Digest of Articles - QST Sep 95 (Long - 49k)

Digest of Articles - QST Sep 95 (Long - 49k)

Post by W. E. Van Hor » Wed, 11 Oct 1995 04:00:00

Following are digests of articles printed in the September, 1995 issue of
QST.  Such digests are being prepared for each issue of QST, and posted
periodically.  They are archived, beginning with the January, 1993 issue,
and available by ftp from:
(USA) oak.oakland.edu/pub3/hamradio/arrl/infoserver/digests
and
(Europe) ftp.funet.fi/pub/ham/arrl/infoserver/digests

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.

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 numbers indicated - counting from CUT HERE line)

TECHNICAL ARTICLES (TA)

TA1:A Receiving Antenna That Rejects Local Noise                      75
TA2:A K6STI Low-Noise Receiving Antenna for 80 and 160 Meters        146
TA3:Hot-Rod Your ICOM IC-725 Series Transceiver - Part 1             197
TA4:An Automatic, Remote Antenna-Tuning Controller                   269

PRODUCT REVIEW (PR)

PR1:Japan Radio Company JST-245 Transceiver                          316

TECHNICAL CORRESPONDENCE (TC)

TC1:Adjusting HF Yagi Matches                                        405
TC2:Matching Small, Shielded Receiving Loops                         427
TC3:More on Cylindrical Capacitors                                   471

LAB NOTES (LN)

LN1:Computer Interference                                            504

HINTS & KINKS (HK)

HK1:More on Silent Amplifier Control With the Kenwood TS-850S        554
        Transceiver
HK2:A Super Simple Mobile Hand-Held Holder                           572
HK3:Better SM-220/BS-8 Station Monitor Operation With the Kenwood    591
        TS-440S Transceiver
HK4:Two Speakers Help Beat Hearing Loss                              620
HK5:Open-Wire Spreaders With a Twist                                 636
HK6:Pipe Insulation Bundles Cables                                   653
HK7:Correction to "Curing MF/HF Ceiling-Fan Noise                    672

NEW HAM COMPANION (NHC)

NHC1:Beep...What Did That Repeater Say?                              689
NHC2:Nine Hours at Headquarters                                      721
NHC3:The Doctor is IN                                                750
NHC4:Travel Highlights for Radio Buffs                               765
NHC5:Bricks to the Rescue                                            780

RADIO TIPS (RT)

RT1:Instant DX Information                                           816

GENERAL INTEREST ARTICLES (GI)

GI1:Holocaust in Oklahoma City                                       828
GI2:Thrills, Butter Churns and Honeycombs: A Visit to the Hammond    850
        Museum of Radio
GI3:Like Son, Like Father: One Ham's Dad Earns a New Way to Call     870
        Home
GI4:Hard-Core QRP                                                    896
GI5:California Mobile Antennas and the Moment of Truth               919
GI6:A Gift for Teaching                                              954

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

Title>TA1:A Receiving Antenna that Rejects Local Noise
Author>Beezley, Brian - K6STI
Source>QST Sep 95, pp. 33-36
Abstract>Presents the design of an MF receiving antenna that
discriminates against locally-generated noise.

Digest>It is a frequently observed fact that vertical antennas pick up
a great deal more noise than horizontal ones.  This article explains the
reason.

Locally generated noise, both atmospheric static and electrically
generated, is propagated primarily by ground wave transmission, but
most amateur communications are conducted using sky waves.  Vertical
antennas are very effective in receiving and transmitting ground wave
signals, whereas horizontal ones are largely insensitive.  It is for
this reason that all AM broadcast stations use vertical antennas.  In
contrast, for sky wave reception, horizontal antennas provide
significant gain over verticals.

Horizontal antennas are, however, sensitive to one component of ground
waves, the so-called surface wave.  This sensitivity is maximum in the
direction of the antenna wire, just the opposite of its sensitivity to
all other signals.  With these facts in mind, the author has designed a
receiving antenna that is nearly omnidirectional in its response to sky
waves but rejects all ground waves, including the surface wave
component.  To eliminate the surface wave, he borrowed a concept from
the "8JK Beam"; that is, he splits his antenna into two halves and feeds
them out of phase.  His design is most effective on lower frequencies,
especially the 160- and 80-meter bands.  He does not recommend its use
on frequencies higher than the 40-meter band.

The antenna is made up of two horizontal loops, shaped like 45-degree
triangles; that is, triangles with one right angle and two 45-degree
angles.  The two hypotenuses run parallel, spaced closely together.  In
fact, they are formed from a single length of 450-ohm ladder line.  The
two triangular loops are in the same plane and form a square, 25-feet
(7.6-m.) on each leg.  The ladder line is twisted a half turn so that,
electrically, the two loops form one continuous conductor like a
distorted figure "8" that crosses in the center.  The antenna is fed at
the center of the square through a kind of transformer balun.

The transformer is wound on a ferrite core.  One winding connects to the
coax feed line; the other to the antenna.  The winding that is connected
to the feed line is wound of nine turns of enameled wire.  The antenna
winding is made up of eight turns.  A variable capacitor of 100-pF.
maximum capacitance must be connected in series with it; Mr. Beezley
likes to split the eight turns at the center and connect the capacitor
between the two halves of the transformer coil to preserve absolute
balance.  The two ends of the antenna winding are attached to the two
sides of the ladder line at its center point, thus driving the two loops
in opposite phase.

