[WVARC] Band Pass Filters

Tree tree at kkn.net
Tue May 27 14:27:19 CDT 2003

On Tue, May 27, 2003 at 11:05:41AM -0700, Robert A. Wilson wrote:

> Bandpass filters are definitely a "must" for Field Day, 
> though if your antennas are too close, and your receivers 
> are too poor, bandpass filters alone may not be enough.  
> You'll have to build tuned stubs.
> The current "state of the art" in bandpass filters are the 
> W3NQN design.  See 
> http://www.arraysolutions.com/Products/wx0bbpf6.htm.

Those are FB - but can add up to lots of $$$.

Typically, I have been able to deal with most of my problems with quarter
wave stubs.  You might need a 20 meter trap on the 40 meter station.  If 
built out of good coax, you can get a 20 db null.  Use one of those neat
SWR analyzers to tune them.

Here is a good article on tuning:


And here is another article that might be of interest:



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