Often simply referred to as a "GenRad connector", the GR-874 system of coaxial connectors is a sort of RF tinker-toy set that you could use to glue various oscillators and whatnot together in test setups, often in combination with some custom electronics. An interesting feature of the 874 connector is that it is Hermaphroditic (there is no male and female), so gender-changers are not needed. At the time it was designed, it also had superior high frequency microwave performance. The GR874 was soon joined by a family of circuit elements and adaptors using it. The GR874-equipped instruments were added to solve the special measurement problems of vhf and uhf and the availability of these precise measuring instruments in turn made possible a continuous refinement of the basic connector.
The GR874 connector is available in both the common nonlocking version and a high-performance locking version. The locking version has a threaded coupling nut that permits the two connectors to be mechanically locked together in a stable, semi-permanent union for better electrical repeatability, lower leakage, and less chance of accidental disconnection. The quick-connect / disconnect feature is retained if the coupling nut is not engaged.
The GR874 connector has low level of reflections at high frequencies, superior SWR performance, and very low contact resistance - minimizing intermodulation in multichannel communications systems.
The elements of a GR874 include an inner conductor, an outer conductor, a supporting polystyrene bead, a phosphor-bronze retaining ring, and a threaded coupling nut. All metal parts are machined and formed to very close tolerances, and made of hard-drawn brass, except for the center conductor, which is heat-treated beryllium copper to ensure good gripping capability and long wear. A bright-alloy finish on all surfaces produces good conductivity for low loss and gives long-lasting protection against tarnish. Inner and outer conductors are similar—each is a tube with four longitudinal slots in one end, with two opposite quadrants displaced inward. When two connectors are joined, the undisplaced quadrants of one overlap the displaced quadrants of the other.
GR874 cable connectors are for use with more than 40 different RG types of coaxial cable. Each cable connector consists of a basic connector, plus inner and outer transition pieces, a soft copper ferrule, a heat disk, and a flexible cable guard. The transition pieces maintain the 50 Ω characteristic impedance of the connector throughout the reduction to the cable diameter. The cable inner conductor is soldered to the inner transition piece. The cable braid and jacket are crimped to the outer transition by the specially perforated ferrule. Braid and jacket are thus securely fastened, to minimize reflections and leakage. A neoprene cable guard serves as a protective handle. Sized to grip the cable securely without compressing it, the cable guard adds to the quick-connect/disconnect convenience of the connector.
- 874-CA / C8A / C58A / C62A / C174A non-locking, 874-CLA / CL8A / CL58A / CL62A / CL174A locking
- Frequency: DC to 7.5 GHz
- Impedance: 50 Ω
- Input voltage, peak: Depending on model, up to 300 / 500 / 1000 V