Digest of Articles - QST Jun 94 (Long - 45k)

Digest of Articles - QST Jun 94 (Long - 45k)

Post by W. E. Van Hor » Wed, 03 Aug 1994 19:20:31

DIGEST OF ARTICLES - QST June, 1994

Following are digests of articles printed in the June, 1994 issue of
QST.  Such digests are being prepared for each issue of QST, and posted
periodically.

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:Key Components of Modern Receiver Design - Part 2                 80
TA2:Inexpensive Interference Filters                                 114
TA3:Beginner's Boomers: Two Phased Vertical Arrays for 30 Meters     150
TA4:An Automatic Temperature-Controlled Fan                          209
TA5:Overvoltage Protection for AC Generators                         237
TA6:Simple, Effective, Elevated Ground-Plane Antennas                269

PRODUCT REVIEW (PR)

PR1:Kantronics KAM Plus Multimode TNC with G-TOR                     330
PR2:Nye Viking MB-V-A Antenna Tuner                                  393

HINTS AND KINKS (HK)

HK1:Better Linearity During 50-MHz. SSB Transmit With the Kenwood    445
    TS690S Transceiver
HK2:A Counting Bar Graph for the WD0O Timer                          467
HK3:PacTOR Backspace with the Kantronics KAM+                        492
HK4:Curing Transmit and Receive Distortion in the Heath HW-5400      510
    Transceiver
HK5:How to Remove Connector Sealant from Coaxial Hardware            536
HK6:Modified Grounding Cures RF Feedback in a GM Mobile              550
HK7:Lower Monitor-Mode Current Drain for the CMOS Super Keyer II     572
HK8:Tips on Installing and Connecting to Ground Rods                 589

TECHNICAL CORRESPONDENCE (TC)

TC1:Vester SSTV/FAX480/FAX System Upgrades                           608
TC2:VLF Listening Can Be Rewarding                                   630
TC3:Relay Chatter                                                    655

LAB NOTES (LN)

LN1:Setting Up for Field Day                                         673

FEEDBACK (FB)

FB1:"Radio Gear of Yesteryear" QST Mar 94, p. 41                     688

NEW HAM COMPANION (NHC)

NHC1:You Never Forget the First Time...                              710
NHC2:The Doctor is IN                                                722
NHC3:Getting More Replies to Your CW Calls                           735
NHC4:"At the Tone..."                                                749
NHC5:Be a Bone Yard PhD                                              766
NHC6:8-Band Backpacker Special                                       788

RADIO TIPS (RT)

RT1:Buying on the Packet Network                                     822

GENERAL INTEREST ARTICLES (GI)

GI1:St. Paul Revisited                                               843
GI2:Moonbeams on Montserrat: An EMExpedition to VP2M                 862
GI3:Wally and Mike: Wally Meets the Internet                         897
------------------------------------------------------------------------

TECHNICAL ARTICLES (TA)

Title>TA1:Key Components of Modern Receiver Design - Part 2
Author>Rohde, Dr. Ulrich L. - KA2WEU
Source>QST Jun 94, pp. 27-31
Abstract>Circuits are presented which would bring about the improvements
in receiver design described in Part 1 of this series.

Digest>In Part 1 of this series, the author specified dynamic range,
AGC, and synthesizer action as the three receiver factors most in need
of improvement.  First, improved dynamic range requires automatically
controllable attenuation ahead of the first mixer.  He presents a
schematic diagram of a PIN-diode attenuator, used with a d.c. amplifier.
The combination provides a very low noise figure and a high intercept
point.

Next, he describes a dual AGC system.  The first AGC acts as an
overload-control loop.  When a strong signal appears that is inside the
bandwidth of the first i.f. filter (roofing filter), it reduces the gain
ahead of the second mixer.  The second AGC loop is conventional and
controls the gain at the second i.f.  In his system, he places the
roofing filter immediately after the first mixer.  In order to avoid the
necessity of a post-mixer amplifier, he uses a roofing filter made of
discrete crystals having a very low insertion loss, followed by a first
i.f. amplifier with a noise figure no more than 2-dB.  When this is
followed by a second i.f. filter with good shape factor, an overall
noise factor of less than 12 dB. can be achieved.

Finally, he describes synthesizer designs that achieve low phase noise.
He illustrates a system that uses direct digital synthesis (DDS) to
drive a phase-locked loop (PLL), using a novel single-VCO that generates
less phase noise than does  a more complex and costly multiple-VCO
system.                        _________

Title>TA2:Inexpensive Interference Filters
Author>Bloom, Alan - N1AL
Source>QST Jun 94, pp. 32-36
Abstract>Single-band filters at the transceiver antenna terminals reduce
adjacent band interference in Field Day multi-transmitter operations.

