I need a couple of 10 GHz bandpass filters for a down-converter to test my 10 GHz station and decided to build a evanescent mode circular waveguide filter. Evanescent mode filters work below waveguide cutoff frequency and in order to famliarise myself with their properties I started by modelling 2nd and 3rd order filters in CST Studio using designs by K5TRA and G4JNT. I also found a useful paper by Sam Mandev that runs through an example of determining distances between tuning screws.
I’ve spent the last few weeks putting together some equipment for a small 10GHz station using a mixture of pre-built and homemade modules. The block diagram shows the main components of the system.
The core of the system is a simple transverter designed by W1GHZ and a DF9NP PLL local oscillator board running at 9936MHz for the 432MHz IF. It’s probably overkill but I decided to repurpose the 4 channel Ardunio sequencer I was planning to use for the 2m EME station.
I recently salvaged a 1m offset dish that I’m planning to use on 10 GHz and need to build a suitable feed. To determine the dish properties and parameters for a suitable feedhorn I used the Wifi calculations option in Parabola Calculator version 2.0 (same code as W1GHZ’s HDL_ANT program).
Dual-mode feedhorns are frequently used for offset dishes because of their performance. The W2IMU Horn Design and Template option in HDL_ANT generated the following dimensions for a dish with a f/D = 0.