The author analyzed the antenna at 3.5-MHz. with it elevated 10-feet
above ground.  Signal-to-noise improvement is at least 24.6-dB. above
that of a vertical monopole, assuming that the desired signal is
arriving at a 20-degree elevation angle.  For signals arriving at
higher angles, the enhancement approaches 30-dB.

The same configuration of loops can be made in different sizes and/or
raised to higher elevations.  Raising the height will have little
effect on the signal-to-noise ratio, but will produce higher signal
levels.  Making the antenna smaller size will reduce the signal and
noise levels equally.  It may become necessary to make up for the lower
level by using a preamplifier.

Mr. Beezley's theoretical results have been borne out in practice by a
number of hams.  The following article reports on the results found by
two of them.
                               _________

Title>TA2:A K6STI Low-Noise Receiving Antenna for 80 and 160 Meters
Author>Andress, Edwin A. - W6KUT
Source>QST Sep 95, pp. 37-41
Abstract>Construction and operating results of a W6STI "square"
receiving antenna.

Digest>W6KUT has erected a 21-foot (6.4-m.) square receiving antenna in
accordance with W6STI's square design.   His good results are especially
interesting because his station is located between the arms of a "Y"
formed by 6900-volt a.c. distribution lines.  They generate continuous
noise that usually registers over S-9 on his receiver.  He had tried to
improve his reception by erecting a shortened 80-meter dipole at 84-feet
(25.6-m.) height, and also by using vertical rotary loops, but neither
made much improvement because the noise arrives from multiple sources.

Mr. Andress erected his antenna 10-feet off the ground and fed it with
RG-213 coax.  The transformer balun windings were made with No. 24
enameled wire on an Amidon FB-77-1024 core.  The antenna winding is
20-turns, with a tap at 10-turns.  The full winding is used for
160-meters and the tap for 80-meters.

For band switching, he provided two tuning capacitors selected by a
relay. One is of 80 pF. maximum capacitance and is in the circuit at all
times. It, alone, tunes the 80-meter band.  For 160-meters, a relay
switches a 500-pF. maximum capacitor in parallel with the smaller one.
At the same time, another relay switches taps on the antenna winding on
the transformer balun.

The capacitors and relays are located at the center of the antenna,
along with the transformer balun.  Twelve volt d.c. operating current to
the relay coils passes through the coax feedline.  It is prevented from
flowing through the transformer by a 0.1-mfd blocking capacitor; r.f. is
blocked from getting into the relay coils by a 2.5-mH. r.f. ***in
series with them.

Tests were made of the S-meter readings comparing the phased verticals,
the dipole at 84-foot elevation, and the square.  The square provided
signal-to noise enhancement very near to the theoretical value of 24-dB.
over the verticals and the dipole.

In a side-bar with the article, Keith A. Fowler - W6BCQ also reported
experiences with a square.  He had previously tried practically every
known kind of noise-reducing antenna for 80- and 160-meters, with
results less than satisfactory.  Then he built a square for 80-meters
and, compared to his other antennas, he states: "Any and all line noises
are reduced simultaneously from typically S-9 to S-1, or less.  With a
15- to 20-dB. preamplifier in the receive line, the desired signal is
nearly the same level as when received on the transmitting antenna."
                               _________

Title>TA3:Hot-Rod Your ICOM IC-725 Series Transceiver - Part 1
Author>Vermasvuori, Jukka - OH2GF
Source>QST Sep 95, pp. 42-45
Abstract>Analyzes design deficiencies in the IC-725 and proposes
modifications to overcome some of them.  More in next issue.

Digest>OH2GF uses an ICOM IC-725 transceiver which is very similar, if
not identical, to the Models IC-721, IC-726, and IC-728.  In reviewing
the performance of his rig, he found a number of "drawbacks".

1. The audio frequency response was too narrow.  High frequencies were
attenuated badly.  At 2.0-KHz., the response was already 6-dB. lower
than at lower frequencies.  This severe attenuation of highs
significantly reduces SSB intelligibility.

2. The AM-mode audio had a "mega-bass" quality.

3. The in-band intermodulation products seemed quite high.

4. On CW, signals from outside the passband caused phantom audible beat
notes that sometimes interfered seriously with weak signals.

5. The AGC compressed SSB signals, then allowed noise and splatter to
rise to high levels during even short pauses between syllables.
Switching the AGC control from FAST to SLOW made almost no detectable
difference.

6. Lack of selectivity early in the i.f. chain gave little protection
against adjacent strong signals.

7. Synthesizer phase noise was disagreeably high.

8. The AF gain control was severely compressed.  Almost all the
variation in gain occurred with less than 1/4-turn of the control knob,
making the adjustment unnecessarily critical.