Digest>This article describes the construction of single-band band-pass
filters originally designed to reduce interference between transmitters
operating on multiple bands simultaneously from a single Field Day site.
Some have found them to be useful for other purposes, as well.  The
author cites a case in which similar filters were used to eliminate
problems from a nearby broadcast station, and other cases in which a
40-meter filter reduced interference from short wave broadcast stations
outside the ham band.

Filters for five bands are built in a single cabinet, selected by a
two-pole, six-position rotary switch.  The sixth position provides
straight-through operation, by-passing the filters.

Each filter is made of two coils wound on T-94 powdered-iron toroids.
Each coil is shunted by a fixed capacitor to form a tuned circuit
resonant in the respective bands.  The two tuned circuits are coupled by
a coupling capacitor.  The Q of the tuned circuits and the value of the
coupling capacitor are calculated to provide the optimum filter shape
factor.

Photographs illustrate single band filters without switches as well as
the multi-band model.  Mr. Bloom provides a table listing the core size,
winding specifications, and capacitor values for each amateur band from
160- to 10-meters.  All the coils were wound using No. 16 wire and, for
the higher frequencies, the windings were made of two or three strands
twisted together.  He rates the power level of the filters at 150-watts.
Operation at that level has been confirmed in Field Day operations.
                               _________

Title>TA3:Beginners' Boomers: Two Phased-Vertical Arrays for 30-Meters
Author>Borich, Gary D. - W5UDV and Logan, Robert S. - NZ5A
Source>QST Jun 94, pp. 37-40
Abstract>Building two two-element vertical phased arrays on 30-meters.
One provides figure-8, the other cardioid, radiation patterns with 3-dB.
gain.

Digest>These two authors have each built a phased-vertical array using
two elements on 30-meters.  One uses quarter-wave spacing, and the other
half-wave.  The article includes plots of theoretical radiation
patterns; shown are the pattern for in-phase and 180-degree out-of-phase
operation of the array with half-wave spacing, and in-phase and
90-degree lagging phase for the one with quarter-wave spacing.  The
pattern for the half-wave spaced array is a classic figure-8 end-fire;
that for the in-phase connection is a broadened figure-8, shifted
90-degrees in azimuth.  For the quarter wave array, the 90-degree lag
phasing provides a cardioid pattern whereas the in-phase pattern is
close to omnidirectional.  Both produce gain near 3- or 4-dB. over a
monopole.

The elements in both antennas are quarter wavelength (23.5-foot or 7.16
neter) poles made of aluminum or steel tubing.  The bottoms are mounted
on glass bottles for insulation.  At the base of each element, the
builders drove two ground rods, connected to the feedline and to each
other with very heavy gauge copper wire.  In addition, they laid 540
square feet (50 square meters) of steel mesh on the ground around the
array, carefully bonded to the rods.  This is so-called "re-mesh" left
over from driveway or patio concrete construction.  They report that
they obtained it free from builders who were glad to have it carried
away without charge.

The feed system includes a weather-proof box containing relays to switch
from either in-phase or out-of-phase operation.  Accurate phasing was
obtained by cutting lengths of coax to an exact one-quarter or one-half
electrical wavelength.  For in-phase operation, two half-wavelength
lines branch from the common feed point to the base of each element.
For the out-of-phase condition, an additional half-wavelength line is
added to one of the two elements of the half-wave spaced array.  For the
other array, the cardioid pattern is obtained by adding a quarter-
wavelength phasing line to the feed going to the element that is located
forward in the desired direction.

Physical phasing lines work well only if the antenna current is equally
divided between the elements and the standing-wave ratio (SWR) is low at
the base of each element.  The authors outline the method that they used
to ensure these conditions.  First, they drive each element by itself
and tune it to resonance by adjusting its length (height).  With a
wattmeter, they measure the power flow in each to ensure they are equal.
If the SWR at the base is below 1.5:1, they proceed; if not, they will
do whatever is necessary to get it down, including building a simple
antenna tuner to be permanently mounted at each element.

After the elements are independently tuned, they are driven in phase and
the phasing lines adjusted to insure that the SWR remains low at both
element feed points.  Finally, they follow a similar procedure while
switching the phasing line into each element, in turn.
                               _________

Title>TA4:An Automatic Temperature-Controlled Fan
Author>Kolts, Bertram S. - WA0WZI
Source>QST Jun 94, pp. 41-42
Abstract>Building a temperature-controlled box to hold gear needing
cooling.

Digest>In order to save power, and also to reduce the noise level, one
can use a temperature control system to turn on the cooling fans only
when they are needed.  This article describes a temperature-controlled
box that the author built to house a power supply.

