5 March 2014

MIL-STD-188-141 Alternate Quick Call ALE

Alternate Quick Call ALE (AQC-ALE) is derived from the MIL-STD-188-141B, Appendix A standard. 
When poor channel conditions exist, such as high noise levels, static crashes and weak signals that causes problems during a LINKing attempt where NORMAL-ALE fails to link the use of AQC-ALE can also be made to overcome such channel conditions.

AQC-ALE provides a link establishment technique that requires significantly less time to link than the baseline ALE system and is significantly better at establishing and maintaining a link on under poor channel conditions.
This is accomplished by some additional technology and trading-off some of the lesser used functions of the baseline ALE system for a faster linking process. The primary focus of AQC-ALE is to establish a link between two or more stations as rapidly as possible. Once linked, information can be exchanged in the most efficient manner as is common between stations. 

AQC-ALE is basically a tactical tool, in that although it supports Scanning/Sounding and most things that baseline (a.k.a. NORMAL ALE) supports, AQC-ALE is usually used in small tactical network operations rather than fixed point 24/7 ALE Network operations.
AQC-ALE allows for a maximum of a 6 character (2 ALE word) address for both the OWN, OTHER and NET address. In addition, AQC-ALE does NOT support AMD, DTM or DBM during link set up, or an AMD at link clear or an MOTD or initiating an QC-ALE link by use of a MIL-STD-188-110 modem associated link request.
AQC-ALE has a very fast calling handshake and all parties must be using FAST AGC and the Scanning/Sounding station MUST be operating at a 5 ch/sec scan rate for best results. A 2 ch/sec scan rate will work depending on the number of channels in the Scan Group and timing considerations as to when the calling station starts transmitting and when the Scanning station comes to that channel next, a 1 ch/sec. scan rate will not work reliably. An AQC-ALE call will reliably capture a station Scanning that is using a 6 channel or less Scan Group at a 2 ch/sec. scan rate and has “Listen Calls” checked and “Listen Time” set to 400.
Quick AMD Dictionary
AQC-ALE offers additional tactical features not found in baseline ALE, such as Quick AMD Dictionary operation. QAMD works from three dictionaries in a code book fashion where no actual text of the message is being sent out over the air. It is a table lookup value in the code book which are the dictionaries. There is no data encryption going on here. Using a combination of a fixed dictionary for most commonly needed words and mission specific expressions in the additional two dictionaries, which can be changed to fit the scenario of the Exercise or non-Exercise.
AMD Dictionary is a quick mouse double click system of selecting words and phrases to create an AMD when using AQC-ALE. The operator can not enter any words on the fly, the word or phrase must pre-exist in the dictionaries. If all the users are not using the same dictionaries then the receiving station will not print the proper message.

AQC-ALE provides the “Meet Me” dialog for rapid frequency changes that can steer an entire net on the fly, the “Meet Me” Orderwire command capability.

The “Meet Me” capability requires that all stations in the link be under computer control and all are using the exact same GROUP/Channels configuration, then the NCS or any station can steer the group (or individual station) to a new channel instantly without the need for a voice announcement or even an AMD message.
The process simply requires entering the RX and TX frequency in Hz (channel based pull down from current GROUP is planned) and checking LSB if required and clicking OK, then an Ordewire message is sent and all the stations will QSY to the new frequency/mode pair if entered correctly and if existing in the current GROUP of all linked stations. Optionally stations may be added or deleted from the linked stations and an acknowledgement (Ack This) may be requested.

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