5-4 RECEIVER ADJUSTMENTS

Receiver adjustments must be performed after software adjustment (0) and (1). SUB band must be OFF when adjusting MAIN band, or main AF volume (max.counter clockwise) and SQL volume (max. clockwise) must be set when adjusting SUB band.

 

 

 

 

 

MEASUREMENT

 

 

ADJUSTMENT

ADJUSTMENT

ADJUSTMENT CONDITION

 

VALUE

POINT

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

UNIT

 

LOCATION

 

 

UNIT

ADJUST

 

 

 

 

 

 

 

 

 

144 M

1

• Display frequency: Any

PA

Connect an RF volt-

Maximum level

PA

L521

RECEIVER

 

• Disconnect P501 (PA unit) from J51

 

meter to check point

 

 

 

 

 

PEAK/GAIN

 

on the MAIN unit.

 

 

P501 via

the

JIG

 

 

 

 

 

 

 

• Connect a standard signal generator

 

cable (A).

 

 

 

 

 

 

 

 

 

to [VHF ANT] connector and set as:

 

 

 

 

 

 

 

 

 

 

 

 

Frequency : 146.0000 MHz

 

 

 

 

 

 

 

 

 

 

 

 

Level

: 7.1 mV* (–30 dBm)

 

 

 

 

 

 

 

 

 

 

 

 

Modulation : OFF

 

 

 

 

 

 

 

 

 

 

 

 

• Receiving

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

2

• Receiving

 

 

 

 

 

 

 

–14 dBm

 

R547

 

 

 

 

 

 

 

 

 

 

 

 

After adjustment, connect P501 (PA unit) to J51 on the MAIN unit.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

144 M PEAK

1

• Display frequency: 145.9800 MHz

Rear

Connect an distortion

Minimum audio distor-

MAIN

Adjust

in

(MAIN BAND)

 

• Mode

 

: FM

panel

meter to [EXT

SP]

tion level

 

sequence

 

 

• Connect an SSG to [VHF ANT] con-

 

connector

with

an

 

 

L51,

L52

 

 

nector and set as:

 

 

8 load.

 

 

 

 

s e v e r a l

 

 

Frequency : 145.9800 MHz

 

 

 

 

 

 

 

times.

 

 

 

 

Level

: 3.2 µV* (–97 dBm)

 

 

 

 

 

 

 

 

 

 

 

 

Modulation : 1 kHz/±5.0 kHz Dev.

 

 

 

 

 

 

 

 

 

 

 

 

• Receiving

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

2

• Mode

 

: USB

 

Connect an AC milli-

Maximum noise output

 

L53, L352,

 

 

• Set an SSG as

:

 

volt meter to [EXT

level

 

L353, L354

 

 

Frequency : 145.9815 MHz

 

SP]

connector

with

 

 

 

 

 

 

 

Level

: 0.1 µV* (–127 dBm)

 

an 8 load.

 

 

 

 

 

 

 

 

 

Modulation : OFF

 

 

 

 

 

 

 

 

 

 

 

 

• Receiving

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

144 M

1

• Display frequency: 145.9800 MHz

Rear

Connect an AC milli-

1.0 V (0 dB)

Front

main [AF]

TOTAL GAIN

 

• Mode

 

: USB

panel

volt

meter

to [EXT

 

panel

volume

(MAIN BAND)

 

• Set an SSG as

:

 

SP]

connector

with

 

 

 

 

 

 

 

Frequency : 145.9815 MHz

 

an 8 load.

 

 

 

 

 

 

 

 

 

Level

: 1 mV* (–47 dBm)

 

 

 

 

 

 

 

 

 

 

 

 

Modulation : OFF

 

 

 

 

 

 

 

 

 

 

 

 

• Receiving

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

2

• Set an SSG as

:

 

 

 

 

 

100 mV (20 dB of AF

MAIN

R360

 

 

Level

: OFF

 

 

 

 

 

level difference as step

 

 

 

 

 

 

• Receiving

 

 

 

 

 

 

 

1.)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

144 M PEAK

1

• Sub display freq. : 145.9800 MHz

Rear

Connect an distortion

Minimum audio distor-

MAIN

Adjust

in

(SUB BAND)

 

• Mode

 

: FM

panel

meter to [EXT

SP]

tion level

 

sequence

 

 

• Connect an SSG to [VHF ANT] con-

 

connector

with

an

 

 

L651, L652

 

 

nector and set as:

 

 

8 load.

