Hanging out with hotspots
A hotspot (personal access point) is a combination of hardware, firmware, and software that enables a ham with internet connectivity to link directly to digital voice (DV) systems around the world. Hotspots can link to DV repeaters, DMR talkgroups and reflectors, D-STAR reflectors, YSF rooms, QuadNet Smart Groups, and so on. Basically, hotspots act as your own personal digital voice repeater and gateway, which can be really fun.
This illustration shows what it looks like for D-STAR:
For someone like me 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. I particularly enjoy participating on the Northern Colorado DMR (NoCO DMR△) Hotspot Discussion net held each Friday at 7:30p MTN on talkgroup 31088.
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.
Disclaimer: These are my personal notes and opinions based on my experience as a non-technical user playing around with hotspots, as well as by learning from what others are sharing. I'm not affiliated with any hotspot projects, except as an enthusiastic user. If anything needs correcting, please let me know.
This is an article about personal hotspots, specifically, low-power personal access points1, not repeaters.2
- Many hotspots are boards that mount on computers like the Raspberry Pi; others are thumb drives that plug into computers.
- Some can handle many digital modes, including DMR, D-STAR, YSF, P25, NXDN, POCSAG, and various cross modes; others work with 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); a few include their own AMBE Vocoder chip so you can operate them without the need for a radio at all, for example, by using a headset with a microphone that is connected to the computer the hotspot is plugged into.
I've been playing around with hotspots since 2016, during which time I've tried a bunch of hotspot devices and apps, including the DVMEGA, BlueStack-Micro+, SharkRF openSPOT v1, DV Access Point (DVAP), and a couple DV4 products. For more info about these devices, see Other hotspots△. While each of these taught me something, ultimately they all had limitations I didn't like:
- Some had clunky hardware or awkward software.
- One worked only with a wired internet connection.
- Some were limited in the digital voice systems they supported.
- Some tried to push me into using their preferred digital voice system rather than the one I wanted to use … no thanks!
ZUMspot and Pi-Star – And then I tried an MMDVM-based hotspot called the ZUMspot (discussed in more detail below) with an app called Pi-Star (discussed in more detail in the Playing with Pi-Star article△), and all the rest of my hotspots got given away or tossed into a box and forgotten. For me, the combination of the ZUMspot and Pi-Star is taking personal digital voice hotspots to a new level.
Multi-Mode Digital Voice Modem – The MMDVM project was conceived in early 2015 by Jonathan, G4KLX, and developed by Jonathan and Jim, KI6ZUM. Jonathan wrote all the software, Jim created the hardware, and both worked on the early firmware. Later, Andy, CD6JAU, took over working on the firmware. Andy also created the cross modes (DMR2YSF, DMR2NXDN, YSF2DMR, YSF2NXDN, YSF2P25).
Overview presentation – There's a quite good overview presentation from Pacificon 2017, which contains an introduction to digital voice and multimode by Jim, K6JM, as well as a keynote about MMDVM by Jim, KI6ZUM: MultiMode Digital Voice: The Exciting New Trend in DV△.
 When I first started playing around with hotspots a few years ago, there tended to be more of a distinction between "hotspots" and "personal access points" (see the article Hotspots vs Access Points? by Jim, K6JM△). While both perform a similar function—bridging radio and the internet to extend a local digital voice setup—hotspots tended to refer to higher-power devices, while access points referred to lower-power (~10 milliwatts) devices meant primarily for personal use. As the growth of the lower-power devices exploded over the past couple years, the term personal access point has pretty much disappeared, and now the term hotspot is commonly used to refer to the lower-power devices, too.
 For some extensive info about repeaters, see: Repeater Builders△.
2) Zooming around with the ZUMspot
The ZUMspot Pi Board by ZUM Radio is the same size as and works well mounted on a Raspberry Pi Zero W. It also can be mounted on the RPi 3B (a bit faster) and various other RPis.