It uses a thermistor as a temperature sensor.  An electronic circuit
utilizes two transistors to control the power to a d.c. motor-driven
fan in an on-off manner.  A single-turn potentiometer adjusts the
temperature set-point.

One of the transistors is an N-channel MOSFET power transistor capable
of making and breaking the full load current of the fan motor.  The
author warns that the starting current of a motor is usually several
times greater than the steady-state running current, so the transistor
must be selected for its ability to handle the maximum load.

The circuit diagram and parts list are included.  A PC-board is
available from FAR Circuits, 18N640 Field Ct., Dundee, IL 60118-9269 for
the price of $4.75, including domestic USA shipping.
                               _________

Title>TA5:Overvoltage Protection for A.C. Generators
Author>Paquette, Jerry - WB8ROW
Source>QST Jun 94, pp. 43-44
Abstract>When using portable a.c. generators, protect equipment from
voltage surges.  The article tells how.

Digest>The circuit described in this article protects equipment used in
Field Day operation, or in any other situation requiring portable power,
against any damage from voltage surges.  It utilizes a device known as a
Ground-Fault Circuit Interrupter (GFCI) to interrupt the power anytime
the a.c. voltage rises above a safe level.

A simple electronic circuit circuit is provided to actuate the GFCI.  It
contains a step-down transformer that reduces the 120-volt line voltage
to 12-volts a.c., and a rectifier to convert it to a d.c. potential.  A
separate adjustable reference voltage is provided by a circuit
containing a Zener diode as a reference.  Whenever the rectified line
voltage rises above the set-point, the GFCI cuts the power and it must
be manually reset.

If, as is commonly the case during Field Day operations, equipment is
scattered over considerable distances and fed from a central power
generator, a separate GFCI must be used at each operating location.

A circuit diagram and parts list is included in the article.  No kits
are available, but a PC-board template can be obtained from the ARRL
Technical Department Secretary, 225 Main Street, Newington, CT
06111-1494.  Send an SASE and ask for the Overvoltage Protection
Template from June, 1994 QST.
                               _________

Title>TA6:Simple, Effective Elevated Ground-Plane Antennas
Author>Russell, Thomas - N4KG
Source>QST Jun 94, pp. 45-46
Abstract>A rotary beam on a tall tower can form a top-loaded vertical
antenna.  Tune it to resonance and feed it by using raised radials.

Digest>It is common practice for hams who have rotary beams atop tall
towers to utilize the tower in some way as part of a low frequency
antenna.  Some use it to support wire antennas, such as slopers; others
resonate the tower, itself, as a grounded vertical fed against buried
radials.  In this article, Mr. Russell describes what may be the most
efficient and easiest way.

He observes that a Yagi antenna on top of a metal tower can act as
effectively as a capacitance "hat" for top loading.  He cites an
empirical formula developed by ON4UN that allows one to calculate
approximately how much equivalent electrical height is added by an array
of a particular size.

       L = 0.38*F*(H+SQRT(2*S-H/500))

          in which: L is electrical length in degrees
                    F is frequency in MHz.
                    H is tower height in feet (1 m.=3.28 ft.)
                    S is the Yagi area in sq. ft.

As an example, a full-sized three-element 20-meter beam provides the
equivalent of about 40 additional feet of tower height as far as
resonance is concerned.

Recent computer studies, now confirmed in many installations, have shown
that elevated radials perform even better than buried ones.  In fact,
four radials ten feet high have been shown to be equivalent to 120
buried ones!  Mr. Russell used that principle to solve one other
problem: how to adjust the equivalent height to quarter-wave resonance.
He does it by raising the radials on the tower to the point where the
upper part the tower plus top loading resonates at the desired
frequency.

In building the antenna, the author cuts four radials accurately to a
quarter-wavelength and solders one end of each to a wire ring around the
tower.  He attaches the coax feed line with the center conductor to the
ring and the shield to the tower.  He experimentally moves the ring up
or down to find the spot where a dip meter, or other means of measuring
resonance, finds it at the desired frequency.  Then he permanently
mounts the ring on the tower with insulators.

Because of the top loading, the radiation resistance of the antenna is
considerably lower than the 35-ohms that would be normal for a full-size
grounded monopole.  Mr. Russell's antenna measured 17-ohms, so either an
antenna tuner, or other means of matching, is necessary if 50-ohm coax
feed will be used.  For his 80-meter antenna, he used a matching
section made of two paralleled lengths of 75-ohm RG-59, 46-feet (14.02
meters) long.  Then he fed it with 75-ohm CATV hardline.
------------------------------------------------------------------------

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

Title>PR1:Kantronics KAM Plus Multimode TNC with G-TOR
Author>Ford, Steve - WB8IMY
Source>QST Jun 94, pp. 70-72
Abstract>An upgraded KAM now provides G-TOR operating mode, which is
described in the article.

