Editing APC-7 connector

{{Infobox connector
|name               = APC-7
|type               = [[RF connector|RF coaxial connector]]
|image              = [[File:Apc7_1.png|300px]]
|logo               = 
|caption            = Recessed threads (left), Protruding threads (right)
|designer           = 
|design_date        = 
|manufacturer       = Originally [[Amphenol]], then [[Hewlett-Packard]], then others
|diameter           = {{convert|7|mm|in|abbr=on}}
|width              = 
|height             = 
|electrical         = 
|earth              = 
|maximum_voltage    = 
|maximum_current    = 
|cable              = 
|passband          = 0–18&nbsp;GHz
|physical_connector = 
}}

The '''APC-7 connector''' (also referred to as a '''7&nbsp;mm connector''') is a precision coaxial connector used on [[laboratory]] [[microwave]] test equipment for frequencies up to 18&nbsp;[[GHz]]. APC-7 connectors are advantageous because they have a low [[reflection coefficient]], make repeatable [[coaxial cable|coaxial]] connections, and are [[Gender of connectors and fasteners|genderless]].<ref name="HP1979p90">{{Cite book|title=Coaxial & Waveguide Catalog and Microwave Measurement Handbook|publisher=Hewlett-Packard|year=1979|location=Palo Alto, CA|pages=90|id=5952-8207D}}</ref> The connectors are expensive, so they are seldom used outside the laboratory where their cost can be justified by their accuracy and convenience. Due to their high cost, their 18&nbsp;GHz frequency limitation, and new laboratory practices,<ref group=note>Connections at the instrument front panel don't need to be repeatable because those connections remain mated during tests. Modern network analyzers focus on the reference plane near the device under test and have features such as automated calibration, adapter removal, and models for calibration references.  The advantages of the APC-7 connector have been diminished.</ref> the connectors are now uncommon.  Modern low-frequency microwave equipment often uses the less expensive 3.5&nbsp;mm (26.5&nbsp;GHz) connector.  Higher-frequency equipment must use higher-performance connectors such as the 2.92&nbsp;mm (40&nbsp;GHz), 2.4&nbsp;mm (50&nbsp;GHz), 1.85&nbsp;mm (67&nbsp;GHz), or 1.0&nbsp;mm (110&nbsp;GHz) connectors.<ref>{{cite web|date=2009-05-03|title=Microwave Coaxial Connectors|url=http://www.microwaves101.com/encyclopedia/connectors.cfm|url-status=dead|archive-url=https://web.archive.org/web/20090512011851/http://www.microwaves101.com/encyclopedia/connectors.cfm|archive-date=2009-05-12|access-date=2010-04-05|website=www.microwaves101.com}}</ref>

== Features ==
APC-7 connector pairs have several desirable features:
* The connectors are genderless. This avoids some awkward adapters or duplication of laboratory standards. With a gendered connector, a laboratory might need a precision male load and a precision female load. With a genderless connector, only one load is required. Although the illustration shows threads on one connector of the pair, all connectors contain a retractable male thread which can be revealed or retracted by turning the outer locking nut. Any two can be mated by retracting the thread in either one and leaving it protruding in the other.<ref>{{Cite web |title=How to Mate APC-7 mm Connectors - Technical Support Knowledge Center Open |url=https://docs.keysight.com/kkbopen/how-to-mate-apc-7-mm-connectors-925976044.html |archive-url=https://web.archive.org/web/20250520152100/https://docs.keysight.com/kkbopen/how-to-mate-apc-7-mm-connectors-925976044.html |archive-date=2025-05-20 |access-date=2025-05-20 |website=docs.keysight.com}}</ref>
* The connectors have a well-defined reference plane. Consequently, the connectors simplify some measurements.
* The mated pair of APC-7 connectors has a low reflection coefficient and thus low [[voltage standing wave ratio]] (VSWR). The low reflection coefficient means better measurement accuracy. The typical VSWR is 1.025:1 at 18&nbsp;GHz.<ref name="HP1979p90"/>
* The mated pair makes a repeatable connection. A pair has a repeatable reflection coefficient to ±0.001.<ref name="HP1979p90"/> Consequently, laboratory measurements have reduced uncertainty.

==Adapters==
APC-7 connectors require adapters to change from the connectors used in the laboratory to those used on everyday products. These adapters are expensive precision devices. For example, an APC-7 to type N (f) cost $105 in 1979.<ref name="HP1979p87">{{Cite book|title=Coaxial & Waveguide Catalog and Microwave Measurement Handbook|publisher=Hewlett-Packard|year=1979|location=Palo Alto, CA|pages=87|id=5952-8207D}}</ref> Such adapters bought new today (as of July 2012) can cost as much as $294.<ref>{{Cite web|last=|title=11525A Adapter, APC-7 to Type-N (m), DC to 18 GHz|url=https://www.keysight.com/us/en/product/11525A/adapter-apc-7-type-n-m-dc-18-ghz.html|access-date=2022-02-24|website=Keysight|language=en-US}}</ref>

==History==
"APC" stands for [[Amphenol]] Precision Connector and "-7" for 7 millimetres.<ref>{{cite web|title=Capabilities - Custom RF Products and Engineered Solutions - Amphenol RF|url=http://www.amphenolrf.com/products/precision.asp?N=0&sid=4A4D4A002301E17F&|url-status=dead|archive-url=https://web.archive.org/web/20190502000007/https://www.amphenolrf.com/capabilities/|archive-date=2019-05-02|website=www.amphenolrf.com}}</ref> Hewlett-Packard started developing the connector in the mid-1960s. Amphenol improved the design and manufactured the connector.<ref name="HP1979p90"/>

== Notes ==
{{reflist|group=note}}

== References ==
{{reflist}}

==External links==
{{Commons category}}
*http://www.rosenberger.de/ok/images/documents/spez/07.pdf [inactive - 4 Feb 2019] Rosenberger RPC-7 document that shows interface dimensions; RPC is Rosenberger's designation for its APC-7 connector
*https://web.archive.org/web/20170707175918/http://www.rosenberger.de/ok/images/documents/spez/07.pdf [active - 4 Feb 2019]
*https://www.rosenberger.com/0_documents/de/specs/tm/07.pdf [active - 4 Feb 2019]

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