For reasons that will become clear in a future post or series of posts, we’ve been busy lately—don’t worry, it’s a good thing. I did manage to sneak away from my regular (usually desk-bound analysis) work into the lab and tune-up an eBay-special cavity filter for 903 MHz with our new network analyzer. It’s really amazing how you can dial these things in if you have the right tools. This one is a 3-cavity filter about 10x8x3 cm.
Passband insertion loss is about 1.2 dB. Harmonic rejection at 1.8 GHz is 70 dB down. I’ll take it.
I also have some eBay-special helical filters that were advertised to be for 432 MHz. So, I need to cobble up some carrier boards to try them out. Another day, another project.