Featured: DX Engineering Crimp/Solder 8U PL-259 Connectors (12 pack) at DX Engineering.
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Low-loss double-shield coax is a popular choice behind an amplifier, but it creates a connector problem. Standard solder-type PL-259s are made for single-braid cable, and soldering to a foil-and-braid shield does not make a good joint. DX Engineering's Next Generation Crimp/Solder 8U PL-259 connectors, sold as part DXE-PL259CS8U-12, crimp the shield and solder the center pin instead.
Why crimp the shield
DX Engineering states that engineering studies have confirmed the absolute best RF connections for double-shielded cables like LMR-400 and DXE-400MAX are made by crimping the shield, not soldering. A proper crimp clamps the braid evenly all the way around, without the heat that can melt a foam dielectric or leave a lumpy, partial solder joint on the shield.
What the connectors are
- Attachment: crimp shield, solder center.
- Cable fit: listed as fitting all RG-8U size cables with center conductors up to 10 AWG, including DXE-400MAX and LMR-400 as well as RG-213U.
- Materials: all silver-plated brass shell and body, with a silver-plated center pin securely mounted in PTFE dielectric.
- Center pin: full length and full diameter, so it connects properly even with worn SO-239s. It accepts large conductors, and a scalloped tip allows generous solder flow.
- Quantity: sold as a set of 12.
The right tool matters
A crimp connector is only as good as its crimp. DX Engineering's Ultra-Grip 2 crimp tool, part DXE-UT-CRMP2, includes one set of DXE-UT-DIE-8U crimp dies for RG-8U/213/LMR-400 size cable. The dies are cut to enable crimping both the ferrule and the center pin, and an included 2.5 mm Allen wrench is used to change to other optional die sets.
Pliers and a hammer do not make a reliable crimp. A ratcheting tool with the correct die gives the same result every time, which matters when a jumper will carry amplifier power.
Building a good jumper
- Strip to the connector's dimensions with a proper coax stripping tool, and keep braid strands out of the dielectric.
- Solder the center pin cleanly without overheating the dielectric.
- Inspect the crimp. The ferrule should be firmly and evenly compressed, with no loose braid showing, and the connector should not move when you tug on the cable.
- Test before use. Check continuity on the center conductor and on the shield, and confirm there is no short between center and shield.
Once a jumper checks out, it can go into service with confidence. For connections that will live outdoors, weatherproof them properly, because water that gets into a connector can work its way down the cable and raise loss over time.
If you already build single-braid jumpers with solder-type connectors, the extra step here is simply the crimp. The payoff is a shield connection that suits the cable it is made for.
And the usual reminder: external linear amplifiers are not legal for use on CB radio. Well-made jumpers belong in every legal amateur station.
Where to get it
Check current price and availability: DX Engineering Crimp/Solder 8U PL-259 Connectors (12 pack) at DX Engineering.
This is an affiliate link: Hood's Finds may earn a commission from DX Engineering at no extra cost to you. More picks on the gear page.
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