UHF Heliflex Stubby, 403-440 MHz

The Motorola 8505816K24 UHF 403–440 MHz Heliflex Stubby Antenna is a compact replacement antenna designed to provide reliable UHF transmit and receive performance for compatible Motorola portable two-way radios.

Operating across the 403–440 MHz UHF frequency range, the 8505816K24 is designed for compatible radios operating within the lower portion of the commercial UHF band.

The antenna features a compact 9 cm (approximately 3.5-inch) Heliflex stubby design, providing a lower-profile alternative to traditional full-length whip antennas.

Motorola's Heliflex antenna design is engineered to provide dependable communication performance while maintaining a compact and flexible form factor suitable for everyday professional radio use.

Its short profile makes the radio more comfortable and convenient to carry, particularly when worn on a belt. The compact design also helps reduce the likelihood of the antenna catching on clothing, equipment, shelving, vehicle interiors, or other surrounding objects.

The 8505816K24 is an excellent replacement for a lost, damaged, bent, or worn original antenna and can also be kept as a spare for businesses and organizations maintaining fleets of compatible Motorola portable radios.

Key Features

• UHF Heliflex stubby antenna

• 403–440 MHz frequency range

• Compact 9 cm antenna design

• Approximately 3.5 inches long

• Heliflex construction

• Compact, low-profile design

• Designed for compatible Motorola portable two-way radios

• Provides transmit and receive antenna functionality

• Tuned for lower-band UHF operation

• Ideal for belt-worn portable radios

• Helps reduce snagging on clothing and equipment

• Compact design improves carrying comfort

• Suitable for everyday commercial and professional radio use

• Suitable for indoor and outdoor applications

• Direct replacement for compatible original antenna

• Useful as a spare antenna for radio fleets

• MX antenna connector

• No integrated GPS

• No programming required

• No external power required

• Portable radio sold separately

• Genuine Motorola Solutions accessory

• Motorola part number: 8505816K24

Frequency Range

The 8505816K24 operates across:

403–440 MHz

This places the antenna within the UHF frequency band.

The antenna should only be used with compatible UHF portable radios operating within the supported frequency range.

Compatible Radios

Documented applications include:

• Motorola CP100d

• Motorola CP125

• Motorola CP150

• Motorola CP185

• Motorola CP200d

• Motorola CT150

• Motorola CT250

• Motorola CT450

• Motorola EX500

• Motorola EX600

• Motorola EX600 XLS

• Motorola HT750

• Motorola HT1250

• Motorola HT1250 LS / LS+

• Motorola PR400

• Motorola PR860

• Select additional compatible Motorola UHF portable radios

The 8505816K24 has been used across multiple generations of Motorola commercial and professional UHF portable radios.

Always verify both the portable radio model and programmed operating frequency before ordering an antenna.

Heliflex Stubby Design

The 8505816K24 features a:

9 cm / Approximately 3.5-Inch UHF Heliflex Stubby Antenna

The compact configuration provides a lower-profile alternative to traditional whip antennas while retaining the flexible characteristics of Motorola's Heliflex antenna design.

This makes the 8505816K24 particularly convenient when the radio is:

• Worn on a belt

• Carried on a work vest

• Used in warehouses or retail environments

• Used around machinery or equipment

• Carried inside vehicles

• Used in confined spaces

• Carried throughout extended work shifts

The shorter profile helps reduce interference with clothing, equipment, and surrounding objects during normal use.

MX Connector

The 8505816K24 uses Motorola's:

MX Antenna Connector

Physical connector compatibility alone does not guarantee that an antenna is appropriate for a particular radio.

The radio model, connector type, and operating frequency should all be verified before ordering.

Related Motorola UHF Antennas

Motorola offers several UHF antenna options for compatible portable radios:

• 8505816K24 – UHF 403–440 MHz Heliflex Stubby Antenna

• PMAE4002A – UHF 403–433 MHz Stubby Antenna

• PMAE4003A – UHF 430–470 MHz Stubby Antenna

• NAE6522AR – UHF 438–470 MHz Stubby Antenna

• PMAE4016A – UHF 403–520 MHz Wideband Whip Antenna

Selecting the correct antenna depends on both the portable radio model and its programmed operating frequencies.

Important

The 8505816K24 is a UHF Heliflex stubby antenna designed for compatible radios operating within:

403–440 MHz

It is not a VHF antenna.

Do not select a portable radio antenna based solely on physical fit. Antennas are designed for specific frequency ranges, and the antenna should match both the radio platform and its programmed operating frequencies.

Do not confuse the 8505816K24 with other similar Motorola UHF stubby antennas:

8505816K24 = UHF 403–440 MHz Heliflex Stubby Antenna

PMAE4002A = UHF 403–433 MHz Stubby Antenna

PMAE4003A = UHF 430–470 MHz Stubby Antenna

Although these antennas may have similar compact profiles, they are designed for different frequency ranges and applications.

Always verify the radio model and operating frequency before ordering.

The portable radio is not included.

Specifications

Manufacturer: Motorola Solutions
Part Number: 8505816K24
Accessory Type: Portable Radio Antenna
Antenna Type: Heliflex Stubby
Band: UHF
Frequency Range: 403–440 MHz
Length: 9 cm / Approximately 3.5 Inches
Connector: MX
Integrated GPS: No
Programming Required: No
External Power Required: No
Radio Included: No
Application: UHF Portable Two-Way Radio Communications