It doesn't. I've had that proven to me with my recent install. No RF choke on the feedline = noise on computer speakers which changes when I pick up the mike. RF choke = no noise.
Marconi, please be careful about what you read on Cebiks site. Cebik's death was untimely, and unfortunately it's now not possible to question him or challenge his writings. There are a number of issues on which his lack of any formal RF engineering training have led him to make fundamental mistakes, but Jack Stone, who runs Antennex magazine and the Cebik web site, has taken the decision he wants to leave everything just as it is, error or not.
There are a few times he has made limited measurements and then jumped to a conclusion which isn't true.
I might agree M0GVZ. Any antenna can act badly with common mode currents (CMC).
I've read W8JI, and he sometimes refers to this as a "worst case scenario." I take that to mean when CMC is excessive, and maybe causing RFI problems and/or pattern skewing.
IMO, my modeling, and my personal experiences suggest to me that antenna construction, height, and length of feed line can have a lot to do with how much Common Mode Currents we're likely to see...presenting problems. Of course a suitable feed line choking device can help in such situations. I think that sometimes a modest change in antenna height can help mitigate such problems. I've also experienced a reduction of RFI at my own station, just by running my feed line all the way to the ground, and then on the ground to my station. The Earth has a way of absorbing such currents, but this doesn't change the fact that the line down to Earth
is still radiating excessive currents for others nearby or skewing your antenna pattern.
For me, CMC are only a problem when the magnitude is enough to cause RIF and/or skewing of the antenna pattern...and there may be a number of ways to help fix that.
This thread on the best angle for an Imax GPK was just a fluke with me. It happened when I read a post on Cooper's about an old report where Tech 833, once made a claim that 30* degree angle radials would preform better than the stock radial angle on the GPK of about 40* - 45* degrees.
For years I thought he meant to angle the radials further down, and I disagreed, thinking the theory of 45* degrees was probably the best angle.
When I modeled this idea at 40' feet high, I noticed he was right, but that the angle went up higher toward horizontal, and not down lower. I then fixed the GPK to horizontal, and I noticed the benefit increased some more. So, now I think the Imax works better with the GPK radials 30* to horizontal, and that 72" radials work a bit better than full length 1/4 wave radials.
At the time, I didn't set the models at different heights, but after doing that I noticed this affect is not linear up to about 40' feet high. After going higher it seems the radial angle doesn't seem to make as much difference.
I can't think of anything specific in dispute regarding what Cebik has said or written right here and now, but I'm sure he had plenty of arguments and dissenters over his years. That is likely the way life is...among a group of highly technical folks in the world he lived in.
