DV hotspots – overview

By Toshen, KEØFHS – last updated Jan 2018
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1) Introduction to hotspots

A hotspot, a.k.a., a personal access point, is a combination of hardware and software that enables a ham with internet connectivity to link directly to digital voice (DV) repeaters, D-STAR reflectors, DMR talkgroups, etc. Basically, these devices act as your own personal digital voice repeater and gateway, for example, here's what it looks like for D-STAR:

Diagram of DV HTs connecting via personal access points to a reflector and a DV repeater

For someone like me who doesn't live within range of a DV repeater, a hotspot is an important key to accessing digital voice systems, and is a gift that opens doors to the whole wide world.

Originally, my discussion about DV hotspots was a section of my D-STAR article. When I added an article about DMR, there also was a section in there about hotspots. As the hotspot hardware and software became more capable and I began using the same ones for D-STAR and DMR, I realized that a standalone article about them was warranted.

Be aware: Digital voice, especially in the area of hotspots, is like a Wild West frontier of amateur radio. There's lots of experimentation going on, which means both excitingly rapid progress as well as some abandoned dead-end branches of exploration. For more about this, see the note in my D-STAR article: The Wild West of amateur radio!

2) Hotspot hardware

There are many different hotspot hardware devices being developed by innovative hams to work with the different flavors of digital voice:

What follows is a sampling of some of the "low-power" hotspots that are available as of late 2018, along with my personal opinions about them.

ZUMspot RPi UHF Hotspot

Thumbs up! Thumbs up!

Created by the MMDVM (Multimode Digital Voice Modem) team: Bruce Given, VE2GZI, Jonathan Naylor, G4KLX, Jim Mclaughlin, KI6ZUM.

MMDVM boardThe ZUMspot works with D-STAR, DMR, System Fusion, and P25 (and Jonathan Naylor is working on adding NXDN, too). It's the same size as a RPi Zero W and works really well mounted on it as a hat. It also can be mounted on the RPi 3 and various other boards. Requires a digital-voice cable radio (includes a stubby antenna).

The ZUMspot is now my default hotspot in my shop for D-STAR and DMR, the two digital modes I use. It pairs well with the Pi-Star dashboard, discussed below, and its firmware can be updated easily via Pi-Star's command line. For more info, see Zooming around with the ZUMspot.

The ZUMspot also is now one of the hotspots I use for mobile. For more info, see: ZUMspot + Pi-Star – An invitation to play more.

The MMDVM team has made some other modem boards, too, and have more planned. Keep an eye on ZUMspot.com, an online shop for their products launching in early 2018.


DVMEGA-UHF mounted on Raspberry Pi board

Thumbs up!

Created by Guus van Dooren, PE1PLM, Dooren Electronic Solutions.

The single-mode (UHF) DVMEGA is pictured mounted on a Raspberry Pi 3, and there are other models as well, including dual-mode VHF/UHF, pictured below. With firmware 3.07 and later, the DVMEGA can support D-STAR, DMR, and System Fusion. Requires a digital voice-capable radio (includes a mount for a stubby antenna).

DVMEGA-DUALThe DVMEGA was my default D-STAR hotspot in my shop for the first year or so I used D-STAR, and I still think it's a solid choice. It's dependable, pairs well with Pi-Star, and once you've soldered the firmware update jumper wire in place, it's easy to update via Pi-Star's command line. For maximum flexibility, I chose the DVMEGA-DUAL (VHF and UHF); however, I've only used UHF frequencies, so the less-expensive DVMEGA-UHF would've been fine. That said, the DUAL is a more compact board. I discuss this choice more further in this article.

One minor irritant: The standoff hole was designed for an earlier RPi board, so when it's mounted on the RPi3, the only thing holding it down is the GPIO connector. Consequently, since the antenna mount is in the corner diagonally across from the connector, if the connector isn't glued down in some way (I used hot glue), the standoff acts like a pivot: if you touch the antenna, the connector tends to lift off the GPIO pin header. Since the RPi3 has been out for a couple years now, I'm really surprised Guus hasn't figured out a solution for this yet.

For more info about my implementation for D-STAR, see: 3d) Booting up the DVMEGA in my D-STAR article. For more info about updating the firmware via Pi-Star, see: 7) DVMEGA firmware update in my D-STAR notes.


Thumbs up!

Created by Ruud Kerstens, PE1MSZ.

BlueStack-Micro-plus boardThe DVMEGA RPi board also can be paired with a BlueStack-Micro+ board instead of an RPi, which enables bluetooth connection to an Android phone running BlueDV for Android or a serial connection to a Windows computer running BlueDV for Windows. (There also are experimental versions available for iOS, RPi, and Linux.)

When powered by a portable battery pack, the BlueStack + DVMEGA combination provides a mobile solution that can be used with D-STAR, DMR, and System Fusion radios. For more about this mobile solution, see 4b) Just can't wait to get on the road again in my D-STAR article.