It's a multi-mode digital voice modem that works with DMR and D-STAR (the two digital modes I use), and also with YSF, P25, and NXDN, as well as various DMR and YSF cross modes.
The ZUMspot also supports POCSAG, which is used to transmit data to pagers.
The ZUMspot pairs well with the Pi-Star app△, and set up is relatively easy, especially because it can use Pi-Star's Auto AP feature for wireless network configuration. It requires a digital voice-capable radio.
Don, W6GPS, released a good video: ZUMspot setup with Pi-Star for the Kenwood TH-D74△. In the first half of the video, Don explains the general initial configuration of a ZUMspot using Pi-Star. In the second half, he explains setting up the Kenwood TH-D74A for use with a hotspot.
In the U.S., the ZUMspot is available from Ham Radio Outlet as a bare Board△ or a Kit△. The kit includes a Raspberry Pi Zero WH and a microSD card preloaded with Pi-Star. HRO also carries a variety of other ZUM Radio boards and accessories; just do a search on "ZUM Radio."
In the U.K., the ZUMspot is available from ML&S (Martin Lynch & Sons) as a Kit△.
More about the ZUMspot
2a) What makes up a hotspot?
2b) A note about the LEDs, buttons, and through-holes
2c) In case you're interested
2d) C4Labs cases
2e) Nextion screen customizations
2f) Putting the vroom in zoom (going mobile)
Jump to: 3) Other hotspots△
2a) What makes up a hotspot?
Low-power hotspots like the ZUMspot are sometimes referred to as radio/modem boards. But what does that actually mean?
I had the good fortune to meet, via email, Dave, KC6N, who shared some great insights with me about how hotspots work. What he pointed out made me appreciate these little boards even more.
Here's what I understood from my chat with Dave: These low-power hotspot boards have two primary chips, and the radio and modem functions are distributed between them.
One chip is an Analog Devices ADF7021 Integrated Chip, a low power 2FSK/3FSK/4FSK transceiver. (FSK = Frequency Shift Keying; 2FSK is used for D-STAR, and 4FSK is used for DMR, YSF, P25, and NXDN, which helps explains why cross-mode operation is possible between the latter four, but not so easily with D-STAR.) The ADF7021 generates RF signals and handles audio tones used by our digital radios to represent 1s and 0s.
The other chip is a microcontroller, a small computer on a single integrated circuit. It does the digital work, builds the packet frames, and programs and controls the ADF7021.
The other component of a hotspot is the Gateway, which is what communicates with the internet. That functionality is handled by the Raspberry Pi that boards like the ZUMspot are mounted on.
If you'd like to dive into all of us this a bit more deeply, Dave created a very good presentation: Digital Voice for Amateur Radio△.
Thanks, Dave, for taking the time to share your knowledge and patiently explain this to me. It's at times like these that I get most excited about amateur radio.
2b) A note about the LEDs, buttons, and through-holes
A hotspot is like your own personal repeater and gateway computer. As such, it's capable of receiving and transmitting RF, as well as connecting to the internet to send and receive data. It has firmware it runs, and it can also run a display.
You need to view the LEDs from the perspective of the hotspot:
- PTT (Push-to-Talk) – Lights up when the hotspot is receiving data from the internet and is transmitting (Tx) it out via RF. When this is happening, your HT will be receiving.
- COS (Carrier Operated Switch) – Lights up when the hotspot's receiver squelch is open and a signal is being received (Rx). This happens when your HT is transmitting, in other words, when you press PTT to key up.
- Modes (D-STAR, DMR, YSF, P25, NXDN) – Light up when the hotspot is in that mode. If you have multiple modes active and there is no activity, the hotspot will scan those modes looking for activity, so the LEDs will flash in succession. When there is activity, the current mode's LED is lit, and it will remain lit after the activity finishes for the amount of time the hotspot continues listening on that mode (see the Hangtime setting△ in Pi-Star configuration).
There are two push buttons on the board.
- RST – The reset button forces a reset of the STM32 chip.
