"Wavemeter Type 2"
This is an early RAF wavemeter, or to be more precise a Royal
Flying Corps wavemeter
It's a very old device of which I know very
little except that recent research has led me to the fact that
there were three similar equipments around during WWI. Below is
a picture of the other two.
The set of models were designed by a Professor J.S.Townsend.
The last owner said his father-in-law got it from a disused
RAF Station in the 30's
I imagine this must have been before re-armament started so
it must have been early 30's
From the label inside the lid (see below) it must have been
RAF Kidbrook in Kent.
The dial is marked from 1000 to 2000 metres and a multiplier
switch engages a second band, 2000 to 4000 metres.
The wavemeter uses either a lamp or a buzzer, selected by
the switch at the top right, to indicate when it is tuned to a
local transmitter. I wonder whether it was used with spark transmitters?
An impressed marking on the mahogany case says it was patented
in May 1917 and from its construction, it must date from the period
1917 to say the mid-20s. The manufacturer's mark can be seen as
"JP Ltd". Who were they?
Where was RAF Kidbrook and when was it open
for business?
On the left is a miniature buzzer and on the
top are what looks like a couple of ancient condensers.
The rubber wiring insulation has completely perished so probably
predates all my older stuff from the late 20's
A front panel switch selects either the buzzer or the lamp
which is fitted on the front panel. This is a type I haven't seen
before and has a small reflector. The filament is an S-shaped
length of shiny wire rather than the usual coiled-coil of tungsten.
Tuning is not by variable condenser but by
a variometer. This comprises two coils one of which is connected
to the tuning knob. This is an underside view showing the pairs
of twin windings for the two longwave bands.
Here are two other wavemeters dating
to the same period as the No.2 shown above.
On the left is a No.3 covering 300-4,000metres in two bands
and on the right a No.50, made by ATM and covering 3,000-12,000meters
also in two bands.
I spotted one in a "radio" junk shop but despite
going back I didn't manage to make my visits coincide with those
of the proprietor so I departed empty handed.
See another new wavemeter>>
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