Advantest 4131a Spectrum Analyzer 10kHz to 3.5GHz. In excellent condition. Checked response with HP signal generator and spot on after 30 minute warm up. 

Wide frequency Coverage 

Excellent Phase Noise Sideband Characteristics: -80 dBc @ 20X Resolution Offset

Small and Light, Weighing Only 10 kg (22 lb.)  

SaveiRecail Measurement Conditions, Including Waveforms

Characteristics:

Frequency Range - 10 kHz to 3.5 GHz.

Center Frequency Display - DIsplayed on the CRT with a maximum resoiution of 1 kHz. 

Center Frequency Oisplay Accuracy (after zero calibration at local feed through) - * 100 kHz *3% of span, ~2.5 GHz at a sweep time of 5 ms/div to 0.5 sidiv); 210 MHz, r2.5 GHz. 

Frequency Span - 50 kHz to 4 GHz in IO divisions on the horizontal scale on the CRT. selectable in I-2-5 sequence. 

With zero span, operates as a fixed tuned receiver. 

Frequency Span Accuracy - +/-5% 

Frequency stability (at tixed frequency, after 30-minute warm-up}: 10 kHz max/lO minutes 12.5 GHz at sweep time of 5 ms/div to 0.5 s/div. 

Residual FM: 2 kHz p-p max,100ms 

Noise Sideband - -80 dBc max at resoluton bandwidth of 1 kHz {at 20 kHz from the carrier, with a 10 Hz video filter).