On Sat, 02 Oct 2010 03:47:48 +0000, _JD_ wrote:

Other neat PIC I found. The lamps mounted on the wall I think maybe
ballast tubes // then again.. It could be some kind a signaling device
for incoming transmissions?
The cylinder?? Look as if it's wrapped with wire like an oscillator coil
& has a lid on top. _JD_ TIA

I can only guess but here goes:

The lamps might be a tuning indicator for the transmitter. If so, they
would be connected in series with the antenna and the transmitter would
be tuned for maximum brightness which would indicate maximum antenna
current. This system was frequently used by amateurs up into the '50s or
even later. Another, later, variation was to use an RF ammeter.
Presumably in this instance they switched the lamps out of the circuit
after the tuning was done to avoid wasting precious transmitter power.

The lamps could also be a dummy load for testing the transmitter. Again,
common practice for amateurs until solid state transmitters came along
that couldn't deal with the odd impedance load.

By the "cylinder" I assume you mean the tall vertical thing, not the
little horizontal thing at the top. If so, it looks like a loose coupler
to me. It would be an odd one since they were usually horizontal. This
is part of the tuning system for the receiver. The idea was to reduce
the coupling between the tuned circuit and the rest of the system to get
the highest Q possible. Since reducing the coupling also reduced the
received signal, the coil could be moved in or out of another coil so
that the best compromise could be achieved. This is the reason most
loose couplers were horizontal; they would stay where they were set
without something to hold them in place. This one would have had to have
some type of clamp or other device to keep it from sliding all the way
down.

--
Jim Mueller

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