Digest>The Model KAM Plus is an upgrade of the well known Kantronics
KAM.  It contains all the features of previous models plus one major
addition and several other added features.

The original KAM was the first multimode TNC that offered simultaneous
dual port operation.  Users could operate UHF/VHF packet at the same
time as HF digital modes.  They could also link the two to provide a
gateway service.

The most important addition of the Plus model is the G-TOR operating
mode.  This is similar to PacTOR in many ways, but adds Golay
self-correction coding.  That is the scheme that is used in the Voyager
spacecraft for transmitting scientific data across the vast reaches of
outer space (now more than 5-billion miles) using very low power
transmission.  Using indicators within each data frame, it is able to
correct for up to 3 missing or mistaken characters per frame.

Other features added in the new model are additional memory (to a
maximum of 512k bytes), higher sensitivity in the demodulator, and a
front-panel LED to indicate that a message is waiting in the mailbox.

A number of tests have been made and reported in the literature,
including several by Mr. Ford, that show G-TOR's ability to transmit
data at more than 2.5:1 increase in rate over PacTOR when operating
under difficult propagation conditions.

Wnen one is calling CQ in G-TOR, the transmission is identical to that
of AMTOR FEC.  When the call is finished, the KAM will respond to
replies in either PacTOR or G-TOR.  For listening to existing G-TOR
links, the unit uses a modified WEFAX receiving mode.  This uses a new
software package called G-MOM.

With the new KAM Plus model, Kantronics is also offering a new operating
software package.  The reviewer tested it along with the TNC and used it
for AMTOR, PacTOR, RTTY, CW, and Packet, as well.  He reports that his
results were excellent in all cases.

The KAM Plus, when receiving PacTOR, processes the received signals on
the basis of a signal strength threshold determined by firmware.  Under
very weak signal conditions, this method is theoretically weaker than
the original German design that took account of the minute-by-minute
variation of overall signal strength and set the threshold between a
"zero" and a "one" accordingly.  Nevertheless, in operation, the
reviewer reports that he had excellent results using PacTOR with very
weak signals.

Kantronics has announced their willingness to license G-TOR to all other
manufacturers of TNCs, so it is likely that this new mode may catch on
nearly as rapidly as PacTOR has.  But only the market will decide.

The manufacturer's list price for the KAM Plus is $339.95.  Older KAM
models can be upgraded to the level of the new unit.  The costs of doing
so are dependent upon how old it is.  The price for the HostMaster II+
software is $69.95.
                               _________

Title>PR2:Nye Viking MB-V-A Antenna Tuner
Author>Cain, Jim - K1TM
Source>QST Jun 94, pp. 72-73
Abstract>Review of a top quality, manually controlled antenna tuner.

Digest>The Viking MB-V-A is a heavy duty antenna tuner capable of
operating at full 1500-watt output continuously on all bands from 160-
to 15-meters.  On 12- and 10-meters, it will handle full power using SSB
or CW, but must be operated at slightly reduced power in digital modes.
It will tune essentially any kind of antenna on all bands from 80- to
10-meters using coax, open-line, or single-wire feed.  It will also tune
many 160-meter antennas, but does not contain enough internal inductance
to handle all.

The unit is built of very heavy components.  It is a pi-network with a
fixed 230-pF. capacitor at the input, a large, silver-plated,
copper-ribbon roller inductor, and a split-stator capacitor with 70-pF.
per section and 7,000-volt spacing shunted with three 195-pF. fixed
capacitors, switch-selected, at the output.

The front panel contains two large diameter dials, two meters, 4
push-button capacitor switches, and a 5-position push-button antenna
selector switch.  The first dial is a spinner-knob turning a 25:1
vernier drive to adjust the inductance. The other is a similar size,
non-spinner knob that directly turns the variable capacitor.  The
inductor dial is graduated 0-25 and the capacitor knob 100-0-100.

One meter reads SWR and other shows forward power in RMS watts.  The
wattmeter has two scales for low and high power, respectively.  It
automatically switches scales when the input power exceeds 300 watts.

For initial tuning, instructions advise to tune a received signal for
maximum strength using first the inductor, and then the capacitor.  Once
the received signal is maximized, the transmitter should be tested at
low power and the controls adjusted for minimum SWR and proper loading
using the meter indicators.

The reviewer used the unit with a variety of antennas, and had good
results with all on bands from 80- to 10-meters.  He was unable to tune
a 200-foot dipole on 160-meters because the tuner did not have
sufficient internal inductance; but after he added 35-feet of wire on
both ends, it tuned very well.

