I was looking for coax to replace the Quarter wave transformer in a commercial VHF Folded Dipole Antenna.
Calculations for coax required to match 300 ohms to 50 ohms revealed that a coax with an impedance of approx 120 ohms is required.
Z= √300 x 50 equals 122 ohms. RG63 has an impedance of 125 ohms and will be the obvious replacement.. but can you find a place to buy short lengths?
I couldn’t ….But in my search I found this
http://ve2azx.net/technical/CustomImpedanceCoax.pdf
Thanks VE2AZX and VE2BPD