Kenwood VFO 820 Manual

The Kenwood VFO 820 is a professional VHF/UHF transceiver designed for amateur radio operations, featuring dual-band capability, cross-band repeat function, wide frequency coverage, multiple scanning modes, programmable memory channels, CTCSS/DCS encode/decode, weather alert function, and robust construction for reliable performance. Below are key sections for safety, features, installation, setup, operation, and troubleshooting.

Features at a Glance

Key components: Dual-band transceiver, microphone connector, DC power input, antenna connector, speaker output, external speaker jack, programming port.

Feature	Description
Frequency Range	VHF: 136-174 MHz, UHF: 400-520 MHz
Output Power	50W VHF, 45W UHF (adjustable)
Memory Channels	200 programmable channels
Cross-band Repeat	Full duplex cross-band repeating function
Scanning Modes	Programmable scan, memory scan, priority scan
CTCSS/DCS	50 CTCSS tones, 104 DCS codes
Weather Alert	NOAA weather channels with alert function
Power Input	13.8V DC nominal
Dimensions	140(W) x 40(H) x 180(D) mm
Weight	Approx. 1.2 kg

Installation

Unpack and inspect contents. Mount in suitable location with proper ventilation.

1. Connect antenna: Use appropriate VHF/UHF antenna with PL-259 connector.
2. Connect power: Use 13.8V DC power supply with proper polarity (red positive, black negative).
3. Connect microphone: Use Kenwood-compatible microphone with RJ45 connector.
4. Connect external speaker if required: Use 3.5mm jack for external audio output.

WARNING! Ensure proper grounding and fuse protection. Do not operate without antenna connected.

First-Time Setup

Power on transceiver; follow initial configuration steps.

1. Set operating frequency: Use main dial to select desired frequency band.
2. Configure squelch: Adjust squelch control for optimal reception.
3. Program memory channels: Store frequently used frequencies with names.
4. Set CTCSS/DCS: Configure tone access if required for repeaters.
5. Adjust power output: Select appropriate power level for operation.

CAUTION! Verify frequency authorization before transmission. Follow local regulations.

Specifications

• Frequency Coverage: VHF 136-174 MHz, UHF 400-520 MHz
• Output Power: 50W VHF, 45W UHF (high power), 5W/1W (low power)
• Modulation: 16KΦF3E (FM)
• Spurious Emission: Less than -60 dB
• Sensitivity: 0.25 μV typical (12 dB SINAD)
• Audio Output: 2W at 8 ohms, 10% distortion
• Power Requirement: 13.8V DC ±15% negative ground
• Current Drain: Receive: 0.8A max, Transmit: 12A max
• Operating Temperature: -30°C to +60°C

Controls and Settings

Front Panel: Power switch, volume control, squelch control, channel selector, function keys, LCD display.

Microphone: PTT, up/down buttons, programmable function keys.

Menu Settings: Frequency step, scan resume, time-out timer, busy channel lockout, battery save, display contrast, backlight control, beep tone, power-on message.

Connecting Devices

Antenna: PL-259 connector. Power: DC input with fuse protection. Audio: External speaker jack. Data: Programming port for PC connection.

1. Turn off power before connecting accessories.
2. Use quality coaxial cable for antenna connection.
3. Ensure proper polarity for DC power connection.
4. Use Kenwood programming cable for PC interface.

Tip: Use ferrite beads on cables to reduce RF interference.

Operating Modes

Supports simplex, repeater, cross-band repeat operations.

1. Frequency Mode: Direct frequency entry via keypad or dial.
2. Memory Mode: Recall stored frequencies from memory channels.
3. Scan Mode: Programmable scan with skip/lock functions.
4. Cross-band Repeat: Activate cross-band repeating function.
5. Weather Alert: Monitor NOAA weather channels with alert.
6. Dual Watch: Monitor two frequencies simultaneously.

WARNING! Verify cross-band repeat authorization in your area. Follow FCC regulations.

Memory Functions

200 memory channels with alphanumeric tags.

1. Store Memory: Hold [F] + [MR] to store current frequency.
2. Recall Memory: Press [MR] and select channel number.
3. Memory Name: Assign 6-character names to memory channels.
4. Memory Group: Organize memories into groups for scanning.
5. Memory Lock: Protect important memory channels from changes.

Care & Maintenance

Keep unit clean and dry. Use soft cloth for cleaning. Avoid harsh chemicals.

CAUTION! Do not use solvents or abrasive cleaners. Keep away from moisture and extreme temperatures.

Regulatory Information

FCC Part 15: Class B digital device; complies with interference limits. FCC Part 97: Certified for amateur radio service. Copyright © Kenwood Corporation. For technical support, visit www.kenwood.com or contact authorized Kenwood service centers.

Troubleshooting

Symptom	Possible Cause	Corrective Action
No power	Power connection/fuse	Check DC power connection; verify fuse integrity; ensure proper voltage.
No transmission	PTT/microphone	Check microphone connection; verify PTT function; check antenna.
Poor reception	Antenna/squelch	Verify antenna connection; adjust squelch; check for interference.
Memory loss	Backup battery	Replace internal backup battery; reprogram memory channels.
Overheating	Ventilation/power	Ensure adequate ventilation; reduce transmit power; check duty cycle.

Reset: Hold [F] + Power On to reset to factory defaults.

Service: Contact authorized Kenwood service center for repairs.