This unit has a loose front knob, the knob still adjust frequency it just needs the tension nut tightened. Selling this unit AS-IS as I dont have the time or patience to disassemble. Powers on, no further testing,

The HP/Agilent/Keysight 83572A is a WR‑28 waveguide sweep‑oscillator plug‑in covering 26.5–40.0 GHz, designed for the 8350A/B sweep oscillator mainframes; it offers internally or externally leveled outputs, optional calibrated external leveling (Option 001), and optional internal pulse/square‑wave modulation (Option 006). Use the OEM service manual and datasheet for calibration, leveling setup, and connector/waveguide mating details.


 technical overview


Performance highlights (OEM specs)

Parameter Typical / Spec Notes / Options
Frequency range 26.5 GHz – 40.0 GHz Full plug‑in band.
Frequency accuracy (25°C ±5°C) ±100 MHz (CW) All sweep modes wider; see manual for sweep‑mode tolerances.
Minimum unleveled output ~3 dBm (83572A) 83572B variant offers higher minimum power.
Externally leveled calibrated output (Opt 001) Specified calibrated level (adds ~1 dB loss at coupler) Option 001 supplies coupler, detector and calibration for regulated power.
.
Source VSWR (50 Ω nominal) < 2.5 (internally leveled) Externally leveled VSWR typically better.

Modulation & dynamic behavior