Topband: Inverted L improvements - Part 3 (now with data)

[Wes]

As always Frank makes good points.  In my case my one lowly tower is 90 feet 
from the inverted-L and in fact supports the horizontal wire.  It's much too 
short to exhibit any resonance near topband, but I have observed an interesting 
effect.

The tower also supports a pair of inverted-vee dipoles, fed in parallel, one for 
40 the other for 80.  With a vector analyzer I can sweep the inverted-L and 
looking at the trace on a Smith chart and see a little discontinuity around 1.8 
MHz that goes away if I lower the vee to the ground or terminate the shack end 
of the coax.  It's a really minor effect and apparent;y not even an intellectual 
curiosity as I've not bothered to investigate it further.  It does point out 
however, that "detuning" by leaving things open circuit isn't necessarily the 
way to go.

Wes  N7WS

On 1/23/2019 3:45 PM, donovanf at starpower.net wrote:
> Hi Todd,
>
>
> In my opinion you're giving up too easily on your tall antenna.
> I suggest that you focus more on evaluating its on-the-air performance ,
> and not focus as intently its feed point impedance and VSWR bandwidth.
>
>
> I hope you've been measuring the impedance and bandwidth
> of your tall antenna with your 43 foot vertical disconnecte d from
> its both its 160 meter matching components and its feed line,
> otherwise it will interact very strongly with your tall antenna.
>
>
> Very few of us have the opportunity to install our 160 meter
> antennas a thousand feet or more from other antennas and tall
> towers. As a result, the feed point impedance and other characteristics
> of our antennas can't possibly match theoretical values. Nonetheless,
> we enjoy our imperfect antennas with their imperfect soil conditions.
>
>
> I hope you'll enjoy yours too.
>
>
> 73
> Frank
> W3LPL
>