Cobra 19 Plus, Manual

Page: 11 / 27

3. Adjust L301, L302 r L303 and L304 for maximum amplitude of
the scope display.
4. Increase the power supply voltage to 13.8V, and then adjust
L305 and L306 until the watt meter indicates 3.8W.
5. Measure the transmit power output at all channels, and make
sure that the power output différence between any channels
is less than 0.3W.
6. Measure the transmit frequency at all channels, and make
sure that the frequency is /-800Hz from the assigned
channel center frequencies.
c. Transmit Frequency Check
1. Set the radio into transmit mode with no modulation.
2. Connect the frequency counter to the antenna load or to the
tab provided at the watt meter.
The frequency should be within +/-800HZ from each channel
center frequency as tabulated in Table 1.
d. Modulation Sensitivity Alignment
1. Set the unit to transmit mode of operation. Feed 1kHz, 30mV
signal to the microphone input circuit, and adjust RV501 so
that 100% modulation is obtained.
2. To set the transceiver into transmit mode without a
microphone, insert the plug, wired as shown below, into the
MIC jack on the transceiver. When applying the audio
modulation signal to the microphone input circuit, use the
same plug.
(
1
) (
2
)
A+B
3 .
Next, reduce the signal input level to 4.5mV, and make sure
that the modulation is higher than 60%.
19 PLUS -10-