"F1EKU via groups.io" <rfconsulting.fr@...> writes:
From experience, the 8481A series does not perform up well beyond 18
GHz. The response drops very quickly towards 19/20
GHz, and at 26.5 GHz, the response difference is more than 3 to 4
dB. The N connector is not responsible for this poor
performance, as 85025A detectors easily perform up to 40 GHz with only
a few glitches due to VSWR beyond 18.6 GHz.
Conversely, an 8485A often performs up to 30 or even 33 GHz.
I can confirm that. Last week i tried to do flatness calibration on my
83752A sweeper. As i only have a 8485D that accepts a max input level
of -20dBm, i tried the 8481A instead. But exactly as you said, the
levels where low by at least 3dB above 19GHz.
