SGC some time ago took to the idea of having just a single
"wire" exit the SG-230 tuner. That "wire" consists of:
1 - thin coax...smaller than RG-58...with a PL-259 (male UHF) connector OR, sometimes, a SO-239 female UHF connector.
2. Four thin wires, wrapped around the coax and inside the outside rubber coating. These wires are as described in the manual.
I don't particularly like this setup, but that's what you have to deal with.
The coax, obviously is to carry the RF signal from the radio to the tuner.
The four wires are intended to:
(a) carry the 12VDC current
needed for the tuner....a small amount, about 1A I believe; and
(b) provide for an external small panel which allows remote
indication of when the tuner is actually tuned (a la Erik's post above) and to reset the tuner instead of having to turn it off.
You need to be sure that:
(1) the coax is properly connected to the radio; and
(2) the red and black wires exiting the tuner are supplied with 12VDC current when you are using the tuner.
You can ignore the other two wires.
Note that the Tune button on the 802 does nothing with this tuner. It works only with the Icom AT-140, AT-130, etc.
You need to whistle into the mic to create some output for tuning. You should then hear the tuner clicking clearly. If you don't hear the clicking, either the tuner isn't working right or there's no 12VDC connection to the tuner.