www.cqham.ru

\главная\р.л. конструкции\ схемы и мануалы\...

PLL CARIER OSCILLATOR PORTION

Test equipment required:

     

Power Supply: 13,2 V

DC Volt Meter

Oscilloscope

Frequency Counter

Preparation alignment:

     

Clarifier

Center

   

RF Power

Clockwise

   

VR205 and VR206

Center

   

Remove

PB 201

   

Step

Condition

Adjustment

Procedure

1

RX AM
27.405 MHz

L405

Connect the DC Voltmeter to TP2
Adjust for 2.5 +/- 0.1 V

2

RX AM
26.965 MHz

 

Same as Step 1
More than 2.0 V

3

TX AM
27.205 MHz

L401

Connect oscilloscope to TP1
Adjust for 37.900 MHz +/- 20 Hz

4

RX AM
27.205 MHz

Check

Same as Step 3
37.900 MHz +/- 20 Hz

5

TX FM
27.205 MHz

Check

Same as Step 3
37.900 MHz +/- 20 Hz Reading

6

RX FM
27.205 MHz

Check

Same as Step 3
37.900 MHz +/- 20 Hz Reading

7

TX USB
27.205 MHz

VR211

Connect oscilloscope to TP1
Adjust for 37.9025 MHz +/- 20 Hz

8

RX USB
27.205 MHz

Check

Same as Step 3
37.9025 MHz +/- 20 Hz

9

TX LSB
27.205 MHz

L402

Connect oscilloscope to TP1
Adjust for 37.8975 MHz +/- 20 Hz

10

RX LSB
27.205 MHz

Check

Same as Step 3
37.8975 MHz +/- 20 Hz

11

TX AM
27.205 MHz

L406

Connect oscilloscope to TP 3
Adjust for10.695 MHz +/- 20 Hz

12

TX FM
27.205 MHz

Check

Same as Step 11
10.695 MHz +/- 20 Hz Reading

13

TX USB
27.205 MHz

L408

Connect oscilloscope to TP 3
Adjust for10.6975 MHz +/- 20 Hz

14

RX USB
27.205 MHz

Check

Same as Step 13
10.6975 MHz +/- 20 Hz Reading

15

TX LSB
27.205 MHz

L402

Connect oscilloscope to TP 3
Adjust for10.6925 MHz +/- 20 Hz

16

RX LSB
27.205 MHz

Check

Same as Step 15
10.6925 MHz +/- 20 Hz Reading

17

RX FM
28.755 MHz

Check

Same as Step 1
Less than 4.2 V

18

RX USB
26.065 MHz

Check

Same as Step 1
More than 1.2 V

       

Oscillator-frequency at 27.205MHz

VFO OSC- TP1

Adjust

X-tal OSC - TP3

Adjust

Mod.

37.9000MHz

L401

10.6950MHz

 

RX - AM

37.9000MHz

 

10.6950MHz

 

RX - FM

37.9025MHz

 

10.6975MHz

L408

RX - USB

37.8975MHz

L402

10.6925MHz

L407

RX - LSB

37.9000MHz

 

10.6950MHz

L406

TX - AM

37.9000MHz

 

10.6950MHz

 

TX - FM

37.9025MHz

VR211

10.6975MHz

 

TX - USB

37.8975MHz

 

10.6925MHz

 

TX - LSB

  

TRANSMITTER PORTION


Test equipment required:

     

Power Supply: 13,2 V

DC Current Meter

Oscilloscope

RF Power meter

RF VTVM

AF Oscillator

FM Linear Detector

Dummy Load (50 ohm)

AF VTVM

     

Preparation alignment:

     

VR208

Clockwise

   

VR205 and VR 206

Middle position

   

VR207, VR201, VR202, and VR 203

Counterclockwise

   

Mic gain

Clockwise

   

Meter SW

RF

   

SWR/CAL Volume

Middle position

   

RF Power

Clockwise

   

Test frequency

27.185 MHz

   

Step

Condition

Adjustment

Procedure

1

LSB 27.185 MHz
No Mod.

