Decodium 4.0 Mobile

IU8LMC Martino Merola

About this app

Decodium 4 brings the digital-modes station to your phone: it decodes FT8, FT4
and FT2 on the device itself, shows the waterfall in real time and controls the
rig over CAT.

Decoding happens on the phone, not on a server: the app uses the same engine as
Decodium for the computer.

⚠ IMPORTANT: YOU NEED A RADIO AND THE DECOLINK PROGRAM ON A PC

This app is not a receiver: on its own it hears nothing. The audio comes from
the computer connected to the radio, through the free DECOLINK program
(Windows), available at decolink.ft2.it.

Decolink takes the audio from the transceiver's USB codec and sends it to the
phone; it also acts as a CAT service, so there is no need to install Hamlib
separately. No OTG cable is required.

THE TWO WAYS TO CONNECT

1) LOCAL NETWORK — the phone is on the same WiFi as the computer
This is the simplest route and needs no registration at all: no data leaves
your home. In Decolink you enter the phone's IP address; on the phone you
choose Setup > AUDIO > Connection = LAN and press "Receive".
For CAT: TRANSMIT tab > Connect, with the computer's IP and port 4532.

2) REMOTELY, THROUGH THE RELAY — the phone can be anywhere, mobile data included
This needs a free account on decolink.ft2.it: you register from a browser at
decolink.ft2.it/registrati giving your callsign and station, and the request
is approved by the station owner. Once signed in, in Decolink you pick the
station from the drop-down list, and on the phone you set Connection = Relay
with the same credentials.
This is the mode that always works: computer and phone both reach out to the
relay, so there is no router to configure. On mobile data it is the only
practicable one, because the phone sits behind the operator's NAT and cannot
be reached from outside.

The role you are given may be listen-only: in that case you receive the audio
but you neither transmit nor control the radio. That is the station owner's
choice, not a shortcoming.

WHAT IT DOES

• Decodes FT8, FT4 and FT2 with the full decoder, not a cut-down version
• Waterfall and spectrum in real time, resizable, in portrait and landscape
• QSO sequencer following the real rules of the protocol: call, report,
confirmation
• Clock synchronisation over NTP, essential because digital modes work in
windows of a few seconds
• CAT control over the network, or directly over USB-OTG on compatible radios
• PTT and transmit audio, voice included
• Frequency table by band and mode, DXCC entities, map of contacts
• DX cluster and reception reports to PSK Reporter
• Demonstration mode: one button and the app works on example signals, with
waterfall, decodes and a complete contact. It is there to show you how it
works before you connect anything
• Interface in fifteen languages — Italian, English, German, French, Spanish,
Catalan, Dutch, Danish, Hungarian, Romanian, Latvian, Russian, Japanese,
simplified and traditional Chinese — picked from the phone on first start and
changeable on the fly from the settings

WHO IT IS FOR

For licensed radio amateurs who have a station to control.

PRIVACY

No advertising, no analytics, no tracking. The data stays on the phone: only
what you choose to put on the air or send to the amateur radio networks leaves
it (PSK Reporter, DX cluster), as the nature of the service requires. The
microphone is used only for voice, while you hold the button down, and is never
recorded. The account is only for the remote connection: anyone working on the
local network needs to register nothing.

What’s new

First published version.

• FT8, FT4 and FT2 decoding on the phone, with real-time waterfall and spectrum
• CAT rig control and transmission, voice included
• Interface in fifteen languages, picked from the phone and changeable on the fly
• Demonstration mode: one button to see the app at work with no radio connected