🔀Multi-Radio

What it does

• Nine systems, switched with a single button — the new one ready in about a second
• Registers on the network, joins talkgroups, transmits and receives voice
• Text messages with delivery reports and position reports on a map
• Cycles through the systems on its own and stops wherever someone is transmitting
• Driven from a touch front panel, your phone or a browser

Normally every communication system means another radio and another bill. Multi-Radio flips that: one small device covers nine systems, and you pick the one you're working in with a single button. You don't even have to pick — the radio can cycle through the systems itself and stop wherever someone is transmitting. Everything needed to log in is entered online — no programming cable, no vendor software, no codeplug procedure.

Modes that work today

• Analog FM — receive and transmit, narrow- and wideband
• AM and SSB (LSB/USB) — new analog modes alongside FM
• TETRA DMO — live monitoring of direct-mode traffic
• TETRA TMO — terminal registered on a network, checked against a Motorola base station and a TetraSpot
• DMR — two-way voice, confirmed on air against an AnyTone AT-D878UVII Plus
• P25 — two-way voice, confirmed on air against a Harris P7100
• D-STAR — two-way voice, confirmed on air against an ICOM ID-51
• YSF (System Fusion) — two-way voice, confirmed on air against a Yaesu FT-991A
• M17 — the open digital standard, receive and transmit between our own stations
• NXDN — full voice path (transmit and receive); not yet verified against a commercial radio
• dPMR — full voice path (transmit and receive); not yet verified against a commercial radio
• Scanning across systems — the radio cycles through the modes and stops on activity

Where it helps

• An affordable terminal where a commercial radio costs too much
• A monitoring and test position while building out a network
• Learning and experimentation — full insight into what's on the air
• Nine systems from one device, without buying several radios

What it does in TETRA mode

• Network registration with authentication
• Joining talkgroups
• Group and individual calls — setup and release
• Incoming calls — ringing, accept or reject, two-way conversation
• Calls from the telephone network through the base station's gateway
• Voice reception
• Text messages — sending, receiving and delivery reports, with retries for lost ones
• Statuses and position reports read back by the base station
• A view of network parameters and received signal level

What it does in the digital modes

• DMR: live monitoring — who is transmitting, on which talkgroup and frequency
• DMR: voice transmission straight to air with a PTT button
• DMR: your own ID, talkgroup, Color Code and power set from the app
• P25: voice reception and transmission, with radio and talkgroup identifiers
• P25: automatic monitoring — digital mode switches itself on
• D-STAR: two-way conversation with a commercial radio, with text alongside the voice
• YSF and M17: two-way voice, with your own callsign and group
• Digital voice without buying a vocoder chip — the device does the encoding itself
• An S-meter plus receive and transmit indicators in every mode

Three ways to drive it

The radio doesn't force one interface on you — you drive it whichever way suits the moment. All three show the same state and work together: you can key up from the front panel while speaking through your phone.

• A touch front panel — the physical display that turns this into a radio rather than a computer: PTT, tuning, squelch, encryption and mode switching under your finger, without opening anything
• The panel connects over Bluetooth or by cable — over Bluetooth it needs nothing but power
• An Android app — full control from your phone, and you choose the link yourself: automatic, Bluetooth or Wi-Fi
• The app also carries the audio: microphone and speaker, PTT and live monitoring
• Cross-system scanning started from the app, showing the mode the radio stopped on
• A browser panel — the same functions with the audio, when you're at a computer
• The app also manages the station itself: battery (UPS) status, phone pairing, remote restart and shutdown

In development

• Verifying NXDN and dPMR against commercial radios
• Transmission in TETRA direct mode (DMO)
• Voice transmission in networked TETRA mode
• Mutual authentication
• Packet data
• DMR through a repeater
• Operating in several modes at once
• A “Plecki” back-plate module — the whole Multi-Radio station on the back of a smartphone, with its own battery and a 2 W amplifier (architecture and parts list done, schematic and PCB next)