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Old 21st Apr 2014, 9:53 am   #16
mole42uk
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Join Date: Aug 2010
Location: Resolven, Wales; and Bristol, England
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Default Re: Chinese valve FM receiver kit

Quote:
Originally Posted by boxdoctor View Post
Could the "4" be 4mm - the length the 5 turn coil should occupy? Tony
I've looked at the Chinese text using several different translate engines, and they are all pretty much of the opinion that it's '4 turns'. The line above always translates as '1mm wire 2 turns' and the symbol after the number 2 is the same as the symbol after the number 4 on the next line.

I have seen another photo of the kit where the 1mm copper wire was supplied coiled. It looks like it was wound on a former about 6.35mm diameter, the turns spaced about half a wire diameter apart.

I've been doing LC calculations to try and arrive at something which seems to work as a starting point for a 100Mc/s receiver but I'm not sure how to factor in the valve capacitance so I'm making rather wild guesses at the moment!

I think I'll probably just put it together with a best guess coil and see what frequency it tunes to.

Richard
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