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For some years after
WW2 there was an abundance of cheap ex Gov't radio, radar and
electronic components, equipment and part assemblies available
through numerous shops. The best of these were in Lisle Street
in London's Soho district or 'Henry's Radio' in Edgeware, London.
I often made trips to these shops and bought components, equipment
and valves to either repair or make up units. In 1955 ITV introduced
a new commercial channel on the UK TV network. The problem was
that only recently bought TV's were already set up in readiness
for it, so there came a demand for 'converters' to enable the
switching to the new frequency. Our TV was a very early 'Cossor
237T', with an 11" tube bought by my grandfather in 1936.
Our favourite magazine of the time was the 'Practical Wireless',
which promptly published circuits for them. These were the very
basic unsophisticated ones .... just two valve units which you
plugged in between the arial lead and the arial input socket
on the TV set. You could either make it with it's own power supply,
or simply like I did with leads connected to the TV power supply
circuit. Or you could make it slightly more sophisticated with
a switch to change over betwen channels mounted on it. The first
one I built using a tobacco tin as the chassis. I then built
an improved model, the whole unit inside a small wooden box.
I made about half a dozen more of these units which I sold to
family and friends. |
