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.
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.
I would be
pleased to hear from anyone who has any more ideas or information about this
equipment. Photographs of contemporary equipment might be very helpful. |