- BOOT0 – When BOOT0 is pressed, the STM32 chip starts in bootloader mode and will wait for a firmware update.
Note 1: To initiate a manual firmware update, you can either press BOOT0 while powering on the board, or press BOOT0 and RST simultaneously when the board is powered on. For more info, see the manual firmware update process outlined on the ZUMspot/MMDVM_HS GitHub page△.
Note 2: If you run a firmware update via SSH using the easy built-in Pi-Star command, the script automatically toggles the BOOT0 and RST pins. For more info, see Performing firmware updates via Pi-Star△.
You can use the plated through-holes to connect various peripherals, for example, you might solder in a 4x1 straight or right-angle pin header connector that you can use to connect the cable from a display.
- Serial – Connected to the Universal asynchronous receiver/transmitter (UART) on the STM32 chip. Used as part of the serial passthrough in MMDMVMHost. Can also be used as a debug port, and used by Pi-Star for Nextion displays
Note 1: TX on the Nextion display connects to the RX through-hole, and RX on the display connects to the TX through-hole.
Note 2: My 3.5″ Nextion Basic NX4832T035 and 3.2″ Nextion Enhanced NX4024K032 displays run fine using the 3V3 (3.3 volt) connection. I've tested this with both the RPi 3B and Zero W using a quality 2.5A power supply. I've heard others have needed to connect to a 5-volt GPIO pin.
- I2C (Inter-Integrated Circuit) – On the v0.4 board, connected to the clock (SCL) and data (SDA) pins on the STM32 chip.
2c) In case you're interested
For fun, I decided to make some hotspot cases out of some mahogany thinwood I had left over from my woodworking projects. I ended up building a bunch of cases as I experimented with different combinations of RPi boards, batteries, displays, and shapes, before I settled on one design for my shack and another for mobile.
The setup for my shack is a ZUMspot mounted on a RPi 3B with an Alchemy Power Pi-UpTimeUPS, which uses type 18650 3.7V batteries for uninterrupted power. (Adafruit has a good battery tutorial△.)
Since Pi-Star can run headless, the hotspot really doesn't need any external ports except for power in. It basically can be a black (or mahogany) box, optionally with on/off switches between the external power port and the UPS and between the UPS and the RPi, and maybe a display screen. In this case, I made a simple rectangular box case: 4.5″ wide × 4.7″ deep × 3.5″ high.
The height of the case was determined by the stack of boards, which has a plexiglass base. The stack slides into the case, with the base sliding under a rectangle of wood to secure the stack in place.
The display fits into the opening in front of the stack of boards. To reduce the footprint of the display, I soldered wires directly to its back rather than using the connector that plugs into its side. Since I'm using those same soldered wires to connect the display directly to my PC for programming via a USB to TTL UART CH340 Serial Converter, I also didn't need to leave space or cut a slot for inserting a microSD card into the display. That means I can fit a 3.5″ display into a space that's nearly the same size as the width and height of the stack of boards.
For the on/off switches, the best option I could find is the LoveRPi Power Switch, which includes a green status LED showing when it's on (important in a black box scenario). It includes three different colored rubber covers for the switch.
The cables and switches, which I attached to the case with hot glue, determined the depth of the case. Here you can see them crammed into the remaining space. The case piece with the switches exposed screws into the back opening.
The power switches and the single port (the micro-USB power input) are located on the back of the case. The cable with the green switch controls power between the UPS and RPi. The cable with the black switch controls power between the input port it provides and the UPS, which it's plugged into.
Theoretically I could leave the UPS powered on all the time, but ever since we had a (fortunately relatively small) fire in our home several years ago that was caused by an electrical short sparked by some poorly done wiring by a previous owner, I've been a bit paranoid about leaving things on when I'm not using them.
2d) C4Labs cases
Even though I like making cases, I also use some of the creative cases made by C4Labs in Tacoma, Washington: C4Labs ZUMspot cases△.