VR203

Remove the PB201
Connect a DC current meter to TP202 (+) and TP203 (-)
Adjust for 330 mA

2

Same as Step 1

VR201

Connect a DC current meter to TP202 (+) and TP201 (-)
Adjust for 85 mA

3

Same as Step 1

VR202

Connect a DC current meter to TP202 (+) and TP201 (-)
Adjust for 170 mA

4

LSB 27.185 MHz
Two-Tone
400 Hz and 2.500 Hz
1 mV Mod.

L221

Re-install the PB201
Adjust for maximum on the RF VTVM
Set the AF-oscillator, so that the output is less than 32 V

5

LSB 27.185 MHz
Two-Tone
400 Hz and 2.500 Hz
30 mV Mod.

VR208

Adjust for 25 V on the RF VTVM

6

SSB 27.185 MHz
No Mod.

VR209

Adjust the carrier leakade at LSB and USB become minimum and almost equal

7

AM 27.185 MHz
No Mod.

VR205

Adjust for 3.9 Watt on the WattMeter

8

AM 27.185 MHz
No Mod.

VR204

Adjust for RF Meter at "9" just light on

9

AM 27.185 MHz
1 kHz 30 mV Mod.

VR207

Adjust 90% negative

10

AM 27.185 MHz
1 kHz 3 mV Mod.

VR213

Adjust for Modulation Meter at "9" just light on

11

FM 27.185 MHz
No Mod.

VR206

Adjust for 3,9 Watt on the WattMeter

12

FM 27.185 MHz
1 kHz 30 mV Mod.

VR212

Adjust for +/- 1.9 kHz Deviation

  

RECEIVER PORTION


Test equipment required:

     

Power Supply: 13,2 V

SINAD Meter

Oscilloscope

 

AM/FM SSG

(AM: 1 kHz 60% Mod.)

(FM: 1 kHz 1.2 kHz Deviation)

 

Preparation alignment:

     

NB/ANL

Off

   

HI CUT

Off

   

SQUELCH

Counter clockwise

   

Volume

Clockwise

   

RF Gain

Clockwise

   

Clarifier

Center

   

Frequency

27.185 MHz

   

Step

Condition

Adjustment

Procedure

1

AM
60% Mod.

L17 L2 L6 L7 L11 L12 L13

Adjust for maximum reading on the AF VTVM

2

FM
1.2 kHz Dev.

L16

Adjust for maximum reading on the AF VTVM

3

AM
No Mod.

VR4

SSG: 40dB (50uV) Adjust "9" just light on

4

AM
No Mod.

VR2

SSG: 66dB (1mV) Just apper AF level

5

USB
No Mod.

L15 and L14

Adjust for maximum reading on the AF VTVM

6

USB
No Mod.

VR3

SSG: 40dB (50uV) Adjust "9" just light on

7

USB
No Mod.

VR1

SSG: 66dB (1 mV) Just apper AF level

8

USB
No Mod.

L1

Connect Oscilloscope to TP4. Set Oscilloscope to DC range and adjust to reach max. reading.

9

AM
26.065 MHz
60% Mod.

Check

SSG: 10dB
More than 20 dB SINAD

10

AM
28.755 MHz
60% Mod.

Check

SSG: 10dB
More than 20 dB SINAD

Improved receive gain

Quieting of AM reception and improving gain of incoming signals is a common request from radio operators. In the first stages of the HF input 2SC1674 (Q8) transistor can be found. This transistor is responsible for the amplification of a small detected signals. A problems exist if the transistor itself is noisy as is such the case of the 2SC1674 when compared to other low noise packages. Along with the amplification of the incoming signals is transistor noise. Replacement of this transistor with a higher gain, lower noise transistor greatly improves the signal to noise ratio of your receiver.
The transistor Q8 operates at VCE= 6Volt and IE= 2,5mA. We will use an 2SC2999 transistor that has higher gain and lower noise characteristic. Replace
2SC1674 (Q8) with 2SC2999 (or similar low noise and high gain transistor) to achieve this improved signal to noise ratio.
Re-adjust L2.
The gain will improved with more than 6dB with the same signal to noise ratio.

Возврат