ICOM IC-7410 HF and 6 Meter Transceiver
Reviewed by Rick Lindquist, WW3DE
The IC-7410 replaces the IC-746PRO and adds an improved receiver, much faster DSP performance and new features to the mix, but drops 2 meter coverage. Although the new radio does a lot, the '7410 user interface will be familiar to users of current ICOM radios.
The ICOM IC-7410 is the now discontinued IC-746PRO writ larger — at least physically, since this radio does not include 2 meter capability. In nomenclature it follows the IC-7400, never marketed in North America but which served as the IC-746PRO in other parts of the world, including Europe.1 ICOM continues to capitalize on this excellent and popular radio foundation with the nearly simultaneous release of the IC-9100, a higher tier model that does include 2 meters, 70 cm, an optional 23 cm module, satellite features and a heftier price tag. So, you could say the IC-7410 is the IC-9100 for the rest of us.
ICOM's description of the IC-7410 as "an excellent balance of technology and performance" may suggest some measure of compromise, but it's quite capable. Keep in mind, too, that ICOM has incorporated the incremental technological improvements — faster signal digital signal processing, no waiting for the radio to "boot up," for instance — that have been showing up in offerings preceding the IC-7410, such as the IC-7600.
What's It Like?
Given its slenderized form factor you could find yourself doing a bit of juggling to fit the longish IC-7410 comfortably on your operating desk. It's narrower by about an inch from the IC-756PRO series or IC-7600 models, but it's certainly deeper. I managed to perch it atop my IC-756PROIII, so I could do some side-by-side (so to speak) comparisons, but I ended up using a mirror to locate rear-panel connector since the newer radio extends about two inches beyond the edge of its older relative.
The '7410 offers a pleasing countenance, with a 10.25 x 6 cm monochrome display window, accented on the left and bottom edges with an inset ogee-style half frame. This is not the more commodious color display of the IC-7600 or even of the PROIII, but it is quite sufficient. The IC-7410's frequency readout seems larger than life within the slightly smaller display screen. The metallic F-1 through F-5 buttons immediately below the display window are easier to differentiate from the MODE buttons that I am always pressing in error on rriy PROIII. ICOM slightly offset the function buttons from the five MODE buttons, to minimize this possibility on the '7410.
The hefty main tuning knob possesses the sort of solid counterbalanced feel that puts the operator in the driver's seat. The knob has a substantial, easy-to-grip, rubberized outer ring plus the now customary tuning dimple, and I preferred it to the PROIII's main tuning knob. It's possible to manually adjust the tuning dial tension with a slider beneath the knob — no screwdriver needed! ICOM followed through elsewhere on the front panel with larger knobs that offer a more positive sense of control. Even the inner concentric controls are easy to maneuver.
The front panel's bold lettering contrasts nicely with the dark, smooth (easy-to-clean) finish, making legends easy to read. This is a welcome improvement from earlier ICOM designs, which sometimes sacrificed utility at the altar of style. I especially appreciated the conspicuous round XFC and TS buttons, which are much easier to access than on the PROIII. (Press XFC to listen to your transmit frequency when split; TS changes the tuning step.)
The four "stem" controls on the front panel's lower lip are shorter and sturdier than on earlier ICOM models, although it can be a bit difficult to discern the unpainted pointers on these shafts. The stem controls' legends are above the shafts and much easier to read than the ones on the PROIII. These make available adjustments for (L-R) KEY SPEED, BK-IN DELAY, COMP and MONI GAIN. I appreciated not having to dig to adjust the keyer speed.
None of the front panel buttons on the IC-7410 are illuminated (for example, to indicate that a given function is enabled). I missed this. You must rely instead on smallish text legends along the lower portion of the main display (below the frequency readout) to determine if a function is enabled. That display can get pretty busy once you've switched on a few things. This forces the operator to pay pretty close attention. I found it extremely easy to neglect to disable the NOTCH feature, for example, after having used it earlier.
The menu system on the IC-7410 hearkens back to the system ICOM introduced with its revolutionary IC-706 series in the mid 1990s. IC-706 and '746 users will feel nearly immediately at home with this interface, although it is easier to use than the initial incarnation. In fact, the radio itself is a bit of an amalgamation of the PRO and '706 series — not that there's anything wrong with that — and some of its finest features remain hidden until you need them. The menu text consists of light, segmented characters. These are serviceable but not always easy to decipher. I found the similar menus on the IC-706 series more readable.
There are actually three menus, all accessible via the front-panel MENU button: Press it quickly, and the M1 and M2 menus allow selecting a few common parameters using the F-1 through F-5 keys. These F key selections are mode dependent. For example, in SSB mode M1 has a TBW (transmit bandwidth) 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, letting you enable or adjust those parameters less-traveled. I found menu scrolling to be counterintuitive. You press the v key to ascend the menu tree and the a key to descend.
The power supply connector is not compatible with earlier ICOM gear, so if you're upgrading from a previous model (such as my '756PROI11) 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 pigtails, 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 available 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-7410does 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-lone IMD (see Table .1), the IC-7410 stacks up as essentially identical to the 1C-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 blocking 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 absent," 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 blocking figures are still very good." Allison reports that he was unable to detect 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 disccrnable signal). "Many receivers tested arc pretty dead down there," he said. "This receiver is very sensitive 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 narrow filters for the 1 st IF (64.455 MHz), which install easily. Each has a unique socket, so you cannot inadvertently install them incorrectly. 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 I st IF fi Iter 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, introduced 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 frequency 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 receiver is muted during scanning). The scan limits depend upon how closely you want the band scope to check for signals — every...............