ZUM-PI Zero case
2e) Nextion screen customizations
My screens are a customization of the Nextion_ON7LDS△ screens. My goal was to be able to look at the display from anywhere in my shop and tell at glance what's being received, so I made the screens look quite different from one another, with colors related to their logos. I also like simple, calm screens, so the different text fields are displayed in various subtle colors, and there are no other eye candy embellishments.
Thanks to Rob van Rheenen, PDØDIB, the Dutch ham and digital voice enthusiast who moderates the Nextion Ham-Radio Screens△ Facebook group, and who generously provides excellent tutorials and mentoring. Thanks also to the hams who are sharing inspiring designs and support in the group.
- To connect the Nextion to my PC for programming, I used a RobotDyn USB to TTL UART CH340 Serial Converter, along with some breadboard jumper wires. I also used breadboard jumper wires for soldering onto the display.
- The Nextion Editor can be downloaded from Itead△.
- Tech Tip from Rob, PDØDIB: You can control the active and idle screen brightness via Pi-Star's MMDVMHost Expert Editor, which should help preserve battery life for a mobile hotspot. For more info, see: Brightness settings for Nextion Screen△.
- For a basic selection of Nextion screen layouts as well as the more detailed readme explanations of the differences between the layouts, see the Nextion subfolders of the g4klx/MMDVMHost GitHub page△.
- Rob, PDØDIB, also shares his screens via GitHub: PD0DIB/Nextion_HAM-radio-screens△.
- Ryan, WA6HXG, also shares some nice screens and good explanations on his GitHub project page: WA6HXG/MMDVM-Nextion-Screen-Layouts△.
Conclusion: While I enjoyed learning how to program the Nextion display, in the end I don't really look at it all that much and don't think a display is in any way a necessary component for a hotspot using Pi-Star. That said, I found it worth it to add a display simply because doing so broadened my knowledge about hotspots and electronics. And it's fun.
2f) Putting the vroom in zoom (going mobile)
The design for my mobile hotspot was influenced by two goals: a desire for simplicity and a hunger for operating time. I decided on a minimalist design: just the ZUMspot + RPi Zero W protected in a box and powered by a rugged external RAVPower 10050 mAh portable charger, which gives me a full day's capacity.
I added a right-angled micro-USB adapter inside the box to make plugging in easier (the plugin port aligns better with the port on the charger), as well as to reduce wear and tear on the RPi's micro-USB port. The mahogany case fits nicely on top of the battery, attached with Soft Touch Velour cinch straps.
Width Depth Height
Shack hotspot: 4.50″ × 4.70″ × 3.50″
Mobile hotspot: 3.25″ × 2.50″ × 1.75″
External battery: 4.60″ × 2.80″ × 0.90″
Deck of cards: 3.60″ × 2.60″ × 0.70″
3) Other hotspots
- Alphabetical list of some other hotspots I've tried or heard about.3
3a) BlueDV apps
by David, PA7LIM
David makes some really fun and innovative apps, and he's continuously trying new things and pushing boundaries. BlueDV can be run on Android and Windows (experimental versions are also available for iOS, Linux, and RPi), and is a good solution for a mobile hotspot using the BlueStack-Micro+ paired with a DVMEGA.
Note from David's website: "I am not a company! I just wrote the software for fun! (I have no commercial link with DVMEGA, Combitronics or others.) Hope you have a lot of fun with the software!" Thanks, David!
by Ruud Kerstens, PE1MSZ
A companion board for the DVMEGA. The DVMEGA RPi board can be paired with the BlueStack-Micro+ instead of an RPi, which enables bluetooth connection to an Android or iOS phone running BlueDV or a serial connection to a Windows computer running BlueDV.
- When powered by a portable battery pack, the BlueStack + DVMEGA combination provides a mobile solution that can be used with D-STAR, DMR, and YSF radios. For more about this mobile solution, see: Just can't wait to get on the road again△ in my D-STAR article.
- The BlueStack board also can be used to facilitate a DVMEGA firmware update. For more info, see the note DVMEGA firmware update△.
