Automatic Link Establishment

Question 1

What 3 things make up an ALE system?

Answer 1

1) HF SSB transceiver
2) Internal microprocessor
3) MFSK modem

Question 2

Explain Bit Error Ratio

Answer 2

A measure of signal quality. The ratio of number of bits incorrectly recieved to the number of bits sent during a specific time interval.

Question 3

Expand and explain SELCAL

Answer 3

Selective Calling - is like a lock on a door. Locks all of the signals without the correct key. In ALE’s case it’s a digital code.

Question 4

Name 4 common applications within ALE

Answer 4

1) Email via HF internet
2) SMS
3) File Transfer
4) Geo Positioning Reporting

Question 5

What are the indicators that an ALE link has successfully been setup?

Answer 5

The operator will hear an audible alarm and will see a visual alert.

Question 6

What are the 3 practices that can now be conducted once a link has been setup successfully?

Answer 6

1) Talk in regular conversation
2) Negotiate a data link using voice
3) ALE built in SMS

Question 7

What is ALE convenient for?

Answer 7

Beyond Line of Sight communications

Question 8

Who uses HF ALE?

Answer 8

Disaster relief e.g. Red Cross and Military/Guard forces.

Question 9

Which specific Military force employs ALE?

Answer 9

All U.S. Armed Forces use ALE.

Question 10

How does ALE reach a specific station?

Answer 10

The ALE controller will select the best idle channel and will then send brief selective calling.