491: Difference between revisions
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{{ | {{Instrument Sidebar | ||
|manufacturer=Tektronix | |||
summary=Spectrum Analyzer | |class=Spectrum Analyzer | ||
image=Tek 491.jpg | | |model=491 | ||
caption=Tektronix 491 | | |summary=40 GHz Spectrum Analyzer | ||
introduced= | |image=Tek 491.jpg | ||
discontinued=1980 | | |caption=Tektronix 491 | ||
manuals= | |introduced=1966 | ||
* [[Media:070-0598-01.pdf | Tektronix 491 Instruction Manual | |discontinued=1980 | ||
* [[Media:Tektronix_491_Maintenance_Manual_ARMY.pdf | Tektronix 491 Instruction Manual (US Army TM 9-6625-2467-15 | |designers=Gene Kauffman; | ||
* [[Media:Tek_491_Catalog_Spec_1967.pdf | Tektronix 491 Introduction Spec ( | |manuals= | ||
* [[Media:Tek_491_Catalog_Spec_1979.pdf | Tektronix 491 Final Spec ( | * [[Media:070-0598-01.pdf|Tektronix 491 Instruction Manual 070-0598-01]]'' | ||
* [[Media:Tektronix_491_Maintenance_Manual_ARMY.pdf | Tektronix 491 Instruction Manual (US Army TM 9-6625-2467-15)]] | |||
* [[Media:Tek_491_Catalog_Spec_1967.pdf | Tektronix 491 Introduction Spec]] (OCR) | |||
* [[Media:Tek_491_Catalog_Spec_1979.pdf | Tektronix 491 Final Spec]] (OCR) | |||
<small> | <small> | ||
'''Modifications and Calibration''' | '''Modifications and Calibration''' | ||
* [[Media:050-0692-03.pdf | Tektronix 491 Band C Oscillator Replacement Modification ( | * [[Media:050-0692-03.pdf | Tektronix 491 Band C Oscillator Replacement Modification]] (OCR) | ||
* [[Media:Tek 491 mod wa.pdf | Tektronix 491 Mod WA | * [[Media:Tek 491 mod wa.pdf | Tektronix 491 Mod WA]] | ||
* [[Media:Tek 491 fcp nov 1966.pdf | Tektronix 491 Factory Calibration Procedure, November 1966 | * [[Media:Tek 491 fcp nov 1966.pdf | Tektronix 491 Factory Calibration Procedure, November 1966]] | ||
</small> | </small> | ||
}} | }} | ||
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{{BeginSpecs}} | {{BeginSpecs}} | ||
{{Spec | | {{Spec | Frequency | | ||
* 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) | * 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)}} | * 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)}} | ||
{{Spec | Dispersion | {{Spec | Dispersion | (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 | 1 kHz to 100 kHz (6 dB) }} | ||
{{Spec | | {{Spec | Input | 50 Ω, max. −30 dBm for linear operation, +15 dBm (25 mW) diode mixer power limit }} | ||
{{Spec | IF Attenuator | 0 dB to 51 dB, in combinations of 1, 2, 4, 8, 16, and 20 dB }} | |||
{{Spec | | {{Spec | Sweep Speed | 0.5 s/div to 10 µs/div in 1, 2, 5 sequence; Uncalibrated to approx 1.25 s/div }} | ||
{{Spec | Sweep Speed | |||
{{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 | Dynamic Range | 80 dB (Max sensitivity of −110 dBm minus Max input power of −30 dBm); display range ≥40 dB }} | |||
{{Spec | Dynamic Range | 80 dB (Max sensitivity of −110 dBm minus Max input power of −30 dBm) }} | {{Spec | Calibrator | 200 MHz }} | ||
{{Spec | Calibrator | |||
{{Spec | Weight | 13.6 kg / 30 lbs (Rackmount version 18 kg / 40 lbs) }} | {{Spec | Weight | 13.6 kg / 30 lbs (Rackmount version 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 and 180−272 V<sub>AC</sub> in six ranges, 48−440 Hz. At 115 V<sub>AC</sub>, 60 Hz, 55 W }} | ||
{{Spec | Front panel | {{Spec | Front panel | | ||
*RF INPUT (A) [[BNC connector]] (50 Ω, 10 MHz to 275 MHz) | * RF INPUT (A) [[BNC connector]] (50 Ω, 10 MHz to 275 MHz) | ||
*RF INPUT (B) [[N connector]] (50 Ω, 275 MHz to 2 GHz) | * RF INPUT (B) [[N connector]] (50 Ω, 275 MHz to 2 GHz) | ||
*WAVEGUIDE (C) [[ | * WAVEGUIDE (C) − receptacle that accommodates either a coaxial mixer, 119-0096-00, with an N connector input for 1.5 to 12.4 GHz, or a [[119-0104-00]] waveguide mixer adapter connecting to external mixers for up 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>) }} | * 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 | {{Spec | Rear panel | | ||
