[TowerTalk] coax stubs /bandpass filter

[jimlux]

k2qmf at juno.com wrote:
> Dave,
> 
> Can you design a lumped element filter that
> can handle 1.5 KW????
> 

Of course he can.  There are lumped element filters handling gigawatts 
to suppress the harmonics on the output of the Sylmar HV converter station.

Consider if you didn't want to get fancy, and just have a series LC trap 
to ground to duplicate the stub.

The filter is going to "short" the transmission line to ground at the 
"evil" frequencies.  It's going to (hopefully) look like an open circuit 
at the carrier frequency where you've got the 1.5kW.  So it's mostly a 
matter of having enough voltage rating on the capacitor.

Even if you have a multisection BPF, it's a matter of voltage and 
current ratings for the components.  In this application, you're 
probably not looking for a high Q in the sections, so the circulating 
energy (e.g. resonant rise) is going to be fairly small.


However, this *is* one advantage of stubs.. They're cheap, so if you 
screw up, replacing is easy.