Hey guys
I know this is somewhat off-topic but I felt this is the best place other than maybe a new thread to discuss this.
I finally got around to doing a little microwave experimentation. However, since I never jumped on some crappy but cheap-ish ebay WR42 horns for my coax to waveguide adapters when I had the chance, and been somewhat reluctant to 3d print (and paint) some, I instead opted for a couple of ~10GHz gunnplexers. In my recent experimentation, I used one as a transmitter, and then measured the output of the detector diode on the other which is thus used as the receiver.
As you can hopefully see in the attached image, I printed a mount for them that allows me to adjust the angle on the longitudinal axis from 0 to +/-90 degrees in 22.5 degree increments, with the center of rotation being the center of the gunnplexer.
So in my little experiment, I was getting some baseline voltage reading at the detector when both tx and rx were oriented at the same angle (same polarization), and then measuring the decrease in voltage as they're rotated relative to one another. I wanted to compare and contrast this with what polarizer experiments seem to show.
At 22.5 degree relative angle, the received voltage is 75% of baseline. This makes sense from a trigonometry standpoint. At 45 degrees however, it drops to 25%, which is not expected. These results are consistent regardless of distance between tx and rx, and the way I orient them to get the relative angle differences. Right now I'm thinking these unexpected results are due to my hardware. Soon I'll be modifying some satellite LNBs, specifically because they use round waveguides/horns, to perform the experiment with. However, I was also hoping someone here could duplicate the experiment on their hardware and post their results if they could find the time. Any of you guys willing to do that?