Timewave PK-900, Operating Manual

Page: 191 / 392

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ADDress "n" Default: $0000
Mode: ALL Host: AE
_________________________________ Parameters: __________________________________
"n" - Zero to 65,535 ($0 to $FFFF) setting an Address in the PK-900 memory.
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The ADDRESS sets an address somewhere in the PK-900's memory map. This
command is usually used with the IO, MEMORY and the PK commands. It is used
primarily by programmers and is of no use for normal PK-900 operation.
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ADelay "n" Default: 4 (40 msec.)
Mode: AMTOR, PACTOR Host: AD
_________________________________ Parameters: __________________________________
"n" - 1 to 9 specifies transmitter key-up delay in 10-millisecond intervals.
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ADELAY is the length of time in tens of milliseconds between the time when the
PK-900 activates the transmitter's PTT line and the ARQ data begins to flow.
The ADELAY command allows you to adjust a variable delay, from 10 to 90
milliseconds to handle the PTT (Push-to-Talk) delay of different transmitters.
In most cases, the default value of 4 (40 milliseconds) is adequate for the
majority of the popular HF transmitters. If the AMTOR signal strength is good
and you observe periodic errors caused by loss of phasing (shown by rephase
cycles in the middle of an ARQ contact) during contacts, it may be necessary to
adjust the ADELAY value.
o Be sure that errors and rephasing effects are not caused by the distant
station before changing your ADELAY.
o If changing your ADELAY values does not improve link performance, reinstall
your original value and ask the other station to try changing his ADELAY.
Because the ARQ mode allows 170 milliseconds for the signal to travel to the
distant station and return, increasing ADELAY will reduce the maximum working
distance. The maximum theoretical range of an ARQ contact is limited to about
25,500 kilometers. Using some of that time as transmit delay leaves less time
for signal propagation. Thus the maximum distance available is reduced.
Regardless of the setting of ADELAY, ARQ (Mode A) AMTOR may not work very well
over very short distances, e.g., one or two miles. However, in very short
distance work, ARQ should not be necessary to achieve error-free copy.
PACTOR is less sensitive to transmitter turn on timing and values up to 10
(100 ms) may be used.
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