Wavemeters Class "D" No. 1 Mk 2
This device was used to tune the WS 19 to a calibrated frequency to make
netting of a group of
transmitters possible without live broadcast.
modest box contains de Wavemeter Class "D" Mk 2.
Measurements: ~ 19,8 x 16 x 18,5 cm.
At the back two thumb screws that hold the wavemeter frame.
the lid is opened, this is what it looks like.
In the lid a brief user guide is attached. Unfortunately it is damaged, because of the profiles in the cover.
It can generate signals on every 1 Mc on the dial. It is also possible to tune a wanted frequency in the ranges 1900 tot 4000 KC or 4000 to 8000 KC.
Using headphones one can tune the unit on "zero beat". The frequency tuned is as precise as the built in crystal can generate.
This unit is not as precise as the BC221 is.
At the back is the crystal unit visible.
At the right the vibrator unit is mounted. The tube at the back is in use, the one in front is a spare. The empty tube socket is for a spare vibrator.
In the cabinet two spare light bulbs are mounted.
The shielded compartment contains the varco.
|At the back.|
is how a vibrator looks from the inside.
The electro magnet pulls the weight to its center and the bottom contact is broken. The weight falls back to its resting position, opening the other contact. This is repeated endlessly. Thus a current through the primary coil of a transformer is alternated, inducing a current through the secondary coil(s).