9. The rig contained no speech processor, so its "talk power" was not
commensurate with its 100-watt output.

In trouble-shooting the audio problem, he found that the low-pass filter
was designed to roll off at an absurdly low frequency.  He then
discovered the probable cause for such a seemingly poor design.  A
spurious signal at 7,000-Hz. was being generated by the synthesizer
board and was getting into the audio amplifiers.  Instead of correcting
the problem, apparently the design engineer merely lowered the
low-frequency cutoff to hide the problem!

Mr. Vermasvuori solved the spurious-signal problem by changing a ground
lead on the synthesizer board, then corrected the high-frequency rolloff
by changing several resistors and one capacitor.

When he examined the AM detector, he found that it was designed contrary
to all diode-detector rules of good practice.  Standard procedure is to
make the diodes' audio load impedance at least ten times higher than
that of its d.c. load, but the IC-725 designer saw fit to make it ten
times smaller!  To avoid completely rebuilding the AM detector, he
applied a "Band Aid"; he added a 3300-ohm resistor at a strategic point
that partially ameliorated the poor performance.

In analyzing other circuits, the author similarly found other problems
which he describes in detail in the article.  He uses restrained and
polite language in discussing his findings, referring to the transceiver
as "a well-designed radio".  But, in the light of his findings, others
might use quite different language.  At least in the case of the AM
detector and the audio amplifier chain, it seems more appropriate to say
that it was very poorly designed.

In the next issue, Part 2 of this article will describe further
additions and modifications that he felt necessary.
                               _________

Title>TA4:An Automatic, Remote Antenna-Tuning Controller
Author>Mandelkern, Mark - KN5S
Source>QST Sep 95, pp. 46-49
Abstract>Construction details for a remote controller to operate the
capacitor drive motor of an antenna tuner located at the antenna.

Digest>KN5S operates the low bands using a vertical antenna, 42-feet
(12.8-m.) high, tuned against elevated radials.  Since the vertical
radiator is less than a quarter-wavelength on 80- and 160-meters, a
wide-range antenna tuner is necessary.  Furthermore, especially on
160-meters, retuning is necessary after almost every change of
frequency.  For reasonable efficiency in such an antenna setup, a tuner
located at the base of the monopole is highly advantageous.  As the
author states, remote control of the tuner from the shack is not
necessary, but after making many trips out to the antenna during rain
and snowstorms, one comes to feel that it would be very nice, at least!

He has designed and built a very versatile and totally automatic system
for controlling the remote tuner.  This article describes the controller
only, since it can be used to drive a wide variety of motor-adjusted
capacitors or inductors.  

His controller is built around a conventional directional coupler that
tells the controller when the SWR is too high, and a phase discriminator
bought from military surplus to instruct the controller which direction
the motor should drive.  In addition to the directional coupler and
phase discriminator, the system requires some additional electronics
which the author illustrates in a complete schematic and parts list with
the article.

Shown in photographs, but not described in detail, is KN5S's complete
antenna tuner showing the motor drive train, the vacuum-variable
capacitor, separate coils for 40-, 80-, and 160-meters, and other
associated equipment.  He leaves the controller operating continually
while he is operating.  As soon as he begins to transmit, the tuner goes
into action to tune the SWR to minimum.  Automatic means reduce the
power output of both the transceiver and external amplifier to low
values if the SWR is above 2:1 and restores full power as soon as it
goes below that value.
------------------------------------------------------------------------

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

Title>PR1:Japan Radio Company JST-245 Transceiver
Author>Swanson, Glenn - KB1GW
Source>QST Sep 95, pp. 86-92
Abstract>Performance review of a new HF transceiver that also covers the
6-meter band.  Its features include all those common to top-line rigs,
and more. Reviewers rated its performance highly in all respects.

Digest>The new Japan Radio JST-245 has all of the features of an
up-to-date, top-of-the-line HF transceiver, and then some!  Its cabinet
is medium-sized with a built-in power supply.  The rig provides two VFOs
and 200 memories.  The frequencies of both VFOs can be displayed
simultaneously.  The memories store not only frequency, mode, i.f.
filter settings, and AGC setting; they also store the antenna port in
use (one of three), information on split frequency operation, and
whether the r.f. preamp is to be on or off.

The RIT/XIT control is adjustable over a 10-KHz. range with a separate
sub-display showing the amount of offset.  The VFO resolution is 2-Hz.,
so it can be set to within 1.0-Hz. although the resolution of the
frequency counter is limited to 10-Hz.  (There is a zero-beating
procedure that one can use that allows the beat to be set to within
1-Hz.!)

Receiver performance is excellent.  There is a switchable preamp, and
with the preamp on, the noise floor with 500-hz. i.f. filter in use
ranges from -132 to -140 dBM.  The blocking dynamic range with the
preamp on ranges from 118 to 126 dB.; higher with it off.  The
second-order intercept is +64 dBM with the preamp on, and the
third-order ranges from +0.2- to +4.6-dBM. through the main part of the
HF bands.

Audio quality was rated superb by all those who tested the rig.  When
one is using headphones, there is not a trace of high frequency hiss.

Performance on CW was also rated as excellent.  The shaped keying is
very good, although there is a barely detectable shortening of the
leading character element when operating semi-breakin.  CW operators
will be especiallly pleased by the fact that one can select the sideband
on which the CW signal is heard.  This simple feature, which was always
standard equipment with old vacuum-tube receivers, is the one feature
that many old-time brass-pounders miss the most.  It is a wonderful QRM
evader!

