ATU-21CS Antenna UHF 420-440 MHz Super Stubby

The Motorola AAM28X502 ATU-21CS UHF Super Stubby Antenna is an ultra-compact antenna designed for compatible Motorola and Vertex Standard portable two-way radios operating within the 420–440 MHz UHF frequency range.

Measuring just 2 inches (50.8 mm) in length, the ATU-21CS provides a low-profile alternative to traditional full-length whip antennas. Its super stubby design helps reduce snagging on clothing, equipment, and other objects, making it particularly convenient for users who wear their radio on a belt or carry it in a pocket.

The compact antenna design makes the AAM28X502 well suited for applications where portability, comfort, and discretion are important. It is an ideal replacement for a lost, damaged, or worn antenna on compatible radios operating within the specified frequency range.

Ideal for security, hospitality, retail, education, property management, maintenance, event staff, and other professional applications, the ATU-21CS provides a compact antenna solution for everyday portable radio use.

Key Features

• UHF Super Stubby portable radio antenna

• 420–440 MHz frequency range

• Ultra-compact 2-inch (50.8 mm) design

• Low-profile design helps reduce snagging on clothing and equipment

• Ideal for belt-worn and pocket-carried radios

• Easily screws onto compatible portable radios

• Designed for professional and commercial radio applications

• Suitable as a replacement for lost, damaged, or worn antennas

• Genuine Motorola Solutions accessory

• Motorola part number: AAM28X502

• Antenna model: ATU-21CS

Compatible Radios

• Motorola / Vertex Standard EVX-S24

Important

The ATU-21CS is tuned for the 420–440 MHz UHF frequency range. Always verify the operating frequency of your radio before ordering an antenna.

Super stubby antennas prioritize compact size and convenience. Their reduced physical length may result in different RF performance compared with a properly tuned full-length whip antenna, particularly in situations where maximum communication range is important.

Specifications

Manufacturer: Motorola Solutions / Vertex Standard
Part Number: AAM28X502
Model: ATU-21CS
Accessory Type: Portable Radio Antenna
Antenna Type: Super Stubby
Frequency Band: UHF
Frequency Range: 420–440 MHz
Length: 2 in. (50.8 mm)
Compatible Radio: EVX-S24
Color: Black