An absorption meter is a simple instrument comprising a variable tuned circuit, detector and a meter. With the capacitor dial calibrated in frequency this simple instrument can be used for the following measurements: 1. Indicating the approximate frequency and relative power output of a transmitter. 2. Indicating the approximate frequency and relative level of significant harmonic or spurious outputs from a transmitter. 3. Checking to see if an oscillator is oscillating. 4. Measuring the relative antenna field strengths so that the relative performance of antennas or ASTUs can be checked. 5. Plotting rough polar diagrams of beam antennas. The absorption meter described in this column was built by Hugh, GOWWQ, during our club construction night and is shown in the photos. It covers the frequency range 1.8 to 60MHz in four ranges.
展开▼
