Bulletins from the Pacific Packet Radio Society - page 060


to: AMICON Standards Committee
from: Den Connors KD2S

Please take a look at this draft, and give comments to Hank or me....

Amicon Interim System Specification
for the
AMSAT Phase III Satellite Channel L1

This document is meant to be used as an adjunct to the AMICON SYSTEM SPECIFICATION. The applicability of these interim standards shall be for a period to be determined by the Amicon Coordinator. Any part or all of this interim standard shall be subject to revision or elimination as the system matures. Refer to the main document for additional information on each interface level.


1.1 Channel Assignment and Characteristics

An attempt shall be made by system nodes to keep the frequency of the unmodulated carrier as close as possible to 11.25kHz above the received frequency of the general beacon, measured locally.

1.2 (not applicable)

1.3 Carrier and Modulation Specifications

Access to the Amicon channel shall be by appropriate transmitting/receiving equipment, with a design capable of providing a signal-to-noise ratio on reception by the satellite of about 20dB or better.

Audio Frequency Shift Keying (AFSK) shall be used to modulate the transmitter. Input to the modulator shall consist of a steady 120OHz tone to indicate a mark condition, and 220OHz for space (Bell 202 tones). Total bandwidth of the modulated RF signal shall be restricted to 15kHz, within which will be contained all signals with levels in excess of 20dB below the carrier level. \ This modulation technique is compatible with all currently available amateur packet modems. A separate effort will be pursued, using the mode X transponder to experiment with advanced modulation techniques for introduction into the Amicon Standard.}

1.4 (not applicable)

1.5 Data Terminal Equipments

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