In digital modes, the rig performs well using AFSK (although the panel
switch is labelled "FSK").  It is one of the few transceivers that makes
all i.f. filters available when AFSK is in use.

Although the JST-245 is called an HF transceiver, the general coverage
reception covers from 100-kHz. to 54-MHz. and the transmitter covers the
6-meter band.  One VHF expert called it the best 6-meter rig that he had
ever used!

Another extra feature is a built-in keyer that can be adjusted over the
range of 8- to 40-wpm.  The dot-to-dash ratio comes with a default
setting of 1:3, which is the accepted standard, but it can be adjusted to
fit personal preferences from 1:2.5 to 1:4.5.

The rig comes with a built-in computer interface and most of the
functions can be controlled from a personal computer.  The transmitter
uses MOSFETs in the final amplifier and power output is adjustable from
5-watts to more than 150-watts on all bands and in all modes, except AM.
A built-in automatic antenna tuner is standard.

Standard i.f. filters include 2.7-KHz. for SSB and wide CW, and 6.0-kHz.
for AM.  Several optional narrow filters are available for the second
i.f. (9.455-MHz.) and third (455-KHz.)  They include a pair of 500-Hz.
CW filters and a pair of 1.8-KHz. SSB filters.  A 300-Hz. CW filter is
available for the second i.f.  All of these optional filters can be
installed at once and selected from the front panel.  A pass-band shift
control continuously adjusts the bandwidth of the receiver by narrowing
the i.f. from both sides at once.

JRC has also announced a Model JST-145, which is identical to the -245,
with the omission of 6-meter operation and built-in antenna tuner. Also
the i.f. bandwidth control function is disabled, but can be added with
the insertion of the optional 2.7-kHz. i.f. filter in the second i.f.

In summary, the JST-245 was found by all reviewers to be a worthy
contender for a top-quality amateur transceiver.  The manufacturer's
list price is $2990 and there are a number of peripheral accessories
available at extra price, including mikes, a monitor, external speakers,
a tone unit, and a number of other items.  The price for the JST-145 is
not quoted in the article.
------------------------------------------------------------------------

TECHNICAL CORRESPONDENCE (TC)
                               _________

Title>TC1:Adjusting HF Yagi Matches
Author>Beezley, Brian - K6STI
Source>QST Sep 95, p. 95
Abstract>K6STI proves that matching adjustments can be accurately made
with Yagi antennas on the ground, pointing upward.

Digest>For many years, ham "conventional wisdom" has held that it is not
necessary to raise a Yagi antenna to full height before making the
adjustments to match the input impedance to the feedline; it can be done
accurately from ground level by aiming the antenna vertically at the
sky.  K6STI, the well-known supplier of antenna analysis software, felt
some uneasiness at that assumption.

Using his NEC-based software that accurately accounts for ground
effects, he modelled two yagi antennas: a five-element 20-meter beam
with high F/B ratio and a four-element 20-meter Yagi with low F/B. His
calculations show that the input impedance of both antennas change only
a negligible amount when moved from the ground position to free space.
Therefore, at least in this example, "conventional wisdom" is correct.
                               _________

Title>TC2:Matching Small, Shielded Receiving Loops
Author>Ellington, Scott - K9MA
Source>QST Sep 95, pp. 95-96
Abstract>Describes an efficient method of matching and tuning a
receiving loop antenna.

Digest>Small loop antennas make excellent receiving antennas, especially
on 80- and 160-meters.  A single loop can be used to reject interference
broadside to the loop, or else a phased array of loops can be used as a
directional antenna.  Shielding the individual loop or loops provides
deeper nulls and also minimizes coupling to the feed line or surrounding
objects.

Tuning a loop to resonance requires a capacitor that is often inserted
into the loop on the side opposite from the feed point, for symmetry.
With shielding, symmetry is not a problem and Mr. Ellington describes a
way that two capacitors, one tuned and the other fixed, can be used to
match the feedline to the loop,

The method is illustrated in a schematic diagram showing a square loop
5-feet (1.5-m.) on each side, made of RG-62 and fed at the center of the
bottom leg.  The shield of the coax is cut and a gap left in the center
of the top leg, which is horizontal.

An equivalent circuit is also shown; it is a "pi-section" made up of a
capacitor, C(1) across the input, the loop in series, and another
capacitor, C(2) across the output.  The radiation resistance of the loop
acts as the load.  C(1) is fixed and C(2) is the variable tuning
capacitor.

Typical capacitor values for the 5-foot loop are: for 1.8-Mhz. - C(1) =
4970-pF. and C(2) = 696-pF.  For 3.5-MHz. - C(1) = 2950-pF. and C(2) =
83-pF. The operating bandwidth can be broadened at the expense of signal
capture efficiency by adding a small-value non-inductive resistor in
series with the loop.  The author suggests 3.3-ohms, which provides a
2:1 bandwidth of about 50-khz. on both bands.  With a receiver pre-amp,
the efficiency is more than adequate.

