491: Difference between revisions

From TekWiki
Jump to navigation Jump to search
No edit summary
(trimming/streamlinig; inroduction date per 1971 Tek calendar)
Line 7: Line 7:
discontinued=1980 |
discontinued=1980 |
manuals=
manuals=
Need Service Manual
* [[Media:070-0598-01.pdf | Tektronix 491 Instruction Manual needed]]
* [[Media:070-0598-01.pdf| Tektronix 491 Instruction Manual {Qservice Scan} (PDF, OCR)]]
* [[Media:Tektronix_491_Maintenance_Manual_ARMY.pdf | Tektronix 491 Instruction Manual (US Army TM 9-6625-2467-15) (PDF)]]
* [[Media: Tektronix_491_Maintenance_Manual_ARMY.pdf | Tektronix 491 Instruction Manual {US Army Technical Manual TM 9-6625-2467-15} (PDF)]]
* [[Media:Tek_491_Catalog_Spec_1967.pdf | Tektronix 491 Introduction Spec (PDF, OCR)]]
* [[Media:050-0692-03.pdf| Tektronix 491 Band C Oscillator Replacement Modification (PDF, OCR)]]
* [[Media:Tek_491_Catalog_Spec_1979.pdf | Tektronix 491 Final Spec (PDF, OCR)]]
* [[Media:Tek 491 mod wa.pdf|Tektronix 491 Mod WA (PDF, needs OCR)]]
* ''Service manual needed ''
* [[Media:Tek 491 fcp nov 1966.pdf |Tektronix 491 Factory Calibration Procedure, November 1966 (PDF, needs OCR)]]
<small>
* [[Media:Tek_491_Catalog_Spec_1967.pdf| Tektronix 491 Introduction Spec (PDF, OCR)]]
'''Modifications and Calibration'''
* [[Media:Tek_491_Catalog_Spec_1979.pdf| Tektronix 491 Final Spec (PDF, OCR)]]
* [[Media:050-0692-03.pdf | Tektronix 491 Band C Oscillator Replacement Modification (PDF, OCR)]]
* [[Media:Tek 491 mod wa.pdf | Tektronix 491 Mod WA (PDF, needs OCR)]]
* [[Media:Tek 491 fcp nov 1966.pdf | Tektronix 491 Factory Calibration Procedure, November 1966 (PDF, needs OCR)]]
</small>
}}
}}
The '''Tektronix 491''' is a spectrum analyzer with a frequency range of 10 MHz to 12.4 GHz (up to 40 GHz with external waveguide mixers).
The 491 was [[introduced in 1966|introduced in August 1966]].  Due to severe performance limitations, the 491 was replaced by the completely redesigned [[492]] in 1980.


