W0QE provides more insight into the workings of the ubiquitous ‘UHF’ connector on his web site…

UHF Connector Need for Compensation

W0QE's test setup

The DUT on W0QE’s test bench

Key takeaways and insights include:

  • Cutaway views of some higher quality UHF connectors;
  • Comparison of calculated and empirical attributes;
  • Improvements to the UHF connector using passive compensation;
  • When the UHF connector’s impedance bump is constrained to the small area within the PL-259/SO-239 interface, the loss mechanisms are tolerable;
  • SO-239 connectors with a mostly air dielectric raise the impedance closer to 50 ohms.

W0QE’s findings agree with my measurement of the ‘PL/SO’ in my tests.

From a well documented, pre-WWII, bygone world, where the term ‘UHF’ meant frequencies 30 MHz or above, modern users of the ‘UHF connector’ continue to squeeze higher frequencies through the well known impedance discontinuities.  Squeeze on…

About John Huggins

John is an electrical engineer working in astronomy and aerospace including antenna/RF design spanning 36 years with experience in antenna design including improvements (US20170201002A1 & USD798847S1) to the J antenna.

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