Automatic Link Establishment Flashcards
Automatic link establishment is the worldwide standard for what ?
For digitally initiating and sustaining HF radio communications
What is the purpose of automatic link establishment?
To provide a reliable, rapid method of calling and connecting HF communications
What does a automatic link establishment radio consist of ?
An HF single side band radio transceiver
An internal microprocessor
A MFSK modem
It also has an unique ALE address
What does an automatic link establishment system do when it is not actively in contact with another system ?
The HF SSB transceiver scans through a list of HF frequencies listening for any other ALE signals
What is BER
Bit error rate
What is the bit error rate used for ?
To store a quality score for frequencies and sender addresses that other stations have used
What is the bit error rate
It is a measure of signal quality.
What is an error in telecommunications ?
It is the ratio of the number of bits, elements, characters or blocks incorrectly received to the number sent during a specific time interval
How does an automatic link establishment reach a specific station ?
The called enters the ALE address,
The selects the best available idle channel for that destination address
Then sends a selective calling signal identifying the recipient
What is selective calling ? Or SELCAL
It is similar to a locked door. Selective calling locks out any signal unless it has the correct key ( a specific digital code )
If a radio has carrier squelch unlocked, what will happen ?
It will allow any signal in
What happens when a automatic link establishment system detects ALE activity ?
It will stop scanning and stay on that channel to confirm if the call is for itself or someone else
What happens if an ALE station detects a call for itself?
The two stations will automatically handshake to confirm the link is sufficient quality.
It will then notify the operators
What happens upon a successful link of two ALE stations ?
The receiving station generally emits an audible alarm and shows a visual alert to the operator.
It will also indicated the incoming call sign
What are some common applications ALE provides ?
Voice conversation Alerting Data exchange Texting Instant messaging Email File transfer Image Telemetry Geo position tracking
