2021-08-05, 08:36:13
(This post was last modified: 2021-08-05, 10:06:34 by VE3WI Dave.)
I noticed a link on eHam.net to an in-depth technical article about this antenna, written by it's developer Brian Austin G0GSF (ex ZS6BKW). It's taken from a UK QRP magazine called Sprat & starts part way down page 1. https://www.nonstopsystems.com/radio/pdf-ant/ZS6BKW.pdf
He determined the optimum impedance for the parallel-line matching section of feedline is about 400 ohms. That's convenient as the actual impedance of the "450 ohm" window line you can buy is about 400 ohms.
Claimed performance is impressive for a no-ATU antenna:
band 40m 20m 17m 12m 10m
center freq. 7.1 14.2 18.1 24.9 28.97
min. SWR 1.1:1 1.1:1 1.3:1 1.4:1 1.4:1
2:1 BW (kHz) 360 270 380 260 400
73
Dave, VE3WI
He determined the optimum impedance for the parallel-line matching section of feedline is about 400 ohms. That's convenient as the actual impedance of the "450 ohm" window line you can buy is about 400 ohms.
Claimed performance is impressive for a no-ATU antenna:
band 40m 20m 17m 12m 10m
center freq. 7.1 14.2 18.1 24.9 28.97
min. SWR 1.1:1 1.1:1 1.3:1 1.4:1 1.4:1
2:1 BW (kHz) 360 270 380 260 400
73
Dave, VE3WI