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3-1/8" EIA Connector for 4" Coaxial Cable, Gas stop/ Gas pass,O-Ring Sealing

Rev : 05 | Rev date : 22 Apr 2021
Radio Frequency Systems line of high-performance HELIFLEX® coaxial cable connectors are characterized by excellent gas tightness and extremely low losses. HELIFLEX® connectors can be installed with basic hand tools. Tab flange of outer connection and use of o-ring sealing simplifies installation of the connector.
RFS connectors are fully tested for mechanical and electrical compliance to specifications.
HELIFLEX® connectors have excellent electrical values and provide outstanding performance for the most demanding applications. The RFS connector design provides maximum sealing integrity and gas tightness.


  • Easy installation utilizing only basic hand tools.
  • Tab flare of outer contact attachment means quick and simple installation.
  • No need for sealing compound. The connector is ready for pressurization immediately after installed to the cable.
  • Excellent gas tightness. Overpressure for increased voltage handling is maintained throughout the system.
  • Outstanding VSWR performance improves overall system performance.
  • Totally waterproof, assures safe, long term operation in the harshest of environments. 
  • RoHS (EU) and CRoHS (China) compliant, can be used on a global basis.

318EIA Connector for HCA400 Cable

Technical features

General Specifications

Transmission Line TypeCoaxial Cable
Cable Size4"
Cable TypeAir Dielectric
Model SeriesHCA400-50 Series
Connector Interface3-1/8" EIA
Connector Type
Gas stop /Gas pass - See Note 1)
Sealing Method
O-ring seal
GenderFemale - See Note 2)

Electrical Specifications

Insertion loss dB

< 0.05dB

VSWR, Return LossVSWR (dB)0 <f ≤ 860 MHz: 1.02 (40)
860 MHz <f ≤ 1.5 GHz: 1.05 (32)

Mechanical Specifications

Plating Outer/InnerTri Plate/Silver
Length mm (in)195 (7.7)
Outer Diameter mm (in)140 (5.5)
Outer Contact AttachmentTab Flare

318EIA-HC400-019 connector, dimensions in mm

External Document Links


1) The connector is converted to gas pass by drilling through the pilot hole in the insulator.
2) Connector model with -019KT suffix denote connectors that are supplied with an inner connector and flange
Connector model -019 does not include an inner connector and flange hardware.