Specifications

Reprinted from October 2011 QST © ARRL
choice on F-4, while in CW mode, the same
key opens one of two selectable KEY menus,
and in RTTY mode it opens the decoder
screen. Pressing and holding the primary
MENU button takes you into SET MODE, let-
ting you enable or adjust those parameters
less-traveled. I found menu scrolling to be
counterintuitive. You press the ∨ key to as-
cend the menu tree and the ∧ key to descend.
The power supply connector is not com-
patible with earlier ICOM gear, so if you’re
upgrading from a previous model (such as
my ’756PROIII) you’ll need to change some
station wiring. The ACC (accessory) socket
is a 13 pin DIN connector. ICOM included a
compatible DIN plug with color coded pig-
tails, obviating the need to solder directly to
the connector. The SEND jack to key a linear
amplifier is an RCA phono connector. The
contacts are rated for a maximum of 16 V at
0.5 A, compatible with any modern power
amplifier. The rear-apron ground connection
uses a fairly short Phillips head screw with two
flat washers and one lock washer on its shaft.
A wing nut would have been easier to manage.
Two SO-239 coax antenna ports are avail-
able on the rear apron. If your station setup
only requires a single coax connection to your
transceiver, you can disable the unneeded port,
so you don’t inadvertently transmit into an
open load. Very thoughtful! The IC-7410 does
not provide the means to connect a separate
receive antenna, such as a Beverage.
How Does It Play?
If I had just one word to describe the
IC-7410 it would be competent, and the
numbers from the ARRL Lab support this
impression — not the best but very good. In
reciprocal mixing testing for two-tone IMD
(see Table 1), the IC-7410 stacks up as essen-
tially identical to the IC-7600, and blocking
gain compression was superior. The ’7410
pretty much blows away the IC-746PRO’s
much older technology, but it’s right on par
with the higher tier IC-7800, at least in terms
of two-tone IMD on 14 MHz. The numbers
are even very good on 50 MHz.
ARRL Lab Engineer Bob Allison,
WB1GCM, noted an oddity while testing
the ’7410’s blocking gain compression at
5 kHz and 2 kHz spacings. “I experienced
receiver overload at the point when the block-
ing signal caused the audio to drop by about
0.5 dB, such that strong noise jumps up at this
threshold and the desired signal becomes ab-
sent,” Allison recounted. “Raising the level of
the blocking signal further caused an unrelated
audio tone to bleed through.” For example, he
said, if the radio is tuned to 14.020 MHz (pre-
amp off) and a 50 dB over S-9 signal shows
up at 14.018 MHz, the receiver will overload.
“Needless to say,” Allison added, “the block-
ing figures are still very good.”
Allison reports that he was unable to de-
tect any receiver images during lab testing.
He further notes that the receiver actually is
usable down into the VLF range — 30 kHz
(–99 dBm minimum discernable signal).
“Many receivers tested are pretty dead down
there,” he said. “This receiver is very sensi-
tive at 137 kHz and 505 kHz — spots where
some nations already allow amateur activity.
You may think that that doesn’t matter much,
but it does if you’re using an active antenna
or a small loop antenna.”
Flexible DSP IF filters and twin pass-
band tuning (PBT) with a graphical display
of passband setting have become hallmarks
of this generation of ICOM transceivers. The
IC-7410 augments these with optional nar-
row filters for the 1st IF (64.455 MHz), which
install easily. Each has a unique socket, so
you cannot inadvertently install them incor-
rectly. While ICOM does not refer to these as
roofing filters in the Instruction Manual, the
display does show an R ahead of the current
filter setting. This appears to be a “rose by
another name” situation, since the net effect
is the same. Narrower filters at this point in
the circuit will reduce the impact of other
in-band signals on the signal you’re trying
to pull out, especially when the band is busy
(think Field Day or pileup).
Pressing and holding the F-5 button
changes the optional 1st IF filter selections —
stepping through the default 15 kHz (roofing
filter passband), 6 kHz and 3 kHz settings.
Quickly pressing the F-5 key changes the
second IF (36 kHz) DSP filter contour from
“sharp” to “soft.” It takes a little practice to
make this button do just what you want, and
you may have to squint at the display to see
the setting itself.
The sharp and soft contours did not make
much difference to my ear on CW signals,
although narrow filter settings seem more
likely to sound “ringy” in the sharp profile
as opposed to the soft. You may detect a
smoother, even more pleasing sound with
SSB audio by enabling the soft contour on
a given DSP filter setting. The soft setting
also seems to ameliorate some noise profiles.
By the way, the IC-7410’s noise reduction
(NR) appeared superior to the PROIII’s NR.
That makes sense, since the IC-7410 is more
closely related to the IC-7600 and its more
advanced DSP technology.
I thought a few things could be improved.
The IC-7410 offers two levels of RF pream-
plification but just one level of attenuation. I
missed having multiple levels of attenuation
to deal with noise and interference on the low
bands. The AGC attack, at least at default
settings, seemed a bit severe. Static crashes
actually killed the audio momentarily until
it recovered. The speaker crackled a bit at
higher AF GAIN settings.
Worth Mentioning (or Repeating)
The IC-7410 retains the most useful
features of its predecessors. Take the voice
squelch control (VSC), for example, intro-
duced with the IC-746PRO. The VSC checks
all signals for “voice components” before it
breaks squelch. This feature is really cool,
especially if you tend to monitor an HF fre-
quency for activity (for example an emergency
or traffic net). This means, too, that while
scanning, the radio does not stop on every
carrier, cable birdie or kerchunker, and it’s
available on AM and FM, as well as on SSB.
The automatic antenna tuner is excellent.
It uses variable capacitors instead of clacking
relays, and it works essentially as advertised
— quickly and quietly. It can be set to auto
start on HF or to start when PTT is activated
on a new frequency. You can even set “band
edges” for an especially narrowband antenna
system. A rear-apron jack allows connection
of an external ATU as well.
While the ’7410 does not have a spectrum
scope, it does have what ICOM dubs a simple
band scope (SCP). At first glance, this might
not seem a very useful operating aid, but it
certainly came in handy during the ARRL
June VHF QSO Party. I was expecting it
to operate much in the same manner as the
similar utility on the IC-706 series, but it’s
way faster. At any of the available settings it
scanned the given swath of spectrum nearly
instantly, leaving “blips” on the horizontal
line representing signals detected (the re-
ceiver is muted during scanning). The scan
limits depend upon how closely you want
the band scope to check for signals — every
Figure 4 — The
uncluttered rear panel of the IC-7410.