Because of the distributed capacity in the coax, the 5-foot loop may be
too large to resonate on 75-meters, so it may be necessary to reduce the
size slightly.
                               _________

Title>TC3:More on Cylindrical Capacitors
Author>Formato, Richard A. - K1POO
Source>QST Sep 95, p. 96
Abstract>Shows a formula for calculating the effective dielectric
constant of a cylindrical capacitor, the dielectric of which is made up
of any number of concentric cylinders of different materials.

Digest>In Technical Correspondence, QST May 95, W9KWD provided a formula
for calculating the effective dielectric constant in a capacitor with
two separate dielectrics, Teflon and air in his example.  Mr. Formato, in
this letter, generalizes with a formula for calculating it for any
number of separate layers of different materials.  The formula is as
follows:

K(eff) = LN(b(N)/a) / LN( (b(1)/a)^(1/k(1)) * (b(2)/b(1))^(1/k(2)) ...
                 * (b(N)/b(N-1))^(1/k(N)) )

        where: a = radius of inner conductor, in mm.
               b(1), b(2)...b(N) = outer radius of insulating layers
               N = number of insulating layers

               (Note: b(N), the outer radius of the last insulating
               layer is the inner radius of the outer conductor)

For example: in a capacitor having four layers of insulating materials
with radii of 2, 4, 6, and 10 mm. and dielectric constants of 3,4,7, and
10 and inner conductor radius of 1.0 mm., the effective dielectric
constant is 4.4855.
------------------------------------------------------------------------

LAB NOTES (LN)
                               _________

Title>LN1:Computer Interference
Author>ARRL Laboratory Staff
Source>QST Sep 95, pp. 97-98
Abstract>Suggestions for reducing or eliminating RFI from computers.

Digest>Computers operate with high-frequency digital signals, i.e.
pulses with square edges.  Inherently, they internally generate noise
over a broad spectrum of HF and VHF.  Unless they are very well shielded
or isolated, they will certainly cause RFI to HF and VHF reception. This
report gives a number of suggestions for mitigating the interference.

The FCC rates two classes of computers: Class B for home use and Class A
for industrial environments.  Class B devices are much less noisy!  Any
computer being sold by retail stores to the general public is almost
certainly Class B.

Most noise picked up by receivers comes in through the antenna.  Noise
from the computer can be reduced by physical separation and by improved
shielding of the computer case.

Some noise gets out of the shielding on power lines and other
connections leading out of the case.  All cables should be shielded. In
addition, often noise radiation can be reduced if the power leads,
and other external cables, are wound several times around ferrite cores.

Before buying a computer, one may find it possible to test it in the
store for noise output.  Arrange with the store manager to take a
portable radio, tuned to the frequencies of interest, to the store at
times when all computers are shut off; then turn the one being
considered on, for test.  If one store will not cooperate, shop until
you find one that will.

To trouble-shoot an existing computer installation, turn it on first
with no accessories plugged in (i.e. without keyboard, mouse, or
monitor).  If it is noisy in that configuration, and if the noise is
broadband hash that decreases in intensity with each switch to a higher
frequency band, the noise is probably emanating from the power supply.
Install a common-mode ***on the a.c. line cord at the computer.  If
that does not cure the problem, try an a.c. line filter.

For more information, obtain the ARRL book: RADIO FREQUENCY
INTERFERENCE: HOW TO FIND IT AND FIX IT.
------------------------------------------------------------------------

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

Title>HK1:More on Silent Amplifier Control With the Kenwood TS-850S
        Transceiver
Author>Krausse, Howard - KE8M
Source>QST Sep 95, p. 93
Abstract>Eliminate clicking noise from keying relay by replacing it with
a reed relay.

Digest>KE8M found the clicking noise of his TS-850S amplifier-keying
relay to be annoying.  He replaced it with a silent reed relay from
Radio Shack, their part No. 275-233.

The operating coil of the relay is rated at 11-ma. at 12-volts, but the
TS-850S can supply only 10-ma. through pin 7 of its REMOTE jack.  The
author put a 100-ohm resistor in series with the coil to reduce current
flow.  Apparently the relay operates reliably with the reduced current.
                               _________

Title>HK2:A Super Simple Mobile Hand-Held Holder
Author>Harris, Art - N2AH
Source>QST Sep 95, p. 93
Abstract>Using the dashboard cup holder in a Dodge minivan to hold an
H-T.

Digest>N2AH likes to use his HT while driving his Dodge minivan.  To
support the rig, he makes use of one of the cup holders molded into the
dash just above the car radio.  He found a heavy plastic cup that fits
snugly into one of the holders and clips the H-T's belt clip over the
side of the cup.  Since the cigarette lighter jack is only a few inches
away, the power cable can be neatly dressed.

To prevent the cup from bouncing out of the holder, he cut a small piece
of wood to fit tightly into the holder and applied sealant to hold it in
place.  Then he screwed the bottom of the cup to the wood.
                               _________

Title>HK3:Better SM-220/BS-8 Station Monitor Operation With the Kenwood
        TS-440S Transceiver
Author>Berlin, Michael A. - WU1M
Source>QST Sep 95, p. 93
Abstract>How to use the Kenwood BS-8 Panoramic Adapter and SM-220
Monitor with a TS-440.

