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Old 30th Jun 2017, 11:00 pm   #115
FERNSEH
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Join Date: Mar 2005
Location: Gateshead, Tyne and Wear, UK.
Posts: 7,444
Default Re: HMV 1804 Television.

The first attachment shows the very crudely made aerial input coil. There is no proper input transformer to match the low impedance aerial to the grid of the first valve. As things are at the moment that's probably just as well because I'm having difficulties taming this high gain receiver. A correctly matched and tuned input transformer would increase the gain of this receiver even further.
The second attachment shows the very "soot and whitewash" picture displayed with both the contrast and sensitivity controls turned well down. To reduce the signal level even further an 18db attenuator is inserted in series with the aerial input.
The CRT is excellent, it's even becoming brighter with use. The burn mark is less noticeable.

DFWB.
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