See Networking on Purpose for the why of dedicated links.
Each link runs asynchronous to each other link and so you could have inbound traffic on one link while transmitting a message on another. While it is possible to receive on a radio while transmitting on another on the same band without blocking the receiving radio, it is much easier to do that when on different bands. It may seem difficult or complex to do multiple bands. However, it is easier to do multiple bands than to do two radios on the same band. Here is a block diagram for a typical TARPN node design. Click to see supplemental detail and larger images.The images appear to specify that we must use NinoTNC to build a TARPN node. We designed NinoTNC ourselves to be the most versatile and inexpensive KISS TNC. It's also cheap. There are other solutions and the Raspberry PI with G8BPQ's linbpq program is very versatile. You could build a node which uses radio with built-in TNC, or uses TNCs which are stand-alone units using USB to talk to the PI, and the radios could be handie-talkies.
The antennas shown include a separate antenna for each radio. You could use a multi-band vertical. Some stations are close enough together that very trivial indoor antennas will perform. However, the hardest part of building a TARPN, so far, has been distance and antennas.
The only required part of the node is that it uses a Raspberry PI. We actually have a well described and specific set of rules for participation. (see Rules for TARPNS) Everything else is dependent on the situation the node/switch is being built for.
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