 

 

 

 

s e v e r a l

 

 

Frequency : 145.9800 MHz

 

 

 

 

 

 

 

times.

 

 

 

 

Level

: 3.2 µV* (–97 dBm)

 

 

 

 

 

 

 

 

 

 

 

 

Modulation : 1 kHz/±5.0 kHz Dev.

 

 

 

 

 

 

 

 

 

 

 

 

• Receiving

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

2

• Mode

 

: USB

 

Connect an AC milli-

Maximum noise output

 

L653, L851,

 

 

• Set an SSG as

:

 

volt meter to [EXT

level

 

L852, L853

 

 

Frequency : 145.9815 MHz

 

SP]

connector

with

 

 

 

 

 

 

 

Level

: 0.1 µV* (–127 dBm)

 

an 8 load.

 

 

 

 

 

 

 

 

 

Modulation : OFF

 

 

 

 

 

 

 

 

 

 

 

 

• Receiving

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

144 M

1

• Display frequency: 145.9800 MHz

Rear

Connect an AC milli-

1.0 V (0 dB)

Front

sub [AF]

TOTAL GAIN

 

• Mode

 

: USB

panel

volt

meter

to [EXT

 

panel

volume

(SUB BAND)

 

• Set an SSG as

:

 

SP]

connector

with

 

 

 

 

 

 

 

Frequency : 145.9815 MHz

 

an 8 load.

 

 

 

 

 

 

 

 

 

Level

: 1 mV* (–47 dBm)

 

 

 

 

 

 

 

 

 

 

 

 

Modulation : OFF

 

 

 

 

 

 

 

 

 

 

 

 

• Receiving

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

2

• Set an SSG as

:

 

 

 

 

 

100 mV (20 dB of AF

MAIN

R857

 

 

Level

: OFF

 

 

 

 

 

level difference as step

 

 

 

 

 

 

• Receiving

 

 

 

 

 

 

 

1.)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

*This output level of a standard signal generator (SSG) is indicated as SSG’s open circuit.

5 - 4

Page 22
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Icom IC-910H service manual Receiver Adjustments

IC-910H specifications

The Icom IC-910H is a highly regarded and versatile transceiver that is designed for amateur radio operators who are particularly interested in V/UHF and microwave communications. Known for its exceptional performance, the IC-910H encompasses a suite of features that make it a standout choice for both casual and dedicated hams.

One of the main features of the IC-910H is its dual-band capability, allowing for simultaneous operation on both 144 MHz (2 meters) and 430 MHz (70 centimeters) bands. This dual operation enables users to engage in various communication modes, including SSB, CW, FM, and digital. Its high frequency stability ensures that users can rely on the transceiver for accurate and consistent transmissions.

The IC-910H is equipped with a high-performance 10 MHz IF filter that improves selectivity and reduces adjacent channel interference. The optional 1.2 GHz module enhances the transceiver’s capabilities, allowing operators to venture into microwave frequencies. This expandability is a significant advantage for users who wish to progress in their amateur radio pursuits.

Another notable aspect of the IC-910H is its large, easy-to-read LCD display, which features various color options for enhanced visibility. The front panel layout is user-friendly, providing quick access to important controls and functions. The built-in DSP (Digital Signal Processing) technology offers noise reduction and filtering capabilities, significantly improving overall audio quality and making weak signals more intelligible.

The transceiver also includes extensive memory functions, with up to 1,000 memory channels available for storing frequencies, modes, and operational settings. Additionally, it supports CTCSS and DCS tones, which facilitate the use of repeater systems and private group communications.

In terms of build quality, the IC-910H features a robust construction designed for durability and long-term use. Its efficient power supply management ensures excellent performance while minimizing heat generation, making it suitable for extended operating sessions.

Overall, the Icom IC-910H is a powerful and feature-rich transceiver that is favored by many amateur radio enthusiasts. With its versatile operating modes, advanced filtering capabilities, and clear display, it stands out as a reliable tool for both casual operators and serious DXers. Its well-thought-out design and comprehensive features make it a valuable addition to any ham's station collection.