[TowerTalk] measuring/cutting CATV cable

[w8ji.tom]

Hi Pete,

> Doesn't this calculation assume 1:1 (50 ohm) SWR at the various antenna
> feedpoints? 

Yes

 The picture gets more complex with real-world antennas and
> some mix of R and J. 

Yes it does, but it also gets unpredictable. SWR bandwidth might get
better, worse, or stay the same. Center frequencies might change. The
combinations are endless.  

 Also, for the casual reader, this "electrical length"
> must be multiplied by the velocity factor to get the physical length of
the
> cable.  

Of course.

> Incidentally, I was warned by some local experts to expect some fairly
> severe SWR excursions on 10 meters, since I wasn't terminating the
feedline
> in pure 50 ohms.  

You should have the least bandwidth because the cable is so many 1/2 waves
long.
You also should have the least highest SWR at peak SWR frequencies for a
given termination, because cable losses go up.

73 Tom

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