The manufacturer's suggested list price for the MB-V-A is $791.00.
------------------------------------------------------------------------

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

Title>HK1:Better Linearity During 50-MHz. SSB Transmit with the Kenwood
        TS-690S Transceiver
Author>Pelham, John - W1JA
Source>QST Jun 94, p. 75
Abstract>A circuit change to improve audio quality of this transceiver.

Digest>The author's TS-690S produced a "scratchy sounding" six-meter SSB
signal.  He found that the cause was cross-over distortion because the
bias level on IC-1, the 10-watt driver module that drive the final
amplifier, was too low.  It only measured 7.2-volts and should be
9-volts.  His solution was to add a Darlington transistor and a 3.9-volt
Zener diode in a circuit to increase the bias to the proper level.
Schematic diagrams are included to show the "Before" and "After"
circuits.

The editor appended a note that the original QST Product Review did not
find the signal distorted and concludes that the problem might have been
a peculiarity confined to Mr. Pelham's unit, or perhaps only a portion
of the units produced.
                               _________

Title>HK2:A Counting Bar Graph for the WD0O ID Timer
Author>Aughenbaugh, Thomas F.- NY6Q
Source>QST Jun 94, pp. 75-76
Abstract>An added LED bar-graph displays minutes counted.

Digest>Mr. Aughenbaugh offers an improvement feature for the 10-minute
ID timer described by Conklin in Hints and Kinks, QST Nov 93, p. 82.  As
described, the timer generates a one-second beep each 10-minutes to
remind the operator to identify his station.  This author's suggestion
is to add a bar-graph that illuminates one bar each minute during the
10-minute countdown.

It is simply and inexpensively done by connecting each segment of a
10-element bar-graph display (Radio Shack 276-081) to each of the
outputs of the IC-4017 used in the original timer.  The ten cathodes
leads from the bar-graph are connected together and flow to ground
through a single 470-ohm resistor.

This modification also makes it easier to calibrate the timer, since one
needs only to be sure that it take exactly one minute for the first bar
to light to be sure that the full 10-minute time period will be
accurate.
                               _________

Title>HK3:PacTOR Backspace with the Kamtronics KAM Plus
Author>Schwartz, Allan - WA6EHA
Source>QST Jun 94 - pp. 75-76
Abstract>Adding a <Backspace> function to PacTOR on the KAM Plus TNC.

Digest>Mr. Schwartz points out that the Kamtronics KAM Plus TNC does not
support the back-space character in PacTOR mode, although that is one of
the most useful functions in PacTOR.  By experimenting, he discovered
that one of the functions in the Packet program will also work in
PacTOR.  That function is <Backspace>, which is initiated by two
keystrokes: <Control-V>, <Control-H>.

His terminal program is Q-Modem, which allows Macros to be programmed.
He programmed one of his function keys to give the <Control-V>,
<Control-H> sequence, and can now use that key as a <Backspace>.
                               _________

Title>HK4:Curing Transmit and Receive Distortion in the Heath HW-5400
        Transceiver
Author>Pierpont, Ken - KF4OW
Source>QST Jun 94, p. 76
Abstract>Improving audio quality with the Heath HW-5400.

Digest>Mr. Pierpont had known ever since he built his HW-5400 eight
years ago that its audio is distorted in both transmit and receive.  He
discovered that the problem is caused in the second and third audio
stages (Q902) and (Q903).

He found that it was solved by (1) changing the feedback resistor (R922)
from 10,000-ohms to 3300-ohms; (2) in the power lead to the balanced
modulator, which uses a Motorola MC-1496G (U902), the voltage at pins 6
and 9 should be equal but were not.  He solved that by adding a 2700-ohm
resistor between pin 6 and the supply rail.

Next, he found that the BFO signal level to the modulator was too
low and increased it by changing C921 to 0.1 mF.  The product detector
also uses an MC-1496G (U904), and he found the same unbalanced supply
voltage to that IC as in the modulator.  Again, he corrected it by
adding a 2700-ohm resistor between Pin 6 of U904 and the supply rail.
With those changes, audio is now much clearer.
                               _________

Title>HK5:How To Remove Connector Sealant From Coaxial Hardware
Author>Reihl, Edgar - WA9ULU
Source>QST Jun 94, p. 76
Abstract>Remove coax sealant by soaking it in turpentine, then wiping.

Digest>Anyone who has ever used the sticky sealant for coax connectors
is painfully aware of the problems of removing it.  The author has found
that if he cuts as much as possible of the black goop away with a knife
and soaks the hardware in turpentine for 10 or more minutes, he can wipe
the remainder away with a paper towel.  He may have to repeat this
procedure a second time to get it all.
                               _________

Title>HK6:Modified Grounding Cures RF Feedback in a GM Mobile
Author>Melanson, William A. - W1LID
Source>QST Jun 94, p. 76
Abstract>Don't believe all instructions from manufacturers regarding
installation of equipment in vehicles.

