Moderated Discussion Areas
ContinuousWave: Small Boat Electrical
|Author||Topic: Coaxial Connectors|
posted 05-13-2006 06:08 PM ET (US)
I need connectors. Hooking up my new Icom 302 to a 4' Digital Brand SS antenna. I am planning on using the Shakespeare SS rail mount with lever. I have the coax from West Marine, but they had no connectors in stock and the sales guy was clueless on what I needed to hook up the VHF rig.
I think that I need PL-259 on both ends of the feed line....one to the radio and the other into the antenna. Correct ?
posted 05-13-2006 09:23 PM ET (US)
That's correct. A pain to solder per the instructions that come with a Shakespear antenna, but that's the correct connector. I just did mine last week.
posted 05-13-2006 09:34 PM ET (US)
Be sure to use the correct PL259 connector. If your coax is RG-8X, it is smaller than "normal" coax.
The correct one has 8x in the part number...and states that it is appropriate for RG 8X cable right on the front of the package.
It's an easy connection, and you don't NEED to solder it if you're in a hurry, though you should eventually go back and solder the connection for permanence.
posted 05-13-2006 09:35 PM ET (US)
Actually, depending on which antenna you have, you may only need one PL259....my Shakespeare antennaes came with about 10 feet of RG-8X coax already connected to it...
posted 05-13-2006 10:50 PM ET (US)
A PL-259 is a UHF series connector that mates with an SO-239, the connector commonly found as the output from most Marine VHF Radio transmitters. This connector designator refers to a connector designed to be used with coaxial cable in the RG-8/U series, which is about 0.5-inch in diameter.
The connectors are described here:
To use a PL-259 connector with smaller diameter cable you need an adapter. These are available in two sizes, one for RG-58/U cable, and one for RG-59/U cable.
Many marine antennas are sold with a strange coaxial cable which is something of a hybrid cable. It is the diameter of RG-59/U (a 75-ohm cable) but it is made with a larger center conductor so that its characteristic impedance is closer to 52-ohms. To use this cable with a PL-259 connector, you use the RG-59/U adapter.
These links are to high-quality connectors. A lot of marine stores sell junk connectors. Many of these are so low quality you cannot even solder to them.
Personally, I avoid those "marine" grade products, particularly the junk connectors and the weird hybrid cables.
posted 05-13-2006 11:10 PM ET (US)
Although the PL-259 and SO-239 are in the UHF series, no one really uses them for UHF work, and they are really borderline for VHF work. The reference dates back to the 1940's.
The designator for the reducer for RG-58 cables is UG-175.
The designator for the reducer for RG-59 or 8X cable is UG-176.
Here is a good chart from a vendor. Note the prices--probably quite a bit lower than the boat (jewelry) store prices:
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