Original poster: "Gerry Reynolds" <gerryreynolds@xxxxxxxxxxxxx>
Hi Bart,
This is very believable. The Medhurst correction was around 3
(iirc). My Q calculation without proximity effects was about 600 so
that would make the "real" Q about 200. I will measure the Q soon
for closure.
It sounds like having wire diameter >= 5sd isn't important for good
Q (my coil has diam = 2.5 sd). Maybe we ought to replace the wire
size recommendation in JavaTC with the Fraga resistance and Q
predictions and leave it to the designer to choose the best tradeoffs.
Gerry R
Original poster: "Barton B. Anderson" <bartb@xxxxxxxxxxxxxxxx>
Hi Gerry,
Fraga is looking "real". Have you checked your coils predictions
with Fraga? I'm showing a Q of 207. My high turn 8.5" coil is
showing a Q of 155. If memory serves, that's close to measurement.
I'm trying to dig up my misc. Q measurements (scattered via emails,
hand written notes, etc.). Anyway, could only get on the internet
for a second, but wanted to mention that. I still need to do a lot
of verification with the equation and values as I did it rather
quickly. But, it certainly ballparked well.
Take care,
Bart
Tesla list wrote:
Original poster: "Gerry Reynolds" <gerryreynolds@xxxxxxxxxxxxx>
Hi Bart,
After looking at the Fraga equation again, it does look and L and
C directly. It uses the product of L and C by virtue of the
frequency needed for skin depth. Your Les and Ces are the
frequency determining equivalents that are suppose to be accurate to like 1%.
How accurate are Medhurst C and Wheeler L in predicting the
correct frequency. I doubt there will be any significant
difference especially since f gets sqrt'd which will cut the error in half.
Gerry R.
Original poster: "Barton B. Anderson" <bartb@xxxxxxxxxxxxxxxx>
Also, with Fraga, Gary used Medhurst C and L. I wonder how it
plays out with Ces and Les in place of Medhurst? As a matter of
fact, I wonder how well a lumped effective L and C would work
with all the equations? They probably won't change a great deal
(but, I haven't looked at that).
Take care,
Bart