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Re: Re: MicroWave: 1296 Transverter design advice



Here's another little bit of information from our San Diego Microwave
Group.  For filters ahead of our mixers and power amplifiers we have had
great experience with the Evanescent mode filters (waveguide below cutoff).
These are extremely simple, always work and can be constructed for the
bandwidth required. They consist of a short section of waveguide or
rectangular tubing (typically about 3 inches of  WR-75 or WR-90) with a
tuning screw or Johanson style microwave capacitor in the middle of the
broad side, and two connectors spaced about .7 " on each side of the center
with the center oin protruding through and soldered to the far side of the
waveguide. Depending upon the tuning screw/capacitor these filters will
tune down to 900mMHz and up through 5. 7 GHz & have About 2-3 db loss. I
have made filters for 24 GHz using brass hobby tubing. The filter original
article I  use is by Reed Fisher W2CQH.
 - Kerry N6IZW -

********************
Kerry Banke
kbanke@qualcomm.com
Qualcomm Inc.
Voice - (619) 658-3318
FAX - (619) 651-1988
Pager (text) kbanke@pager@qualcomm.com
pager - 619-636-0273
Office Location R-202D

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