If I was going to do this, I would do the following:
1. Route all cables either down the center of the tower, or taped to one
leg. The cables should be routed such that they are always close to the
tower. I would think that the rotator loop would be small enough to be
acceptable. ALL cables should exit at the bottom of the tower.
2. Connect the shields of all cables at the bottom of the tower at the
same point where the vertical feedline shield connects. The radial
system should connect to this same point. Connection of the cable
shields to the tower, at the top, should not matter for this purpose.
3. Retract the SteppIR elements when using the tower as a vertical.
4. A good radial system is required. If you have a poor radial system,
you can have large current flow on the cables to the shack if they
happen to be an odd multiple of 1/4 wavelength. I would probably measure
this current to verify there is no problem. I am most worried about the
SteppIR controller box.
If all these were done, then I would feel comfortable about trying
this. Unfortunately, some of the above are impossible to do with a
crank-up, hence my decision to not implement this on my crank-up. You
should be able to do all of this on a fixed tower.
Jim Jarvis wrote:
>I've been contemplating using a 3 el steppIR as top loading on
>a 50' tower, to get on 80 & 160. The recent thread on this topic
>suggests that there have been no observed problems with control
>wiring. I'm concerned about that, however.
>For the folks who HAVE top loaded with steppIR's....were there
>ANY observed signs of current flowing in the motor control circuits?
>How did you route the cables?
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