I am testing the NooElec 1:9 balun V1.0.
When I measure the S11 Return Loss, see NooElec_Balun_9-1_S11_Return-Loss.png,
it behaves like the original curve balun_one_nine_return_loss_comparison_to_70mhz.png.
My measurement setup is shown in photo RF_Balun_1-9_S11_DSC08237.jpg.
The secondary side of the balun is terminated with 400R + 50 Ohm.
If I want to measure the balun *Loss* I have a problem.
See the original curve from NooElec: balun_one_nine_insertion_loss_comparison_to_70mhz.png
I replace now the 50 Ohm resistor at the SMA plug with a coax cable RG316
to the nanoVNA CH1.
To my surprise the S11 Return loss looks much different, than with the 50 Ohm resistor.
See: NooElelc_Balun_9-1_S21_Loss.png.
What In am doing wrong?
73, Rudi DL5FA
