Specifications

54 June 2009
below your receive frequency,
rotating both knobs cw will move
the passband higher in frequency,
eliminating the interfering sig-
nal.
The width of the passband can
be changed by adjusting the knobs
separately. If you turn the inner
(high edge) knob cw you are raising
the upper frequency limit — widen-
ing the passband. If you turn the outer
(low edge) knob cw you are raising
the lower frequency limit — narrow-
ing the passband.
Notch Filters
The automatic and manual notch filters
are DSP functions used to notch out a very
narrow sliver from within the IF passband.
This allows you to remove an interfering
carrier that is too close to your desired signal
for PBT manipulations to eliminate. The
digital notch filters are more useful against
heterodynes, CW and digital signals than
voice modulation.
The automatic notch filter (ANF) scans
the IF passband, detects up to two interfering
signals and notches them out with between
40 and 50 dB of attenuation. The ANF will
also track interfering signals as they move
across the passband.
The manual notch filter (MNF) is op-
erator controlled using the
MNF knob at the
lower right. You rotate the knob, moving
a stationary notch of 75 dB attenuation
across the passband, until the interfering
signal is removed. The MNF can only notch
one signal at a time and will not track a
moving signal, but it provides a noticeably
deeper notch. The width of the MNF can
be adjusted. The ANF and MNF cannot be
used together.
Noise Reduction
The DSP noise reduction (NR) feature
distinguishes between noise and a signal
and then acts, digitally, to reduce the noise
with minimal effect on the signal. It will
only take one evening of operating on 80 or
160 meters to appreciate its usefulness. With
a signal tuned in, just press the
NR button
to activate the feature, and then hold
NR to
open the adjusting menu. Turning the dial
will vary the NR value between 0 and 15.
Don’t be tempted to crank the NR up to 15
and just leave it there, though. At low levels
of NR, audio quality is not affected, but at
the higher levels some audio quality will be
lost. Begin with the lowest level of NR and
raise it to get the best balance between noise
and readability.
Last but not least is the noise blanker
(NB) This is the great granddaddy of all
noise controls and limits pulse type noise.
Keeping Track
The IC-7200 is equipped with
201 memory channels. Channels
1 through 199 are memories that
can store the transmit and receive
frequencies and the operating
mode. The remaining two (P1, P2)
are band edge channels used as
upper and lower frequency limits
for the scanning feature.
Programming the memory chan-
nels is simple. In VFO mode, set
your frequency, rotate the
M-CH
knob to select a channel and hold
the
MW (memory write) button. The
’7200 will respond with three beeps
when the frequency is stored. That’s it! Now
you never have to look up that net frequency
again. Programming memory channels in
memory mode is similar except you first
select the channel to program and then set
up the frequency.
Recalling the channel is just as simple
— press the
V/M button to activate the
memory mode;
MEMO will display. Use
the
M-CH knob to select the channel you
want and you’re there. In less time than it
takes to say DX, the selected frequency is
transferred to the active VFO and you are
ready to radio!
Once you have 201 frequencies stored,
a scanner becomes a necessity. The ’7200
is equipped with two scanning modes: pro-
grammed and memory. The programmed
scan uses the band edge channels ( P1 and
P2) as its lower and upper limits, scanning
each frequency between those two points.
The memory scan steps through only those
frequencies stored in memory channels. It
starts from the lowest programmed channel
and continues to the highest, then jumps back
and starts over.
When it reaches an active frequency, it
stops. The scan resume function controls
the stop time. With scan resume
OFF, the
scan stops at the first active frequency and
the scan is canceled. If scan resume is
ON,
the scan will stop on the active frequency
and wait. If the frequency remains active for
10 seconds or goes quiet for 2 seconds, the
scan will resume.
Configuring the Radio
There are many aspects of the ’7200’s
operation that can be customized to meet
your operating style. The Set Mode (SM)
menu is where you convert the stock radio
into your radio. The Set Mode includes 41
items that are of the set-and-forget type.
This is where you adjust settings such as
LCD backlighting, meter peak hold and the
internal keyer’s dot/dash ratio.
There is also a Quick Set Mode (QSM)
in addition to the regular set mode. QSM
is where you find those items that change
often, RF power output or keyer speed for
instance. QSM items vary according to the
operating mode in use. Pressing
SET opens
the QSM, and holding
SET opens the SM.
Interfering with Interference
The ’7200 has many interference fighting
features, most of which use its digital signal
processing (DSP) system. The IF passband
width is DSP controlled, according to the
operating mode, from 50 Hz to 8000 Hz.
Each mode has three filter widths — narrow,
middle and wide. Each width is separately
adjustable. I’m primarily a phone operator
and found the default phone widths of 1800,
2400 and 3000 Hz to be very good choices.
For those CW folks out there, the narrow CW
filter default is 250 Hz. This is thoroughly
up to date compared to the IC-718 with its
limited selection of optional crystal filters
and DSP add-on for notch filter and noise
reduction
Passband Tuning
The DSP passband tuning (PBT) feature
allows you to shift the entire IF passband
slightly higher or lower in frequency or to
narrow and enlarge the passband width.
PBT is controlled by the
TWIN PBT dual
knob located on the upper left of the front
panel. The inner knob adjusts
PBT1 (the
high frequency edge of the passband) and
the outer knob
PBT2 (the low frequency
edge). The manual’s description of the PBT
is somewhat thin, so some clarification is
in order.
The neutral position for the PBT is with
both the inner and outer knobs at detent. In
this position the IF passband is centered on
the IF frequency and the width is set to the
filter passband width setting. If you move
both knobs simultaneously counterclock-
wise (ccw), you move the passband lower
in frequency without changing its width.
Moving both knobs clockwise (cw) shifts
the entire passband higher in frequency.
So if an interfering station appears slightly
Figure 4 — The rear panel of the IC-7200 includes
antenna and power connectors, ALC and TR control
for a linear amplifier, provisions for digital modes and
computer control.