Digest>This author installed a Kenwood TS-440S in his Oldsmobile 98 in
accordance with the instructions contained in a GM bulletin describing
radio installations in their vehicles.  He found severe r.f. feedback
that caused the rig to oscillate in many cases each time he pushed the
push-to-talk button.  Contrary to the instructions, he found that it was
necessary to run a ground lead from the bolt and wing nut on the
transceiver directly to the automobile frame to eliminate the problem.

He reports that he used a length of RG-8 coax as his power cable.  The
editor appended a footnote cautioning that cables labelled "RG-8" vary
greatly in construction and many use rather light gauge wire for the
center conductor.  Consequently, they would be inadequate to carry the
currrent load of a 100-watt transceiver.
                               _________

Title>HK7:Lower Monitor-Mode Current Drain for the CMOS Super Keyer II
Author>Vogel, Adolph - DL3SZ
Source>QST Jun 94, p. 76
Abstract>Circuit modification to eliminate excess current drain.

Digest>Mr. Vogel built the CMOS Super Keyer II, originally described by
Russell and Southard in QST Nov 90, pp. 18-21.  He was very happy with
all aspects of its operation except for the 40-milliamp current drain in
the Monitor mode was disappointing.  He reduced it to only 9.8 ma. by
using a 200-ohm telephone earpiece as the speaker and replacing the
2N2222 transistor (Q2) with a BC517 Darlington transistor.  He notes
that any other small-signal NPN Darlington would work equally well.
They will match the 200-ohm speaker well, providing adequate sound
level.
                               _________

Title>HK8:Tips on Installing and Connecting to Ground Rods
Author>Edwards, A. W. - K5CN
Source>QST Jun 94, p. 76
Abstract>A way to improve electrical connections to ground rods.

Digest>In his letter, Mr. Edwards notes that driving a ground rod with a
sledge often splays the end of the rod into a flare so that certain
connectors will not pass over it.  He suggests that a pilot hole be
drilled in the end of the rod before driving, and that after the rod is
in the ground, the hole be drilled out to tapping diameter and threaded.
Then a bolt can be screwed in to make a secure connection.
------------------------------------------------------------------------

TECHNICAL CORRESPONDENCE (TC)
        Conductor: Pagel, Paul - N1FB
                   Associate Technical Editor
                               _________

Title>TC1: Vester SSTV/FAX480/FAX System Upgrades
Author>Vester, Ben - K3BC
Source>QST Jun 94, pp. 77-78
Abstract>Revisions in the SSTV software described in QST Jan 94.

Digest>Mr. Vester is the author of the article: "An Inexpensive SSTV
System", QST Jan 94, pp. 27-29.  It describes a software system that can
be used with any DOS computer to receive SSTV and FAX.  He has continued
to add to, and improve, the system and has issued three revision
updates.  In this letter, he briefly describes Revisions A and B.  In a
footnote, the editor notes that Revision C had become available by the
time this issue of QST went to press.

His instruction manual can be down-loaded from the ARRL Bulletin Board
System, phone: (203) 666-0578, file: Vester_B.Zip.  The descriptions
listed in this letter have little meaning to anyone who is not already
using the system.  Those who are should down-load the full text from the
BBS.
                               _________

Title>VLF Listening Can Be Rewarding
Author>Fischer, Robert W. - K2ND
Source>QST Jun 94, p. 78
Abstract>Listen to signals below 100KHz. to learn about Sporadic E
VHF openings, and also propagation on 80- and 160- meters.

Digest>Mr. Fischer worked for many years with VLF signals from the Omega
System (10-14 KHz.) and Loran Systems (100 KHz.).  In monitoring signal
levels daily, he discovered a close correlation between propagation
conditions on VLF and those on the longer HF bands, as well as on the
VHF bands.

The omega system is made up of 8 transmitters scattered around the
world.  Usually, at least three of them are heard at all times.  He
found Omega propagation closely matches that on 160- and 80-meters over
similar paths.

The Loran-C system covers almost the entire Northern Hemisphere and the
100-KHz. signals show both skywave and groundwave characteristics.  It
is possible to differentiate between the two and close monitoring of the
skywave gives a good indication of the availability of Sporadic E
clouds, among other characteristics of VHF propagation.
                               _________

Title>TC3:Relay Chatter
Author>Huston, Jack - W0JAW
Source>QST Jun 94, p. 78
Abstract>Component variation caused a problem in one unit out of many
built.