Digest>Mr. Berlin wanted to use a Kenwood SM-220 Station Monitor and a
BS-8 Panoramic Adapter with his TS-440SAT, but the BS-8 adapter was
designed to be used with older rigs, such as the TS-520.  It requires
direct access to the 8.83-MHz. second i.f. signal, and that signal was
not made available at the rear panel of the -440.

He tapped directly into the circuitry at the cathode lead to the diode
D3.  That point is electrically available by soldering onto jumper W-12,
so he attached one short lead of 70-pF. mica capacitor to it and the
other lead to the center conductor of a 12-inch (30-cm.) length of
RG-174 coax.  The capacitor end of the cable shield is grounded to the
chassis by a short jumper.

To pass the cable out through the rig, the author lists several options.
One is to push it through one of the vent slots; another is to attach it
to the rear panel ACC2 jack, if it is not being used.  A phono plug is
attached to the cable's free end and it is plugged into the jack on the
SM-220 rear panel.  He reports excellent results with no apparent loss
of i.f. signal due to circuit loading.
                               _________

Title>HK4:Two Speakers Help Beat Hearing Loss
Author>Freedom, Tom - W3HVE
Source>QST Sep 95, p. 94
Abstract>Mounting two speakers to replace headphones.

Digest>W3HVE suffers from some hearing loss, especially at high
frequencies.  Disliking headphones, he assembled two speakers atop his
transceiver facing with him, with each speaker aimed directly at one of
his ears.

He mounted the two 4-inch (10-cm.) speakers in cigar-box baffles filled
with fiberglass.  He finds that the arrangement works well and provides
improved intelligibility.
                               _________

Title>HK5:Open-Wire Spreaders With a Twist
Author>McMullin, Mac - W6DSY
Source>QST Sep 95, p. 94
Abstract>Assembling home-made open-wire lines.

Digest>W6DSY has rediscovered the trick that was commonly used many
years ago when open-wire ladder lines were almost always home made.  To
fasten the plastic spreaders to the two wires, he drills a small hole
near each end and inserts a short piece of fine wire through each.  Then
he lays the spreader between the two parallel conductors and fastens it
in place by twisting the fine wires around them.

He states that this allows him to avoid having to thread the spreaders
down the entire length of the main conductors (!)
                               _________

Title>HK6:Pipe Insulation Bundles Cables
Author>Noftz, Edward A. - WB8TCZ
Source>QST Sep 95, p. 94
Abstract>Use slit-tube thermal insulation to bundle neatly wires and
cables.

Digest>To bundle cables in his shack, Mr. Noftz uses foam pipe-
insulation tubes, obtained at a hardware store.  These are slit along
the entire length and are sold in 3- and 6-foot (0.9- and 1.8-m.)
lengths.  In use, he cuts them to whatever length he needs, pulls the
slit open, inserts the wires, then lets the slit reclose itself.
Finally he wraps wire ties, or electrical tape, around the circumference
at intervals.

The insulation comes in different sizes; he finds that made for use
around 1-inch (2.5-cm.) pipe to be most convenient.
                               _________

Title>HK7:Correction to "Curing MF/HF Ceiling-Fan Noise"
Author>Michaels, Charles J. - W7XC
Source>QST Sep 95, p. 94
Abstract>Clarification to a hint in H & K, QST Jun 95.

Digest>W7XC's hint printed in H & K, QST Jun 95, applies only to
Casablanca fans that use "Intelligent Controls", not conventional
switches.  The ***that he described is installed in the bell-shaped
ceiling housing, not the motor housing.  The warning not to operate the
fan with part of the bell housing removed was to obviate the possibility
of the fan's falling from its housing.
------------------------------------------------------------------------

NEW HAM COMPANION (NHC)
                               _________

Title>NHC1:Beep... What Did That Repeater Say?
Author>Bowles, Chester S. AA1EX
Source>QST Sep 95, p.75
Abstract>How courtesy tones are used in repeater operation.

Digest>In this article, Mr. Bowles explains the fundamentals of repeater
operation.  Specifically, he discusses the "courtesy tone", or beep,
that most repeaters use to mark the beginning of a period of
availability.

All repeaters keep transmitting so long as the user is talking unless a
timer times out in the meantime.  But they do not shut off instantly
when the talker stops; they typically continue for a short time in case
the user is only taking a breath.  That period is called a "tail";
depending upon the repeater, it may range up to 30-seconds, in some
cases more.

The timers are used to prevent one user from monopolizing the facility.
When either the user stops talking and the tail expires, or the timer
times out, the repeater resets itself and sounds its courtesy tone.  At
that point, the next user can begin talking.

Some repeaters do not use a courtesy tone, and some of those use a very
long tail; others use no tail at all!  The long tail encourages many
short exchanges of a few words each.

To avoid confusion, before using an unfamiliar repeater, listen to how
others use it and, at all times, obey the rules of common courtesy.
Remeber that repeaters are meant to be shared.
                               _________

Title>NHC2:Nine Hours at Headquarters
Author>Ford, Steve - WB8IMY
Source>QST Sep 95, pp. 76-78
Abstract>The events of a typical day at ARRL Headquarters.

