(click each image for a bigger picture.)
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| BNC: Quick-connect half turn, same as on 10base2 ethernet. They can be fairly high loss at 2.4GHz, but they are common and cheap. 'BNC' stands for 'Bayonet Neill-Concelmann'. Popular opinion is that they're okay for 2.4GHz work as long as they're new, but ditch them if they are at all loose. |
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| TNC: Threaded version of BNC. Works well through 12GHz. |
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| N: Threaded, larger connector common on many commercial 2.4GHz antennas. They perform quite well, although they are larger than some (but are perfect for thicker cable, like LMR-400.) 'N' was evidently Neill's connector. |
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| UHF: This looks like a coarse-thread, big center conductor version of the N. Not usable for 2.4GHz, but frequently confused with the N. According to the ARRL Microwave manual, the Socket is an SO-239, and the Plug is a PL-259. Most call it 'UHF'. Avoid. |
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| C: A quick-connect version of the N. It has been described as "a BNC on steroids." As with the BNC connector (or any bayonet connector), don't use it if it is at all loose fitting. 'C' was evidently Concelman's connector. |
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| SMA: Very popular, small, threaded connectors. Work great through 18GHz. 'Sub-Miniature A'. Small and common, but no good for bigger cable (like LMR-400) without using an adapter. |
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| SMB: A very small version of the SMC. |
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| SMC: A push-on version of the SMA. |
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| APC-7: 7mm plug, usable through 18GHz. A sexless connector (i.e. any APC7 can connect to any other.) High grade, expensive, fairly rare. 'Amphenol Precision Connector'. Virtually no loss at 2.4GHz. |
Can't find the connector you are looking for? For even more exotic connectors, take a look at this table from the University of Colorado.
Remember that each connector in the system introduces some loss. Avoid adapters and unnecessary connectors whenever possible. Also, commercially built cables tend to be of higher quality than cables you roll yourself (unless you're really good and have the right tools...) Whenever possible, try to buy a premade cable with the proper connectors already attached, at the shortest length you can stand. 802.11b gear doesn't put out much power at all, and every little bit helps extend your range and reliability.
When matching cables, you may encounter connectors of reverse polarity (male + female swapped, with same threads), reverse threading (left-hand instead of right-hand thread), or even reverse polarity reverse threading (both). Make sure you know what you're getting before you order parts online!
(All above photos copyright 2001, Rob Flickenger, unless otherwise noted. Please don't steal 'em.)
