This is only a preview of the August 2004 issue of Silicon Chip. You can view 22 of the 104 pages in the full issue, including the advertisments. For full access, purchase the issue for $10.00 or subscribe for access to the latest issues. Items relevant to "Video Enhancer & Y/C Separator":
Items relevant to "Balanced Microphone Preamplifier":
Items relevant to "Appliance Energy Meter, Pt.2":
Purchase a printed copy of this issue for $10.00. |
Vintage Radio
By RODNEY CHAMPNESS, VK3UG
Peter Lankshear: vintage radio from
the other side of the ditch
The title “Vintage Radio by Peter Lankshear”
headed an accurate, informative column that
ran in “Electronics Australia” magazine from
June 1988 until September 1996. The column
was highly respected on both sides of the
Tasman due to the author’s vast knowledge of
the subject.
I have corresponded intermittent-ly
with Peter over the years and late in
2003 I had the opportunity to visit
him in Invercargill, New Zealand.
The weather in Invercargill at the
time was cold, wet and windy – a
complete contrast to the warm reception I received.
Peter was born in 1928. His father
actively encouraged his interest in
things electrical and radio and by the
time he was 11, he knew that his life’s
work would be in this field. Around
this time he built his first radio, a
single-valve tetrode model “Hiker’s
One”, using a 49 valve. According to
Peter, he has had a soldering iron in
his hand ever since.
Peter has a very inquiring mind
and this has stood him in good stead
throughout his career in electronics,
television and radio. He qualified as
NZ vintage radio enthusiast Peter
Lankshear.
a Registered Engineering Associate in
Electronics, and with his enthusiasm
and ability he eventually became the
Broadcasting and Television Transmission Superintendent for Southern
New Zealand with the New Zealand
Broadcasting Service. He held this
position for 15 years.
Quartz Hill Receiving Station
Shown here are just two of Peter’s Atwater Kent receivers, the Atwater Kent 317
(left) and the “Golden Voice” 84. The 317 used all metal valves and was one of
the last models made, while the “Golden Voice” 84 (1930/1) was the first Atwater
Kent receiver to use an arched cabinet.
88 Silicon Chip
Among his many and varied work
activities, he was closely involved
with the New Zealand government’s
Quartz Hill Receiving Station during
the 1950s. This station would have
been equivalent to the Australian Communications Authority’s Quoin Ridge
monitoring station near Hobart.
Primarily, these stations monitor
shortwave radio transmissions from
around the world. They can hear stations we can only dream of hearing due
to their superior receivers, high-gain
antennas and low noise locations.
They also have facilities for direction
finding of radio transmissions.
At Quartz Hill, the search radios
were Eddystone type 680 communication receivers. As a result, Peter
developed a keen interest in Eddyssiliconchip.com.au
tone receivers and has quite a few in
his collection (see photos). He also
belongs to the Eddystone Users Group
and often writes articles for their magazine, which is called “Lighthouse”.
During the course of our conversation, Peter informed me that he is
now gradually reducing the size of
his collection because, as he pointed
out, he isn’t getting any younger. He
subscribes to the view that as we get
older, we should each look at ways of
reducing our collection so that it is
not left to people who have no interest
or knowledge of our radio heritage. If
that’s not done, our collections could
easily end up in the rubbish tip.
I mentioned to him that I had recently written an article on this very
subject, in the May 2004 issue of
SILICON CHIP. That said, Peter is keeping his favourite receivers, mostly
Eddystones and Atwater Kents – he
is only disposing of the sets that hold
less interest for him.
Shown here are an Atwater Kent 217 at left and at right, an Atwater Kent 165.
The latter featured an 8-inch speaker plus the American “Police Band”, which
was around 1700-1800kHz. Tuning the “Police Band” usually involved using
tapped broadcast band coils, to achieve a slightly higher frequency tuning range
than available with the standard coils.
Atwater Kent receivers
Atwater Kent receivers form the
most impressive section of Peter’s collection. In Australia, the importation
of foreign-made radio receivers was
allowed until 1932. However, after
1932, the popular Atwater Kents and
all other imported sets were no longer
allowed entry. This denied Australians
the opportunity to purchase some
of the very advanced receivers that
became available in the following 4-5
years.
By contrast, New Zealand did not
prohibit the importation of foreign
receivers until 1936, so some quite
advanced receivers did find their way
into that country, particularly the
later Atwater Kents. The cabinets of
these receivers were quite elegant, as
can be seen in the photographs, and
the electronic design of the sets was
cutting edge – just two of the reasons
Peter concentrated on this particular
manufacturer for his collection.
