I designed my uhf cross yagis to have 2x25ohm impedance, used 2 parallel 50hm coax to phase them, and also 2 parallel 50ohm coax(Quarter wave transformer) to convert the 12.5ohm impedance to 50 ohm. It's much simpler to make and got perfect vswr without any tuning.
Interesting approach using the coax in parallel to get the desired characteristic impedance of 25 ohms; thanks for sharing. I think most of my difficulty tuning comes from using ring lugs as connections between coax pieces as discussed more in the 2nd video. Had I designed a PCB with connectors, I imagine I would have had a better time with that part. Commercial antennas seem to like the approach of making nice connections via PCB and RF connectors, so if I design something else I may try that. I like your idea that only requires 50 ohm coax though.
@@RobertResearchRadios I seen your calibration approach with the ring lugs, have you measured them separately? It can be interesting to measure both connections in symmetric mode with baluns. I used rg174u coax and soldered the conductors directly with a small footprint ~5mm. Here's a picture from one of my antennas: pasteboard.co/JH1lFOc.jpg
@@peterkis4798 I made no attempt to measure the ring lugs. I'd consider doing something to characterize them if I ever revisit connecting coax in that way. Your antenna looks great, and I really like that your solution doesn't have matching stubs and instead only uses quarter wave transformers. If I do something like this again, I will likely be doing the phasing/matching harness your way and designing to 25 ohms input impedance for each yagi.
