UHF connector
UHF connectors (from English Ultra High Frequency for German "Ultra-High Frequency" ) are comparatively simple and inexpensive coaxial connectors that are used up to frequencies of around 300 MHz.
history
The coaxial connector was developed in the 1930s by the American electrical engineer E. Clark Quackenbush while working for Amphenol , a company that was founded in 1932 and is now steeped in tradition . The diameter of the inner conductor is 4 mm and thus corresponds to that of a conventional banana plug .
Originally, these connectors were designed for relatively moderate frequencies (a few MHz) for use as video connectors for the visible parts of the radar devices of that time. But they quickly became common for radio and radio-technical applications and are still used today, mainly due to their comparatively low price. They are used for high-frequency applications at relatively low frequencies, in particular in the short-wave range (3 MHz – 30 MHz) and below, or for applications in which metrological precision and good anechoic matching are not the focus.
The term “Ultra High Frequency (UHF)” for the connector is to be understood from the perspective of the time when frequencies above around 100 MHz were considered “ultra high”. From today's point of view, such a designation would be considered exaggerated, in fact even wrong. Today, UHF is understood to be the decimeter wave range , i.e. frequencies between 300 MHz and 3 GHz. The connector is not suitable for this because of its imprecise impedance , which can deviate considerably from the desired 50 ohms. Depending on the structure, the connector's impedance is sometimes only 30 ohms. So it causes a considerable mismatch (at high frequencies) . As a rule, no standing wave ratio is specified for UHF connectors , which excludes their use in high-quality devices. It is therefore jokingly said that UHF stands for "unsuitable for high frequency".
The US military's name at that time was " PL259 plug" and " SO239 socket" for the UHF plug and the UHF socket, respectively. This has resulted in the alternative designation PL connector , which is actually incorrect.
application
In amateur radio it is used in the shortwave and ultra- shortwave range. UHF connectors are also still in use in CB radio and VHF marine radios . For high-quality devices and with frequencies in the UHF range and higher, however, other connector systems are used, for example N or SMA connectors . The main advantage of UHF connectors is their low price, which is probably the main reason for their use today.
Mini UHF
The mini UHF connector is a modified and reduced design of the UHF connector, which is characterized by improved electrical and mechanical properties. Due to the toothing of the screw cap, it is particularly intended for mobile use and thus prevents loosening or twisting of the plug connection triggered by vibrations. In contrast to the UHF connector, one can speak of a defined wave impedance of 50 Ω. It is used up to around 3 GHz.
Web links
- Data sheet at amphenolinfocom.eu (English)
- UHF Connector Series at amphenolrf.com (English)
- UHF Connector SO239 & PL259 at electronics-notes.com (English)
Individual evidence
- ↑ data sheet at amphenolinfocom.eu (English), p. 1, accessed on July 8, 2019.
- ↑ UHF Connector SO239 & PL259 electronics-notes.com (English), accessed on July 8, 2019.