You are right, Don. I think I wrote this before having read Hans' description of the method to obtain negative bias for 1N4007 in the manual. I guess I was exhausted by the building process and at the same time excited by how well it worked, so I stopped reading early :)
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Jindra
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On Fri, Jan 5, 2024 at 01:25 PM, Donald S Brant Jr wrote:
To keep it simple in an emergency situation you could just use outboard lowpass filters, swapping them manually as needed.? ?Put your highest-band filter in the box (always inline) and add lower-band ones when required.??
Instead of "...and a small SMPS giving ~ -300 volts to shut down 1N4007..."? ?you could just tap and rectify/voltage-double the RF output.? This would guarantee always having sufficient voltage to bias your diodes off.
73, Don N2VGU
