Similarly do NOT operate at a setting of R5 beyond the recommended setting (see previous
section). A higher setting (more clockwise) can produce more power output for a given supply
voltage, but it also increases the risk of spurious output and glitches.
8
Measurements
8.1 Power output vs Supply voltage
This is a measurement of output power vs supply voltage for the production models assembled for
testing. In each case (each band 80, 40, 30 and 20m) the input power was provided by a QCX
powered at 12V supply. The power was measured as 3.2W into a 50-ohm dummy load in all
cases. Then the dummy load was removed and a short coaxial cable used to connect the QCX
output to the 50W PA input. The 50W Power Amplifier set-up adjustment was as per section 7.4. A
50-ohm dummy load was used at the output of the 50W PA and the peak-peak voltage measured
using an oscilloscope.
50W QCX PA kit assembly
1.00q
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