MMDVM Duplex Hotspot Module Dual Hat V1.5.2 - Duplex MMDVM Hat

In this review of the MMDVM Duplex Hotspot Module Dual Hat V1.5.2, the bottom line is clear: the board is aimed at amateur radio operators and makers who want a compact, Raspberry Pi mounted duplex hotspot that supports multiple digital modes. It stands out for its duplex capability with two onboard ADF7021 radios, allowing dual-slot DMR operation and simultaneous RX/TX paths on supported bands. Installation and compatibility with common Pi images like pi-star make it appealing for hobbyists who want a ready-to-mount, tested MMDVM solution.

Key Features

• Wide mode support: The board supports DMR, P-25, D-Star and System Fusion, providing flexibility for multi-mode digital operators.
• Duplex operation: Two ADF7021 transceivers onboard enable duplex hotspot use with two time slots on DMR for more advanced routing and network setups.
• Raspberry Pi mounting: Designed to mount cleanly on current Raspberry Pi models including the Pi Zero, simplifying hardware integration for single-board computer projects.
• Tested hardware: Each unit is fully tested and uses an original ECS-TXO-3225 crystal, which contributes to reliable frequency stability.
• Upgradeable firmware: Ships with V1.5.2 and supports upgrading to later firmware such as V1.6.1 through documented pi-star commands when required.

Who It's For

The MMDVM Duplex Hotspot Dual Hat is best for ham radio enthusiasts and makers who already use Raspberry Pi single-board computers and want a compact duplex hotspot supporting multiple digital voice protocols. It suits hobbyists who value a tested MMDVM_HS hat with clear upgrade steps and those running pi-star or similar software images.

It is less suitable for users who need compatibility with the Raspberry Pi 4, as the product is not compatible with that model, or for absolute beginners unwilling to use SSH and jumper settings during firmware upgrades. Users requiring official customer support channels for commercial deployments should consider more fully supported commercial hotspots.

Pros & Cons

Pros

• Supports multiple protocols including DMR and P-25, making it versatile for multi-mode networks.
• Duplex design with two ADF7021 chips allows dual-slot DMR and improved network flexibility.
• Mounts directly on Raspberry Pi boards including Pi Zero, keeping projects compact and tidy.
• Good build quality and original crystal provide dependable frequency stability.

Cons

• Not compatible with Raspberry Pi 4, limiting use with newer Pi models.
• Some firmware upgrade steps require comfort with SSH and jumper manipulation, which may challenge new users.

Specifications

Brand	GOOZEEZOO
Firmware	V1.5.2 (upgradeable to V1.6.1)
Supported Modes	DMR, P-25, D-Star, System Fusion
Frequency	144-148, 219-225, 420-475, 842-950 MHz (best 430-440 MHz)
Mount	Raspberry Pi (including Pi Zero); not compatible with Pi 4
Onboard Radios	Two ADF7021 transceivers for duplex operation
Package	1x MMDVM duplex HotSPOT Module, 2x Antenna

Our Verdict

The MMDVM Duplex Hotspot Module Dual Hat V1.5.2 is a practical, value-minded choice for amateur radio enthusiasts who want a compact, Raspberry Pi mounted duplex MMDVM solution. It combines multi-mode support, solid components, and a tested build while requiring moderate technical comfort for firmware updates and setup. For hobbyists running pi-star who need duplex DMR capability, it delivers strong functionality for the price.

Frequently Asked Questions

Does this work with pi-star?
Yes, customers report it works with regular pi-star images and the review includes the specific pi-star upgrade command for the hat.

Can it run on Raspberry Pi 4?
No, the product is not compatible with Raspberry Pi 4; it is intended for current Pi models including Pi Zero.

What bands does it cover?
The module covers 144-148, 219-225, 420-475 and 842-950 MHz, and performs best on the 430-440 MHz amateur subband.