home *** CD-ROM | disk | FTP | other *** search
- 1
-
- TECTIDB Version 1. 3 3/1/92
-
-
-
- TECHNICAL TIDBITS
- [Category TEC]
-
- ALE : Automatic Link Establishment, A Discussion
- The following was submitted by Nathaniel McMillian, NTIA/ITS.
- Federal Standard 1045 (FS 1045) defines Automatic Link
- Establishment or ALE as the capability of an HF radio to initiate
- a circuit between itself and another radio without operator
- assistance and usually under processor control. As the Federal
- community moves more toward ALE, not only will HF radio
- operations become more efficient, but the capability of shared HF
- radio resources (or SHARES) will be enhanced. A review of some of
- the basic features of ALE will demonstrate its potential.
- An ALE radio is designed to continuously monitor an HF network or
- networks on up to 100 predesignated channels. Upon detecting an
- incoming call, ALE tunes the transmitter, sends a reply to the
- caller, and waits for an acknowledgement. Once the
- acknowledgement is received, the ALE sounds an alarm announcing
- the incoming call, activates the speaker, displays who is
- calling, on what frequency, in what mode, and waits for operator
- intervention. After the transmission is completed, the ALE units
- returns to monitoring the predesignated channels. If the incoming
- call is for data traffic, the controller automatically routes the
- call to a data terminal without operator intervention. For
- outgoing calls, the operator tells the controller the destination
- station or stations and the desired mode of operation. The
- controller picks the best available preprogrammed channel,
- completes all the tuning and handshake work and, when the link is
- established, waits for operator intervention. Besides simple
- network monitoring and linking, ALE also provides for linking all
- stations in a network with a single call; or automatically
- responds to a net, or multiple net, collective call.
- With ALE, most of the work is efficiently done by the processor,
- leaving the operator free to do other things. As impressive as
- ALE is today, additional features are under development. These
- features include automatic networking, automatic message store
- and forward, anti-interference, privacy, automatic relaying, and
- automatic networking with other media. RB192-91
-
- FERRITE BEADS AND RADIO INTERFERENCE
- "Using Ferrite Beads to Keep RF Out of TV Sets, Telephones,
- VCR's, Electronic Equipment, Burglar Alarms and Other" is
- available with a SASE from the Stanislaus Amateur Radio
- Association, P.O. Box 4601, Modesto, CA 95352. Many of us have
- been bedeviled with HF-SSB interference on EOC telephone lines
- from RACES, CAP, MARS and other transmitters. If you have or have
- had similar problems, this handout has a wealth of information
- for serious troubleshooters. (Thanks to the SARA, N6OCV, and
- Palomar Engineers. ) RB 026
-
-
-