He described the Atwater Kent receivers and their manufacturer (Arthur
Atwater Kent) in considerable detail in
the September 1996 issue of “Electronics Australia”.
The Atwater Kent 627 also featured
an arched cabinet.
The Atwater Kent 708 was a highperformance receiver, built in 1933.
It tunes from 550kHz to 20MHz in
four bands & features separate local
oscillator & mixer valves, an RF stage
& a 2-stage (472.5kHz) IF amplifier.
She’ll be right
If we were to go through the
Australian Official Radio Service
Manuals (AORSM), we would see that
many Australian receivers made up
until the 1940s lacked AVC/AGC and
siliconchip.com.au
An Eddystone 750 double-conversion 5-band communications receiver. The set
tunes from the broadcast band to 30MHz.
August 2004 89
Above: this Western Electric moving-iron speaker
measured about 2’6” (760mm) in diameter and was used
in the original New Plymouth radio station in 1928.
Left: built in 1934, the Atwater Kent 447 console receiver
tuned from 550kHz to 23MHz in four bands. A split stator
tuning capacitor is used to provide band-spread on the
shortwave bands. The set also features an RF amplifier
and a number of refinements to assist in accurate tracking
and dial scale calibration. These include semi-circular
dial scales that are raised or lowered with the bandchange switch, so that the appropriate scale is visible
through the dial escutcheon. The window at the bottom of
the dial escutcheon is for a “tuning” meter.
had poor selectivity. Or to put it more
bluntly, they simply lacked good design features. It really was a shame
that some Australian manufacturers
didn’t venture out into the world
(either in person or via magazines
and books) to acquire good electronic
designs for their radios.
Of course, we did have some very
good design engineers but overall,
there was too much of the “she’ll be
right, mate” attitude. However, let’s
not bag just the mediocre designers
in Australia. There were also plenty
in America and New Zealand whose
designs left a lot to be desired.
As noted in my article on the Astor
OZ in the March 2004 issue, the design
of valve receivers in the USA at least
had almost reached its zenith by the
mid 1930s. The only improvements
from then on were in valve types,
the use of permanent magnet speakers, and smaller and more efficient
components and coils. However, the
circuitry did not change to any great
extent, even towards the end of the
valve era.
Philips Theatrette
Another Eddystone receiver, this time a model 640. This was one of Eddystone’s
first post-war receivers (1947) designed for amateur radio operators and
covered from 1.8-31MHz. It boasts electrical band-spread, two dial pointers and
a total of nine octal valves.
90 Silicon Chip
Although it is quite evident that
Atwater Kent and Eddystone receivers
hold particular importance to Peter,
he also has some other very interesting receivers. These sets include a
Philips Theatrette V7A, a BrowningDrake, a Majestic, an RCA (Radiola
20) and the New Zealand-made Bell
Colt. All are very collectable receivers, with perhaps the Bell the odd one
out because it’s a 50s/60s Bakelite
mantel receiver.
In fact, this set was manufactured
between 1951 and 1971, being New
Zealand’s best selling radio ever.
Naturally, a large number of Peter’s sets
appeared in his articles for “Electronics Australia”.
I remembered the Philips Theatrette
siliconchip.com.au
Silicon Chip
Binders
REAL
VALUE
AT
$12.95
PLUS P
&
P
The bottom receiver in this photo is an Eddystone 940, a 13-valve 5-band
communications receiver which tunes from the broadcast band to 30MHz. This
was the last of Eddystone’s valved receivers and used a twin-triode cascode RF
amplifier for low noise. The top unit is an Eddystone 870, a 5-valve ship’s cabin
receiver covering 150-300kHz and 510kHz to 24MHz in four other bands. This
receiver was not considered a communications receiver, as it was used solely
for entertaining the ship’s crew.
H SILICON CHIP logo printed in
gold-coloured lettering on spine
& cover
H Buy five and get them postage
free!
Price: $A12.95 plus $A5.50 p&p.
Available only in Australia.
Just fill in the handy order form in
this issue; or fax (02) 9979 6503;
or ring (02) 9979 5644 & quote
your credit card number.
Made from 1925, the Radiola 20 was RCA’s first TRF receiver. It uses the UX199
and UX120 valves, along with three ganged tuning capacitors plus adjustable
trimming capacitors for tweaking the tuning. The righthand thumbwheel dial is
the regeneration control.
from Peter’s article and in fact, had the
opportunity to acquire one some time
back. However, I declined the offer as
the set had been “ratted” for some parts
and I didn’t have a circuit to help with
the restoration. Peter commented that
the wiring was like a “dog’s breakfast”
and there was no chassis! However,
they worked well, sounded good into
an 8-inch (200mm) loudspeaker and
rarely required servicing.
