Tonight’s
training tip will cover power cords. Power cords come in two main flavors:
120VAC
and 12VDC.
Before
you plug a 120VAC power cord into an outlet, be it from commercial mains or a generator,
you ought to test it to make sure the hot, neutral, and ground are wired ok. An
inexpensive ground tester can be acquired for a few dollars from a hardware or
electrical supply store, and you should invest in one for your go kit. Mine is
made by GB Electrical, Inc., it’s yellow, and has three lights on it – a red
and two orange. The pattern of which lights glow when you plug it in determines
the condition: open ground, open neutral, open hot, hot/ground reversed,
hot/neutral reversed, or correctly wired. It’s important to know what quality
of electricity you’re dealing with before you plug your own or someone else’s
expensive rig into it.
Ok,
let’s say you have one of these gadgets, and you’re on assignment. You’re
setting up your station and you have access to commercial mains or a generator,
you’ve tested the juice, and you’re good to go. What next?
That
all depends on the distance from your power source to your station location. It
might be 3 feet or 30 feet. It’s an inexpensive investment to have three prong
extension cords of a couple of different lengths in your go kit. You never know
what kind of distance you’ll be facing. I keep a 50 foot orange utility cord in
my go-kit. It’s easy to see, so that diminishes the tripping hazard. I also have
a 25-foot three-pronged cord, as well as two shorter two-pronged polarized
extension cords, and an assortment of two and three prong multi-outlet
connectors so that from the orange cord’s single outlet, I can plug in multiple
things.
One
of those things is a surge protection power strip. I got a small one at Staples
that has 4 outlets on it, but you can get them with six or more outlets. You
can even get an uninterruptible power supply but there is a weight
consideration there – those beasts are heavy.
Ok,
so now you have your power source where you want it, and it’s surge protected,
and you’ve plugged your fused power supply into it…you did bring extra fuses
with you, didn’t you? Of course you did. Make sure your go-kit has back-up
fuses for every piece of gear in it. And your power supply works fine because
you’ve tested the output with your digital multimeter, right? Of course you
have one of those in your go-kit, too. For less than $15 at most any hamfest
you can pick up a bright yellow digital volt-ohm meter that will measure AC and
DC volts, current and resistance. Buy one and reserve it just for the go-kit so
you’re sure to have it ready.
So
your power supply is putting out its nominal 13.8 volts DC and you’re ready to
plug in the rig and accessories. Unless the power supply has a plug matched for
the rig you’re using, a fairly common occurrence only with HF rigs and matching
power supplies, you’re going to connect the rig’s cable with the power supply’s
terminal screws.
The
“old way” of doing this was to terminate the 12V red and black cable from the
rig directly to the terminal screws. You could have just twisted the copper
wires and perhaps tinned them with solder or maybe even crimped or soldered a
spade or circular lug onto the ends. The new way to do it is to permanently
mount a short piece of cable to the power supply, and use Anderson Powerpole
connectors to mate that cable to the rig’s cable. These are special connectors
that come in different current capacities – the 30 amp ones are usually
sufficient. They come in red and black and to attach them, you first strip the
ends of the cables, then crimp or solder special metal spades to the ends of
the wires. It’s critical to do this part neatly: if you glob too much solder on
the spade, it won’t fit into the plastic housing. If you don’t crimp it right,
the wire will come loose from the spade. And once the spade is in the housing
it’s permanently locked in, so you have to throw it away and start over. Trust
me on this, I know.
Once
the spades are on the wires, you put the red and black plastic housings
together and snap them onto the spades and you’re done. Do the same with the
other cable and now these two identical matching plugs can only be connected in
one way – the RIGHT way. Anderson Powerpole connectors are quite clever in this
regard. The technique is not hard to do. In fact it’s easier than putting a
PL-259 plug onto coax. To learn the proper technique to attach Powerpole
connectors, visit the web site www.westmountainradio.com
and see their tutorial. There is also a good article on these connectors in the
March issue of QST.
The
ARRL and others are promoting these connectors as the universal standard, so
your rig can fit into my power supply and my rig can fit into your power supply
if we need to swap. Without a standard, that’s unlikely to happen, so Amateur
Radio’s collective usefulness as a communications resource is hampered by our
inability to swap out rigs if a rig dies. The only fault with this concept is
that Anderson Powerpole connectors are not easily found at a lot of places.
Most hamfest dealers don’t carry them. I asked a dealer at the recent Mansfield
Hamfest why this was, and he said that Anderson is a difficult company to work
with and won’t cut the dealers any slack on pricing. You’ll find them around,
but they’re not as common as antenna connectors. They cost roughly a dollar per
pair of red and black ones – that is to say, about a dollar per plug.
Two
other items are good to have in your go-kit: A spool of hook-up wire you can
use for an rf ground, earth ground, or just to hook up other stuff. I carry a
15 foot length, but more is better. The last item I recommend is a cigarette
lighter plug and short cable with inline fuses that you can use to power any
rig from an automobile or truck to which you might be assigned. What connectors
will you have on the end of this cable? Anderson Powerpole connectors, of
course!
So,
scrounge around in your junk box for the stuff you can delegate to the go-kit,
and make a trip to the store or go online to get the items you don’t have on
hand. A good investment in power cables will pay off in time saved and
efficiency gained in setting up your emcomm station.
That’s
tonight’s training tip. All comments and suggestions are welcome.