D-STAR

D-STAR is a digital protocol that allows connecting interlocutors using a bandwidth of 6 kHz.

In analog, there are few parameters to set: receive frequency, transmit frequency (or shift), and possibly the audio subtone.

The DR mode is what is used on RTX transceivers to switch to D-STAR mode. To communicate in D-STAR, besides the transmission frequency and the shift, four fields must also be specified:

• UR: the callsign of the destination, i.e., the peer to whom we are routing the communication. It can be the callsign of a radio amateur, a Reflector, a starnet (smart group), or a string identifying a command executed by the system receiving it (in this case, the repeater or the hotspot we are connected to)
• R1: the callsign of the hotspot or radio repeater receiving us
• R2: the callsign of the gateway we want to use to make non-local calls (i.e., not limited to repeater users only)
• MY: our callsign

Let's see the various cases.

Direct point-to-point communication

We have two operators (IZ5ABC and IZ0ABC) who want to call each other on 145.500 MHz without shift. What needs to be done is to set the communication channel with the following parameters:

• Frequency: 145.500
• DUP: 0
• UR: CQCQCQ (or the callsign IZ5ABC on IZ0ABC's radio and vice versa on the other)
• R1: —
• R2: —
• MY: IZ5ABC (or IZ0ABC)

What does CQCQCQ mean? It is the classic string meaning "To anyone on this frequency". Generally, it is used when we want to send the call to everyone listening and not to a specific destination.

Communication on a radio repeater (local)

If we want to communicate only on the repeater (for example IR5UBO) without going further, and we want only those under its coverage to hear us:

• Frequency: 430.275
• DUP: +.1600
• UR: CQCQCQ
• R1: IR5UBO B
• R2: —
• MY: IZ5ABC

Note that R1 and R2, besides the repeater callsign, also have a letter. Conventionally:

• A: indicates that we want to use module A of the repeater, i.e., the one connected to gigahertz frequencies
• B: indicates UHF in the 430 band
• C: indicates VHF in the 144 band
• G: is always the gateway port

Suffixes are always in the last position.

Communication on a radio repeater with Gateway call - Zone Routing

This practice is not very widely used, however, in D-STAR, repeaters being connected to the Internet, it is possible to make calls to operators on another repeater. For example, if we are on IR5UBO B and want to talk to users of IR5AY C, then:

• Frequency: 430.275
• DUP: +.1600
• UR: /IR5AY C (the C is in the eighth position)
• R1: IR5UBO B
• R2: IR5UBO G
• MY: IZ5ABC

Users of IR5AY C must, in order to reply, set:

• Frequency: 145.575
• DUP: -0.600
• UR: /IR5UBOB (the B is in the last position, i.e., the eighth)
• R1: IR5AY C
• R2: IR5AY G
• MY: IZ0ABC

When making a call of this type, it is always best to start by saying "I am transmitting from IR5UBO B on gateway call IR5AY C". This way, whoever is listening knows how to configure their radio to reply.

Communication on a radio repeater with reflector

Reflectors are servers that have a 6-character callsign (for example, XLX585) and modules. Think of reflectors as houses and modules as rooms. When a user connects to a module of a reflector, they can talk to other users connected to the same module of the same reflector. To link to a reflector, you need to "shift" the repeater to that reflector. So once we have ensured that no one is using it, we configure the radio:

• Frequency: 430.275
• DUP: +.1600
• UR: XLX585RAL ← L stands for LINK, A is the module of the reflector XLX585
• R1: IR5UBO B
• R2: IR5UBO G
• MY: IZ5ABC

To know what to write instead of the UR field, i.e., to know which module of which reflector to connect to, we can consult a dynamic list (it changes over time as reflectors are created and destroyed by their sysops). The one shown is the link to the Dashboard of Reflector XLX585. Depending on the protocol used, reflectors can be named XRF, DCS, XLX... it is of no concern to the connecting user.

Once the link is established, we move to the communication:

• Frequency: 430.275
• DUP: +.1600
• UR: CQCQCQ
• R1: IR5UBO B
• R2: IR5UBO G
• MY: IZ5ABC

Once finished, you can unlink the repeater from the reflector (which generally also happens automatically after a certain period of inactivity):

• Frequency: 430.275
• DUP: +.1600
• UR: U ← Unlink
• R1: IR5UBO B
• R2: IR5UBO G
• MY: IZ5ABC

Communication with a single operator in call routing

When two operators link to two repeaters under the same ircDDB network (ircddb.net for repeaters and openquad.net for hotspots... at least in general), it is possible to send a call in call routing. When a radio amateur links to a repeater (or hotspot), the network it is connected to knows where their repeater is. When another operator calls them, the network will route the communication to them without the caller having any idea where they are. If from IR5UBO I want to call IZ0ABC:

• Frequency: 430.275
• DUP: +.1600
• UR: IZ0ABC
• R1: IR5UBO B
• R2: IR5UBO G
• MY: IZ5ABC

The communication will be point-to-point. If instead of using repeaters you use hotspots, you are to all intents and purposes talking in private without anyone else hearing you on the frequency (unless there is a radio amateur listening 10 meters away from you under the coverage of a 10 mW hotspot...)

Communication with multiple operators in call routing via smart group (starnet)

With the previous technique, it is only possible to talk in pairs. If we want to talk to multiple people scattered around the world, we can do it via call routing as long as everyone is subscribed to the same starnet. Starnets are entities that, by subscribing, become aware of where you are (i.e. which repeater you are linked to) and will route to you (and to all other subscribers) any traffic sent to the starnet. Unlike reflectors, there is no list of starnets. It's done by word of mouth.

[May the big mole be with you]

[EOF]

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