[CQ-Contest] W3NQN Bandpass Filters (Was: Re: 419 band passfilters..

[Marijan Miletic', S56A]

W0UN wrote:

I am sorry to disagree with you in the extreme.  I did much of the original
testing (along with K3LR) on the W3NQN filters as well as additional testing
on ICE and Dunestar filters, and the W3NQN filters are DRAMATICALLY better.

Which is what one would expect since the W3NQN filters are top-coupled with
an additional resonant circuit rather than just using a capacitor as 
is done in the
ICE and Dunestar filters.

There are 5 years old DL2NBU filters measurement data available in German at:

http://www.bavarian-contest-club.de/projects/bandpassfilter/100W-BP.pdf

Not much drama in there as one would expect from W3NQN DIRECTLY coupled fiters with additional tapped parallel L/C stubs.  Dunestar is top-coupled in optimal configuration for 50 Ohms.  ICE the elegant simplicity with 21/28 MHz problems.

My measuring instruments are better than your$ :-)

73 de Mario, S56A, N1YU