> Mike said:
>
> >I would use bandpass coax stubs to keep harmonics down with
> >only an "L"network.
>
> For some reason (advancing age?) I forgot to mention the 'half wave
> filter', popular back in the early days of dealing with TVI. Being an
> electrical half wave, it reproduces the load impedance back at the
> input terminals, and by using coax stubs to provide the capacitors,
> can be made to handle high power.
Before using coaxial stubs, you might check the impedances by
measuring them or running numbers on them, and make sure the
system will tolerate the loss in Q.
Coaxial stubs (and capacitors made from coaxial cables fed at one
end) have very low Q compared to other components, because the
cable is nearly perfectly mismatched. While they sometimes are
useful, their inherent low Q when compared to other lumped
components does limit the obtainable impedances.
73, Tom W8JI
W8JI@contesting.com
--
FAQ on WWW: http://www.contesting.com/FAQ/amps
Submissions: amps@contesting.com
Administrative requests: amps-REQUEST@contesting.com
Problems: owner-amps@contesting.com
|