Pi-Star from scratch: setting up a hotspot for the DMRhub server

Pi-Star is a ready-made firmware for a Raspberry Pi with an MMDVM board that turns the little "Pi" into a full-fledged digital hotspot. Flash the image to an SD card, connect over Wi-Fi, open the web interface — and within ten minutes your radio is already on the air. In this article we walk through the whole journey: from flashing the card to the moment the hotspot connects to your own DMR master — in our case, the DMRhub network. No fluff, step by step, the way it's done by hand.

Step 1. Flashing the Pi-Star image to SD

Grab a fresh image from the official site pistar.uk (the Downloads section). You'll download a .zip archive containing a .img file. You don't have to unpack it beforehand: modern flashers read zip directly.

Two programs will do the job — pick either one, but don't mix them up:

• Raspberry Pi Imager — the official Raspberry Pi utility. Click "Choose OS → Use custom", point it at the downloaded image, select the card, and flash.
• balenaEtcher — a cross-platform flasher. "Flash from file" → image, "Select target" → card, "Flash!".

Flashing and verification take a few minutes. Afterward Windows will see a small FAT partition on the card and offer to "format" it — do not agree: the second, main partition is in ext format that Windows simply can't read, and the image is intact.

Step 2. First boot and Auto AP

Insert the card into the Pi and power it up. If Pi-Star doesn't find a known Wi-Fi network within about two minutes, it brings up its own access point for initial setup.

• Network name (SSID): Pistar-Setup
• Wi-Fi password: raspberry

Connect to this network from your phone or laptop and open the control panel:

http://pi-star.local/
# or directly via the setup access point's IP:
http://192.168.50.1/

If pi-star.local doesn't resolve (it happens on Android and in some networks without mDNS), use the IP address. The default login/password for the dashboard and SSH is pi-star / raspberry. Change the password right after setup.

Step 3. Connecting the hotspot to your home Wi-Fi

In the dashboard, go to Configuration (the /admin/configure.php page), and in the Wireless Configuration block scan for networks, pick yours, enter the password, and save. Pi-Star applies the settings only after a reboot — the Pistar-Setup access point won't disappear right away.

After the reboot, the hotspot will show up on your main network. From then on, open the same http://pi-star.local/ from your home network — the setup access point is no longer needed.

Step 4. Basic configuration: frequency, Color Code, mode

In General Configuration, fill in the essentials:

• Hostname — the hotspot's name on the network (you can leave it as pi-star).
• Node Callsign / DMR ID — your callsign and DMR ID.
• Radio Frequency — the working frequency of the simplex hotspot (RX = TX).
• Controller / Modem — the MMDVM board type (for most clones, MMDVM_HS_Hat / generic works).
• Color Code — must match what's set in the radio's codeplug.

Which frequency to use

A hotspot is a low-power simplex transceiver, and its frequency is taken from the amateur bands (for licensed hams with a valid permit) or from license-free bands. Reference points:

• 2 meters — 144–146 MHz (amateur band);
• 70 cm — 430–440 MHz (amateur band);
• LPD — 433.075–434.775 MHz (license-free short-range channels);
• PMR — 446 MHz (license-free segment).

Most often a free frequency around 433–434 MHz or in the 70 cm segment is chosen for a hotspot. The key thing is that the radio's RX and TX must exactly match the hotspot's Radio Frequency, otherwise there will be no link.

Enabling DMR

In the MMDVMHost Configuration block, flip on the DMR Mode toggle. The other modes (D-Star, YSF, P25, NXDN), if you don't need them, are best disabled — less load and less confusion. Click Apply Changes; the page will reload and a new DMR settings block will appear.

Step 5. DMR Configuration — entering your DMRhub master

This is the key step. By default, the DMR Master dropdown only lists public networks (BrandMeister, TGIF, FreeDMR, DMR+, and so on). To make the hotspot connect to the private DMRhub network, you need a "homebrew" master.

1. In DMR Configuration, in the DMR Master field, choose the manual/homebrew connection option (on modern builds this is done via DMRGateway or MMDVMHost direct mode).
2. Enter the connection parameters for the DMRhub master server:
   • Address — the address of the network's master server;
   • Port — the master's UDP port (the standard homebrew port is 62031);
   • Password — the connection password issued by the network.
3. Specify your private hotspot DMR ID (in DMRhub this is the 10000000+ block).
4. Save with Apply Changes.

If everything is correct, the dashboard status (Pi-Star:Dashboard) will show a green indicator next to the DMR network showing the connection to the master. From this point on, a radio tuned to the hotspot's frequency and Color Code goes on the air of the DMRhub network.

Step 6. Verification and fine-tuning

• Live Logs in the dashboard show what's happening on the air in real time — handy for catching errors during your first QSO.
• If the radio keys up but the hotspot "doesn't hear" it — the culprit is almost always a mismatch in frequency, Color Code, or time slot (a simplex hotspot uses TS2).
• RF calibration. Cheap MMDVM clones often drift by hundreds of Hz. If the connection is unstable, adjust the offset in the expert settings (RXOffset/TXOffset).