The blue RV1 is the bias set for the IRF. The drive is set by the preset
R136 before the driver transistor.
At 17/12/2016, you wrote:
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Another nice video Peter.? Thanks.?? In your comment on
the pot in the RF amp stage, I think you made the same mistake that I
did: assuming that that pot was for setting the IRF-510 bias (as was the
case in all earlier BITX circuits).?? But take a look at the
schematic:? The bias is set by a regulator chip (smart move Farhan!)
and that pot just sets the RF level going to the driver (thus allowing
VK3YE to go QRPpppppppppppp from the beach!). 73? Bill
On Saturday, December 17, 2016 1:59
AM, "parkerp@... [BITX20]"
wrote:
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There's not much in it that most people here won't already know, but a
video review I've just uploaded could still be of interest.
Raj vu2zap