BlueDV running on Android

The BlueStack board also can be used to facilitate a DVMEGA firmware update. For more info, see 7) DVMEGA firmware update in my D-STAR notes.

Note: I originally ordered my BlueStack-Micro+ board directly from Combitronics in The Nederlands, but they're now available from various shops in the U.S.

SharkRF openSPOT

Thumbs up!

Created by Ákos Marton, HG1MA, and Norbert Varga, HA2NON, SharkRF.

SharkRF openSPOT

This is a standalone device that uses a wired connection to your WiFi router. Requires a D-STAR, DMR, or System Fusion radio. Quite easy to set up and use. Includes a stubby antenna, power supply, and all the necessary cables. Unique among all of these hotspots, they also have excellent documentation, which is posted online.

The openSPOT was my default DMR hotspot for the first year I used DMR. For more info, see 2b) Choosing a hotspot in my DMR article, as well as the note: A couple openSPOT hints.

I also was able to use the openSPOT to create a mobile hotspot by connecting it to a nano router that was in turn connected wirelessly to my Android phone acting as a portable WiFi hotspot. See the note in my DMR article: On the road with the openSPOT.

ThumbDV and PiDV

Created by Bryan Hoyer, K7UDR, Basil Gunn, N7NIX, John Hays, K7VE, and Dennis Rosenauer, AC7FT, NW Digital Radio.

ThumbDV and PiDV mounted on a Raspberry PiThumbDV shown plugged into a small single-board computer, but also can be plugged into a PC running Windows or a Mac. PiDV hat shown mounted on the computer. Both include an AMBE chip. D-STAR only.

Since I was looking for a hotspot to use with a D-STAR radio, these solutions with their own AMBE chips weren't interesting to me, so I never gave them a try; however, I did watch a video review and they appear to work quite well.

Note: As of late 2017, it looks like the PiDV hat has been discontinued.

NW Digital Radio also has a board called the Universal Digital Radio Controller (UDRC) that apparently can provide coverage to a larger area when connected to a higher-powered analog radio. This is in the "medium to high-power" hotspots category, which is different than the other low-power hotspots mentioned here. I tried a UDRCII; however, I was unable to get it working with my radio. I think it requires a level of technical ability that is beyond me.

Nano-DV and Nano-Spot

Created by Mark Guidbord, K7IZA, Micro-Node.


The Nano-DV is a standalone device with a small, built-in display. Requires a D-STAR, DMR, or System Fusion radio. Includes a stubby antenna. The software it runs is a package developed by Torsten Schultze, DG1HT, and others, and looks similar to the software for the DV4mini, discussed below. For me personally, this device is way too expensive for what it does, so I never gave it a try.

Nano-DVThere's also a new MMDVM-compatible device (as of Dec 2017): the Nano-Spot. Requires a D-STAR, DMR, System Fusion, or P25 radio. It looks like a nifty little plug-n-play device and is less expensive than the Nano-DV, probably due at least in part to the much smaller display. Includes both RF and WiFi antennas. Runs Pi-Star. If you're not into building your own hotspot from components (for example, the ZUMspot and an RPi), this could be a nice, ready-made solution.

Internet Labs dongles

Created by Robin Cutshaw, AA4RC, and Moe Wheatley, AE4JY, Internet Labs.

DV Dongle and DV Access Point Dongle devices
DV 3K Dongle
Blue: DV Dongle; red: DV Access Point (DVAP); white: DV 3K Dongle

These devices can be connected to a PC running Windows or a Mac. The DV Dongle includes an AMBE chip, the DVAP requires a D-STAR radio (includes antenna). I don't know anything about the DV 3K.

When running their own software, Internet Labs products work only with DPLUS (REF) reflectors, and intentionally block access to XRF, DCS, and XLX reflectors (and don't support DMR, Fusion, or P25); consequently, I found this to be a restrictive solution and ended up giving my VHF DVAP away.

DV4mini and DV4home

Created by Uli Altvater, AG0X/DH6SAB, and Torsten Schultze, DG1HT, Wireless Holdings.


The DV4mini is a USB stick that can plug into a PC running Windows or Linux, or a Raspberry Pi. Requires a D-STAR, DMR, or System Fusion radio (it includes a mount for a stubby antenna), and comes in UHF and VHF flavors. There's also a model with an AMBE chip.

The DV4home is a standalone digital voice device that has two AMBE chips as well as its own screen, microphone, and speaker.

Reviews for the original DV4home were mixed. They have since released DV4home V2, and the first reviews I've read have said that it's significantly improved compared to the original.

While I know people who use and like the DV4 devices, I personally found both the DV4mini and the original DV4home clunky to use when I tried them in late 2016, and ended up giving them away.

3) Hotspot software

There's also all sorts of different software available to run the various hotspot devices:

What follows is a sampling of some of the software applications available to run hotspots as of early 2018.


