Guidelines for Use and Implementation of Regenerative Packet Nodes

A regenerative node is a node that starts to relay a packet frame before it has received a complete frame, and is transparent to the stations using the node. You don't connect or link via the regenerative node, it simple passes all traffic heard on it's input.

This type of node greatly reduces 'hidden terminal' effect that is encountered when stations on either side of a topographic feature (hill, ridge etc) try to link on the same frequency via a node on top of this hill or ridge, causing clashes on the input.

However because of its transparent nature, certain precautions should be taken in the use and in the licensing of this type of node:
  • The input frequency (Rx) for regenerative nodes, will only be used for that purpose, and will not shared with other mailbox to mailbox links or node to node links.
  • The input frequency will be paired with an output frequency (Tx), again this will only be used for this purpose.
  • Cross-band regenerative nodes will be permitted, but the above guidelines should be followed with regard to their input and output frequencies on the respective bands.

Guidelines for the use of regenerative packet nodes
  • CW idents received on the input frequency must not be allowed to appear on the output frequency but should cause the transmitter to energise and to send flags to indicate that the input is busy. (prevent contention with CWIDs). This would also make sure that the regenerative node doesn't relay CWI's which would contravene the terms and conditions of BR68.
  • All uplinking stations should use directional aerials with a beamwidth (at -3 dB points) of not greater than 90 degrees. i.e. if using a Yagi, it should have not less than 3 elements. This will prevent frames of users being relayed by other regenerative nodes sharing the same frequency pair.
  • The transmit power of an uplinking station should be not greater than required to give a reliable link to the regenerative node. This is a similar requirement to that of a satellite transponder.
  • Uplinking stations should be nodes or mailboxes rather than individual users. This would give control over the number of stations accessing the regenerative node and ensure the points raised above would be compiled with.
  • The received data must be decoded, i.e. no audio to audio packet repeaters allowed.

RSGB DCC November 1995

This page last updated: 10-Mar-01

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The information contained within is deemed to be accurate at the time of writing.
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