Frank - Thanks for the comments and information. The calibration for the first attachment was the standard Open, Short, and 50 ohm Load calibration done at the Channel 0 SMA connector on the NanoVNA. The first attachment would show the antenna with transmission line as seen by a transmitter or receiver.
The calibration for the second attachment used the same Open, Short, and 50 ohm Load calibration but at the antenna end of the transmission line. That effectively removes the transmission line from all measurements to show the characteristics of the antenna itself. That is one of the more powerful features of a NanoVNA.
The two legs of the dipole were bent down slightly to improve the match. Technically it is an Inverted V Dipole. The feed line does come straight down from the feed point.
The coax is Berk-Tek RG-58A/U low loss foam coax. The characteristic impedance is 50 ohms.
I believe the first attachment shows the resonant frequency of the antenna just ahead of the low point in SWR. Compare that low with the second attachment.
73, Kent
AA6P
