# Info

Total

Example: 615/120 = 5.125 Amps 5.125/0,8 = 6.4 Amps total

Take the total power and divide by 120 to get me current, and then divide by 0.8 lo account for any power factor. The number you get is the Ampere load you will have to supply from the ac line.

their shacks with both 12 and 5 vofts dc

Qt Why would I want to do that?

A. Typically, you will end up with a main rig and then a half dozen soiid-state accessories, If you build them independently,, there also will be a half dozen smafl dc supplies, each of which must be plugged into the ac line. If you plan ahead a little and set up a 12-volt power supply at a few Amps, you can power al! of these units from the one supply. Most of the c ircuits around these days use 12 volts dcH with the exception of those using S-volt digital logic. You can add a separate 5-volt dc supply or tncfude a dropping resistor and voltage regulator m each of the 5-volt units

Q. Will I be safer if t connect the ground bus to the ac power system?

A. Unless you are an experienced electrician, the only grounds you should use with the ac line are those built into the three-wire cords common on some equipment. Keep your ground bus separate,

Q. Since the ground bus is not connected to the ac line, what do I need it for?

A,. You need a good ground primarily for safety. I use a V x 1/2" aluminum bar, running the length of my operating table. Every 6" I have drilled and tapped it to connect braid from the bus to each of the pieces of equipment. When I put a piece of equipment down on the operating table, I connect it to the ground bus before I plug it in, and when I want to remove it, I unplug before I disconnect the ground. If anything goes wrong, at least ( don't end up with the 120-vott line voitage on the front pane! of the equipment See Fig 3

Q. Where is the ground bus connected to? Can I use a hot-water pipe rather than a cold-water pipe? How about the radiators? How about the this or the that?

A. Yes, yes, yes If in doubt, connect it to all of them. No one has an ideal ground and you cannot hurt anything by connecting it to more than one ground, lust stay away from the ac wiring. The most important thing is to use wide braid or heavy aluminum wire, securely clamped. You should also remember that these mechanical (non-soldered} connections corrode and should be cleaned and tightened periodically

Q. Is this ground bus the same ground that is shown in the pictures of antennas?

A. If you are using a coax-fed antenna, such as a dipole or beam, the shield of the coax will be connected through your rig or matchbox to the ground bus. But the bus plays little if any part in the antenna performance However, if you are using a matchbox to feed a long wire with no radials, the ground bus provides the other end of the antenna circuit and is doubly important. See Fig, 4.

Q. What about antennas in setting up my shack?

A Your shack must be located in such a way that you can run your antenna feed-lines to the operating position, For this reason it is always nice to be close to an outside wall, Remember that no ham in history has ever had enough antennas, either. Plan ahead, and if you expect to run three lengths of coax into the shack, plan for at least six or eight and make whatever opening you drill through the wall big enough for the additional feedlines. It is much easier to stuff the extra space with loose fiberglass insulation than to go back and drill some more Fig. 5 shows one possibility,

Q, I keep seeing pictures of ro water