency Power Sources
Author>Ford, Steve - WB8IMY
Source>QST Apr 1993, pp. 76-77
Abstract>Questions and answers regarding emergency power sources,
especially for use in Field Day operations.
Digest>The questions regard how much rated power a generator should have
to operate a typical Field Day setup; whether extra contest "points" can
be obtained for operating with 5-watts or less; whether batteries can be
used with a 100-watt transceiver; whether solar power can be useful;
whether there are batteries other than lead-acid that can be used; and
what kind of information does ARRL have about emergency power sources.
------------------------------------------------------------------------
FEEDBACK (FB)
Title>FB1:High-Performance, Single-Signal Direct-Conversion Receivers -
QST Jan 1993
Author>Campbell, Rick - KK7B
Source>QST Apr 1993, p. 75
Abstract>In the Campbell article in QST Jan 1993, pp. 34-35 there are
many errors in the schematic (Fig. 3).
Digest>R33 can be omitted and replaced with a wire jumper. R32 is not
used. R35 is shown twice; both are 10k ohms. R49 and C41 should be
reversed; C41 connects to ground. Q10 is a 2N3906, NOT 2N3904. The
schematic shows two Q9s. The 2N3904 labeled Q9 next to Q5 and Q6 is
actually Q4.
------------------------------------------------------------------------
NEW HAM COMPANION (NHC)
This is a regular section of QST devoted to articles of primary interest
to newcomers to ham radio.
_________
Title>NHC1:7 dB. for 7 Bucks
Author>Loucks, Nathan - WB0CMT
Source>QST Apr 1993, pp. 54-55
Abstract>Construction of a simple 2-meter, 3-element beam.
Digest>Described is a simple 3-element beam for 2-meters built out of
3/4" PVC pipe with elements cut from steel welding rods or brass rod
found in some hobby stores.
The author used a 3/4" tee for the center of the boom, and inserted an
18" piece of tubing in each side of the crossbar of the "T" to form the
boom. In the base of the tee a 36" piece of tubing was inserted as the
mast. He fastened the tubing into the tee using wood screws, then cut a
35" rod for the director and inserted it in holes drilled through the
tubing 3/4" from one end of the boom. At the other end, he similarly
mounted a 40" rod as the reflector.
Holes were drilled for the driven element 16" from the reflector, which
put it 20" from the director. The driven element is in two pieces;
each piece is pushed into a pair of holes drilled through both walls of
the tube. The two pairs of holes are about 1" apart, so the PVC acts as
the center insulator between the two halves of the element. To make the
length variable for fine tuning, a 4" piece of rod is attached to each
end with a "jam-screw" clamp. The braid of the coax feedline is
attached to the driven element at the center, with the braid soldered to
one half and the center conductor to the other, completing the antenna.
The antenna can be mounted on a chimney or vent-pipe and aimed at a
favorite repeater, for example, or else put on a TV rotator for general
use. The diagram and photographs in the article show the antenna built
with the elements vertical for vertical polarization, which is best for
FM work. If it is to be used for 2-meter SSB and CW, Mr. Loucks
recommends assembling the boom with the elements horizontal.
_________
Title>NHC2:Scanning the VHF Aviation Band
Author>Ford, Steve - WB8IMY
Source>QST Apr 1993, pp. 56-58
Abstract>How to listen to the VHF Aviation Band and what the listener
will hear.
Digest>In this article, Mr. Ford acquaints amateurs about radio
activities on frequencies located between the FM broadcast band and the
2-meter amateur band. They are primarily aviation communications. Some
2-meter hand-held rigs cover these frequencies and allow one to
listen-in. Otherwise, it will require a VHF scanning receiver designed
to cover the aviation band.
_________
Title>NHC3:Confessions of a Conversation Hunter
Author>Elliott, Jock - KG2GOM
Source>QST Apr 1993, p. 59
Abstract>Ways to draw people into interesting conversations by asking
leading questions, or otherwise taking the QSO beyond a bare-boned
exchange of signal reports.
_________
Title>NHC4:Rockets and Radio
Author>Patterson, Dave - WB8ISZ
Source>QST Apr 1993, p. 61-62
Abstract>Describes the hobby of model rocketry and how ham-radio can be
utilized in it.
Digest>This is a description of the hobby of model rocketry. Many people
enjoy assembling and firing model rockets using solid-fuel engines
available from various manufacturers. Some enjoy the help of hams
equipped with HT rigs to monitor the flight visually and report the
track of the rocket on its descent by parachute, to avoid losing it.
Even better is a "foxhunt" in which the rocket is equipped with a tiny
transmitter that can be tracked by radio as it is coming down and found
after it has landed. This is especially important when high- altitude
rockets are being fired that may drift for more than a mile during
descent.
_________
Title>NHC5:The Doctor is IN
Author>Various
Source>QST Apr 1993, p. 63
Abstract>The monthly Question and Answer column which addresses subjects
of interest to newcomers to ham radio.
Digest>This month the questions relate to the difference between
1/4-wave and 5/8-wave antennas for use in 2-meter mobile service;
on-glass mobile antennas; whether a technician-class licensee can
operate digital modes on 10-meters; whether a battery pack can be
damaged if left connected to the charger too long; and what is wrong if
an old receiver receives well on every band except one.
