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Hi Roy,

The design of the GR-874 is unique (except for its bigger brother) in the electronics industry. It is brilliant design which is why it has lasted so long.
The connectors are hermaphroditic, in other words it has both male and female parts so they can mate to themselves. There is no need for male plugs and female sockets.

To insure the outer leaves are positioned properly with each other it was necessary to place a slight outward bend (or flare) at the end of two opposite outer leaves on each GR-874 connector. This simple mechanical feature insure that the leaves properly position themselves with respect to each other each time you mate two GR-874 connectors. You will notice this also requires you to orient the connectors with a 90 degree turn between them so the leaves with the flair are always opposite leaves with no flair. This wasn't necessary to do for the leaves of the inner conductor. Instead two of the inner leaves are positioned ever so slightly inward closer to the center. This insures the leaves from the other connector (rotated 90 degrees) which our further out from the center will mate perfectly with them. The result is that the outer leaves form a circular pressurized contact with each other and the inner leaves do the same. The circular design with simple mechanical self-alignment insured excellent performance past 7GHz. They are rugged as well, and didn't require any special locking mechanism. GR manufactured numerous adapters, terminators, extenders, power splitters, detectors, slotted lines, tunable filters, etc. with these connectors on them so it quickly became the standard HF connector in the electronics industry.

For more information see the article in the GR Experimenter from 1949 which introduced the GR-874:


To see some of the hundreds of things made with GR-874 connectors take a look at this 20 page long excerpt from the GR 1975 catalog:


General Radio made outstanding products. Few companies make products that ae still in use 75 or 100 years after they were designed. The Variac was one of their designs from 1934. They licensed the design to several other companies but the original design was so perfect that the other manufacturers always followed the same design principles. The Variac has been in widespread use for 85 years. I'll bet that at least 50% of the TekScopes members have one and that it gets used. GR-874 connectors aren't quite that old - only 70 years now - but they too are still in widespread use.

Dennis Tillman W7PF