On Mon, Mar 17, 2025 at 03:13 PM, W0LEV wrote:
... If you used only the NANOVNA connected to NOTHING, not even holding the VNA, you might
not see as much difference.
...You need to decouple the feedline/NANOVNA/PC/laptop from the transformer!
Yeah, I've been thinking about that...although I will note that the laptop was NOT plugged into the AC adapter when I made the two measurements. What I'll try on my next visit will be to leave the nanoVNA dangling without ANY connection to the laptop, and then see if the patterns look more similar when reversing the dipole wires. And of course, I can also observe the impact of touching the nanoVNA SMA and see how that impacts the view...a classic test for common mode effects in the unbalanced system. But all of this points out the challenge of trying to capture what the Zachtek is actually "seeing" when connected to the antenna. It seems that with this type of setup it would be very difficult to get an accurate picture...not that it really matters much, though, given it's tolerance of any load.
I will say that based on the WSPR performance over the past day, reversing the dipole wires does seem to have had a positive effect (567 versus 504 unique spots for W9HIF), assuming the solar activity has been similar to that earlier in the week. And if that holds, that is consistent with the SWR pattern showing a lower average for the higher frequency bands...even if that means the transmission line is "participating" more to radiate some of the RF energy.