Thumbs up! Thumbs up!

Created by Andy Taylor, MW0MWZ.

Pi-Star Digital Voice

Pi-Star works with many devices, can be used in hotspot or repeater mode, and supports DMR, D-STAR, System Fusion, and P25. I've run the Pi-Star dashboard with D-STAR and DMR on Mac, Windows, Android, and a Raspberry Pi. It works really well, is feature rich, and is enthusiastically developed and supported by Andy and team. It has one of the best communities I've come across, the Pi-Star Users Support Group.

Pi-Star dashboard

As of Nov 2017, Pi-Star became my default hotspot software for the two digital radio modes I use: D-STAR and DMR. At this time, I'm using Pi-Star with a ZUMspot mounted on a Raspberry Pi. Initially, I used it with a DVMEGA mounted on a Raspberry Pi. They're both great combinations, though the ZUMspot has the advantage of simultaneous multi-mode capability and P25 support.

ZUMspot, Pi-Star, DMR, in mobile mode

For more info, see Playing with Pi-Star.


Thumbs up! Thumbs up!

A hobby project by David, PA7LIM.

This app can be run on Android and Windows (experimental versions of BlueDV are also available for iOS, Linux, and RPi), and is a great solution for creating a mobile hotspot using the BlueStack-Micro+ paired with a DVMEGA board.

DVMEGA & BlueStack in custom case

For more info about using BlueDV as a mobile hotspot, see 4b) Just can't wait to get on the road again.

There's also an interesting new "pre-beta"¹ feature available called DMR Simple Mode. All you need to do is add talkgroup 9, color code 1 to your radio for connecting to your hotspot, and then you can switch to other talkgroups in the app itself.

BlueDV running on a PC

[1] David labels all of his software beta, pre-beta, or experimental. In my own experience, his beta builds are what most people would call release versions, and his pre-beta builds are what most people would call beta. His stuff is really good. Of course, there's room for improvement, but that's true of all the software in the world! He's doing really innovative work to push the boundaries of digital voice, which I really appreciate.


Thumbs up! Thumbs up!

Created by Jonathan Naylor, G4KLX.

Jonathan creates the firmware for the MMDVM, and some of his applications are also used in other hotspot software, for example, Pi-Star and DStar Commander.

For more info, see GitHub g4klx and MMDVM group.

SharkRF openSPOT

Thumbs up!

Created by Ákos Marton, HG1MA, and Norbert Varga, HA2NON.

Works with the SharkRF openSPOT device. Supports DMR (Brandmeister, DMRplus), D-Star (DCS, REF/DPlus, XRF/DExtra, XLX), System Fusion (FCS, YSFReflector). The openSPOT was my default DMR hotspot for the first year I used DMR.

For more info, see Choosing a hotspot in my DMR article, as well as the note: A couple openSPOT hints.

DStar Commander

Thumbs up!

Created by Bob Scott, W6KD.

Compatible with the RPi models B, B+, 2B, 3B and Zero/Zero W(ireless). Works well with the DVMEGA device, but also can be used with some other devices. DStar Commander was my default D-STAR hotspot software in my shop for the first year I used D-STAR. It's solid.

For more info about DStar Commander, see 3b) Creating the DStar Commander image and 3d) Booting up the DVMEGA.

Note: DStar Commander also will work with a DVAP connected to a Raspberry Pi, which I've heard is a way to get around the REF-only restriction imposed by DVAPTool. But be aware that it should be the UHF DVAP. Apparently there's an issue with the VHF DVAP firmware that causes PTT lockups when working with the G4KLX software that is a part of the DStar Commander image.

KB5RAB RPi Image

Created by Russell, KB5RAB.

I don't know much about this actively maintained image, but it looks like a kitchen sink full of software to run many aspects of Digital Voice on a Raspberry Pi. "Image supports DMR, DSTAR and Fusion and each mode can be enabled as desired." I'm guessing it's aimed at real tinkerers because you end up with all this software loaded onto Raspbian Jessie, and it's up to you to install and configure each of the various components you want to use. Includes:

DVTool and DVAPTool

Created by Robin Cutshaw, AA4RC, and Moe Wheatley, AE4JY.

For running the DV Dongle and DVAP Dongle. I tried DVAPTool and found it worked fine, but because of the DVAP's limitation of working only with DPLUS (REF) reflectors⊃, I found it an insufficient solution and ended up giving it away.

[1] Pure speculation on my part, but the reason for this may be related to the fact that the DV Dongle and the DVAP originally were designed to enable DPLUS (REF) repeater administrators to remotely monitor their repeaters, rather than for end users playing around with digital voice more broadly.

DV4mini Control Center and DV4home firmware

Created by Uli Altvater, AG0X/DH6SAB, and Torsten Schultze, DG1HT.

For running the DV4mini and DV4home. I found this software pretty clunky when I tried using it in late 2016, but I've read that there have been significant improvements made since then.

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