Digest>For the benefit of ARRL members who never have the opportunity to
visit, Assistant Managing Editor Ford prepared this article to
illustrate the major happenings during one day of office routine at the
Newington, CT Headquarters

The Headquarters building contains 40,000 square feet of floor space,
where 113 employees work.  They average 42-years of age and use 110
computers.

On the average day, 1200 telephone calls, 600 E-mail messages, 70 FAXs,
7000 pieces of mail arrive, both incoming and outgoing.  During that
same day, the QSL Bureau processes approximately 8000 cards.

The article lists major happenings that occurred during May 25, 1995,
which was selected as a typical day.  The listing includes the routine
happenings that might be found in almost any office in any enterprise of
similar size.  Included was an unscheduled power outage; a surprise
party for a female employee about to have a baby; a luncheon for the
editors and production staff, cooked by the managing editor, to
celebrate the day that one more monthly issue of QST was "put to bed";
among other activities.
                               _________

Title>NHC3:The doctor is IN
Author>Various
Source>QST Sep 95, pp. 79-80
Abstract>Questions and answers of interest to newcomers.

Digest>Questions addressed in this issue include: how to use QSL
bureaus; how the term "ham" originated; how to connect a TNC to a
computer that has no unused serial ports; how to track down an apparent
loose connection; whether or not to use a balun at the center of a
dipole; RFI that sets off an intrusion alarm; what kind of battery to
use for emergency backup; use of Esperanto on the air; and other
subjects.
                               _________

Title>NHC4:Travel Highlights for Radio Buffs
Author>Kleinschmidt, Kirk - NT0Z
Source>QST Sep 95, pp. 81-83
Abstract>A listing and description of historical museums of radio across
the USA.

Digest>There are a surprising number of museums scattered across the USA
that collect and display old radio equipment of all types.  This article
lists, and briefly describes, 19 of them.  Seven are on the East Coast
between Providence and Baltimore, one in West ***ia, three in
Illinois, one each in Wisconsin, Minnesota, Nebraska, and Colorado, and
two in California.
                               _________

Title>NHC5:Bricks to the Rescue
Author>Ford, Steve - WB8IMY
Source>QST Sep 95, pp. 84-85
Abstract>Describes VHF/UHF amplifiers for use in amateur transmitters.

Digest>Many amateurs start out in the hobby with a VHF or UHF hand-held
transceiver (H-T) with maximum output power of 2- to 5-watts. Generally,
this is enough power to access local repeaters and, via simplex
operation, nearby amateurs.  When the time comes that they want to reach
out to farther distances, they need more power.

"Bricks" are slang references to solid-state amplifiers that are
available to boost the power output of an H-T up to 25-watts or more.
They are called bricks because they are often built in a package about
the size and weight of construction brick.

To use a brick, one must also have a power supply capable of delivering
13.8-volts at from 5- to 25-amps.  For mobile use in a vehicle, the
power can probably be taken directly from the vehicle's battery if the
drain is modest.  But if it is above 15- or 20-amps, it may be necessary
to install a heavy-duty alternator and battery.

Most bricks have a switch labeled SSB/FM.  The only function of this
switch is to change the delay time that it takes for the brick to switch
from transmit to receive.  When operating FM, this should be
instantaneous, but in SSB mode it should delay for a second or two
before switching to be sure that the user is really finished talking.
------------------------------------------------------------------------

RADIO TIPS (RT)

These are short items, scattered among the articles in the New Ham
Companion section, of interest to newcomers.
                               _________

Title>RT1:Instant DX Information
Author>Kleinschmidt, Kirk - NT0Z
Source>QST Sep 95, p. 85
Abstract>This brief item explains call sign prefixes and how to
determine the country of origin of a station with a callsign having an
unfamiliar prefix.
------------------------------------------------------------------------

GENERAL INTEREST ARTICLES (GI)
                               _________

Title>GI1:Holocaust in Oklahoma City
Author>Webb, Thomas M. - WA9AFM/5
Source>QST Sep 95, pp. 24-28
Abstract>Amateur public service during the communications emergency
caused by the terrorist destruction of the Oklahoma City Federal
Building.

Digest>On April 19, 1995, a terrorist explosion destroyed the Alfred P.
Murrah Federal Building in Oklahoma City.  The same explosion caused
lesser damage to many other buildings and facilities in the center of
the city and put a severe overload on all communications in the area.

Under the leadership of the ARES Emergency Coordinator, Jim Jones -
K5PER and the Trustee of the Salvation Army Emergency Communications
Center, Frank McCollum- N5FM, the Oklahoma City amateur radio community
organized and operated HF nets, VHF repeaters, packet nodes, and public
service radio.  This article details many of the services that were
provided over several days, and some of the lessons learned during the
emergency conditions.
                               _________

Title>GI2:Thrills, Butter Churns and Honeycombs: A Visit to the Hammond
        Museum of Radio
Author>McElroy, Gil - VE1PKD
Source>QST Sep 95, pp. 29- 32
Abstract>Description of the Hammond Museum in Guelph, Ontario, Canada.

Digest>Fred Hammond - VE3HC has collected antique radio gear of all
types and established a radio museum in Guelph, Ontario, about 50-miles
west of Toronto.  It is one of the largest and finest collections in the
world.  The article contains a description of the collections and also a
series of color photographs showing the very impressive collection.

