Welcome to the ALE Area of Tactical Link Systems
Note that in this area, ALE is NOT a beverage. In
this context, it means
"Automatic Link Establishment".
The "ALE Info" area will be hosting information on
Automatic Link Establishment, equipment field trials, and related
activity, while the "ALE Chat" area is for web-based
discussions on the use of FED-Std 1045 and Mil-Std 188/141 linking
protocol along with a question and answer format that will allow
users of this mode to exchange meaningful and timely discussion.
If you would like to hear what ALE signaling sounds like,
(this sound file is courtesy of Leif Dehio)
Speaking of other sounds heard on HF,
here is a link that I recently ran across:
A fully-documented ALE handbook is available online
Past and predicted solar flux numbers are available at: <ftp://ftp.ngdc.noaa.gov/STP/IONOSPHERE/INDICES/indices.txt>
The terrestrial, 10.7 cm forecast, covering the next
27 days, is also available at:
Downloadable (and free) HF radio channel prediction software
is available at: <http://elbert.its.bldrdoc.gov/hf.html>
The "WUN Club" has an excellent write
up on their webpage that covers
the ALE protocol in some detail.
An excellent book is available which covers the subject of ALE:
"Advanced High-Frequency Radio Communications"
Authors: Eric E. Johnson, Robert I. Desourdis, Jr.
Greg D. Earle, Stephen C. Cook, and
Jens C. Ostergaard
Publisher: Artech House, Boston/London Price: $109.00
(hey, limited interest reference books happen to be expensive)
I purchased this book from Amazon about two years ago.
Search via the ISBN number and this book will come up at
The basics of ALE will also be covered below:
For those who perhaps have heard the term
"ALE", or heard ALE signaling on the air, Below will be a
very short overview of the purpose of ALE and why it exists:
The primary purpose of ALE is to provide a
much more reliable means for one station to call another station via
Prior to ALE, operators of HF radio equipment needed to develop a
body of skills that would allow them to know as accurately as
possible, what specific frequency segment of the HF radio spectrum
could be used at a particular time of day, time of year, and period
of the current sunspot cycle, in order to reliably raise another
specific radio station in which they need contact. Making the right
decision wasn't always easy.
The results would be that a pre-arranged set of specific radio
channels may be defined and each station would call the other on each
of the frequencies until they were able to hook up with one another.
Not a very robust or efficient system, but simplicity can work, given
The next iteration of operations would have been that each station
could monitor all the assigned frequencies simultaneously, through
the use of separate equipment, or would have channel scan capability
to scan channels in order to listen for a call directed to them.
Again, not very efficient.
ALE places all these decision-making requirements inside of the radio
As the power of computing and microprocessors have advanced with
time, MITRE Corporation took the lead in developing a standard method
of allowing the radios themselves to manage their channel-selecting
decisions when the operator needed to call another station.
Below are the key points of how ALE functions. Keep in mind that the
decisions that the radios make, will tend to mirror how a real person
would normally have to manage the operations of frequency selection,
exchanging signal reports, keeping records of which channel is best,
and so forth. So... Here Goes:
(NOTE, This section is under construction:)
REQUIREMENTS FOR ALE TO WORK: