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Hack 63 Microwave Connector Reference

Be able to tell one microwave connector from
another with this field reference.

So you have the radio, an
antenna, and a length of cable. How do you connect them together? You
need to use connectors that work well in the 2.4 GHz range, fit the
kind of cabling you're using, and mate with each
other. Practically all common connectors have two halves, a male and
a female (or a pin and a socket). A few of the more exotic types
(such as the APC-7; see later in this section) are sexless, so any
connector will match up with any other. Here are the most common
connectors you are likely to encounter in the microwave bestiary.

The BNC (Figure 4-16) is a small, cheap connector using a
quick-connect half turn (the same connector found on 10base2
Ethernet). The BNC isn't well suited for 2.4 GHz
use, but is mentioned here because, with the death of 10base2, the
connectors are frequently sold for pennies per pound.
Don't be tempted.

The TNC
(Figure 4-17) is a threaded version of the BNC. The
fine threads help eliminate leakage at microwave frequencies. TNCs
work well all the way through 12 GHz, and are usually used with
smaller (and higher-loss) cable.

An
N connector (Figure 4-18) is a larger, threaded connector found on many
commercial 2.4 GHz antennas. It is much larger than the TNC. It works
very well on thicker cable (such as LMR-400) and operates well up to
10 GHz. The N is probably the most commonly encountered connector
when dealing with 802.11b-compatible gear.

The connector commonly referred to as a
"UHF" connector looks
like a coarse-thread version of the N (Figure 4-19).
It's not usable for 2.4 GHz, but is sometimes
confused with the N. According to the ARRL Microwave manual,
it's a PL-259 (which mates with the SO-239 socket).
It's not designed to work at microwave frequencies.
Avoid.

SMA
connectors (Figure 4-20) are very popular, small, threaded connectors
that work great through 18 GHz. Their small size precludes using them
with large, low-loss cable without using a pigtail.

The SMB (Figure 4-21) is a quick-connect version of the SMC.

The SMC (Figure 4-22) is a very small version of the SMA. It is
designed to work well through 10 GHz, but accepts only very small
cables.

The APC-7 (as seen in Figure 4-23) is a 7mm-sexless connector, usable through 18
GHz. It is a high grade connector manufactured by Amphenol, and is
expensive, fairly rare, and very low loss.

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 terminate yourself (unless
you're really good and have the right tools.)
Whenever possible, try to buy a pre-made cable with the proper
connectors already attached, at the shortest length you can stand.
802.11b gear doesn't put out much power, and every
little bit helps extend your range and reliability.
It's very easy to make a bad cable, and bad cables
can cause no end of trouble.

When matching

cables to your equipment, you may
encounter connectors of reverse gender (sometimes called
"reverse polarity," or male and
female ends swapped with the same threads),

reverse threading (lefthand instead
of righthand thread), or even reverse gender reverse threading
(both). For example, the popular WAP11 uses an RP-TNC. Make sure you
know what you're getting before you order parts
online!