And this is what the antennaware reflector is for. Great discussion, guys!
73, Pete N4ZR
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On 3/5/2019 8:26 PM, Guy Olinger K2AV wrote:
At this point in the experiment, you wind it, put it on the analyzer, read
it, use it. It will show the separate R and X. Measure, measure, measure
and type the facts into the EZNEC loads. The more stuff in the model is
hard fact, the more accurate the model is going to be. Those values of
inductive reactance make for really big coils, like really big.
Be sure and come back with your results.
73, Guy
On Tue, Mar 5, 2019 at 6:35 PM Gedas <w8bya@mchsi.com> wrote:
Hi Guy. ok now that I have an initial model built correctly I can
proceed with my experimentation. You had asked "The next question, what
are you trying to accomplish with this? You wanting to put this in the
air? Coming up with the coils will be interesting. 1265 ohms X is a lot
of wire turns." The simple answer is pure fun mixed with a little science.
In reality I have the property to make a full sized inv-v type dipole
for this frequency and suspend it from 85' but I realize even this would
be a pure cloud warmer as the antenna is kissing the ground. Your
analogy of the 40m antenna is spot on. But I could eliminate the
inductors completely if I wanted to. I am doing this out of curiosity. I
like to see how reality differs from different models using different
models.
Ok, so getting back to this antenna.....I already have the 160m dipole
up in the air operating and it is purely curiosity driving me to try
this antenna. I know with 100% certainty that I will be going with a
vertical radiator fed against some sort of ground but given I like to
play with antennas, in particular model them, build them, and actually
put them on the air this is only for my personal gratification and my
own curiosity.
I should note that the values of "R" for the inductors in my model were
100% guesses on my part before I did any calculations. That was going to
be my next question to you. I was wondering if a half-way accurate
number for the resistive component could be obtained before the
inductors built and measured. I do own a VNA (actually an ENA) from
Agilent that may help me get an accurate number but I am wondering how
accurate the number would be based on the predicted Q from some of the
better Inductor Calculator programs out there.
I have just run several calculations to make a large inductor using a
4.5" dia form and if one can trust the predicted Q at this frequency to
be around 400 is it safe to initially use a value of 3.2 ohms for R?
I will of course measure it with the VNA to see how close this number is
but is this the value for R that I would use (R derived from XL/Q) ?
Gedas, W8BYA
Gallery at http://w8bya.com
Light travels faster than sound....
This is why some people appear bright until you hear them speak.
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