RF Interconnect Field Note: Hirose BNC-P-1.5(40)
The Hirose BNC-P-1.5(40) is a 50 Ohm BNC plug with a male pin contact, designed for cable group 1.5D-2V. The 2 GHz max frequency covers the common VHF/UHF bands, cellular (up to 2 GHz), and ISM applications; above that, the BNC interface geometry itself becomes a limitation, not the contact. The solder termination for the center conductor and clamp for the shield braid give a reliable, field-serviceable assembly — no special crimp tool required, but the solder joint must be clean to avoid cold-flow failures over the 1000 mating cycles the bayonet lock is rated for.
This plug is specified for cable group 1.5D-2V, a 1.5 mm-diameter coaxial cable with a solid or stranded center conductor and a foam or solid polyethylene dielectric. It is not a direct fit for RG58 (which has a 2.95 mm outer diameter and different dielectric) — the clamp and center contact dimensions are sized for the 1.5D-2V jacket and dielectric. Using a different cable will shift the impedance and may not achieve mechanical retention. The shield termination uses a clamp over the braid, which provides consistent 360° shield continuity and strain relief; the center contact is soldered. The dielectric material is PTFE, which maintains stable impedance over the -30°C to 60°C operating range.
Construction and Mating Cycles
Silver plating on the center contact gives lower contact resistance than gold at RF frequencies, but it tarnishes over time in corrosive environments — the 1000 mating cycles rating assumes the silver surface is wiped clean on each mate. The bayonet lock (BNC standard) provides quick connect/disconnect with positive locking; the single-port, free-hanging design is intended for cable assembly termination, not panel mounting. The bulk package means the plug ships loose, not on a tape or reel.