[Elecraft] AX1 Loaded Whip Antenna - Elevation and Counterpoise?

[Mark Goldberg]

Yeah, i didn't catch that he was going to use the internal tuner and just
forgo the external one at the other end of the coax.

In that case, I agree with Dave.

73,

Mark
W7MLG


On Wed, Aug 7, 2019 at 6:19 PM Wes <wes_n7ws at triconet.org> wrote:

> I haven't been following this thread closely but I think Dave makes good
> points.  As to the final fold-back, if I waded through this correctly, I
> understand that the OP has the built-in tuner in his KX2.  That solves
> that issue.
>
> BTW, SWR = 15:1 is a return loss of about 1.1 dB, not 3 dB.
>
> Wes  N7WS
>
>
> On 8/7/2019 5:29 PM, Mark Goldberg wrote:
> > You need to take into account the radio finals. When the SWR is high, My
> > KX3 cuts back because it gets too much reflected power. I expect the KX3,
> > and in fact any other radio or amplifier is similar. 15:1 is about half
> the
> > power coming back.
> >
> > Regards,
> >
> > Mark
> > W7MLG
> >
> >
> > On Wed, Aug 7, 2019 at 5:14 PM David Gilbert <xdavid at cis-broadband.com>
> > wrote:
> >
> >> Rather little of this discussion makes sense to me.
> >>
> >> Let's look at this realistically:
> >>
> >> 1.  The antenna tuner in the KX2 is rated to be good up to 10:1 SWR.
> >> Let's assume it's good to 15:1.
> >>
> >> 2.  Let's assume you're using a decent cable for portable operation like
> >> RG-8X.
> >>
> >> 3.  Let's assume that the length of your coax when operating portable is
> >> not much more than 30 feet long.
> >>
> >> 4.  Let's assume under the current solar flux conditions you're spending
> >> most of your time on 20m or lower in frequency.
> >>
> >> 30 feet of RG-8X has a loss of 0.4 db or less for that length at those
> >> frequencies, and per the charts in the link below the additional loss
> >> due to a 15:1 SWR is no more than 2 dB.
> >>
> >> http://www.astrosurf.com/luxorion/qsl-transmission-line2.htm
> >>
> >> Maybe it's just me, but I don't think that justifies dragging along a
> >> remote tuner.  You could recover a heck of a lot more dB by simply
> >> bringing a somewhat larger portable antenna.
> >>
> >> 73,
> >> Dave   AB7E
> >>
>
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