Timewave DSP-232, Operating Manual

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Chapter 12 PACTOR Operation
The PACTOR MailDrop has been designed with a “Watchdog” safety feature so that it can operate independently
with little attention. If a remote station is linked with your PACTOR MailDrop and no traffic is passed for 5
minutes, the link will drop and your transmitter will shut off.
At this writing however, unattended operation below 30 MHz is not legal for US amateurs unless they hold a
Special Temporary Authorization (STA) from the FCC for this purpose. This restriction may soon change, but until
then US amateurs must be sure to always have control of their HF transmitters when any automatic device such as
the DSP MailDrop is in operation.
Operating Tips and Options
ID’ing Yourself
The FCC requires station identification once every ten minutes while you’re engaged in a QSO. It’s sufficient to
begin with
DE mycall
or end your transmission with
DE mycall
before the
CTRL+Z
changeover, but an easier way
to ID yourself is to use
CTRL+B
to send the text stored in your own Auto-AnswerBack message. (See
AAB
.)
Note : If you want to see your AAB message on your screen as it’s sent to the linked station, turn EAS ON
(while in the Command mode.)
EAS — E cho A s S ent—operates the same as in ARQ AMTOR. With EAS ON , you’ll see characters echoed to your
screen only the first time the DSP sends them and only once, even if the data isn’t acknowledged by the receiving
station. This allows you to observe the progress of your transmission. If progress is very slow, most likely due to
deteriorating atmospheric conditions, then it’s probably time to wrap up the contact.
Long Path Contacts
If the station you’re going to QSO with is more than halfway around the earth (long path), precede the station’s
callsign with an exclamation point. This will change PACTOR’s timing to allow for the extended radio propagation
delay.
♦
If data scrolls across your monitor at an even rate, you can assume that you have a good ARQ link.
♦
If the data hesitates or scrolls in a jerky, intermittent fashion, that’s generally a sign that the radio link isn’t
very good.
♦
If the characters stop appearing on your monitor during receive, the link is failing or has failed. The
STATUS display will tell you this by showing ERROR or REQUEST nearly continuously.
WORDOUT
Some PACTOR users like to have their words sent out only when they are complete, rather than individual letters
sent as they’re typed.
WORDOUT
allows the word you’re currently typing to be edited as long as you haven’t
pressed the Space Bar or any punctuation. Turning WORDOUT ON activates this feature.
Operating on the “Wrong” Sideband
PACTOR, like packet, is mark-space polarity independent—although the reason for this is somewhat different.
Specific header blocks define the mark-space sense for each PACTOR information block and during linked
operation, the mark-space sense is alternated. For this reason, there is no “wrong” sideband. You may operate on
either LSB or USB. If you’re going to change to other modes—for example AMTOR—then LSB is used by
convention. Using LSB keeps mode changes simple as well as keeping the radio dial frequency reading consistent
with other users. If you don’t have a “narrow” filter, switching sidebands and retuning may allow you to reduce
adjacent channel interference during PACTOR operation.
Switching Time Problem?
For operation in PACTOR ARQ, your transceiver or transmitter-receiver combination must be able to change
between transmit and receive within 130 mS. Most modern solid state radios can easily meet this specification.
Many older tube-type radios that use electromechanical relays also operate very well in PACTOR ARQ; any radio
capable of AMTOR ARQ will operate PACTOR ARQ.
12-6 September, 05