NOTE: Due to severe performance limitations, it was replaced by the completely redesigned 492 in 1980
---------------------------------------------------------
The '''Tektronix 491''' is a spectrum analyzer with a frequency range of 10 MHz to 40 GHz.  The minimum resolution bandwidth is 1 kHz, and provides measurement resolution proportional to the frequency accuracy or span. 
Front panel inputs/outputs are: RF INPUT (A) [[BNC connector]] (50Ω, 10 MHz to 275 MHz); RF INPUT (B) [[N connector]] (50Ω, 275 MHz to 2 GHz); WAVEGUIDE (C) [[N connector]] (50Ω, 12.4 GHz to 40 GHz); and a dual function 1 MHz MARKERS OUT [[BNC connector]] (With the INT REF FREQ in the ON position a 1 MHz marker outputs to this connector.  With the INT REF FREQ in the OFF position EXT REF FREQ IN “same” [[BNC connector]] accepts an external signal between 1 MHz and 5 MHz (1 to 5 V peak to peak) applied to the connector becomes the reference frequency for the phase lock operation).
Rear panel inputs/outputs are: TRIG IN [[BNC connector]] (20 Hz to 100 kHz, ≥0.2V); SAW OUT [[BNC connector]] (75mV/div); and RECORDER [[BNC connector]] (≥4 mV/div of displayed signal in LIN mode, DC-coupled, into 600Ω load impedance).
---------------------------------------------------------
<div style='text-align: center;'>Specifications based on final published documentation, unless otherwise specified.</div>
{{BeginSpecs}}
{{BeginSpecs}}
{{Spec | Frequency Range |
{{Spec | Frequency Range |
* Coaxial Input Bands 10 MHz to 12.4 GHz  (Band A-1: 10 MHz to 275 MHz; Bands B-2 & 3: 275 MHz to 2 GHz; and Bands C-4, 5, & 6: 1.5 GHz to 12.4 GHz)
* Coaxial Input Bands 10 MHz to 12.4 GHz  (Band A-1 10 MHz to 275 MHz; Bands B-2 &amp; 3: 275 MHz to 2 GHz; Bands C-4, 5, &amp; 6: 1.5 GHz to 12.4 GHz)
* External Waveguide mixers: 12.4 MHz to 40 GHz  (Band 7: (Ku) 12.4 GHz to 18 GHz; and Bands 8: (K) 18 GHz to 26.5 GHz, and (Ka) 18 GHz to 40 GHz)
* External Waveguide mixers: 12.4 MHz to 40 GHz  (Band 7 (Ku) 12.4 GHz to 18 GHz; Band 8 (K) 18 GHz to 26.5 GHz, (Ka) 18 GHz to 40 GHz)}}
CAUTION: Signals stronger than +15 dBm applied to the input or mixer will damage or burn out the mixer diodes }}
{{Spec | Dispersion Range | (plus 0 Hz) 200 kHz/div to 10 MHz/div in 1−2−5 sequence }}
{{Spec | Dispersion Range (plus 0 Hz) | 200 kHz/div to 10 MHz/div in 1-2-5 sequence }}
{{Spec | Resolution Bandwidth | 1 kHz to 100 kHz (6 dB) }}
{{Spec | Resolution Bandwidth Range | 6 dB bandwidths from 1 kHz to 100 kHz }}
{{Spec | Input impedance | 50 Ω }}
{{Spec | RF Input impedance | 50 Ω }}
{{Spec | Input Power | max. −30 dBm for linear operation, +15 dBm (25 mW) diode mixer power limit }}
{{Spec | Maximum Safe Input Power | -30 dBm for linear operation and +15 dBm (25 mW) diode mixer power limit }}
{{Spec | IF Attenuator Range | 0 dB to 51 dB, in combinations of 1, 2, 4, 8, 16, and 20 dB }}
{{Spec | IF Attenuator Range | 0 dB to 51 dB, in combinations of 1, 2, 4, 8, 16, and 20 dB }}
{{Spec | Sweep Speed Range | 0.5 s/div to 10 µs/div in 1, 2, 5 sequence; Uncalibrated to approx 1.25 s/div }}
{{Spec | Sweep Speed Range | 0.5 s/div to 10 µs/div in 1, 2, 5 sequence; Uncalibrated to approx 1.25 s/div }}
{{Spec | Triggering Modes | Internals, External, and Line. 100 V maximum input (DC + peak AC) }}
{{Spec | Triggering Modes | Internals, External, and Line; 100 V maximum input (DC + peak AC) }}
{{Spec | Display Dynamic Range | ≥40 dB }}
{{Spec | Display Dynamic Range | ≥40 dB }}
{{Spec | Dynamic Range | 80 dB (Max sensitivity of -110 dBm minus Max input power of -30 dBm) }}
{{Spec | Dynamic Range | 80 dB (Max sensitivity of −110 dBm minus Max input power of −30 dBm) }}
{{Spec | Calibrator Frequency | 200 MHz }}
{{Spec | Calibrator Frequency | 200 MHz }}
{{Spec | Included Accessories |Two Instruction Manuals; 6-ft, 50Ω coaxial cable, BNC-BNC; 6-ft, 50Ω coaxial cable, N-N; 2-ft, 50Ω coaxial cable, TNC-TNC; 12.4 GHz to 18 GHz waveguide mixer; 18 GHz to 26.5 GHz waveguide mixer; 26.5 to 40 GHz waveguide mixer; 10 dB attenuator N type fittings; 20 db attenuator N type fittings; two BNC male to N female adapters; two BNC female to N male adapters; Waveguide mixer adapter; power cord; dust and rain cover; 3 to 2 wire adapter; blue light filter; amber light filter; clear CRT protector plate; ornamental ring; mesh filter (installed); two one-ampere fuses; and 1/2 –ampere fuse }}
{{Spec | Weight | 13.6 kg / 30 lbs (Rackmount version 18 kg / 40 lbs) }}
{{Spec | Weight | Portable: 13.6 kg (30 lbs) ; Rackmount: 18 kg (40 lbs) }}
{{Spec | Power | 90−136 and 180−272 V<sub>AC</sub> in six ranges, 48−440 Hz.  At 115 V<sub>AC</sub>, 60 Hz, 55 W }}
{{Spec | Power | 90 − 136 V<sub>AC</sub> in three ranges, 48 to 440 Hz; 180 – 272 V<sub>AC</sub> in three ranges, 48 to 440 Hz.  At 115 V<sub>AC</sub>, 60 Hz, 55 W }}
{{Spec | Front panel inputs/outputs |  
{{Spec | Operating Atmospherics | Temperatures: -15 °C to +55 °C; Humidity: Five cycles (120 hours) of MIL-STD-202C Method 106B; Altitude: Up to 4.6 km (15,000 ft) }}
*RF INPUT (A) [[BNC connector]] (50 Ω, 10 MHz to 275 MHz)
*RF INPUT (B) [[N connector]] (50 Ω, 275 MHz to 2 GHz)
*WAVEGUIDE (C) [[N connector]] (50 Ω, 12.4 GHz to 40 GHz)
*MARKERS OUT/EXT REF FREQ IN [[BNC connector]]: 1 MHz marker output when INT REF FREQ set to ON, otherwise PLL reference frequency input (1−5 MHz, 1−5 V<sub>p-p</sub>) }}
{{Spec | Rear panel inputs/outputs  |
*TRIG IN [[BNC connector]] (20 Hz to 100 kHz, ≥0.2 V)
*SAW OUT [[BNC connector]] (75 mV/div)
*RECORDER [[BNC connector]] (≥4 mV/div of displayed signal in LIN mode, DC-coupled, into 600 Ω) }}
{{EndSpecs}}
{{EndSpecs}}


