Dipole Antenna (2)

First, with a dummy load. This seems to be quite reasonable. Almost no reflection (green), and V1 (red) and V2 (yellow) are almost the same.

Then, my 17m band full-size dipole, which is far from satisfactory.

The voltage ratio V2/V1=0.9085/2.259=0.402, and the delay of V2 against V1 is 41.7deg (=360deg*6.40nS/55.2nS).

The magnitude of the reflection coefficient is 0.749, which corresponds to the VSWR of 6.98.

(%i) V1:1.0+%i*0.0;
(%i) t:2.0*3.1416*(-41.7/360.0);
(%i) V2:0.402*(cos(t)+%i*sin(t));
(%i) Vr:2*V1-V2;
(%i) z:50.0*V2/Vr;
(%i) realpart(z);
(%o) 7.407809291003613
(%i) imagpart(z);
(%o) -9.031478001791401
(%i) abs(z);
(%o) 11.68089180622445
(%i) g:(z-50)/(z+50);
(%i) abs(g);
(%o) 0.74920478622757
(%i) SWR:(1+abs(g))/(1-abs(g));
(%o) 6.974633845344225

The cable length is, if I remember correctly, around 20m, so the antenna impedance should be 17.8+i59.4 ohm, but this is not very likely from the simulation below.