Practical Wireless №2 2020.pdf

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WIRELESS
FEBRUARY 2020
THE UK’S NUMBER ONE AMATEUR RADIO MAGAZINE SINCE 1932
WK
NE O
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CONTEST
A full round up of
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How to get a higher quality inish
Michael Lindsay
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the Chinese guerillas
Portable antenna
Lightweight HF multiband
for enthusiasts in the field
All the latest new
products unveiled
From dual band handheld
to headless transceiver
A bridge to the Revised
Advanced Licence
The gap between the old Intermediate
and new Advanced syllabuses explained
The world of VHF explored
Including a full update on the Open GD77 irmware project
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Contents
PRACTICAL
WIRELESS
February 2020 Vol. 96 No 2
On sale: 9 January 2020
Next issue on sale: 13 February 2020
ISSN 0141-0857
5
Keylines
Don
welcomes in the New Year with some thoughts
provoked by the contents of this month’s issue.
7
News
PW’s
monthly roundup of news from the UK and
internationally, including new products, club news
and recent events.
Practical Wireless
Warners Group Publications plc
The Maltings
West Street
Bourne
Lincs PE10 9PH
www.warnersgroup.co.uk
Tel 01778 391000
Editor
Don Field G3XTT
practicalwireless@warnersgroup.co.uk
Designer
Mike Edwards
mike.edwards@warnersgroup.co.uk
Advertisement Manager
Kristina Green
01778 392096
kristina.green@warnersgroup.co.uk
Advertising Production
Nicola Lock
nicola.lock@warnersgroup.co.uk
Publisher
Rob McDonnell
robm@warnersgroup.co.uk
Subscriptions
Subscriptions are available as little as £11.
Turn to our subscriptions page for full details.
Subscription Administration
Practical Wireless Subscriptions,
Warners Group Publications plc
The Maltings, West Street
Bourne, Lincs PE10 9PH
Tel: 01778 395 161
subscriptions@warnersgroup.co.uk
Components for PW projects
In general, all components used in
constructing
PW
projects are available from
a variety of component suppliers. Where
special, or difficult to obtain, components
are specified a supplier will be quoted in the
article.
Photocopies & Back Issues
We can supply back issues, but we only keep
them for one year. If you are looking for an
article or review that you missed first time
around, we can still help. If we don’t have
the actual issue we can always supply a
photocopy or PDF file of the article.
Technical Help
We regret that due to Editorial timescales,
replies to technical queries cannot be given
over the telephone. Any technical queries are
unlikely to receive immediate attention so,
if you require help with problems relating to
topics covered in PW, please either contact
the author of the article directly or write or
send an email to the Editor and we’ll do our
best to reply as soon as we can.
10
Improving Your Projects
Michael Jones GW7BBY
explains his methods for
achieving a high-quality inish on equipment front
panels.
15
Radio Bookstore
Your one-stop shop for hobby-related titles, biogra-
phies, reference titles, historical accounts, technical
advice and successful building projects.
56
38
Kits and Modules
A power supply rebuild and an RF ammeter;
Geoff
Theasby G8BMI
has two more cheap and cheerful
projects for the shack.
16
An HF Multiband Portable Antenna
Ron Taylor G4GXO
describes a multiband antenna
suitable for lightweight portable operations.
24
The Morse Mode
Roger Cooke G3LDI
has his bi-monthly roundup of
Morse-related news, including a look at non-English
Morse characters.
42
Carrying on the Practical Way
Lee Aldridge G4EJB
returns, this time with a series
of articles based on the
PW
contributions of the late
George Dobbs G3RJV.
26
Valve & Vintage
The story of
Michael Lindsay,
the British amateur
who worked with Chinese guerrillas in World War II
and made possible the irst intercontinental broad-
casts by Xinhua the Chinese news agency.
44
A Bridge to the Revised Advanced
Licence
Tony Jones G7ETW
addresses the gap between
the old Intermediate and new Advanced licence
syllabuses.
30
Book Review
Chris Colclough G1VDP
reviews
Hogwash for Ham-
sters,
a counter to being too serious about the hobby!
48
HF Highlights
Despite variable propagation,
Steve Telenius-Lowe
PJ4DX
reports that the HF bands were buzzing with
activity in late 2019.
34
World of VHF
Tim Kirby GW4VXE,
with a new location and preix,
starts his column with an update on the Open GD77
project.
