Hi, Marek.
Yes, they're identical.
I have tried 21:3 yesterday and found that 20:3 has even better flat SWR.
It is suitable for 1.8 - 21 MHz, not for 28, but in that range it works perfectly with SWR better than 1.3.
But efficient is still 85% , very close to simple 14:2 wiring.
K5NL method is not working at all, I tried many times. Ugly SWR, no inductance compensation.?
