148NWST ALIGNMENT REVISION: 1.111 BURKE
Page:1 print date: 3/27/06
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ALIGNMENT PROCEDURE
MODELS: 148 GTL 148 GTL ST 148 NW ST REVISION: 1.111
DATE: 03/11/03
PREPARED BY: BURKE
Total Pages: 8 pages
148NWST ALIGNMENT REVISION: 1.111 BURKE
Page:2 print date: 3/27/06
148NWST ALIGNMENT INSTRUCTION 1 TEST CONDITION: 1.0. TEST TEMPERTAURE: 25 ±5 °C 1.1. STANDARD DC POWER: 13.8VDC 1.2. MEASUREMENT CHANNEL: CH19 (27.185MHz) 1.3. STANDARD AUDIO LOADING: 4 Ω 1.4. ANTENNA IMPEDANCE: 50 Ω 1.5. STANDARD RF INPUT: 1mV 1.6. STANDARD REF. MODULATION: CB 30% SSB 500Hz and 2400Hz 1.7. STANDARD REF. AUDIO OUTPUT: 0.5W 1.8. PULSE GENERATOR: 1µS pulse @ 100mS and 1V peak-to-peak amplitude, with rise and fall time of less than 10nS. 1.9. FREQUENCY TABLE:
CH NO. FREQ. (MHz) CH NO. FREQ. (MHz) 1 26.965 21 27.215 2 26.975 22 27.225 3 26.985 23 27.255 4 27.005 24 27.235 5 27.015 25 27.245 6 27.025 26 27.265 7 27.035 27 27.275 8 27.055 28 27.285 9 27.065 29 27.295 10 27.075 30 27.305 11 27.085 31 27.315 12 27.105 32 27.325 13 27.115 33 27.335 14 27.125 34 27.345 15 27.135 35 27.355 16 27.155 36 27.365 17 27.165 37 27.375 18 27.175 38 27.385 19 27.185 39 27.395 20 27.205 40 27.405
148NWST ALIGNMENT REVISION: 1.111 BURKE
Page:3 print date: 3/27/06
1.9. TEST EQUIPMENT SETUP AS BELOW: A. TX test equipment setup:
Spectrum Power Analyzer Supply
Modulation 148NWST Meter
Audio Gen.
B. RX test equipment setup: AC VTVM RF Signal Generator Oscilloscope 4 ohm Load
Noise pulse generator
RF Wattmeter
Dummy Load
148NWST
Power Supply
148NWST ALIGNMENT REVISION: 1.111 BURKE
Page:4 print date: 3/27/06
2.0 MAIN ALIGNMENT 2.1 VCO
Alignment STEP PRESET TO CONNECTIONS ADJUST PROCEDURE
1 RX mode, AM, CH1 DC voltmeter to TP9 L19 Adjust for 3.2V, ±0.1V Check CH40 = 4.2V, ±0.2V
2 RX mode, AM, CH19 Oscilloscope to TP10 L21 Adjust for maximum output 3 Same as step 2 Oscilloscope to TP1 L20 Adjust for maximum output
4 RX mode, AM, CH19 Voicelock Midrange
Frequency counter to TP1 L23 Adjust for 34.985MHz
5 RX mode, LSB, CH19 Voicelock Midrange
Frequency counter to TP1
L22 Adjust for 34.9835MHz
6 RX mode, USB, CH19 Voicelock Midrange
Frequency counter to TP1 L59 Adjust for 34.9865MHz
2.2 Carrier Alignment STEP PRESET TO CONNECTIONS ADJUST PROCEDURE
1 TX mode, AM, CH19 Frequency counter to cathode of D17. Disconnect TP7 & TP8.
L31 Adjust for 7.8MHz, then re-connect TP7 & TP8
2 RX mode, LSB, CH19 Frequency counter to TP14
L30 Adjust for 7.7985MHz
3 RX mode, USB, CH19 Frequency counter to TP14 CT2 Adjust for 7.8015MHz
3.0 RECEIVER ALIGNMENT
Connect an AC VTVM across speaker coil. Adjust volume control to obtain a suitable indication. Set generator output low enough to prevent AGC limiting. Preset controls as follows, unless otherwise noted: RF Gain maximum, Voicelock midrange, Squelch minimum, NB/ANL off, Tone normal.
