Hi Don:
At this point I am not trying to equate simulation with real world
performance. Since I am not in the actual building phase just yet, the
Only thing I am trying to accomplish is to understand some of the tradeoffs
In the design of the phasors and matching network. Especially being able
To switch directions without a totally complicated set of matching networks.
The complex math and physics I can handle. It is the actual implementation
in a simulated world
For now that I am trying to address. I know that there will be a lot of
variables when I get to the actual site build. Luckily, or not, I do have
The required test equipment and patients to accomplish the required
engineering to get the array working.
Karin K3UU
-----Original Message-----
From: donroden@hiwaay.net [mailto:donroden@hiwaay.net]
Sent: Tuesday, November 01, 2016 2:35 PM
To: Karin Johnson
Subject: Re: [Antennaware] Phased Verticals
Welcome to the world of "Antenna Snake-Oil".
I have been in AM Broadcast radio for 40 years, and I was always
fortunate to have had a large budget for installing 120 full length
radials and 120 half-sized radials and usually in great soil
conductivity like swamps and wet bogs.
Even then, the formulas only came " close ".
So, without a flat piece of copper out to several wavelengths, real
world values will float around as the seasons change
Don W4DNR
Quoting Karin Johnson <karinann@tampabay.rr.com>:
> Well some progress has been made. I've ordered Low Band DXing to obtain
the
>
>
> Complete software CD so I can be a bit more efficient in my modeling
> efforts.
>
> I did complete my own spreadsheet to compute the mutual and driving point
>
> Impedances for a two element setup. I agrees with some of the ON4UN
>
> Spreadsheets that someone else has sent to me. So in my own mind I am
> getting
>
> To feel comfortable with understanding some of the physics behind phased
>
> Vertical systems. I do have advanced degrees in Math and Engineering so
>
> I'm no novice to complex numbers and issues around designing matching
> networks.
>
> The esoteric things like inductive and capacitive voltage dividers used in
> Phasor
>
> Networks is starting to make some sense now.
>
> What sort of has me baffled a bit is that looking at what Array Solutions
> has
>
> Available for a triangle array Phasor, doesn't seem to take into account
the
>
> Large difference in driving point impedances when switching directions.
The
>
>
> Array Solutions triangle box only works for 50 ohm loads at each port to
> guarantee
>
> the phases required at each antenna port. In other words it only does the
> phasor
>
> portion of the antenna system, not the complex impedance matching required
> at
>
> each antenna. The matching networks required at each antenna will
> contribute
>
> a phase shift of the driving current.
>
> For example for a triangle array of three 40M verticals spaced 0.29
> wavelengths,
>
> The driving point impedance calculated for direction 1 is:
>
> EL1 = 60.16 + 12.29
>
> EL2 = 16.42 - 43.29
>
> EL3 = 16.42 - 43.29
>
> Elements 2 and 3 are driven with a current magnitude of 0.5 angle of +90,
> Element
>
> 1 is driven with a current magnitude of 1 angle of 0. The far field plot
is
> in the
>
> Direction (or off the end) of the Element 1 direction. Elements 2 and 3
are
> behind
>
> Element 1.
>
> If one were to switch directions and there were matching networks at the
> base of
>
> Each vertical the complete matching network would have to be changed.
>
> I can't seem to get my head around a solution just yet. More research on
my
> part
>
> Is certainly required.
>
> This is a fun project for me so far.
>
> Eventually some time early next year I like to get started building this
> array.
>
> I know what most folks might say just put it up and have fun but I'm the
> type
>
> Of person to know the physics and math behind what works and what doesn't
> work.
>
>
>
> Regards,
>
>
>
> Karin K3UU
>
> _______________________________________________
> Antennaware mailing list
> Antennaware@contesting.com
> http://lists.contesting.com/mailman/listinfo/antennaware
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