Thank you for your tests. Perhaps add in the price of the attenuators so we get an idea of how they compare for the price.
I just did some tests myself. Note that I used my best cable but it still introduces error, especially above 3 GHz.
Mini Circuits VAT series of SMA 0-6 GHz attenuators - retail price of 11.95 USD each in small quantities.
Scale is 0.5 dB per division, 10,20,30 dB models measured.
10 dB
20 dB
30 dB
Mini Circuits UNAT+ series N 0-6 GHz attenuators - retail price of 15.95 USD each in small quantities.
Scale is 0.5 dB per division, 20 and 30 dB models measured.
20 dB
30 dB
Pasternack PE7025-30 BNC 30 dB attenuator - only rated to 2 GHz but tested to 3 GHz. Stupid money.
*Scale is 0.1 dB per division* (these work extremely well, especially for a BNC connector)
And for completeness some classic HP 8491A N attenuators, rated to 12.4 GHz and obviously stupid money.
*Scale 0.1 dB per division*
Measured 3,6 and 10 dB
3 dB
6 dB
10 dB