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Hello again Mark.

On Sun, Oct 13, 2024 at 01:27 PM, Augie "Gus" Hansen wrote:

1) The item Jim called Loop Diameter is actually the Loop Length.

?Hi Gus,

?

I mistakenly said "Diameter" when I meant perimeter (I did enter the correct perimeter in the calculator).

Yes, I like the use of "perimeter" because it works for all shapes. Circumference is for circles, although it is often used for octagon and other nearly circular shapes.

In my STLcalc program I use "Loop Length", and emphasize that the total length includes the tuning capacitor body length and any jumpers used to connect the cap to the main loop.

I didn't know about the 66pacific.com calculator's error in computing inductance.? Thanks for bringing awareness to this.?

Several times over the past four years or so I have sent information to the 66pacific webmaster / majordomo about this issue, but have never gotten a reply, nor has anything been done to modify the web app. I've also described the issue in a couple of QSO Today Expo sessions on small transmitting loop antennas to warn users about it. Any results (Q, BW, efficiency, cap voltage, tuning cap value and voltage) calculated from a wrong reactance value are all wrong.

I reran the numbers using this calculator: ?? ?The inductive reactance increased substantially but the radiation and loss resistances stayed the same.

If the loop length and conductor diameter don't change, the Rrad and Rloss values remain the same (assuming the same material). STLcalc shows Reactance = 104.48 Ohms for an octagon, and 105.17 Ohms for a circle. The program also accounts for loss in the cap and any connections, and any soldered or welded joins in the loop conductor. 66pacific only calculates for the octagon shape and doesn't account for any of those other losses.

Wishing you success with your loop project,
Gus, KB0YH