Three units mounted on a
mahogany base, consisting of the Gambrell Variable
Condenser 5006, surmounted by a unit for fine tuning
(right), a Reaction Unit 4118 (middle) and a Sonus Valve
Advertisement in Wireless World, September 1923
The antenna can be
connected at the fine tuning unit; the tuning capacitor
is 240 pF.
The Reaction Unit in the
middle can be used to control feedback by means of a
fixed and a movable coil.
The two coils, labeled
"A" and "B" "(see advertisement), can be used for 60-260
and 100-420 meters respectively (in combination with the
240 pF capacitor).
The Sonus Valve Panel
comprises a valve holder, filament resistance, grid
condenser and leak, and a telephone condenser. On the left of the
unit are connections for the filament current and the
headphones and on the right there are connections for
the HT voltage of the Cossor P1 detector valve. The
price of this unit was £ 0.37.6.
Gambrell coils were made in a
different way than most of the coils at that time,
because they were wound in separate spaced layers, and
not on top of each other, such as in a honeycomb coil.
The ribbed pattern that can be seen on the outside of
the coils is formed by the ebonite strips that hold the
layers in place. These patented coils were reviewed for
the first time in the magazine Wireless World of October
7, 1922. The price of one coil was 5s/9d.
19 × 39.6 x 17 cm
Click on a valve for more
What was broadcast in 1923?
Listen to "My
Buddy" by the orchestra of Bert Ambrose,
recorded on April 3rd, 1923.
The underside of the Sonus Valve Panel
On the left of the rheostat for the filament
voltage of the detector valve, the 5 Megohm grid leak resistor
can be seen. The 50 pF grid capacitor can be seen above the
rheostat, and the telephone capacitor (4nF) is at the right.
Advertisement for the Sonus Unit
Valve Panel in Popular Wireless, July 1st, 1922