3c) DV dongles
by Robin Cutshaw, AA4RC, and Moe Wheatley, AE4JY, Internet Labs, Inc.
The DV Dongle and DVAP were among the earliest personal hotspots available1, can be connected to a PC running Windows or a Mac. The DV Dongle uses a DVSI AMBE-2000™ chip and the DVAP requires a D-STAR radio. The newer DV3K uses a DVSI AMBE-3000™ chip. At the 2017 Hamvention, they announced an upcoming "DV Air" product with built-in Bluetooth, WiFi, and ethernet, but as of autumn 2018, I haven't found anything further about it.
When running their own software, these dongles work with only DPLUS (REF) reflectors, intentionally block access to XRF, DCS, and XLX reflectors, and don't support DMR, YSF, or P25 modes.
3d) DV4 devices
by Uli Altvater, AG0X/DH6SAB, and Torsten Schultze, DG1HT
Another one of the earlier personal hotspots that was available1, the DV4mini was a USB stick that could be plugged into a PC running Windows or Linux, or a Raspberry Pi. The DV4home, released later, was a standalone digital voice device that had two AMBE chips as well as its own screen, microphone, and speaker.
While I know people who have used and liked the DV4 devices, I personally found both the DV4mini and the DV4home V1 clunky to use when I tried them in 2016/2017. The DV4home's rotary knob was particularly poorly implemented—I found it almost unusable—and I've heard similar feedback from someone using V2. I also didn't like its bias for the DMR+ network. Too bad, because I had high hopes for using the DV4home as my digital base station. All their current products appear to be out of stock, and their social media activity ceased in Jan 2018.
Website: Wireless Holdings△.
by Guus van Dooren, PE1PLM
Comes in single-mode (UHF) and dual-mode (VHF/UHF) versions, both of which can be mounted on Raspberry Pi computers, and there are other models as well. The DVMEGA also can be mounted on a BlueStack board. With firmware 3.07 and later, the DVMEGA can support D-STAR, DMR, and YSF. Requires a digital voice-capable radio.
- Works well with Pi-Star, and once you've soldered the firmware update jumper wire in place for Pi-Star, it's easy to update via Pi-Star's command line as well. It's also possible to update the firmware when the DVMEGA is mounted on a BlueStack board (with the jumper wire soldered to different pins) and connected to a PC. For firmware info, see the note DVMEGA firmware update△.
- Guus also recently released a couple new products: the DVstick 30, a thumb drive with an onboard AMBE-3000™ Vocoder chip, and the DVMEGA Cast, an AMBE-3000™ based multi-mode IP radio for DMR, D-STAR, and YSF.
3f) Hotspots by BI7JTA
by Huang Huorong, BI7JTA
Huang appears to be quite enthusiastic about amateur radio. I tried his simplex Nano hotSPOT blueBOX and found that it worked reasonably well, though it's quite slow, presumably due to the specs of the NanoPi computer it uses. He also makes a Duplex hotSPOT for RPi.
Website: BI7JTA blog△.
3g) MMDVM_HS_Hat devices
Produced by Florian, DF2ET, Mathis, DB9MAT, and Andreas, DO7EN; based on work by Jonathan, G4KLX, Andy, CA6JAU, Jim, KI6ZUM, and others.
While it's not exactly a sexy name, the MMDVM_HS_Hat line of boards from Germany is top notch (and shouldn't be confused with the low quality Chinese clones … see below: Be wary of cheap clones).
These boards handle D-STAR, DMR, YSF, P25, and NXDN, as well as YSF and DMR cross modes, and POCSAG (Florian and Mathis are very active in POCSAG-related development). A digital-voice capable radio is required.
Produced by Florian, DF2ET, and Mathis, DB9MAT.
Currently, this MMDVM_HS_Hat simplex board is on version 6, which uses the 12.288 MHz TCXO chip, which is more reliable than the 14.7456 MHz chip. It comes in two versions, one with an onboard ceramic chip antenna and another with an SMA socket external antenna. Works well with Pi-Star, and its firmware can be updated easily via Pi-Star's command line.
