~Now know to be incorrect
history~:
This collection of parts, which appears to have been
a transmitter, was allegedly used by Marconi in Fordingbridge, Hampshire, UK.
However, it seems unlikely that it was used by Marconi himself. The story that
accompanied it was that the former owner's father worked for or with Marconi.
The equipment has been
returned to its original custodian.
It may
have been part of an early 1920s amateur station. The McMichael variable
capacitor (16) probably dates from around 1921 and is looks
like the most recent part. The Negretti & Zambra, loose coupler is similar
to one pictured in Harmsworth's and may date from around 1918. Pictures
7, 8 & 9 show what appears to be a Marconi spark coil
dating from the early 1900s. It is a replacable primary type and may have been
removed from its original base. These were sometimes used as HT transformers
but I can not find evidence of any rectifiers or smoothing in the kit that I
have. Harmswoth's Wireless Encyclopaedia has details of a hot-wire ammeter
similar to that shown in picture 15. The relay is estimated
as being from 1918. Remnants of a crystal set (18) were also with the
collection.
It is a guess
but the rings, in the lower middle of the frame, look about the right shape to
hold an early transmitting valve. This figure, from
Harmsworth's, shows the type of valve but these examples would be too large. A
similar style of construction can be seen in the equipment inthis picture, of J.L. Baird, from "Television" magazine, dated
April 1928. The two insulated rings, in picture 10, are ~33mm inside diameter
and are spaced at about 90mm. The spacing is adjustable. The two larger rings
are connected together and are about 93mm inside diameter.
Addendum: Later information suggests that is was a Poulsen arc based
transmitter. |