_________
RADIO TIPS (RT)
These are short items, scattered among the articles in the NEW HAM
COMPANION section.
_________
Title> RT1:What's Happening on the 2-Meter Band?
Author>Ford, Steve - WB8IMY
Source>QST Apr 1993, p. 60
Abstract>Described are: DX-chasers at the low end of the band; packet
radio from 144.91 through 145.09 MHz., in some areas also on 145.50 to
145.80 MHz.; satellite activity between 145.80 and 146.00; and FM
repeaters covering almost all the rest of the band.
_________
Title>RT2:What Type of Feed Line Should I Use?
Author>Ford, Steve - WB8IMY
Source>QST Apr 1993, p. 60
Abstract>The characteristics of four common types of feed lines are
given: RG-58 - useful for HF lines less than 50 feet long. RG-8 or
RG-213 - for higher power or longer runs on HF and for all uses on
VHF/UHF. Hardline - for VHF, UHF, and microwave. Open Wire - for use
with antenna tuners.
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Title>RT3:The Monoband HF Dipole Antenna
Author>Ford, Steve - WB8IMY
Source>QST Apr 1993, p. 64
Abstract>A description of how to erect a dipole antenna cut to a single
frequency band. Wire lengths are given for 80, 40, 15, and 10 meters.
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GENERAL INTEREST ARTICLES (GI)
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Title>GI1:Don't Get Blown Away by Your Mobile Rig
Author>Battles, Brian - WS1O
Source>QST Apr 1993, pp. 38-39
Abstract>Federal law now requires that all 1994-model and later
passenger cars must have passive-restraint systems for both occupants of
the front seat; after 1998, air-bags on both sides. Hams must consider
the air-bags when installing radios in any car, van, or truck.
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Title>GI2:Big LEOs
Author>Hale, Bruce S. - KB1MW/7
Source>QST Apr 1993, pp. 40-41
Abstract>Description of Motorola's "Iridium" worldwide communications
system to be active by 1996.
Digest>This article is a description of the "Iridium" worldwide
communications system to be built by Motorola. It will be made up of 66
satellites orbiting the world continuously in low-earth orbits (LEOs).
When all are in operation, every point on the surface of the earth will
always be within line-of-sight communication distance of one or more
satellites. It will make it possible for two people anywhere on the
surface of the earth to talk with each other by telephone, at anytime!
Each of the satellites will be 3-feet in diameter, 6-feet tall, and
weigh about 700 pounds. It will have 6 scanning antenna arrays and one
fixed-beam antenna. It will form 37 spot-beam "cells" approximately 400
miles in diameter. On the ground, the customer will have a hand-held
transceiver with the equivalent of a "rubber-duck" antenna and will at
all times be within one of the "cells" of one or more satellites. When
the customer dials a number, it will be received by the nearest
satellite, relayed through as many other satellites as necessary until
it reaches the one that is over the destination point, and that one will
ring the phone belonging to the person being called. As the satellites
move through space, they will "pass-off" each customer to the next
satellite in a way analagous to the way cellular operate now.
Motorola expects to have all 66 satellites in position by 1996. They
expect to attract 700,000 customers in the first year of operation and
reach 1.4 million users by 2001.
The author calls the system "an offshoot of our pioneering MICROSATS".
He has a point!
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Title>GI3:Visiting Amateurs in the Far East
Author>Pataki, George - WB2AQC
Source>QST Apr 1993, pp. 42-45
Abstract>Descriptions of one ham's visits with East Asian hams.
Digest>The author describes the interesting experiences that he had
recently when he travelled with his wife and two children through eight
countries in East Asia and visited hams in each. The article is
illustrated by a number of photographs that he took showing hams with
their shacks and/or antennas in almost all of the countries they
visited.
Mr. Pataki recommends that anyone who would like to meet local hams
during a foreign trip should make preparations well in advance, writing
letters and follow-ups. It is a good idea to make many more contacts
ahead than can be visited in person, for some will not work out.
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Title>GI4:Five Meters or Bust
Author>Syverson, Burt - K5CW
Source>QST Apr 1993, pp. 46-47
Abstract>A nostalgia article, written by a current-day "old-timer"
recalling his first attempts at ham radio in 1934 when he was about 15
years old.
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Title>GI5:Transmtter Hunting: Tracking Down the Fun - Part 1
Author>Moell, Joe - K0OV
Source>QST Apr 1993, pp. 48-50
Abstract>A description of the sport of radio direction finding.
Digest>This is part 1 of a 2-part article describing radio direction
finding (RDF) as competitive activities. Sometimes known as
"fox-hunting" or "T-hunting", they are usually events organized by ham
radio clubs. The majority are on 2-meters, but sometimes are found on
any band from 50 to 450 MHz.
Usually the club arranges to hide a transmitter somewhere within a
defined territory and teams of members equipped with RDF antennas and
rigs set out to find it. The assigned areas are usually from 75 to 2500
square miles (50-by-50 miles), but some are much more ambitious. The
author describes one that started from the top of a peninsula on the
Southern California coast, ran for an entire weekend, and tracked as far
as Arizona and Nevada, more than 200 miles from the start.
Equipment required ranges from an HT with a hand-held 2-element antenna
to multi-element Yagis and quads mounted on the tops of automobiles or
vans.
In the next month's issue, Part 2 will describe more sophisticated RDF
antennas and detection systems.
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