Accuracy And Calibration - Array Solutions PowerMaster II Manual

ACCURACY AND CALIBRATION

The PowerMaster II resolves 14 equivalent bits of analog
to digital data. There are 8 sampling channels: 4 forward
and 4 reverse. A calibration table is generated for each
meter that resides in the processor's non-volatile memory
for each of these channels. This allows the best accuracy
possible over the auto ranging scales. This results in a
display that has 4096 steps for each auto ranging scale.
Chose your bar graph scale so that it is the best choice of
resolution for the power your equipment is running. For
instance, if you have a 2,000 watt amplifier, chose the
2,500 watt bar graph scale. This will result in the bar
graph displaying most of the graph at this power level.
At the highest scale the meter will display a resolution of
2.4 watts, but when you're at exciter levels of 100 watts
or less the auto range scale can display resolutions of 1
watt even though it is resolving .09 watts in the sampling
circuit.
The Power Master coupler are calibrated in two
segments: HF (1-30 MHz) and at 50.1 MHz. It has better
then +/- 3% accuracy on our certified calibrated lab test
equipment. We provide a calibration table on each
directional coupler just like the calibrated sensors we use
from our measurement system. The ability to program the
PowerMaster II RF Wattmeter www.arraysolutions.com
PowerMaster with this calibration "trim" data assures you
that you have the best calibration possible with your
meter. The data supplied has two ranges:

1 to 30 MHz – HF Range noted as 30MHz
on the coupler sticker

50 MHz – 6 Meter Amateur Radio Band
noted as 50 MHz on the coupler
sticker
Program the Forward and Reverse Power trim settings in
your meter to match your coupler for the frequencies you
will use. We typically see +/- 3% accuracy at HF and
even better at the 6 meter band.
If your application calls for better accuracy on a certain
band, you can easily recalibrate the unit to suit your needs
by adjusting the forward power and reverse power trim
settings. In this case, you can enjoy enhanced accuracy
since you have calibrated exactly to your test equipment.
There are no potentiometers or variable capacitors in the
coupler or the display enclosure to adjust. The calibration
values are stored in non-volatile memory.
Rev 4.1 - February 23, 2017
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