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Chapter 9 AMTOR Operation
You can usually monitor a contact between two linked stations using the ARQ Listen mode (also called Mode L).
This mode may need a few seconds to phase or acquire synchronization with the master station, depending on
operating conditions such as interference. Your monitor will display all the retries if the linked stations that you’re
monitoring are experiencing ARQ errors.
Note : When the DSP “syncs” on the ISS station, it won ’t automatically sync with the other station after
the two stations switch control of the link; you’ll have to reacquire and sync with the (now) ISS station
after the changover to copy what’s being sent.
Type
ALIST (or AL ) repeatedly if you lose synchronization.
AMtor
Immediate Command
Mode: Command Host: AM
AMTOR is an immediate command that switches your DSP into the AMTOR Mode—it’s automatically placed in
the ARQ Standby condition. Your station is then accessible by any AMTOR station that sends your SELCALL. The
DSP can communicate using either the CCIR 476 (4-character SELCALL) or the CCIR 625 (7-character
SELCALL) protocol. Your monitor will also display any inbound FEC (mode B) transmissions.
Use
MYSELCAL and MYIDENT to enter your 4- and 7-character SELCALL s.
ARq aaaa [ aaa ] Immediate Command
Mode: AMTOR Host: AC
aaaa [ aaa ]
The distant station’s 4-character or 7-character SELCALL code.
ARQ is an immediate command that initiates an AMTOR mode A (ARQ) SELCALL to another station. To begin
the Mode A (ARQ) selective call, enter
ARQ
followed by the other station’s SELCALL. Example:
cmd:
ARQ WFFA
(4-character SELCALL)
..or
cmd :
ARQ MFTAAAA
(7-character SELCALL)
As soon as
( RETURN ) is pressed, the DSP will begin keying your transmitter in the three-character AMTOR ARQ
burst sequence. If the distant station receives and decodes a SELCALL successfully, the two AMTOR systems
synchronize and begin the mode A (ARQ) AMTOR “handshaking” process.
See
MYSELCAL
and
MYIDENT
to enter your 4- and 7- character
SELCALLs
.
ARQTmo n Default: 60
Mode: AMTOR, PACTOR Host: AO
“
n ” 0 to 250 specifies the number of seconds to send an ARQ SELCALL before automatic transmitter
shutdown.
ARQTMO sets the length of time during which your ARQ call will be sent, shutting down the transmitter
automatically after exceeding its value. As a general rule, if you can’t activate another AMTOR or PACTOR station
in the default time of 60 seconds, you can probably assume that the other station can’t hear your transmission.
ARQTOL
n Default: 3
9-10 September, 05