51
The 11th Practical Wireless
70MHz Contest Results
Contest Manager
Colin Redwood G6MXL
has the
results of the 2019 contest.
54
Technical for the Terriied
Don G3XTT
takes a look at the end-fed half-wave
antenna, a design that has recently come into promi-
nence once again.
56
Using an EFHW Antenna
Daimon Tilley G4USI
discusses the use of End Fed
Half Wave Antennas for portable and home opera-
tion.
60
What Next
24
In the irst of a two-part mini-series,
Colin Redwood
G6MXL
looks at antenna supports.
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4
PRACTICAL WIRELESS
February 2020
Keylines
I
48
63
Hints & Tips
A further selection of handy hints from readers and
elsewhere.
was amused recently while watch-
ing a TV programme about model
railways and their history. It turns
out there are essentially two types
of model railway enthusiast – those
who enjoy building and those who get
the most satisfaction from operating.
Ring any bells? And, funnily enough, one
aspect of the operating side that has
changed in both hobbies is the use of
computers. Most amateur radio stations
where operating is the main aspect have
the PC linked to the transceiver nowa-
days. Similarly, the railway modeller will
use a PC to control the trains, points and
other aspects of the track and signalling.
I daresay there are plenty of other hob-
bies that fall into builders and operators
too. Meanwhile, here in
PW,
I will do my
best to cater for both aspects.
64
Data Modes
Mike Richards G4WNC
is looking at an important
signal quality improvement for FT8 & FT4, along with
ideas for monitoring your signal quality.
The EFHW
One branch of amateur radio where we
can all get involved in construction is
antennas. All it takes, for the HF bands
at least, is a reel of wire, a tape measure
and a few ancillaries (string, insulators
and the like). So, I am pleased this month
to have a couple of features on the end-
fed half-wave antenna (EFHW), with a
further article to follow next month. It’s
hard to believe that anything new can
be said about antennas when the phys-
ics have been known for decades and,
seemingly, every possible coniguration
has been explored. But modern model-
ling software has introduced new possi-
bilities and the EFHW is a good example
of how this has enabled an old design to
be given a new lease of life.
67
Notes from a Small Station
Joe Chester MW1MWD
relects on the highs (and
lows) of low power operating.
70
In the Shop
Harry Leeming G3LLL
describes the uses of a dip
meter, still a handy tool to have around the shack.
ferred tool ‘in the ield’, is the MFJ-226
that I reviewed some time ago in
PW.
It recently went with me to the Gambia
and proved invaluable in setting up
Alan
G3XAQ’s
20m Moxon antenna and my
various single-band dipoles (resonances
were not exactly as calculated because
of all the rebar and other metalwork in
the building) as well as cutting a quarter-
wave stub for the 20m band (you cannot
simply assume the published igures for
velocity factor of coax because batches
vary slightly). But, as Harry says, a dip
meter can still be a useful tool for mak-
ing quick measurements on antennas
and unpowered resonant circuits.
72
Readers’ Letters
The proposed Beginner’s licence features strongly
among this month’s reader correspondence.
70MHz Contest Results
Our long-time contest manager
Colin
G6MXL
has the 70MHz Contest results
for you in this issue. It’s clear that the
atrocious weather put off many potential
entrants but, nevertheless, it is disap-
pointing to see entries well down given
that so many new rigs have the 70MHz
band itted as standard. You don’t have
to go out and about – we are happy to
receive entries from non-portable sta-
tions. But if you feel the contest could be
‘tweaked’ in some way to encourage you
to participate, then do please drop Colin
a line. More participants means more
fun! Meanwhile, I’d like to add my own
congratulations to all who took part and
endured the downpours!
76
Rallies
Locate a rally or event near you; we have our usual
comprehensive list.
78
The Case for QRO (High Power)
Some thoughts from the editor
Don Field G3XTT
Dip Meters
In this month’s
In the Shop
column,
Harry
G3LLL
talks about using a dip meter for
various jobs around the shack, includ-
ing setting up antennas. I too had a TE-
15 Tradiper for many years (actually, it’s
still sitting my cupboard) for exactly the
reasons that he describes. What has
changed, in my shack at least, is that
there are now some excellent antenna
analysers available, not just showing
a resonance (as a dip meter does) but
also information on reactance, a swept
SWR curve and more. I have a miniVNA,
which is great for bench testing of ca-
bles, chokes and more. However, my pre-
67
Don Field
Editor,
Practical Wireless
Magazine
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February 2020
PRACTICAL WIRELESS
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