874-LBA: Difference between revisions

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{{GR Product
{{GR Product
|model=874-LBA
|model=874-LBA
|codes=COAXRUNNER
|class=coaxial elements
|class=coaxial elements
|summary=Slotted Line
|summary=Slotted Line
|image=GR 874-LBA Close-up.jpg
|image=GR 874-LBA Close-up.jpg
|caption=General Radio 874-LBA Slotted Line
|caption=General Radio 874-LBA Slotted Line
|series=874
|series=GR-874
|introduced=1956
|introduced=1956
|discontinued=1965
|discontinued=1965
|designers=
|designers=
|manuals=
|manuals=
* [[Media:GR 874-LLA_LLB Slotted Line 0874-0215-I 04_1966.pdf|General Radio 874-LBA Slotted Line Manual 0874-0215-I 1966]]
* [[Media:GR 874-LLA_LLB Slotted Line 0874-0215-I 04_1966.pdf|General Radio 874-LBA/874-LBB Slotted Line Manual 0874-0215-I 1966]]
{{Catalog History}}
{{Catalog History}}
}}
}}
The {{Title|General Radio 874-LBA Slotted Line}} was introduced in {{Catalog O}} and remained available through {{Catalog S}}.  Its function is to observe the electric field along the inside of a coaxial transmission line using a carriage-mounted probe moving along the line.   
The {{Title|General Radio 874-LBA Slotted Line}} was introduced in {{Catalog O}} and remained available through {{Catalog S}}.  Its function is to observe the electric field along the inside of a coaxial transmission line using a carriage-mounted probe moving along the line.   


By observing minima and maxima of a standing-wave pattern, the characteristics of a circuit connected to the load side of the line can be determined.  Applications include frequency measurement and analysis of antennas, components, coaxial elements, and networks.  
By observing minima and maxima of a standing-wave pattern, parameters like frequency, standing-wave ratio, or impedance can be measured, and thereby the characteristics of a circuit connected to the load side of the line can be determined.  Applications include analysis of antennas, components, coaxial elements, and networks.


The 874-LBA is an update of the [[874-LB]], featuring improved accuracy and carriage construction. The redesigned carriage is controlled by a nylon cord and a series of pulleys to remove its drive control to a fixed position at the load end.  
The 874-LBA is an update of the [[874-LB]], featuring improved accuracy and carriage construction. The redesigned carriage is controlled by a nylon cord forming a complete loop, and a series of pulleys to remove its drive control to a fixed position at the load end.  This reduces changes in probe coupling caused by changing forces on the carriage.  An optional [[874-LV|874-LV Micrometer Vernier]] can be attached for high-resolution measurements.


The 874-LBA was supplied with a protective wooden case, a spare nylon cable, and a crystal detector.  
The 874-LBA was supplied with a protective wooden case, a spare nylon cable, and a crystal detector.  
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* '''Characteristic Impedance:''' 50 Ω, ±0.5%
* '''Characteristic Impedance:''' 50 Ω, ±0.5%
* '''Scale Accuracy:''' ±(0.1 mm +0.05%)
* '''Scale Accuracy:''' ±(0.1 mm +0.05%)
* '''Frequency Range:''' 300 MHz to 5 GHz. At 300 MHz, the slotted line covers one-half of a wavelength.
* '''Frequency Range:''' 300 MHz to 5 GHz; for measurements below 300 MHz, add [[874-L30]] air line sections
* '''Length:''' 50 cm probe travel (λ/2 @ 300 MHz, λ/4 @ 150 MHz)
* '''Constancy of Probe Penetration:''' ±1½%
* '''Constancy of Probe Penetration:''' ±1½%
* '''Residual SWR:''' 1.025 @ 1 GHz, 1.07 @ 4 GHz


==Links==
==Links==
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* [[Media:GR Exp 874-LBA 12_1954.pdf|Experimenter December 1954 describing Type 874-LBA]]
* [[Media:GR Exp 874-LBA 12_1954.pdf|Experimenter December 1954 describing Type 874-LBA]]
* [[Media:1N Series Microwave Diode Data Sheet.pdf|1N23B Microwave Diode Data]]
* [[Media:1N Series Microwave Diode Data Sheet.pdf|1N23B Microwave Diode Data]]
* [[Media:Handbook of Coaxial Microwave Measurements.pdf|Handbook of Coaxial Microwave Measurements]]
* [https://www.youtube.com/watch?v=DovunOxlY1k&t=668s AT&T Archives Wave Machine Tutorial] @ YouTube
* [https://www.youtube.com/watch?v=DovunOxlY1k&t=668s AT&T Archives Wave Machine Tutorial] @ YouTube
* Predecessor: [[874-LB]]
* Successor: [[874-LBB]] (8.5 GHz)


==Photos==
==Photos==

Latest revision as of 18:12, 30 May 2024

General Radio 874-LBA
Slotted Line
General Radio 874-LBA Slotted Line

Available from 1956 to 1965

Manuals
Catalog History
 Document Year Page
Catalog O 1956 46
Catalog P 1959 43
Catalog Q 1961 52
Catalog R 1963 65
Catalog S 1965 82
(All manuals in PDF format unless noted otherwise)

The General Radio 874-LBA Slotted Line was introduced in Catalog O (1956) and remained available through Catalog S (1965). Its function is to observe the electric field along the inside of a coaxial transmission line using a carriage-mounted probe moving along the line.

By observing minima and maxima of a standing-wave pattern, parameters like frequency, standing-wave ratio, or impedance can be measured, and thereby the characteristics of a circuit connected to the load side of the line can be determined. Applications include analysis of antennas, components, coaxial elements, and networks.

The 874-LBA is an update of the 874-LB, featuring improved accuracy and carriage construction. The redesigned carriage is controlled by a nylon cord forming a complete loop, and a series of pulleys to remove its drive control to a fixed position at the load end. This reduces changes in probe coupling caused by changing forces on the carriage. An optional 874-LV Micrometer Vernier can be attached for high-resolution measurements.

The 874-LBA was supplied with a protective wooden case, a spare nylon cable, and a crystal detector.

Specifications

  • Characteristic Impedance: 50 Ω, ±0.5%
  • Scale Accuracy: ±(0.1 mm +0.05%)
  • Frequency Range: 300 MHz to 5 GHz; for measurements below 300 MHz, add 874-L30 air line sections
  • Length: 50 cm probe travel (λ/2 @ 300 MHz, λ/4 @ 150 MHz)
  • Constancy of Probe Penetration: ±1½%
  • Residual SWR: 1.025 @ 1 GHz, 1.07 @ 4 GHz

Links

Photos