It can be challenging to get ahold of one of these, but the quality is good, so I found it worth the effort; however, it's not clear whether they intend to keep working on this form factor. If you're good at assembling electronics, you can Build your own MMDVM_HS_Hat△. There's a pre-configured Mouser cart for several versions, including one for MMDVM_HS_Hat version 1.6△.
Produced by Florian, DF2ET, Mathis, DB9MAT, and Andreas, DO7EN.
This newer duplex board also uses the 12.288 MHz TCXO chip.
The dual boards have one immediate advantage over the simplex hotspots, which is that you can transmit even when your radio is in the middle of receiving. This means that you can easily unlink from a busy talkgroup like TAC 310 even when the hams using the TG don't leave gaps between their transmissions.
Another advantage of the dual boards is that you can use both time slots, for example, you can use two DMR radios, one linked via TS1 and the other linked via TS2, to listen to both linked talkgroups simultaneously.
Just as with their simplex board, they have produced these high quality dual boards infrequently and in small batches, but again, I found it worth the effort and patience to get ahold of one.
by Mark Guidbord, K7IZA
The Nano-Spot appears to be a nifty little plug-n-play device. It includes built-in WiFi, RF and WiFi antennas, and an OLED display, all in a durable extruded aluminum case. Runs Pi-Star. Requires a digital radio and supports D-STAR, DMR, YSF, and P25. I haven't tried this hotspot, but if you're looking for hotspot hardware, it looks like one that may be worth checking out.
3i) SharkRF openSPOT
by Ákos Marton, HG1MA, and Norbert Varga, HA2NON
The openSPOT version 2, released Oct 2018, includes in its case both a built-in antenna and WiFi. It works with D-STAR, DMR, YSF, P25, and NXDN radios, has some cross-mode capability, and also handles POCSAG. It uses its own browser-based software.
by Bryan Hoyer, K7UDR, Basil Gunn, N7NIX, John Hays, K7VE, and Dennis Rosenauer, AC7FT
The ThumbDV is a USB device with a built-in AMBE chip, so it can be plugged into a computer that has a microphone and speaker, and doesn't require a digital radio. I haven't tried this hotspot so can't share much about it. Apparently it can support D-STAR, DMR, and YSF, depending on the hotspot software used.
Website: NW Digital Radio ThumbDV△
4) Be wary of cheap clones!
There are some really good quality, cutting-edge hotspot modem boards available right now. And then there are the clone boards called JumboSPOT (a.k.a., J-Hat), which are inferior, unauthorized copies of an early MMDVM_HS_Hat.
From what I have read in forums, a significant number of people have problems with the JumboSPOT. In particular, it uses cheap versions of the oscillator/TCXO chips, which can cause some serious issues, up to bricking the board.
Many of the vendors of these cheap knock-off clones appear to not even know much about amateur radio. Their focus seems to be making a quick buck. Many don't provide much support to the hams buying their products.
The hams creating the genuine hardware, the firmware it runs, and the MMDVM platform are personally and directly contributing to the amazingly rapid innovation we're seeing in the digital voice space right now.
At first glance, the clone boards may seem to be a bargain because they're a few bucks cheaper than the original boards. But spending a few extra bucks on one of the original boards is worth it: not only do you get quality components and better support, you also get the satisfaction of supporting the innovation that is advancing our hobby.
5) Shout out to the innovators and enablers
In general, hotspots really put the amateur in amateur radio. For the most part, the creative innovation driving this branch of amateur radio forward is being done by passionate hams around the world with day jobs and families who are pouring their energy into these various projects in their spare time.
