Russian Coax Connectors

50 Ohm coaxial cable connector
Made in RUSSIA

The SR-50 is a very robust connector, used in professional and military equipment. The connector resembles a screw-C type, and similar others. Note that the connector is attached by screw threads (as with an N type), not a bayonet mount.

Note also that there is a right-angled variant available, and also others for smaller size cables like RG58.  The version described here, the SR-50-164PV (western letters) is for cables like RG-213/RG-214 and UR67.  There is a physically identical connector designated SR-50-164FV.   "P" is for for Polythene and "F" is for Teflon insulators.

An illustrated how-to for installing these connectors:

1.  Disassemble the connector, you should have a set of parts like this.  Like any coax connector, they get easier with a little practice.

From left to right: connector outer shell, outer insulator, center pin, and inner insulator. In the top picture, and not in the bottom, is a "star washer" - some connectors come with this, some without.  Resuming part identification for both pictures, the next item is a "castellated" washer, then the rubber washer (red in top picture, white in bottom), metal washer, cable clamps and backnut.  The brownish circles above and below the metal washers are paper wafers placed between the metal washers and the clamps to keep all parts seated together properly for shipping.

2.  Cut 5/8" (ca. 16mm) of the black cablesheath neatly from the cable, without nicking the braid; slide the backnut, then the metal and rubber washers over the cable as shown.  Slide the front 'castellated' washer over the exposed braid; seat it in the top of the black outer sheath of the coax.


3.  Fan the braid out evenly, then twist into six equally spaced pigtails, placed in the spaces around the washer, as shown.


4.  Tin the six pigtails and trim them back to the washer.  Use 200W soldering gun and quickly solder tinned braid to castellated washer.  Speed is necessary to prevent melting both inner and outer insulation on the coaxial cable.  Cut center insulator back leaving 1/8 inch or a bit more (3-4mm) remaining in front of washer and braid.  Then cut center conductor, leaving 1/4 inch (6-7mm) protruding from center insulator.


4a.  If the connector you are using came with a star washer, place it over the remaining center insulation, as shown.


5.  Place the inner insulating washer (it can be either teflon or polythene) on the center insulation protruding from the coax.  One side of the washer is shaped to fit over the end of the coax inner insulation.  Make sure this side goes on first.   Slide the center pin onto the coax center conductor; it fits into the hole in the insulating washer all the way to the shoulder on the pin.  Solder in place.  If the washer is polystyrene, don't use too much heat or take too much time; it is possible to melt the washer.


6.  Place the outer insulator over the center pin.


7.  Insert the assembly into the connector shell. Then bring up the washers for installation in the shell.

8.  Pull the rubber and metal washers into the connector shell.  Sometimes it helps to twist the shell, as if screwing the washers into the cylinder, to get the rubber washer to seat evenly in the shell.


9.  Insert the two C clamp pieces into the connector shell.  Note that these engage in machined recesses in the connector shell.


10.  Do up the backnut.  This clamps the cable securely.  Note that there's no torque figure specified in the original text.  Go for what you need to make sure everything's electrically and mechanically sound.

My contratulations! You can assemble Russian coaxial cable connectors.