View source for 494A

{{Instrument Sidebar 
|class=Spectrum Analyzer 
|manufacturer=Tektronix 
|model=494A 
|summary=21 GHz Spectrum Analyzer 
|image=494AP restored.JPG 
|caption=Tektronix 494A 
|introduced=1988 
|discontinued=1993 
|manuals=
* [[Media:070-5557-01.pdf|Tek 494A & 494AP Operators Manual]]
* [[Media:070-5559-01.pdf|Tek 494AP Programming Manual]]
* [[Media:070-5560-00.pdf|494A & 494AP Service Manual Vol.1]]
* [[Media:070-5561-00.pdf|494A & 494AP Service Manual Vol.2]]
}}
The '''Tektronix 494A/494AP''' is a spectrum analyzer with a frequency range of 10 kHz to 21 GHz in coax, and up to 325 GHz with external waveguide mixers.  The '''P''' suffix designation indicates GPIB '''P'''rogrammability.

{{BeginSpecs}}
{{Spec | Frequency                 | 10 kHz to 21 GHz (coaxial), up to 325 GHz using external waveguide mixers }}
{{Spec | Frequency Span            | 10 Hz to 10 GHz in 1–2–5 sequence (plus 0 Hz and MAX) }} 
{{Spec | Resolution Bandwidth      | 10 Hz to 3 MHz in decade steps (-6 dB bandwidth)}} 
{{Spec | RF Input                  | 50 Ω; max. +30 dBm (1 W) CW or 75 W peak pulse (1 µs, 0.1% duty factor) }}
{{Spec | RF Attenuator             | 0 dB to 60 dB, 10 dB steps }}
{{Spec | Reference Level           | –117 dBm to +30 dBm }} 
{{Spec | Sweep Speed               | 10 sec/div to 20 µs/div in 1–2–5 sequence }}
{{Spec | Video Bandwidth           | 0.3 Hz to 30 kHz }}
{{Spec | Triggering Modes          | Free Run, Line, Video, Single, External }}
{{Spec | Displayed Average Noise   | −30 dBm to −131 dBm }}
{{Spec | Display Dynamic Range     | 90 dB }} 
{{Spec | Calibrator (Cal out)      | 50Ω, -20 dBm ±0.3 dB at 100 MHz }}
{{Spec | Weight                    | 22.2 kg (48 lbs) }} 
{{Spec | Power                     | 90 − 132 V<sub>AC</sub>, 48 to 440 Hz; 180 – 250 V<sub>AC</sub>, 48 to 440 Hz, 210 W max }}
{{Spec | Operating Environment     | –15 °C to +55 °C; Humidity: Five cycles (120 hours) MIL-STD-810; Altitude: Up to 4.6 km (15,000 ft) }}
{{EndSpecs}}