[Elecraft] K3 Field Day Note: QRO/Battery

[Carl Clawson]

Don't underestimate the voltage drop in your battery cables.

My old ICOM 735 shipped with a ten-foot #12 battery cable, which I used on
Field Day without thinking. Later I realized that I was losing more than
half a volt in the cable. That's a lot when you're running from batteries
with a rig that ceases to function a little below 12 V. A lot of "12 V" rigs
are spec'ed at 13.8 V +/- 15% (some are even +/- 10%, which hardly qualifies
as "12 V"). You don't have a lot of volts to lose running them on battery.

Now I use two paralleled #10 cords, four feet long, with just a short length
of #12 to the radio. Yeah, it's overkill but it makes me feel better.

So:

1. Kudos to Elecraft for designing a rig that runs down to 11 V!

2. Look up a copper wire table and do the math on your power cables. You
might be surprised. Don't forget that you have two wires in series with the
battery.

73 and thanks for listening,

Carl WS7L
K3 #486