Propagation Velocity

[Coyoteman]

Have been looking into getting some coax RG 8X or RG213 and I noticed a number. Given to Propagation Velocity in %
Rg8x was 82% and rg213 was 66%. In my thinking I would think the higher the percentage the better because if you look up the definition of propagation velocity which is how fast it travels from point a to point B. So I'm curious if any if you guys have any knowledge or input on this? and why does RG8 have a higher number than RG213. I found this info on website that sells coax and other electrical parts. I don't think I can give the website but if I can let me know and I'll put it down so you guys can take a look at it and see.

[The DB]

Propagation velocity, more commonly known as the velocity factor, does play a part, but its not the only thing that has an effect. By itself, the velocity factor really doesn't tell you much, it is simply one of many variables that combine to make the coax what it is. Some people will tell you that the higher velocity factor means less losses because the signal is not in the coax as long, however, of your two examples, RG-213 will have less losses than the RG-8x, even with its lower velocity factor.

The only time you should have to worry about the velocity factor is in the rare event that you need a specific length of coax, which happens far less often than some people are willing to believe. You multiply the physical length by the velocity factor to get the electrical length.


The DB

[MDYoungblood]

The velocity factor of your coax only really comes into play when you are dealing with VHF and UHF communications. The spec is there because these coaxes are used in those applications.

3's

Greg