[Elecraft] OT Wet 450 ohm ladder line

[Wes Stewart]

Indeed I did.  However, a few more words.  The experiments that I ran were by necessity somewhat contrived and weren't very repeatable.  What I was attempting to show was that there can be a detrimental effect when these lines become moist.  Roy Lewallen, W7EL, has also written about this.

The paper was a result of my reading "The Lure of the Ladder Line" (ref 1 in the paper) and saying to myself, "Self, this looks too good to be true." When something looks this way, it usually is.

Something mentioned, but discussed at much greater length in correspondence with Dean Straw, was the total lack of concern about balun and tuner losses at that time.  I showed him by example that the ever popular tee-network used in many tuners that has three adjustable elements can be misadjusted so that it provides a match to the source but has extraordinarily high insertion loss.  There are in effect an infinite number of wrong combinations and one that is correct.

It wasn't long after this correspondence that articles by Frank Witt appeared on evaluating antenna tuners and today it is almost routine to see mention of tuner losses and possible misadjustment in papers on the subject.  Whether this is coincidental or not is left to the reader.

But when I see threads about, for example 43-foot verticals being "matched" on 160-meters with a built-in tuner or a little automatic box at the base of the antenna, or recommendations to use ladder line to feed ground-mounted verticals I really have to bite my tongue.

Wes  N7WS

--- On Tue, 3/17/09, Bob Cunnings <bob.cunnings at gmail.com> wrote:

> From: Bob Cunnings <bob.cunnings at gmail.com>
> Subject: Re: [Elecraft] OT Wet 450 ohm ladder line
> To: "Elecraft Discussion List" <elecraft at mailman.qth.net>
> Date: Tuesday, March 17, 2009, 8:35 AM
> N7WS took a look at precisely this subject:
> 
> http://users.triconet.org/wesandlinda/ladder_line.pdf
> 
> BTW I use 450 ohm ladder line here to feed a c.f. vertical
> wire
> doublet for multi-band operation using a balanced tuner -
> at least
> when dry, it's the best option to keep loss low and for
> mechanical
> reasons too.
> 
> Bob NW8L
> 
> 
> 
> On Tue, Mar 17, 2009 at 8:04 AM, Geoffrey Mackenzie-Kennedy
> <gm4esd at btinternet.com> wrote:
> > Sorry for an off-topic question. Does anyone have any
> information about the
> > dry vs wet characteristics of "450 ohm"
> ladder line? I have never used this
> > type of line, but I might have to use it for
> "mechanical" reasons to feed
> > another antenna now being built. I am told that its
> characteristics change
> > when wet from rain, but which characteristics change
> and by how much at HF.
> > A remote ATU to compensate is not to be used with this
> particular antenna /
> > feeder.
> >
> > Any comment would be appreciated.
> >
> > 73,
> >
> > Geoff
> > GM4ESD
> >
> >
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