Digest>This letter is from the author of the article: "I Wonder If..."
in the New Ham Companion section, QST Nov 93, pp. 72-74.  He notes that
one builder experienced relay chatter.  He found that the problem was
caused by component variation and can be corrected by replacing the FET.
------------------------------------------------------------------------

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

Title>LN1:Setting Up for Field Day
Author>Lau, Zack - KH6CP
Source>QST Jun 94, p. 79-80
Abstract>Optimizing Field Day setup.

Digest>This is an article in Question and Answer form giving advice on
many points regarding Field Day installations.  Included are selecting
sites, which bands and which modes to include, avoiding interference
between the stations at the site, power supply problems, and antennas.
------------------------------------------------------------------------

FEEDBACK (FB)
                               _________

Title>FB1:Radio Gear of Yesteryear, QST Mar 94, p. 41
Author>Shrader, Bob - W6BNB
Source>QST Jun 94, p. 78
Abstract>The wave energy from spark transmitters originated in the
transformer/capacitor resonant circuit.

Digest>This letter quotes Bill Byron - W7DHD, who pointed out that the
primary function of the capacitor across the power transformer in the
spark transmitter diagram, Fig. 1, is not just to provide some
protection of the transformer.  Rather, it provides the power for the
wave train which is transmitted during each half-cycle of the power line
AC.  It is the tuning capacitor of the tank circuit that produces the
RF!
------------------------------------------------------------------------

NEW HAM COMPANION (NHC)

        The New Ham Companion is a regular section of QST. It features
articles of primary interest to newcomers to the hobby.
                               _________

Title>NHC1:You Will Never Forget the First Time...
Author>MacDonald, Michael - N6VIV
Source>QST Jun 94, pp. 58-59
Abstract>First QSO nostalgia.

Digest>This is a description of the first QSO made by the author.  He
relates the e***ment of the event, as well as the pride of achievement
after it was made.  Most amateurs can remember their first QSTs in
similar terms.
                               _________

Title>NHC2:The Doctor is IN
Author>Various
Source>QST Jun 94, p. 60
Abstract>Questions and Answers of interest to newcomers.

Digest>Questions addressed this month include: the problem of detuning a
mobile antenna when a travel trailer is hitched in place; diagnosing a
problem in an older transceiver when the TNC failed to decode digital
signals; microphonics in direct-conversion receivers; and the
functioning of a speech processor during SSB operation.
                               _________

Title>NHC3:Getting More Replies to Your CW Calls
Author>Brogden, Al - K3KMO
Source>QST Jun 94, p. 61
Abstract>Tips for CW operators.

Digest>In this article, Al Brogdon, Managing Editor of QST, offers the
advice of a highly experienced CW operator to help newcomers make more
CW QSOs.  He describes the advantages of replying to other's CQs, rather
than calling it oneself, zero-beating the caller's frequency,
structuring the reply, and even a hint concerning how to break into a CQ
before it is complete.
                               _________

Title>NHC4:At the Tone...
Author>Ford, Steve - WB8IMY
Source>QST Jun 94, pp. 62-63
Abstract>Time and other services provided by WWV  and WWVH.

Digest>This is a description of the services by WWV and WWVH, the
stations operated by the National Institute of Standards and Technology
that continuously broadcast precise time signals.  WWV is located in Ft.
Collins, Colorado, and broadcasts on 2.5-, 5-, 10-, 15-, and 20-MHz.  WWVH
broadcasts from Kauai, Hawaii on all the same frequencies except 20-MHz.

In addition to time signals, the broadcasts include geophysical alerts,
marine storm warnings, omega navigation system status reports, and
global positioning system (GPS) status reports.
                               _________

Title>NHC5:Be a Boneyard PhD
Author>Keith, Larry - KQ4BY
Source>QST Jan 94, pp. 64-67
Abstract>Be smart when shopping for used gear.  Here is help.

Digest>This article contains excellent advice for people shopping for
used radio gear, especially transceivers.

He suggests avoiding "orphans", i.e. don't buy equipment built by a
company that is no longer in the business because spare parts may be
hard to obtain.  Also, avoid rigs that use sweep tubes in the final
amplifier and ones that do not include the WARC bands, since the resale
value will suffer on either count.

He recommends consulting product reviews in back issues of QST and also
asking opinions of as many fellow hams as possible regarding different
models.  To get a feel for reasonable price levels, he suggests
consulting want ads in QST, in the Ham Trader Yellow Sheets, and the
Weekly Ham Trader publications.
                               _________

Title>NHC6:8-Band Backpacker Special
Author>Andera, Jim - WB0KRX
Source>QST Jun 94 - pp. 68-69
Abstract>A highly portable wire antenna that can be used on any two
bands from 10- to 80-meters.

