SGC SG-2020 TEST DOCUMENT Test Manual page 2

SG-2020 BASIC PERFORMANCE TESTS
The SGC factory test procedures as well as the test procedures detailed in the
ARRL Handbook chapter 26 can be used to fully measure the performance of
the radio. The following are simple tests which do not require laboratory test
equipment and can be used to determine if the unit is generally operating
properly.
1. Receiver Sensitivity:
The measurement of sensitivity with signal levels below one micro volt
requires a well shielded signal generator due to the very low level signal
involved. Inexpensive generators of the sort used by amateurs or for service
work leak signals which causes inaccurate readings at low signal levels.
By using a larger signal level and verifying the expected AGC response, a
reasonable sensitivity check can be obtained with an inexpensive signal
generator.
a. Set the SG-2020 to the desired frequency with mode USB and BW 2.2
KHz. Be sure to turn the RF gain fully clockwise.
b. Set the signal generator to the same frequency plus 1 KHz and set its
output level to 50 micro volts.
c. Verify that the 5 LED's in the bargraph display are lit. If the bargraph
reads more than 2 LED's below the expected value, the unit requires
service.
2. Transmit Quality:
Listen to the voice quality on another receiver being careful to avoid over-
load. Most defects can be heard with critical listening tests.
A quantitative measurement of linearity requires a two-tone audio generator
with the results normally viewed on a spectrum analyzer. However, with
care it is possible to use an attenuator and receiver in place of the spectrum
analyzer.
3. Transmit Power:
The transmitter is connected to a power meter and dummy load. The mea-
sured power is compared to the power setting of the SG-2020.
Note that the power meters usually sold for amateur use are not very accu-
rate. A calibrated Bird or similar meter is needed for reliable results.
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P.O.Box 3526, 98009 Fax: 425-746-6384 or 746-7173 Tel: 425- 746-6310 or 1-800-259 7331
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