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Old 10th Jan 2006, 7:42 pm   #19
Neil Purling
Join Date: Jul 2005
Location: Hull, East Yorkshire, UK.
Posts: 1,968
Default Re: My attempt at a TRF

in adibrook's TRF the bogroll tube is horizontally mounted onto the chassis.
Maybe the close proximity of all that metal will have a negative influence on the coil.
I intend to mount mine vertically.
In mine the design is the sketch by heatercathodeshort.
I had varnished a bogroll to stiffen it and I have wound 100 turns for the aerial input and given it a dose of varnish to fix the winding in place.
I place a sleeve of paper onto that and wind 65 turns, tapped at 5 turns.
The 'secondary' of 65 turns is the reaction and tuning coil. It is to be movable over the primary for best stability and volume balance.
Give heatercathodeshort's coil design a try and see if it improves your set.
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