Digest>Mr. Andera describes a very light-weight antenna that can be
rolled up and carried easily, but can be erected to provide a two-band
antenna resonant on any two of the HF bands from 80- to 10-meters.  It
is made as two dipoles fed from a common coax line and spread like a
fan.  The antenna uses No. 20 wire. and is cut for 40- and 20- meters.
Nylon twine provides a combination of support and insulation.

Carried with them are pieces of No. 24 wire, cut to accurate length and
with an alligator clip on one end of each, so that they can be clipped
onto the ends of either of the two dipoles and resonate as either half-
or one-and-a-half-wave dipoles on the respective bands.

A table of accurate dimensions for each of the extensions is included.
Two are required for each band, one for each end of the dipole.

Included is a drawing of the suggested center insulator which is
fabricated from .062-inch (2.5 mm.) PC board material with the foil
removed.  It acts as a center insulator, a center support point, and
also provides strain relief for the coax.
------------------------------------------------------------------------

RADIO TIPS (RT)

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

Title>RT1:Buying on the Packet Network
Author>Ford, Steve - WB8IMY
Source>QST Jun 94, p. 67
Abstract>

Digest>Packet radio is a good source for used equipment.  Connect to
a bulletin board and isse the command:
        L> SALE
           or
        L> FORSALE

Also check DX PacketCluster systems.  Connect and send the command:
        DIR/NEW
You will receive a list of every message that has been posted since your
last access.
------------------------------------------------------------------------

GENERAL INTEREST ARTICLES (GP)
                               _________

Title>St Paul Revisited
Author>Archibald, Fred - VE2SEI
Source>QST Jun 94, pp. 21-23
Abstract>Another dangerous, but successful, DXpedition.

Digest>This is the story of a DXpedition conducted by eight Montreal
amateurs to the northern island of St. Paul in the Gulf of St. Lawrence.
The island is uninhabited and rocky, so landing and embarking with heavy
equipment in heavy seas is difficult and dangerous.

The expeditioners were taken from Dingwall, Nova Scotia to the island by
a fisherman in his 35-foot (11-meter) boat in August, 1993.  They spent
5 days on the island.  They deployed an impressive array of equipment,
set up successfully in an abandoned house on the island, and logged 5650
contacts.  Most importantly, they successfully brought all their
equipment, and themselves, back safely.
                               _________

Title>GI2:Moonbeams on Montserrat: An EMExpedition
Author>Brittain, Perry - VP2MR/W5STI
Source>QST Jun 94, pp. 47-51
Abstract>Putting Montserrat on the air, EME.

Digest>Mr. Brittain is now a permanent resident of Montserrat, West
Indies.  He recently invited Gerald Williamson - K5GW, of the Texas
Towers Company, to visit him.   Mr. Williamson is an enthusiastic
earth-moon-earth (EME) operator from his home station in Plano, Texas
and volunteered to take a disassembled EME array to Montserrat for an
EMExpedition.

In this article, the author describes their first attempts at erecting
the four ten-element beams on 17-foot booms in a 2-by-2 configuration,
all mounted on a 2-inch (50-cm.) diameter steel mast sunk 3-feet
(1-meter) into the soft ground.

After it was up, before being used, it blew over and damaged several
pieces of the assembly.  Replacements were rapidly sent by air freight
from Texas and a new tower support was put up in a much more stable
manner.  Consequently, before the one-week visit was over Mr.
Williamson, using the call sign VP2MBM which belongs to the author's
XYL, Martha, succeeded in making a number of contacts with stations in
the USA, Canada, Sweden, and Germany.  He missed calls from many others
because he accidentally blew out both of his receiving preamplifiers and
could only hear "big" signals.

Since Mr. Williamson's visit piqued his interest, VP2MR has erected an
80-element array made of 8 ten-element beams on a very substantial tower
with remote az-el control, and so Montserrat is now a permanent fixture
on EME.
                               _________

Title>GI3:Wally and Mike: Wally Meets the Internet
Author>Kearman, Jim - KR1S
Source>QST Jun 94, pp. 50-51
Abstract>Internet provides free unlimited communications throughout the
world.

Digest>This is a fictional conversation between two hams who are
discusssing the Internet, the world-wide communications network that
links the computer networks of almost all of the universities and
colleges of the USA with with those of colleges and universities in most
other countries of the world.  It is not limited only to educational
institutions; research-minded companies are also hooked up and,
recently, any individual can get access from his home computer by
signing up with a company organized for the purpose of providing
Internet access for a fee.

Once individuals obtain access to network, an amazing breadth of
information sources becomes available to them.  The two sources of
information of primary interest to radio amateurs are through
participation in "newsgroups" and through "E-Mail" correspondence with
individuals throughout the world.
------------------------------------------------------------------------