I think you may be referring to VSWR.
There are fairly sharp null points of voltage standing on a poorly matched transmission line.
But the current standing at the same point is opposite: it peaks at the voltage null point.
Maybe its better not to think of antenna/coax mismatch that way.
I think it better to think of it in the context of return loss, which is specified in dB.
For example: an SWR of 3 is same as a 6dB return loss, meaning that the power reflected back to transmitter is 6dB down from the transmitter "forward" output power. Another swr, such as 1.2 is a 20dB return loss.
Return loss does not change depending on coax length, except for the coax insertion loss which is small for CB frequencies.
PS: an SWR of 1 is actually physically impossible. nothing in this world is perfect.