Topband: 160m antenna help

[Wes Stewart]

Paul,

It would be nice to have a few more data points.  The two you supplied when 
mapped onto the Smith Chart don't give much evidence of a resonant point and the 
second one doesn't make sense.  With these limited data I suggest that your 
loading wire is too long. I would try shortening it to bring X down to zero.  
Alternatively, a series capacitor of 2800 pf would give you resonance at 1.825 
with SWR= 1.5.  By serendipity the SWR at 1.882 is also 1.5, but on the opposite 
(wrong) side of the Smith Chart

None of this improves the ground loss situation.

Bottom line, I suspect your data is flawed, which seems to be an epidemic with 
the numbers being posted lately from RigExpert equipment.  This is curious as I 
have an AA-55 which, except for tacking on one bogus data point in exported 
files, agrees closely with data taken on the same inverted L with my DG8SAQ 
VNWA. It also overlays modeled data quite nicely.

Wes  N7WS

On 9/21/2018 1:06 PM, Paul Mclaren wrote:
> Looking for the advice of the experienced hams for what if anything I
> should do to make my 160m inverted L more efficient.   Being realistic I am
> limited as I have a postage stamp garden so can't really lay more radials
> or change much beyond the inverted L.  I guess the question is would some
> sort of match at the base help?
>
> Antenna is inverted L with 18m vertical section
>
> Radials are approx 40 x 10m lengths and a layer of copper mesh out to about
> 5 metres from the base as well.
>
> Using my RigExpert AA30 analyser the readings are:
>
> Usual TX frequency:
>
> Freq 1825khz:    SWR: 2.6, R33ohm, X 31ohm, Z 44ohm, L: 2700nH
>
>
> Lowest SWR is:
>
> Freq 1882kHz:   SWR 1.7, R72.5ohm, X20.5ohm, Z77ohm, L: 1900nH
>
> I'll be honest and confess I don't fully understand how to best optimise
> the antenna and what "good" looks like particularly on the low bands.
>
> Help please and thanks in advance.
>
> Regards
>
> Paul MM0ZBH
>
> The antenna works but no
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