MMDVM Hotspot

Under Contruction.

Overview

A personal, low-power hotspot is a combination of hardware, firmware, and software that enables an amateur radio enthusiast with internet connectivity to link directly to digital voice (DV) systems around the world. Hotspots can link to DMR, P25, and NXDN talkgroups; D-STAR reflectors; YSF rooms; and so on.

Basically, hotspots are your own personal digital voice repeater and gateway, which can be really fun. Here’s a simplified diagram of what it looks like when you connect via your hotspot to a BrandMeister-hosted multiprotocol talkgroup, which enables people using different modes to talk with each other:

Diagram of DV HTs connecting via hotspots

For some people, who doesn’t live within range of a digital voice repeater, a hotspot goes beyond being fun to being a critical key to accessing digital voice systems, a gift that opens doors to the whole wide world.

Overall, this is an exciting area of amateur radio that is evolving and progressing rapidly with some excellent work being done by some very innovative hams.

Background

This is an article about personal, low-power hotspots, also known as personal access points1, not repeaters. (For info about digital repeaters, see: How to make a MMDVM Digital Repeater by N5AMD and Repeater Builders.)

  • Many personal, low-power hotspots are boards that mount on computers like the Raspberry Pi, one is an all-in-one board, and some others are thumb drives that plug into computers. There’s even one that’s a handheld radio that plugs into a Raspberry Pi via USB.
  • Some can handle many digital modes, including DMR, D-STAR, YSF, P25, NXDN, various cross modes, and POCSAG; others are limited to only one or a few modes.
  • Most require a digital voice-capable radio to work with them (these typically have stubby or onboard ceramic antennas for nearby connectivity). There’s also another type that has its own AMBE® Vocoder chip so you can operate it without the need for a digital radio, for example, by using a headset with a microphone that is connected to the computer the hotspot is plugged into.
    • Note: A core component of a digital radio is an AMBE® chip, which compresses the digitized signal and adds error correction. If a hotspot has its own AMBE® chip, it doesn’t need a digital radio. Alternatively, a hotspot can use an AMBE® chip for transcoding between modes, in which case, a digital radio is still needed.

I’ve been playing around with my first personal, low-power hotspot since May 26th of this year, and I have been very impressed with the little unit. It has opened a new spectrum in this hobby, with my DMR HT.

Back to top button
error: Content is protected !!
Close
Close