Alignment Procedure - Cobra 148GTL-DX Instruction Manual

Alignment of Transmitter Section
1. Test Equipment Required
a) VTVM (Fuli scalę; IV DC with RF Probe)
b) RF Output Pcwer Meter.
c) Spectrum Analyzer.
d) Frequency Counter (0-30MHz).
e) DC Pcwer Supply (13.8V, 2Amp.).
f) 50 ohm load and Attenuator.
g) Oscilloscope (0-30MHz).
h) AF Oscillator.
i) DC Anmeter.

2. Alignment Procedure

STEP PRESET ТО
1 TX. Mode.
Band SW: Mid
CH
Mode
Mic. VR: CW
CH9
Coarse : Center
2 Same as Step 1.
3
Same as Step 1,
except Mic input
30mV.
Same as Step 3.
4
5 Same as Step 3.
Same as Step 1,
6
except;
Mode
Mic input 90% mod
38
C148GTL DX ALIGNMENT PROCEDURE
ADJUSTMENT
VRll
: 19
: USB
: OFF
VR10
VR12
L53
L52, 54, 55
L53
L44
: AM
PROCEDURE
Remove PC-834 (PCB) and connect DC Am­
meter to TP9(+) and TP8(-). Adjust for
50mA reading.
Connect DC Ammeter to TP9(+) and TP7(-)
and adjust for 50mA
Restore PC-834. T u m VR12 to Mac. CW.
and t u m the core of L53 to the obttcm.
Adjust for Max. reading on RF VTVM.
Set the Band: HI, CH40. And adjust for
Max. reading on RF VTVM, then t u m the
Band: 1 Ш , CH 1, readjust for mimimum
différence in output pcwer.
Adjust for Max. reading on RF VTVM.
reading.