I should like to know the velocity factors which occur on various
twin-balanced transmission lines. We have -

Open wire lines with infrequently spaced, flimsey spacers.

450-ohm ladder lines of various sorts.

300-ohm lines spaced with a thin continuous web.

130-ohm lines with two insulated wires stuck close together like twin
speaker cable.

75-ohm lines embedded in a solid eliptical-shaped polythene.

I daresay some of you have made measurements at one time or another.
The more data received the better. I can then take averages.

Thank you.
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Reg, G4FGQ