ac.8. Antenna Connector
For a number of reasons, you may want to replace the original RCA style antenna
connector with a different style. There are two common replacements.
ac.8.1. BNC Connector
Some may want to replace the "Ant" RCA phono plug with a round "bulkhead" mount
BNC connector. They fit nicely and provide an excellent, solid, 50 ohm antenna
connection. The RCA is also an excellent 50 ohm connector system at 100 watts (better
electrically than the old PL-259 UHF connector system) but after many years the
ceramic insert starts to chip and deteriorate through use (compare it to the other RCA
connectors). RCA connectors are not real good for mechanical retention, especially
where the cables are stressed as they exit the unit.
The BNC connector system is an excellent, low power, 50 ohm system ....both
electrically AND mechanically (and convenient). If you look at the airgaps, insulator
thicknesses, insulator material, and plating materials used, you will find them superior to
the RCA connectors. I've never had a problem with around 100 watts, although I would
not use them at 1KW. A BULKHEAD mount BNC connector does NOT modify the
chassis. Remove the RCA connector and install a bulkhead BNC, which has a small
threaded barrel on the back. The diameter of the threaded portion is actually smaller
than the RCA connector and it mounts in the hole with plenty of room to spare.
ac.8.2. SO-239 Connector
It is also possible to replace the RCA connector with an SO-239 style connector. An
advantage of using this connector is that is probably more commonly used for ham
antenna connections than the BNC connector.
SO-239 bulkhead connectors that mount with a large nut on the threaded portion of the
barrel are readily available on ebay or through other sources. In this case, you only
need to remove the original RCA style connector and enlarge the mounting hole to 5/8”
to accept the new connector. I use a 5/8” Greenlee socket punch as it avoids the debris
associated with drilling a larger hole.
You can also use a standard flange-mount SO-239 connector. This requires enlarging
the hole and drilling additional holes for the mounting screws.
Modifications Page 96
To Next Page
Loading...
Need help?
General
