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AM Broadcast Stations
This radio has an optional Module, shown
above, that can be used to allow you to play
music from your Smartphone or listen to your
local FM Station.
One of the problems for collectors of
vintage radios is that there are very few AM
Stations left in North America. As a result
many valuable radios sit idle. There radios
are designed to be operated on a daily
basis. To enable daily use Old Fidelity adds
a module, hidden on the back of the radio,
that allows the radio to play FM Stations as
well as music on a smart phone via
Bluetooth. The module is accessed via a
switch on the back of the radio. Once the
radio is in the module mode, you can choose
from FM or Bluetooth using the module
switch.
When using the module the radio's on-off
switch, volume and tone controls are fully
active. The signal strength can also be
adjusted by controls on the module. The
great value of this set up is that you can
use this radio on a daily basis to
seamlessly play your local FM Station. When
you turn the radio off, using only the
radio's on-off control, while playing an FM
Station, it will continue playing that FM
Station when you turn the radio back on. You
only need to touch the module if you want to
change FM Stations. This is done by the
module control labeled "FREQ".
This versatility enables the everyday use of
this radio whether or not an AM Station is
available in your area.
Sparton of Canada; London, ON:
Sparton of Canada Ltd. was located at 100
Elm Street, London, Ontario and later at 99 Ash
Street, London Ontario. Sparton of Canada was
established in London, Ontario on January 20,
1930, as the Canadian subsidiary of the American
Sparks-Withington Company based in Michigan. The
company produced radios, phonographs, household
appliances, and even pressed vinyl records under
the Sparton label, operating until 1978.
Model 7140 Specifics
The
Model 7140 was manufactured in 1939/1940 and is
classified as a broadcast receiver. Here are the
key technical details:
• Tubes: 7 tubes —
6SA7, 6K7G, 6K7G, 6Q7G, 6E5, 6F6G, and 5Y4G
•
Circuit type: Superheterodyne with an IF
(intermediate frequency) of 456 kHz
• Tuned
circuits: 7 AM circuits
• Wave bands:
Broadcast, Shortwave, and Police bands
•
Power: AC supply at 115 volts
• Loudspeaker:
10-inch (25.4 cm) electromagnetic dynamic
speaker (field excitation coil type)
•
Cabinet: Wooden case
• Form factor:
Table Model with push buttons — a stylish feature
for the era
• Schematics: Referenced in the
Radio College of Canada documentation and
mentioned in the book Machine Age to Jet Age II
(page 284)
The push-button tuning and
multi-band capability (including a police band)
made it a fairly capable and feature-rich
consumer radio for its time. The wooden cabinet
tabletop design was typical of late 1930s radio
aesthetics.
Owner's Manual
This Radio comes with a Historical and Technical
Manual where you can read about the history of
this 1939 Sparton radio. Sparton of Canada,
located in London Ontario, was the Canadian
subsidiary of the American Sparks-Withington Company, which was well
known for producing quality radios through the 1930s. This manual
also holds important technical information needed
to maintain this valuable antique. |
