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Configuration of the IC-F8101-3X for ALE Operation
Configuration of the IC-F8101-3X for ALE Operation


A .pdf version of this document can be downloaded by clicking here.


 
Configuring the Icom IC-F8101 for ALE Operations
 
 
7 August 2017

Table of Contents
Overview

The IC-F8101-3X does not provide sufficient parameter descriptions to arrive at a radio configuration that provides optimized Automatic Link Establishment (ALE) performance. Further, many of the recommended or default parameter values do not provide the level of performance that the IC-F8101 is capable of achieving.

This article was constructed with input from Icom, and United States Army NETCOM, in order to provide additional guidance in configuring the IC-F8101 for ALE operations. Application of the recommendations in this document will result in maximizing performance of the ALE capabilities of the IC-F8101.


About The Automatic Link Establishment Datalink Layer

The goal of configuring the IC-F8101 is to establish reliable operation within each of the three primary ALE states, and reliable transitions between ALE states.


ALE achieves a high level of reliability by implementing Forward Error Correction (FEC) in conjunction with the transmission of triple redundant data, and majority voting on received triple redundant data. The adjustments that are available in the IC-F8101 reside within Word Sync, Pattern Sync and the FEC sublayers within the Datalink Layer.


During transmit, the FEC sublayer of the Datalink layer is provided a 24-bit ALE data word, which is formatted by the ALE Protocol, and performs the following actions upon the ALE data word:

These transmit operations are illustrated in the figure below.


During reception, the FEC sublayer of the Datalink layer is provided a 48-bit data word, which has to be processed to produce the original 24-bit ALE protocol word. The following actions are performed by the FEC sublayer of the Datalink layer to reproduce the original 24-bit ALE protocol word:

These receive operations are illustrated in the following figure.


The Icom IC-F8101-3X customer programming software provides adjustments to the handling of errors within the Datalink layer. Errors are detected in the recovery of the 48-bit data word (i.e. in the synchronization / demodulator stages), and within the Golay FEC stages. The locations where error detection occurs are illustrated by the dashed red-line shapes in the following image.


Configuration for Optimized ALE Performance

The following image shows the ALE configuration subsection of the Setmode section of the customer programming software.

Select parameters within the ALE settings should be configured as follows:

Select parameters within the Call settings should be configured as follows:

NOTE: The disadvantage of having the radio auto-start the scan process is that manually stopping the scan and selecting a pre-programmed channel, as may occur during NET operations, will see the radio resume ALE scanning after the timer times out if no other activity occurs to cancel the timer (i.e. no PTT, etc.). For this reason, it is recommended that NET operations be conducted in VFO mode with manual entry of the NET frequency.

For all other Setmode parameters, Icom's recommended or default parameter values should be acceptable.


The original post of this article resides at http://www.ciarc.org/projects/ic_f8101_config.shtml.