Revision as of 00:28, 2 November 2019

{{{manufacturer}}} 
Spectrum Analyzer 10 MHz to 40 GHz
Tektronix 491

Produced from 1967 to 1980

Manuals
Manuals – Specifications – Links – Pictures

The Tektronix 491 is a spectrum analyzer with a frequency range of 10 MHz to 12.4 GHz (up to 40 GHz with external waveguide mixers). The 491 was introduced in August 1966. Due to severe performance limitations, the 491 was replaced by the completely redesigned 492 in 1980.

Key Specifications

Frequency Range
  • Coaxial Input Bands 10 MHz to 12.4 GHz (Band A-1 10 MHz to 275 MHz; Bands B-2 & 3: 275 MHz to 2 GHz; Bands C-4, 5, & 6: 1.5 GHz to 12.4 GHz)
  • External Waveguide mixers: 12.4 MHz to 40 GHz (Band 7 (Ku) 12.4 GHz to 18 GHz; Band 8 (K) 18 GHz to 26.5 GHz, (Ka) 18 GHz to 40 GHz)
Dispersion Range (plus 0 Hz) 200 kHz/div to 10 MHz/div in 1−2−5 sequence
Resolution Bandwidth 1 kHz to 100 kHz (6 dB)
Input impedance 50 Ω
Input Power max. −30 dBm for linear operation, +15 dBm (25 mW) diode mixer power limit
IF Attenuator Range 0 dB to 51 dB, in combinations of 1, 2, 4, 8, 16, and 20 dB
Sweep Speed Range 0.5 s/div to 10 µs/div in 1, 2, 5 sequence; Uncalibrated to approx 1.25 s/div
Triggering Modes Internals, External, and Line; 100 V maximum input (DC + peak AC)
Display Dynamic Range ≥40 dB
Dynamic Range 80 dB (Max sensitivity of −110 dBm minus Max input power of −30 dBm)
Calibrator Frequency 200 MHz
Weight 13.6 kg / 30 lbs (Rackmount version 18 kg / 40 lbs)
Power 90−136 and 180−272 VAC in six ranges, 48−440 Hz. At 115 VAC, 60 Hz, 55 W
Front panel inputs/outputs
  • RF INPUT (A) BNC connector (50 Ω, 10 MHz to 275 MHz)
  • RF INPUT (B) N connector (50 Ω, 275 MHz to 2 GHz)
  • WAVEGUIDE (C) N connector (50 Ω, 12.4 GHz to 40 GHz)
  • MARKERS OUT/EXT REF FREQ IN BNC connector: 1 MHz marker output when INT REF FREQ set to ON, otherwise PLL reference frequency input (1−5 MHz, 1−5 Vp-p)
Rear panel inputs/outputs

Options

  • Opt. 01: Limit Frequency Range to 10 MHz to 2 GHz
  • Opt. 02: Limit Frequency Range to 1.5 GHz to 40 GHz

Pictures

Retrieved from "https://w140.com/tekwiki/index.php?title=491&oldid=51903"