All interested people are welcome to visit the museum, located at the
corner of Curtis and Regal Roads in Guelph, but by appointment only.  To
arrange a visit, call or write to Fred Hammond at 81 College Ave. W,
Guelph, Ontario N1G 1S2, (519) 822-8323 (home) or (519) 822-2960
(office).
                               _________

Title>GI3:Like Son, Like Father: One Ham's Dad Learns a New Way to
        Call Home
Author>Smithson, Tony - KN4TX
Source>QST Sep 95, pp. 63-64
Abstract>The father of a ham becomes one.

Digest>KN4TX became a ham at age 18 and, for the following 15-years,
pursued his hobby in the USA.  Then, with a wife, one child and another
on the way, he and his family moved to the Caribbean island nation of
Trinidad and Tobago.  This meant that his father and mother were cut off
from close communications with their son, daughter-in-law, and
grandchildren.  Using the allure of easy and frequent communications, he
persuaded his father to get an amateur radio General Class license.

With great reluctance and self-doubt over his ability to learn Morse
code, the father, Morris Smithson, succeeded and obtained not only a
General Class, but also an Advanced Class license and now holds the
callsign KS4SU.

The son, in the meantime, moved even farther away, to Bogota, Columbia
for two years.  Now, he and his family are back in the USA and are
separated from his parents by only a few hundred miles.  But they still
hold amateur radio schedules two or three times a week on 75-meters.
                               _________

Title>GI4:Hard-Core QRP
Author>Arland, Richard H. - K7YHA
Source>QST Sep 95, pp. 66-67
Abstract>Describes ham activities with power output limited to a few
milliwatts, or less.

Digest>QRP is usually considered to refer to operations with power
output of no more than 5-watts.  But a group of amateurs operate what
they call "hard-core" QRP and establish communication using milliwatts,
or even microwatts.  They measure their accomplishments by calculating
the miles per watt covered in a given QSO.

As of December, 1994, the 40-meter record for hard-core QRP stood at
1,000,000 miles per watt.  On December 26 of that year, AA4XX and
KA3WTF arranged a schedule to try to better the record.  The former was
located about 16-miles south of Raleigh, NC and the latter in
Larksville, PA.  AA4XX set his transmitter to emit an accurately
measured 221 microwatts of power and KA3WTF received his message and
gave him a signal report of 229.  This transmission established the
current 40-meter record of 1,900,000 miles per watt!
                               _________

Title>GI5:California Mobile Antennas and the Moment of Truth
Author>Selman, Robert "Doc" - WE6A
Source>QST Sep 95, pp. 68-69
Abstract>Large home-built mobile antennas surpass common commercial
models in radiation effectiveness.

Digest>A group of about ten California amateurs who like to operate
75-meter mobile with high-power amplifiers and relatively large antennas
on their vehicles organized a competition among themselves.  In a large,
flat, open space, they set up an antenna range and tested their antennas
to determine which produces the best signal, measured by a highly
precise field strength meter 2000-feet away at ground level.

The antennas differed considerably and ranged from modest to outrageous.
Included for reference purposes were two common commercial antennas: a
Hamstick and a Hustler Super-Resonator.  The heights were limited to no
more than 13.5-feet (4.1-m.)

The measured signal strengths ranged from 47.5-dB. to 59.2 dB.  But the
two popular commercial antennas were at the bottom of the list, more
than 6-dB. below the poorest of the others.  The Hamstick measured
47.5-dB. and the Hustler 50.0.  The others, all of which rated better,
are larger and "uglier".  The winner was W6KKT who used an antenna
designed by K6ATP.  It is made of a tubular vertical shaft with a
relatively large diameter coil of few turns, mounted about 3/4 of the
way to the top of the antenna.  Above the top end of the shaft is a
large top hat made of six stiff wires branching outward and upward from
a small disk atop the shaft.  The wires appear to angle upward at about
a 30-degree angle from the horizontal.  It measured 59.2-dB.

Excepting the two commercial models, all the custom-built antennas
measured within 3-dB. of the winner.
                               _________

Title>GI6:A Gift for Teaching
Author>Winter, Patty - N6BIS
Source>QST Sep 95, pp. 70-71
Abstract>How to use amateur radio in becoming an effective middle-school
teacher.

Digest>Bob Maurais - KC1IV was given the Disney American Teacher award
as the outstanding vocational/technical teacher of 1994.  He teaches
fifth, sixth, and eighth graders industrial arts and technology at
Harrison Middle School in Yarmouth, Maine.  He is both a private pilot
and a ham, and uses both avocations in his teaching.

His success in teaching seems to stem largely from his immaginative use
of projects which give the children experience in a variety of
technologies and skills.  One project under way at the time the article
was written was a "boat race" run in two long, narrow troughs filled
with water.  Each trough has an electric fan at one end, blowing down
the trough, to blow the racing "sailboats" down the course.  The
children must design and build their own boats.  Doing so, they use
technical drawing, geometry, computer-aided design, graphic arts,
writing, and other subjects.
--------------------------------------------------------------------------