CNRLS - Abstract

Crossband Node Repeater Linking System - An Abstract for discussion

Here is part one of the 'White Paper" I promised for this Wednesdays (5 June 2019) Tech Net. I have decided to break the paper into two parts - the abstract and the details. To be honest, part of the reason is that there are a LOT of details, and the Abstract is what I need comment on in order to write some of those details.


The Need
Enhance the realized geographic range of the 147.120 N4LGH repeater beyond what simply raising the elevation of the current antenna could possibly accommodate, and allow Amateurs from areas outside of the 147.120 coverage area to participate in 147.120 on-air activities.

The Idea
A system consisting of multiple ‘Nodes’ to link repeaters in the Amateur 2M, 1.25M, and 70CM bands, providing extended coverage to existing repeaters by ‘linking’ them together over amateur frequencies.

The Solution
Programmable multi-radio multi-band ‘nodes’ placed in such a way that each node can maintain reliable communication with at least one other node, allowing for ‘crossband’ linking of repeaters within the range of complimenting nodes.

Repeater linking, IoT device linking, crossband repeat for handheld and mobile range extension, beaconing, propagation study and very much more.

This is an ambitious project. Even with minimal nodes, considerable resources will be necessary. While considerable, it is doable with the team that appears to be available on the 147.120 repeater group. It will require hardware, site locations, programming, representation and coordination. It will require some funding which I have provided so far and have a plan to provide further funding as we progress.

Repeater Linking Area Network (RLAN)
In effect this system creates a Repeater Linking Area Network comprised of the nodes in the system. A functional RLAN will be linked through one another having one or more nodes attached to the internet for communication with the CNRLS servers.


(Some) Theoretical Modes of Operation

Crossband Repeat
This mode can be standalone for the node, meaning only one node location is necessary for this mode and no communication with the system servers is necessary once the mode is set. Each node in the system could conceivably operate with complete independence in this mode. The node simply listens on one band and transmits received signals on another, effectively increasing the range of handheld and mobile stations to any repeater the node is able to communicate with, much like any other cross band repeat equipment.

Crossband Repeater Link
This name may be somewhat misleading as each node is in itself a 'crossband' system; this MODE is crossband repeater linking. This mode is also able to be standalone, linking a repeater on one band to a repeater on either of the other bands.

In Band Repeater Link
This mode requires at least two nodes. Since no node will have a duplexer it will take a second band to form a link between two nodes. In this mode the two nodes will work in tandem to emulate a repeater with a duplexer by using two sites and an offband link. This facilitates the linking of two repeaters in the same band. It will be most common to link either two VHF or two UHF repeaters using a 222 MHz link.

Node to Node Crossband Repeat
This mode facilitates the linking of one or two two simplex frequencies in the same band. At least two nodes are required.

There are other 'modes' of operation, limited only by need and imagination.

Idle Mode Operations
While the nodes have no activity for their assigned tasks, their secondary task activities can be quite ranging. Beacon, scanning, activity reporting, signal strength readings, etc. With additional hardware, data such as temperature, pressure, and humidity can be telemetered to the CNRLS servers for later analysis. Questions we haven't thought to ask about propagation can be answered with the right queries to a database like this.


(Some) Operation Notes

User Interaction
A user should be able to interact with the system in any of several ways, depending upon their status with the system.

Users should be able to access a web page and see what the current configuration of the system is. They should be able to see what settings are automatic and what settings they can change and what settings they cannot. They should be able to request certain functionality of the system and interact with or set other functionality. They should also be able to interact with the system in a limited way via DTMF, packet and digital formats.

Managers of the system should be able to maintain basic functions of the system such as control operations and certain types of user requests. This interaction should be able to take place online and via packet or DTMF.

Administrators should be able to access any part of the system and control all aspects of its operation in any way available.

For whatever user level is assigned, the system needs to be considerably flexible in its configuration. It needs an element of automation within certain rules and some manual control over various aspects of the system. There needs to be a system of menus to facilitate the configurations and automation rules. There needs to be a basic interface for display of system status,

Most of the system needs to be able to be controlled on the air rather than over the internet or wifi. Users need to be able to notify the system of various requests and responses and the system needs to identify itself with an Amateur call during certain operational modes.

Nodes could announce their presence from time to time to allow non-connected amateurs the opportunity to locate and use the link and give instructions for its use.



I would like your feedback on this abstract. I'm currently writing the details including the basic system configuration, the theory of operation including startup and communication with the servers, hardware, software, teams, financing, the works. Next week I will publish the first draft of these details and request discussion on those as well.

Feel free to suggest additions, edits, corrections, etc.

Tracy Markham N4LGH