The upside is that we get this really innovative playground to play around in; the downside—or, depending on how you look at it, another upside—is that this really is an amateur endeavor: things don't always work; there are some rough edges; updates sometimes break stuff; it can take a while for new features that many people want to get implemented; sometimes the only way to make something work is with a soldering iron, a bit of cussing, and a lot of stubbornness; and some features aren't fully documented so it can take a lot of trial and error to figure them out. In other words … lots of fun to be had for an adventurous amateur!
A hearty thanks to all the innovators, tinkerers, mentors, and enablers for making it possible for the rest of us to enjoy the rich variety of systems and features that are now available in the digital voice playground! Here are some of the hams driving all of this forward:
Jonathan Naylor, G4KLX
Jonathan operates in a technical stratosphere way above my head. What I can comprehend is that he has been creating important digital voice-related solutions for years, which he makes freely available to the hams who are innovating in this playground and helping to make amateur digital voice radio so exciting.
The fact that he does this as a side project is truly amazing. (In a video of a talk he gave about MMDVM, he mentioned how at one point his job took him away from home during the week for a period of time to a place that had few disturbances. This, he said with a somewhat mischievous grin, made it possible for him to spend his evening doing something useful … which turned out to be MMDVM!)
Jonathan is particularly passionate about opening things up so hams can participate fully in the hobby, not just as end users of systems and hardware. From his talk at Pacificon 2018: "A closed system in the face of an equivalent open system will never win."
Here's what Pi-Star's Andy Taylor says about this:
There are some more special people who we all owe a debt of gratitude for their willingness to release their software for free. Jonathan Naylor (G4KLX) for his most excellent DStarRepeater, ircDDBGateway suite, and more recently MMDVMHost and DMRGateway. These applications form the core of what makes Pi-Star what it is, and without these excellent applications Digital Voice for Amateurs would be an entirely different and barren landscape.
Andrew Taylor, MWØMWZ
Andy's work has made a huge difference to the thousands of us around the world who use Pi-Star to run our hotspots and repeaters. If this were his full-time job, I still wouldn't understand how he manages to crank out so much code as he keeps updating Pi-Star with the latest cutting-edge features and advances. The fact that he does this as a side project and somehow still manages to find time for his real full-time job, his family, and his studies leaves me awed. Website: www.pistar.uk△; Github: Andy Taylor△.
José Uribe (Andy), CA6JAU
Andy makes the firmware that powers many ZUMspot and MMDVM_HS-based boards, as well as some of the cross-mode gateways. If you ever hear a rumor about some awesome new feature or functionality, check out his GitHub page; chances are he'll already have a release ready with it ! GitHub: juribeparada/MMDVM_HS△.
The tinkerers like Jim McLaughlin, KI6ZUM
There are tinkerers in countries all around the world who are designing boards and wielding soldering irons faster than any of the legendary six-shooter gunslingers of the Old West.
Jim McLaughlin, KI6ZUM, is one of them. He worked closely with Jonathan and Andy on the original MMDVM project, and is the guiding hand behind the ZUM Radio products. There are several others listed in the Other hotspots section above. And there are many more I've read about (try searching Twitter for MMDVM!), and I'm sure there are even more I haven't yet heard about.
For someone like me who thinks it's a pretty amazing accomplishment when I manage to solder on a GPIO header without melting the whole board … well, let's just say I'm impressed!
Here's a video of one of Jim's talks: Multimode Digital Voice Modem△, Pacificon 2018.
There are a bunch of hams hanging out in forums and groups around the internet answering question, solving problems, and giving guidance for all the various aspects of digital voice and hotspots. For the Pi-Star project, this includes Craig, W1MSG, who also produces tutorial videos△, Adrian, MØGLJ, and Andrew, M1DNS, as well as many others. Thanks to all the hams who are helping out in this way; I really appreciate the opportunity to learn by reading your posts!
And all the other enablers
Finally, a shoutout to all the clubs and individuals who are putting up repeaters, reflectors, servers, gateways, bridges, and other equipment, as well as providing trainings for how to use it all.
And a special thanks to a team here in my home state, Northern Colorado DMR (NoCO DMR△); they're doing some great work!