Subject: Re: [Amps] Filter
> Why bifilar???
Bifilar is the BEST choke to use in the filament circuit
for the following reasons:
1. The ferrite core raises the inductive reactance throughout
the HF region so that a minimum of wire is needed, keeping
filament voltage drops low.
2. The bifilar winding technique adds to the bandwidth of the choke
and assures that both filament terminals are at the same RF
I assumed that the application would be multi-band.
Two chokes could be used, but a lot of measurements
would be required to assure RF balance and bandwidth
requirements are met on all bands of interest. For example,
the old B&W FC-15 and FC-30 chokes do not have enough
reactance to cover 160 meters without mods.