Total posts : 45366
Using a specific length of coax is still the easiest, most practical way of adjusting the phase of a signal at a tower for directional purposes, especially for experimenters. The key to success is knowing the exact velocity factor of the coax as well as using the standard formulas for wavelength. The problem is that it simply doesn’t fit into Part 15 rules.
I thought I had a wonderful bit of insight after reading PhilB’s remarks about using a common oscillator circuit. I was thinking of adjusting the length of the common oscillator circuit leads to each transmitter as a phase adjustment. But I suppose the length of the leads might have too big of an effect on the exact frequency of the more distant transmitter or the level might be so low that the second transmitter might not even operate.