On Tue, Aug 24, 2021 at 03:43 PM, Mike C. wrote:

New to the group. I have a SAA-2N w/N connectors and cal set. With the
necessary adapters (SMA to N etc..) I am not sure I understand if my
measurements are correct. Measured (stimulus) from 1MHz - 100MHz;
calibrated w/cal set. I then connected a 30db attn and it reads -25.6db
@ 30MHz, what is going on? Note: this attn is marked 7-16.5GHz and is an
SMA. (I have many of these attenuators and several tests on various
units produces nearly the same results)

I assume that you are connecting the attenuator between CH0 and CH1 and reading the S21 magnitude in dB. Sometimes new users use make a mistake and use S11 Log Mag in dB which is Return Loss. After you do a full calibration (Open, Short, Load, Isolation and Through) do you get 0 dB with the cable between CH0 and CH1?

Why not take a screenshot so we can help you out. You can take one with the PC program NanoVNA Saver or with your camera.

Roger