Ten-Tec SSB-CW-AM Instruction Manual page 111

Antenna Connection and Switching Suggestion
The RCA-type phono jack on the rear panel of the Model 1254 is
intended for "normal use," which means occasional plugging and
unplugging a lightweight shielded cable terminated in an RCA-
type plug. It is not designed to withstand repeated manipulation
of, for example, RG-8 coax with a PL259 plus the required phono
plug adapter. If you expect to use or try out a variety of
antennas, especially those intended primarily for ham transceiver
use, we suggest that you build up a simple "antenna utility box"
for use with your receiver.
Such a box would be connected to your receiver via a few feet
of lightweight shielded cable with RCA plug. The box itself can
provide as many cable connectors and switches as you want,
plus a master grounding switch. Some audio or cable TV switch
boxes from sources such as RadioShack might do exactly what
you need.
Your Antenna Design Notes:
1254 Reference - 18