STEP PRESET TO CONNECTIONS ADJUST PROCEDURE
1 RX mode CH19, USB
Output of signal generator through 0.01µF to TP16 (TR15 emitter). Freq. = 7.8005MHz NO modulation, RF output 200µV
L7, L8, L9, L10, L12, L14
Adjust for maximum output
2 RX mode CH19, AM
Output of signal generator through 0.01µF to TP15 (FET1 Gate 1). Freq. = 455KHz, 1KHz 30% modulation, RF output 100µV
L15, L13, L3 Adjust for maximum output
3 RX mode CH19, AM
Output of signal generator to antenna input. Freq. = 27.185MHz, 1KHz 30% modulation, RF output 1µV
L4, L5, L6 Adjust for maximum output
148NWST ALIGNMENT REVISION: 1.111 BURKE
Page:5 print date: 3/27/06
STEP PRESET TO CONNECTIONS ADJUST PROCEDURE
4
RX mode CH19, AM NB/ANL switch set to NB
Output of signal generator and noise pulse generator to antenna input. Freq. = 27.185MHz, 1KHz 30% modulation, RF output 1µV. Oscilloscope to TP17.
L1, L2 NOISE BLANKER Adjust for maximum pulse amplitude on oscilloscope
5
RX mode CH19, AM Squelch to maximum
Output of signal generator to antenna input. Freq. = 27.185MHz, 1KHz 30% modulation, RF output 1800µV
VR3 SQUELCH RANGE Adjust until audio just appears
6 RX mode CH19, AM
Output of signal generator to antenna input. Freq. = 27.185MHz, 1KHz 30% modulation, RF output 100µV
VR1 AM SIGNAL METER Adjust for a reading of 9 on the analog meter of the CB radio
7 RX mode CH19, USB
Output of signal generator to antenna input. Freq. = 27.186MHz, no modulation, RF output 100µV
VR2 SSB SIGNAL METER Adjust for a reading of 9 on the analog meter of the CB radio
4.0 Transmitter Alignment
Maintain a 50 ohm 25 watt dummy load on the antenna connector for the following steps.
STEP PRESET TO CONNECTIONS ADJUST PROCEDURE
1 TX mode CH19, AM Dynamike minimum
RF wattmeter to antenna input
L47, L48, L46, L45, L38
Adjust for maximum RF output
2 Same as step 1 Spectrum analyzer to antenna input L36 Adjust for minimum at 54MHZ
(2nd harmonic)
3 TX mode CH19, USB Dynamike minimum
RF wattmeter to antenna input VR7 CARRIER BALANCE
Adjust for minimum RF output
4 Same as step 3 Insert ammeter at TP8. VR9 DRIVER BIAS Adjust for 25mA
5 Same as step 3 Insert ammeter at TP7. VR8 FINAL BIAS Adjust for 50mA
6
TX mode CH19, USB Dynamike maximum
RF wattmeter to antenna input. Insert a two-tone, 500mV signal to microphone input.
VR11 SSB ALC Adjust for 12 watts PEP RF output
7 TX mode CH19, AM Dynamike minimum
RF wattmeter to antenna input. VR10 AM CARRIER POWER
Adjust for 4 watts RF output
148NWST ALIGNMENT REVISION: 1.111 BURKE
Page:6 print date: 3/27/06
STEP PRESET TO CONNECTIONS ADJUST PROCEDURE
8 Same as step 7
VR6
RF POWER METER Adjust so that the needle of the CB’s analog meter is at the border between the green and red zones.
9 Same as step 7 Frequency counter to antenna input. VR5 TX CARRIER FREQUENCY
Adjust for 27.185MHz
10 TX mode CH19, AM Dynamike maximum
Modulation meter to antenna input. Insert a 1KHz, 50mV signal to microphone input.
VR501 AMC CONTROL Adjust for 90% modulation
11 CH19, AM
Remove the dummy load. Connect a 100 ohm load to the antenna input. Use the built-in SWR meter to check the SWR.
VR12 SWR METER Adjust for an SWR reading of 2
148NWST ALIGNMENT REVISION: 1.111 BURKE
Page:7 print date: 3/27/06
