User's Manual Part 1

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Automatic Link Establishment (ALE) (Option)
ALE System Overview
The Barrett Automatic Link Establishment (ALE) controller option simplifies the
operation of HF networks, the ALE option automating many of the procedures
necessary to establish and maintain an HF link.
The Barrett PRC-2090 ALE controller option provides complete inter-operability as
required by FED-STD-1045 and U.S. MIL-STD-188-141B standards.
HF network stations equipped with ALE controllers automatically scan a pre-
selected set of channels, listening for ALE calls. If sounding is selected stations at
periodic intervals send out “sounding calls” to other stations. These signals are
analysed for link quality and stored in the “sounded” stations. All stations gradually
build up a table of parameters which determines best channels to use to link
between specific stations. These tables are used by the ALE controller to determine
the best channel to connect on when commanded by its operator to communicate
with another station.
The Barrett PRC-2090 ALE controller’s powerful memory stores up to 10,000 sets
of LQA information, 100 channel configurations, 20 self-address configurations and
100 other address configurations.
Operation Overview
The ALE network parameters are determined by a network supervisor, this person
programs all the transceivers in the network with the required addressing and
channel information using the ALE fill program. This is a PC based program used to
transfer pre-determined network information into each transceiver. A separate
manual is provided as a guide to ALE network setup and for the operation of ALE fill
program. As ALE’s prime purpose is to automate many of the procedures
necessary to establish and maintain an HF link, it is only necessary for the operator
to enter the station he wishes to call and activate ALE call sequence as described
in the following section.
Within the protected menu ALE section various operational parameters can be
changed as required by the operator. The section titled “ALE menus” describes
these functions.