They also had the rather unusual
intermediate frequency (IF) of 125kHz.
However, it must be pointed out that
siliconchip.com.au
this wasn’t considered so unusual in
Europe. It also simplified the circuitry,
as “up-conversion” to 455kHz (or a
similar IF) was not necessary.
Peter and I also discussed the attributes of “space charge” tetrodes
such as the A141 and in particular
the 49 valve, which was used in a
number of configurations. The 49 was
not really designed as a space charge
tetrode but experimenters and hobbyists found that it worked well in that
mode. It was used in the Hiker’s One
and Alf Traeger used it in some of his
pedal radios which were used in the
Australian outback.
I had commented in my soon to
be published book “Outback Radio
– from Flynn to Satellites” that I felt
Traeger had not used the valve to its
Left” a Philco 18B 8-valve archedtop 1934/5 receiver. Peter retrieved
this set from a country rubbish tip
in a very sorry condition. The audio
output section of this model was a
cut above most, boasting a pair of 42
valves connected as triodes in class
AB2 and driving a 200mm (8-inch)
loudspeaker. This output stage was
driven by another 42 valve.
August 2004 91
Photo Gallery: 1933 Van Ruyten B14
data books can be extremely valuable;
so don’t throw them out.
AC power supply
I mentioned to Peter that the AC
power supply for battery sets that he
described in “Electronics Australia”
had been quite popular with vintage
radio enthusiasts. It used the power
transformer from an old black and
white TV set.
According to Peter, the PC board for
this project should still be available
from RCS Radio. It is well made and
has silk screen printing on the non-foil
side to assist component placement.
Peter’s small micro-powered broadcast transmitter has also been built by
a number of enthusiasts. However, if
you do build one, make sure that no
transmissions can be received outside
your premises!
Manufactured by Tilbury & Lewis Pty Ltd, Melbourne, in 1933, the
Van Ruyten B14 circuit was conventional for the time, except that
the high-tension voltage for the rectifier was obtained direct from
the mains rather than via a separate winding on the power transformer. As a result, one side of the mains was connected directly
to the chassis. The valve line-up was: 6A7 frequency changer; 78 IF
amplifier; 6B7 audio amplifier/detector/AVC rectifier; 42 audio output;
and 80 rectifier. Photo: Historical Radio Society of Australia, Inc.
full potential. However, Peter showed
me an early valve data book which set
out how the valve could be used to
achieve various outcomes. As a result,
I had to amend a small section of my
book prior to publication.
By the way, short-form valve data
books such as Philips’ “Miniwatt
Technical Data” are extremely useful
for obtaining the standard operating
parameters of a valve. However, they
generally do not give some of the more
obscure parameters which can make
a valve adaptable to a variety of other
functions.
It just goes to show that old valve
The Eddystone 680 is a 15-valve 5-band communications receiver, again tuning
from the broadcast band to 30MHz. This is one of the search receivers used by
Peter at New Zealand’s Quartz Hill communications station in 1950-1.
92 Silicon Chip
Books & magazines
As expected, Peter has an extensive
library of good books on vintage radio
and on many other subjects that he’s
interested in. Books and magazines are
well worth retaining, particularly the
better quality ones. But even the not
so good ones are worth keeping – they
are all part of our radio history.
Peter is a life member of both the
New Zealand Vintage Radio Society
(NZVRS) and the Historical Radio
Society of Australia (HRSA). He still
writes for a number of publications,
including the NZVRS “Bulletin”, the
HRSA “Radio Waves”, the American
“Old Timer’s Bulletin”, the British
“Radio Bygones” and the Eddystone
User Group’s “Lighthouse”.
He also has a number of other interests besides vintage radio. For example, he is the Southern Vice-President
of the New Zealand Railway and Locomotive Society. He is also active in
his local church, where he looks after
a comprehensive sound reinforcing
and recording system and produces
the weekly “Church Bulletin”.
Of course, it’s not surprising that
he became involved with the sound
system as another of his electronics
interests involves designing and building audio amplifiers.
In the end, my time with Peter was
too limited and I would have liked
to have spent many more hours with
him discussing radio, electronics and
vintage radio in particular. And I learnt
quite a number of things from our very
SC
interesting discussion.
siliconchip.com.au
|