10GHz Circular polarization feed.
|NO TUNE Circular polarized dish feeds. Simple and easy to build feeder for
parabolic dishes that produce circular polarization within 0.5dB of circularity
without need for circularity calibration or adjustment.
The full article (as published in Dubus 33-2/2006)that includes the design for -metric size tubbing-
The additional plans for -imperial size tubbing schedule M-
and the plans for -imperial size tubbing schedule K-
On the left pictures of a prototype by Willi Bauer LX1DB
8.4GHz Circular polarization feed.
|NO TUNE Circular polarizer for dish feed.
The same general design as on the 10GHz example above but resized and optimized for 8.4GHz DSN rx using a specific waveguide diameter.
The waveguide diameter is: 26.0mm ID
The polarizer narrow section length is: 38.0mm
The narrow section separation is: 20.74mm internal distance
5.7GHz Circular polarization feed.
|NO TUNE Circular polarized dish feed. Using imperial tube sizes.|
Based on the 10GHz design but resized for 5.7GHz by VE1ALQ. - 5.7GHz with imperial size tubbing 39mm -
Choque/Rings - scalar feed calculator.
|Calculator for choque/ring dimensions.
This will help you to lay down all dimensions for the metal cut.
The size coefficients are editable and you may use whatever works best for you, either extracted (reverse engineered) from a well known feed or from specific simulation.
The coefficients on file are the original "Chapparal" parameters that work very well for dishes from 0.35 to 0.5 of F/D providing you move it forward or backward to adjust to your particular dish F/D.
You may use whatever waveguide diameter you like but don't deviate too much from the recommended waveguide size or design will fail to work.
Spreadsheet choque/ring calculator (Excel).
8.4 GHz Filter for DSN rx.
|A simple and easy to build filter for the 8.4GHz DSN band.
The diagram his here, "dsnxbandfilter_01.pdf"
On the left the measured performance of a filter with 16mm section separation
constructed and tested by Achim Vollhardt DH2VA based on the present design.
Any comments: Luis Cupido