Cobra 150GTL Alignment Procedure

150GTL ALIGNMENT REVISION: 1.0 BURKE

ALIGNMENT PROCEDURE

MODEL: 150GTL

REVISION: 1.1

DATE: 02/14/06

PREPARED BY: BURKE

Total Pages: 6 pages

Page:1 print date: 2/14/06

150GTL ALIGNMENT REVISION: 1.0 BURKE

150GTL ALIGNMENT INSTRUCTION

1 TEST CONDITION:

1.0. TEST TEMPERTAURE: 77 ±9 °F

1.1. STANDARD DC POWER: 13.8VDC

1.2. STANDARD AUDIO LOADING: 8 Ω

1.3. ANTENNA IMPEDANCE: 50 Ω

1.4. STANDARD REF. MODULATION: AM 30%
FM 2.5KHz

1.5. PULSE GENERATOR: 1µS pulse @ 100mS and 1V peak-to-peak amplitude,
with rise and fall time of less than 10nS.

1.6. TEST EQUIPMENT SETUP AS BELOW:
A. TX test equipment setup:

Power

Supply

Modulation

Meter

RF

Wattmeter

Dummy

Load

150 GTL

Generator

Audio

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150GTL ALIGNMENT REVISION: 1.0 BURKE

RF Signal

B. RX test equipment setup:

AC

VTVM

Generator

Oscilloscope

150GTL

Power

Supply

8 ohm Load

Noise Pulse

Generator

2.0

MAIN ALIGNMENT

2.1 PLL Alignment

STEP PRESET TO CONNECTIONS ADJUST PROCEDURE

RX mode, AM,

1

28.000MHz

2 Change to Band D Oscilloscope to TP1

Oscilloscope to TP1 T712

DC level should be < 6V

Check for range of 0.2 to
7VDC, then set to 2.8V

3 Same as step 1 Oscilloscope to TP2 T713 Adjust for maximum output

4 Same as step 1

5 Same as step 1

2.2 Carrier Alignment

STEP PRESET TO CONNECTIONS ADJUST PROCEDURE

TX mode, AM,

1

28.000MHz

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Oscilloscope to 4th test
point of CON2
Frequency counter to
TP3

Frequency counter to
TP3

T717 Adjust for maximum output

CT1

CT2 Adjust for 28.000MHz

Adjust for 17.305MHz
(frequency – 10.695)