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And now over 70 years
later, below are views of my Philips 2514 showing the windows
through which can be seen the scales for the aerial tuning and
amplifier tuning controls. In the centre is the three position
wavechange switch. Tuning ranges are 200-400; 300-700 and 600-1500
metres. The set was one of the last to have this type of tuning
scale. In 1932 an agreement was reached which set out the frequency
plan for European broadcast stations. After this date all new
receivers carried dials marked with station names. The set was
also one of the last to employ TRF or "straight" design.
Superheterodyne receivers took over and offered the luxury of
single knob tuning instead of the old method of fiddling with
three or more controls. With the old TRF sets it was convenient
to use the reaction control to set the audio volume level. When
this was done it often resulted in a howling noise in neighbours
receivers if they were listening to the same station as you.
Depending on the design of the receiver and the type of aerial
being employed, the interference could extend over a considerable
area.....even measured in miles.
The centre picture shows the
end of the set from which protrudes the end of its old mains
lead. It also carries the volume control at the bottom and the
aerial, or RF amplifier grid, tuning control which is the little
knob on the right. The set may not have been designed in England
as the rotation of the knob turns the dial in the logical direction.
At the top left are three aerial sockets. You were given a choice
of senstivity versus selectivity. Choosing the wrong one with
a big aerial, as with a crystal set, would result in more than
one station being received at the same time
The other end of the set has
the reaction control in the centre and the detector tuning control
above the twin sockets which are provided for the external loudspeaker
or headphones. |
