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Industry News

SMA and QMA Two-piece Connectors for Use on Low Loss Coaxial Cable

March 13, 2005
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Times Microwave Systems has expanded the range of “EZ” style, two-piece coax connectors for its popular LMR240 low loss coax cable. It has also released a series of attachment tools to make field attachment of connectors on LMR-240 cable easy and reliable.

LMR-240 is a 0.240" diameter, low loss coax that is ideal for system interconnects, short antenna feeders and other RF interconnect applications. The combination of a foam polyethylene (PE) dielectric and tape/braid outer conductor results in very low loss and very good flexibility, making this cable a candidate to replace stiffer cables such as 0.250" corrugated copper cables and cables that although larger have comparable loss, including RG-213 and RG-214.

Fig. 1 The new EZ style two-piece SMA connectors.

Added to the already popular Type N and TNC is a new SMA straight plug, SMA right angle, QMA straight plug and QMA right angle, as shown in Figures 1 and 2, respectively. The QMA series of coax connectors is the new snap-on version of an SMA interface. It is gaining popularity with OEMs for use on indoor interconnects where frequencies are below 6 GHz. In the spring of 2005 the company will announce the availability of an EZ style SMA bulkhead jack for LMR-240.

Fig. 2 The EX style QMA connectors.

EZ connectors eliminate the need for soldering and are preferred because they exhibit a positive “snap,” signaling that a solid connection to the cable center conductor has been achieved. A rugged beryllium copper spring finger design on the connector center contact allows the connector to be removed if necessary and re-installed. The outer conductor is attached with a crimp ferrule supplied with each connector along with strain relief tubing and instructions. The two-piece EZ design simplifies the parts count, eliminates material waste and reduces labor. Times also offers several models of crimping tools. The CT-240/200/ 195/100 results in fast, consistent crimps when used with Times connectors and cable sizes from LMR-100 through LMR-240.

The DBT-02 debur tool, shown in Figure 3, is designed to make fast, accurate work of pointing the center conductor on LMR240. It also works with many of the smaller size LMR cables. The DBT-02 is small enough for a key chain yet the cutting edge is case-hardened carbon steel for a long service life. It can be used by hand or in a drill or screwdriver chuck. The design facilitates the removal of any chips after use.

Fig. 3 The DBT-02 deburring tool for LMR cables.

Also available is the new ST-240EZ prep/strip tool for use with LMR-240 cable. The lightweight, ergonomically designed ST-240EZ, shown in Figure 4, eliminates the need to measure and cut each layer of cable or use different tools to prep a cable for termination. Outfitted with case-hardened carbon steel blades for long life, the ST-240EZ tool makes a clean, sharp, 90° cut. It prepares the cable to the exact strip dimensions in one easy step, reducing labor and increasing both accuracy and consistency.

Fig. 4 The ST-240EZ prep/strip tool for use with LMR-240 cable.

Times LMR-240 is the original foam polyethylene dielectric, 0.240" diameter low loss coax. LMR-240 standard has a UV resistant PE jacket for a 20-year outdoor life. Its size, superior RF performance characteristics, ease of use and competitive price make it an attractive and popular alternative to solid Teflon, or solid PE cables of a similar (or in some instances) smaller diameter. Its high flexibility makes it a perfect alternative to corrugated cable without sacrificing low insertion loss. LMR-240 is available in “db” (direct burial), “FR” (fire retardant), “FR-PVC” (riser rated) and other configurations. When used in conjunction with Times connectors, LMR cable assemblies routinely and consistently exhibit lower attenuation and VSWR through 6 GHz as compared to other brands.

With the complete system of LMR-240 cable, EZ connectors and the cable prep tools, assemblies can now be fabricated in the field with high reliability and excellent performance previously achievable only in factory made assemblies.

Times Microwave Systems,
Wallingford, CT
(203) 949-8400,
www.timesmicrowave.com

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