Bird Technologies AT-500-Manual - Manual (Page 66)

Bird AT-500 Antenna Tester
48
ROM, EEPROM, RAM, A/D, TEMPR, PLL Test Fails
Ensure the results are valid by repeating the self test or
turning the unit off then back on. If the problem per-
sists return the unit for service.
Stuck Keys Test Fails
If any characters other than 0 are displayed next to
stuck keys during power up test, perform the keypad
test on page 43 of this section. Remember, if a key is
depressed during power up to display the power up test
results it is normal for other characters to be displayed.
If the key remains stuck return the unit for service.
“Noise” is Displayed During Testing
The Antenna Tester measures background noise to
determine if nearby signals could cause an erroneous
match measurement. Power down all nearby transmit-
ting antennas. All interfering signals must be removed
before resuming measurement.
Antenna Tester indicates a Perfect Match
When measuring the match of an antenna in a high RF
environment, the Antenna Tester indicates a perfect
match (i.e. VSWR = 1.00, Return Loss = -32 dB, or
Match Efficiency = 100%). This is caused by the cou-
pling of interfering signals into the Antenna-Under-
Test. If sufficiently strong, the interfering signals can
over-power the measurement signal inside the Antenna
Tester. Normally, this results in degraded measure-
ment accuracy. Bird Antenna Testers minimize this
effect by measuring the interfering signal during the
time between match measurements. The inter-ferer