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receiver audio through the speaker from
putting the radio into transmit.
Vox Hang is used to define how long the
VOX remains engaged after the end of a
transmission. This is set to prevent the
radio from cycling back and forth between
transmit and receive during the course of a
normal conversation.
(RX) RX MENU
The RX menu is accessible by pressing the
button on the front panel immediately to the
right of the screen next to the "RX"
annunciator.
Sweep Range is used for setting the range
of the real-time spectrum scope that is
available on the main receiver. There are 5
selectable widths of: 4.5, 9, 18, 36, and 72
kHz.
AGC is Automatic Gain Control and is used
to provide a reasonably uniform output at
audio from incoming signal strengths of
varying intensity.
One of the most useful, revolutionary new
features of ORION II is fully programmable
AGC. AGC action can be programmed to
taste on each receiver for FAST, MED and
SLOW settings, and a fourth setting, PROG,
allows the user to adjust any and all of the
AGC characteristics.
Refer to Figure 3-4 above. To adjust a
given parameter for each receiver, first
select the desired AGC on the receivers
before entering the menu system by using
the AGC button (see (33) AGC in Chapter
2).
For FAST, MED, and SLOW: The hang and
threshold parameters are fully adjustable.
AGC hang is the amount of time that the
AGC remains actuated before decay begins.
Threshold is the point at which a signal of a
given strength (expressed in microvolts) will
actuate the AGC system. The threshold
value in the AGC system acts like an IF gain
control for the DSP part of the receiver chain
– turn the value low and the receiver gain
comes up, as may signal levels and
extraneous noise. Decay is used to
determine how fast the IF gain increases in
the absence of a signal above the threshold
value.
566 manual
Part #74410
Printed in USA
The hang value for FAST, MED, and SLOW
is adjustable from 0 to 10.92 seconds. The
threshold value for FAST, MED, and SLOW
is adjustable from 0.37 uV to 191.48 uV.
The decay values available are FAST, 80-
200 dB/second, MED, 20-80 dB/second,
SLOW 5-20 dB/second.
The factory default values for FAST, MED,
and SLOW are FAST: hang 0.00, decay 80
dB/s, threshold 3.03 uV, MED: hang 0.00,
decay 40 dB/s, threshold 3.03 uV, SLOW:
hang 0.00, decay 10 dB/s, threshold 3.03
uV. These default settings apply to both the
main and sub receivers. Any default value
for a given AGC setting (FAST, MED, and
SLOW) can be instantly restored to factory
default value merely by pressing the MULTI
knob encoder toward the front panel while
the parameter is highlighted in the menu.
The PROG (programmable AGC) setting
provides full adjustment of all parameters in
the AGC system. In addition to the hang
and threshold values being fully adjustable
as they are with FAST, MED, and SLOW,
the programmable AGC setting allows the
decay rate to be adjusted over its full range
from 1 to 2000 dB/second.
AGC is an important characteristic of overall
receiver performance for contesting and
weak signal DXing. Please also read the
section in Chapter 4 of this manual titled
"Optimal Uses of ORION II Receiver for
Weak-Signal DXing and Contesting".
PBT Track and BW Track are used to
simultaneously set the PBT and BW values
for each receiver with one turn of the MULTI
knob. The default value is "off", allowing the
PBT and BW values to be adjusted
separately by receiver. If it is desirable to
adjust both PBT and BW on both receivers
at the same time, this control can be set to
"on". Additionally, BW setting can be
copied between VFO A and VFO B when
using the A>B, B>A, or A/B buttons on the
front panel if this value is set to "on" (default
is that BW information is not copied between
VFOs when frequency information is
exchanged).
Hardware NB allows the hardware noise
blanker available for the main receiver to be
turned on and off. This additional noise
blanking system for the main receiver only
can either be used together with or
Version 4 – October 2006
32
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