[TowerTalk] velocity factor?

[Hans Hammarquist via TowerTalk]

Dear Ham Friends,


Recently I checked my feed lines to my tower. I have 1" hardlines, each 88 feet long. I checked the loss by measuring the SWR at various frequencies. (~0.8dB @150MHz)


I decided to also check the velocity factor. I was a little puzzled to get a factor of 0.8. Does that make sense? It's a foam filled coax. I expected something around 0.9. 


My resonances were 2.2, 6.767, 11.228, 15.673, 19.945, 24.335, resp. 28.53 MHz indication an electric 1/4 length of 33.73 meter or 110.67 feet. 88/110.67=0.795.


Any comments? Did I do anything wrong? The coax were open in the other end. Does that give me the wrong value?


73 de,


Hans - N2JFS