*TRIG IN [[BNC connector]] (20 Hz to 100 kHz, ≥0.2 V) | * TRIG IN [[BNC connector]] (20 Hz to 100 kHz, ≥0.2 V) | ||
*SAW OUT [[BNC connector]] (75 mV/div) | * SAW OUT [[BNC connector]] (75 mV/div) | ||
*RECORDER [[BNC connector]] (≥4 mV/div of displayed signal in LIN mode, DC-coupled, into 600 Ω) }} | * RECORDER [[BNC connector]] (≥4 mV/div of displayed signal in LIN mode, DC-coupled, into 600 Ω) }} | ||
{{EndSpecs}} | {{EndSpecs}} | ||
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* Opt. 01: Limit Frequency Range to 10 MHz to 2 GHz | * Opt. 01: Limit Frequency Range to 10 MHz to 2 GHz | ||
* Opt. 02: Limit Frequency Range to 1.5 GHz to 40 GHz | * Opt. 02: Limit Frequency Range to 1.5 GHz to 40 GHz | ||
==Prices== | |||
1979: $10,700 ($41,800 in 2022 Dollars) | |||
According to an [[Media:Tek Schottky Diodes Memo rot.pdf|internal memo]], in 1979 annual sales were estimated at 172 units. | |||
==Pictures== | ==Pictures== | ||
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</gallery> | </gallery> | ||
[[Category: Spectrum | ==Components== | ||
{{Parts|491}} | |||
[[Category:Spectrum analyzers]] | |||
Latest revision as of 06:10, 27 April 2024
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 |
|
|---|---|
| Dispersion | (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 | 50 Ω, max. −30 dBm for linear operation, +15 dBm (25 mW) diode mixer power limit |
| IF Attenuator | 0 dB to 51 dB, in combinations of 1, 2, 4, 8, 16, and 20 dB |
| Sweep Speed | 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) |
| Dynamic Range | 80 dB (Max sensitivity of −110 dBm minus Max input power of −30 dBm); display range ≥40 dB |
| Calibrator | 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 |
|
| Rear panel |
|
Options
- Opt. 01: Limit Frequency Range to 10 MHz to 2 GHz
- Opt. 02: Limit Frequency Range to 1.5 GHz to 40 GHz
Prices
1979: $10,700 ($41,800 in 2022 Dollars)
According to an internal memo, in 1979 annual sales were estimated at 172 units.
Pictures
Components
Some Parts Used in the 491
| Part | Part Number(s) | Class | Description | Used in |
|---|---|---|---|---|
| 155-0157-00 | 155-0157-00 | Monolithic integrated circuit | digital storage vertical control | 7L5 • 7L14 • 7L18 • 491 • 492 • 492A • 492BP • 492PGM • 494 • 494A • 495 • 496 • 497P |
| 155-0158-00 | 155-0158-00 | Monolithic integrated circuit | digital storage horizontal control | 7L5 • 7L14 • 7L18 • 491 • 492 • 492A • 492BP • 492PGM • 494 • 494A • 495 • 496 • 497P |
| 1N3714 | 152-0081-00 | Discrete component | 2.2 mA, 25 pF germanium tunnel diode | 546 • 547 • 556 • 21A • 22A • 3B1 • 3B2 • 3B3 • 422 • 491 • 283 |
| 1N3717 | 152-0381-00 • 152-0125-00 | Discrete component | 4.7 mA, 25 pF tunnel diode | 1L40 • 1S1 • 1S2 • 11B1 • 11B2 • 11B2A • 147A • 1470 • 148 • 21A • 22A • 3B4 • 3B5 • 408 • 432 • 434 • 453 • 453A • 454 • 466 • 491 • 5T3 • 544 • RM544 • 546 • RM546 • 547 • RM547 • 556 • RM556 • 7B70 • 7B71 • 7D11 |
| STD704 | 152-0125-00 | Discrete component | 4.7 mA tunnel diode | 1L40 • 1S1 • 11B1 • 11B2 • 11B2A • 147 • R147 • 147A • R147A • 1470 • 148 • R148 • 148-M • 149 • R149 • 149A • R149A • 21A • 22A • 3B4 • 3B5 • 408 • 432 • 434 • 453 • 453A • 454 • 464 • 465 • 466 • 491 • 5T3 • 544 • RM544 • 546 • RM546 • 547 • RM547 • 556 • RM556 • 7B70 • 7B71 • 7D11 |
| T4910 | CRT | CRT | 491 | |
| TD714 | 152-0402-00 | Discrete component | 2.2 mA, 25 pF tunnel diode | 1401 • 1401A • 283 • R283 • 3B2 • 3B3 • 422 • 491 • 546 • RM546 • 547 • RM547 • 556 • RM556 • SPG11 • SPG12 |
| Y1641 | 154-0506-00 • 154-0510-00 | Vacuum Tube (Triode) | SHF cermet triode | 1L20 • 491 |