I did some TDR measurements on the 260ft wire on the ground. As a dipole on the ground, it is resonant at 1070kHz, (R=185 ohms X=0 ohms) That calculates as a 59.4% VF. I did several iterations while altering the TDR output impedance*, I ended with 439 ohms output impedance. This is the scope shot, I obtained with a minimal 1/8? 2ft ground rod. (it could easily be 200 ohms in my limited experience measuring ground resistance)
I have the total impedance (calculated from the waveform voltage) as515 ohms. (includes Ground resistance) Vout = Vs x R2 / (R1 + R2) // 2.7 = 5 x 515 / (439 + 515). Therefore, 515 ohm Total antenna impedance.
The time to the end of the wire is 0.6us. At a VF of 59.4%, that is107 meters, while the measured value is 126 meters.
I was attempting to get a 50% step. I missed, but got tired of iterating.