What type of connector interface is required?
This can be more fun than selecting coax. Here are a couple of rules of thumb. If you are operating below 300 MHZ, a UHF connector will generally be satisfactory although it is difficult to waterproof. Above 300 MHZ, the UHF connector induces VSWR mismatches. Type “N”, TNC and BNC connectors are preferred at higher frequencies because they maintain a good VSWR. These connectors are low loss and can handle moderate power (250 Watts) up to 1 GHz.
If high power and/or low intermodulation distortion is required, especially where multiple antenna systems are operating in close proximity, the new large 7-16 DIN connector may be required. If small size and low power operation from 1-10 GHz is anticipated, the SMA connector may be preferred.
Regardless of the quality or type of the connector, the potential exists to introduce noise, signal loss and lower reliability through every connector break in the trans mission line. An antenna with an integral jumper or “pigtail” which extends from the antenna to the feedline on the mast may be preferred. An antenna with its connector mounted right on the antenna feed point may be cheaper to buy, but add in the cost of a “jumper” cable, the signal losses, increased maintenance and you may have to reevaluate the “value” of a low cost antenna.
The power-handling capability of an antenna is usually a function of the connector type and the transmission line (if it is an integral part of the antenna).
You should specify the “average” power that will reach the antenna. If your transmitter is emitting pulse or peak power, it is important to inform the antenna supplier the peak power level.
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This information should be used as a guideline only to help you in the appropriate selection of an antenna.