[TowerTalk] Loss in CCS conductors at low freqs (was Voltage Breakdown For Enameled Wire)

jimlux jimlux at earthlink.net
Mon Jan 29 18:08:02 EST 2018

On 1/29/18 2:36 PM, Dan Maguire wrote:
> Jim Brown wrote:
>>>> ,,, but the steel causes losses to increase at lower frequencies as compared to copper or silver coated copper.
> It just so happens that I've been working with a fellow who has been
> measuring loss in Wireman 551 (aka JSC 1318) window line.  The
> conductors are solid #18 CCS.  Using a DG8SAQ VNWA in 1-port mode, he
> made sweeps from 0.25 to 30 MHz with the DUT terminated first with an
> Open and then with a Short.  There was a CMC choke (with
> characteristics unknown to me) on the test fixture cable and OSL
> calibration was done at the end of that cable using 400 ohms as the
> load, not the usual 50 ohm OSL load.
> The OC/SC data was then manipulated using a variation on Chipman
> equations 7.28 and 7.29 with the following results:
> https://postimg.org/image/5mn0wh6bp/
> The way I am interpreting the rise in loss at lower frequencies is due
> to current flowing in the steel rather than the copper.  I would very
> much appreciate hearing comments on the shape of that curve from folks
> more knowledgeable than me.  (Of which there are many!)
> BTW, here's a good N6LF article on the subject:
> http://rudys.typepad.com/ant/files/antenna_wire_conductor.pdf
> Dan, AC6LA

you probably want to plot loss in dB on a linear scale.

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