Vectronics VEC-1220K - Manual (Page 25)

VEC-1220K/1230K/1240K/1280K Owner's Manual
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inadequately-filtered 12-volt wall-adapters. These can cause ripple on the
CW note, and may even damage your kit if the unloaded output exceeds 15
volts. A fully-charged 12-volt battery is a suitable power source, although
transmitter output may be reduced slightly (RF output is specified at 13.8
volts).
The power jack supplied with your kit is a common 2.1-mm DC connector. The
mating 5.0-mm OD x 2.1mm ID plugs are available at your local Radio Shack
store (274-1567). Take care not to reverse-connect the power leads. The plus
(+) or red power supply lead connects to the center pin, and the minus (-) or
black lead connects to the outer sleeve. If your power wires aren't color-coded,
confirm polarity with a voltmeter before installing the plug!
+
-
DC Power Supply
13.8V @ 0.5A
+
-
Important Note: In case of accidental reverse-power connection, your
transmitter is protected against major damage by a "crowbar" diode (D1).
However, activation will blow a "trace fuse" etched onto the circuit board next to
the power connector. This must be replaced by a thin wire or a pig-tail type fuse
before your kit will operate again (see "In Case of Difficulty").
5. RF Cables: Patch cables are needed to interconnect the transmitter to your
wattmeter and receiver. You may make these up using RG-174 "mini-coax"
or RG-58. Install a RCA phono plug at the transmitter end, and the
appropriate connector at the opposite end.
If you already have patch cables, you may purchase 50-ohm coaxial transition
adapters that fit RCA jacks from your local Radio Shack store. For BNC patch
cables, use catalog number 278-250. For a direct PL-238 transition, use a
"scanner adapter" plug, catalog number 278-208. This is a UHF to "Motorola-
jack" type adapter that requires only minor modification to work with RCA
jacks. To modify, shorten the protruding center pin so that it extends about 1/8"
beyond the outer sleeve of the plug using a fine-toothed hack-saw or hobby saw.
De-burr and round off the end. The modified transition will now plug directly
into RCA jacks.