Tim McDonough, Springfield, Illinois, USA
This page was last updated on April 2, 2005

Contact Tim: n9puz[at]arrl.net

Watts Up With Your Station Power?

There are an awful lot of Hams like myself are involved in Emergency Communications and or portable operating of one type of another. Things I'm always concerned about whether at home or in the field is how much electrical power my station is using and how much energy I've pulled out of my battery system. Of course, like most Hams, I tend to like interesting gadgets too!

The meter is not intended to be a lab grade instrument but it does a good job of letting you know what's going on with your equipment. The internal circuitry measures and calculates additional digits of precision that are not shown on the display. Still, the information is very useful for keeping an eye on things and is a lot better than the estimations I used to make.

The picture below is a meter that I use to measure current, voltage, and Watts in electric powered model airplanes and cars. It will measure voltage up to 60 Volts DC, and Current up to 100 Amps for durations of a few seconds or so. At 12 Volts you can leave it in your system indefinitely at currents up to 25-30 Amps.

Here's the "big picture". A cable coming from my station supply connects to the meter. The output of the meter attaches to the DC IN connector of a West Mountain Radio 4005 RigRunner.

A microcontroller inside the instrument calculates power in Watts. One of the more useful features for battery operation is the lower right section of the display. When the instrument is first connected to a DC power source and a load is applied, it begins tracking and displaying Ahr. Quit wondering what your ratio of transmit to receive has been. If you have a battery in decent shape then you can compare the instruments display to the known capacity of your power system.

Information on getting a meter of your own at special Ham pricing can be found here.