On 7/3/2025 6:27 PM, john@kk9a.com wrote:
You're not alone Wes. I also do not understand how having an inductor at
the tuner for an electrically short antenna has a different effect from
putting the inductor at the antenna base.
Dave has provided two excellent responses, which I didn't see before
composing mine. And as he correctly observes, we can learn a LOT by
choosing to display current distribution in EZNEC on the "show antenna"
display, and studying the plots.
When I was getting back on the air in 2003, a colleague in pro audio who
also happens to be great RF engineer strongly urged me to use EZNEC,
specifically because he'd watched me learn from even more powerful
design tools in the design of sound systems. And he was absolutely
right! SimSmith is another very powerful design tool from which it's
possible to learn a lot.
That "adjustable matching network" called an antenna tuner can take many
forms, some of which are more efficient than others. For almost 15
years, I've used stub matching in the shack to broadband my high dipoles
for 80 and 40M, all designed with SimSmith using impedance sweeps of the
antennas by a high quality and well calibrated VNWA as a starting point.
73, Jim K9YC
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
|