VF Wireman 300 ohm window line

[K6JEK]

Anyone  know the velocity factor for Wireman 562 300 ohm window line? The Wireman website says .91 but I vaguely remember measuring a lower figure. Steve G3TXQ (SK) measured  similar looking line at .82. But similar isn’t the same. This window line is #18, stranded copper-clad, poly-clad insulation.

Here Steve’s analysis of water on window line that includes the VF

http://karinya.net/g3txq/wet_ll/

[KD6VXI]

Got a vna or swr analyzer?  If so, sweep it and compare 1/2 wave shorted readings to calculated free space readings.

--Shane
KD6VXI

[K6JEK]

Got a vna or swr analyzer?  If so, sweep it and compare 1/2 wave shorted readings to calculated free space readings.

--Shane
KD6VXI

Yes. I already connected it to the antenna and wish I'd done that first. It would be a bit of a pain to chop it off, make the measurement, and put it back. That's why I was hoping someone just knew.

I'll be doing some cut and try anyway because things have a way of turning out a little different from the calculations. I'll start with .91 VF and slice my way back if necessary.

[KD6VXI]

Ahh, I didn't realize you had it installed already.

I'd say take a 5 foot section and see if you can figure it out from there, but that may be counterintuitive as well....   VF seemingly changes with frequency, at least on coaxial cable.

--Shane
KD6VXI

[WU2D]

The regular old stuff as low as 80 and the windowed stuff will get closer to 90. They advertise the DX Engineering 300 Ohm windowed stuff at 88.