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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 V_CE= 6Volt and I_E= 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.