Now let’s try stub matching. The length of 75 ohm coax cables required is 531.4mm for d1 and 1182.4mm (with open end) for d2.
This is to calibrate the measurement system using a dummy load.
This is my antenna with stub matching. Looks nice. Almost as good as a dummy load.
gnuplot> load "gnuplot1.txt" Freq [MHz]=28.001 V1=2.122 V2=2.362 Cursor 1=0.0 Cursor 2=0.0 vratio=1.11310084825636 phase1 [deg]=0.0 phase2 [deg]=0.0 abs(gamma)=0.113100848256362 swr=1.25504782146653 cz=62.7523910733263
Without stub matching, the VSWR was 2.61, so there is definitely much improvement.