For my SatNOGS station I have built a lightweight 5 element UHF Yagi of DK7ZB model according to this 50 ohm version.
Some construction notes:
Use a good coax connection for the driven dipole. Here I use an old 10 mm dipole from an LFA loop antenna:
I’m using 32 mm PVC pipe and pipe holders for the elements that are 6 mm alu pipes/tubes. The PVC pipe is the 1,8 mm version for water, not the version used for electrical installation.
Finished antenna below. It gives a very good SWR, under 1.3:1 for 10 MHz bandwidth 430 – 440 MHz.