[TowerTalk] EZNEC/AutoEZ Shunt Coil Modelling for Yagis

[David Needham]

Thank you to all that replied. They have all been most helpful. Dan
McGuire, AC6LA also saw the post and made some very elegant upgrades to my
model. I will post a summary of what I have learned once I have implemented
all the changes.

In the "you never know what will happen" category, a ham friend I hadn't
heard from in over 40 years saw my post and listing of previous callsigns
and reached out to me. It will be awesome to reconnect with him.

Thank you!
David Needham, AA4VT (formerly K4AJA and K8AJA)
--------------
On 3/8/2021, 22:59, Wes wrote:
You should probably be using parallel RLC loads in parallel with the
source.? R
+ jX loads are not frequency sensitive, you get the same R and X at every
frequency.

In the EZNEC Help file see "The RLC Loads Window" page and the "Load
Connections" page.

Wes? N7WS


On 3/8/2021 2:00 PM, David Needham wrote:
> I have heard we have several modelling experts out there. I have purchased
> both EZNEC+ and AutoEZ and adapted a 20-15-10m Triband design for separate
> feedlines. I am matching the impedance with shunt coils across the driven
> elements. I built the coils using a coil calculator then tweaked them to
> the correct value with my Rig Expert analyzer. I didn't get anywhere near
> the expected result of the model with the real antenna.
>
> I modeled the shunt coils as R+jX loads connected in parallel to the
center
> of each driven element, but am guessing that wasn't the right way to go?
Is
> anyone able to point me in the right direction? I am trying to get this
> Yagi ready to go for the CQWW WPX contest at the end of this month.
>
> If you reply to me off list,I will send the AutoEZ/NEC file I built for
the
> model.

-- 
Thank you!
David Needham, AA4VT (formerly K4AJA and K8AJA)