ICOM IC-R75 Communications Receiver
By Rick Lindquist, N1RL Senior News Editor
A versatile HF/6-meter receiver that offers a good measure of performance in a compact package. All mode capability for the ham and utility listeners and synchronous AM for the SWLs should make the IC-R75 a popular choice for a wide variety of radio enthusiasts.
If you've ever thought it might be great to have an extra set of ears in the shack, you'd be wise to consider this latest "communications receiver" from ICOM. Let's face it: Hams, as a rule, do not find much use these days for standalone receivers. Most of the boxes we buy also contain the requisite transmitting circuitry; being able to fit that capability into the IC-R75 box (an IC-TR-75?) would make an especially attractive package. But even as a "mere" receiver the IC-R75 is a terrific complement for the typical ham shack.
A Receiver in the Shack?
A dwindling number of us still remember the days when a discrete receiver was standard equipment in every ham shack. Today, that's the exception, of course. Most hams will claim they have no use for a separate receiver—they've got a general-coverage receiver in their transceiver box.
Maybe so, but few "transceiver" receivers are designed for the primary function of listening—something a few of us enjoy doing when the blush is off the latest contest or DXpedition feeding frenzy. For the SWL or BCL, of course, listening is the only game.
The IC-R75 is definitely designed for listening—which is, of course, as it should be. An all-mode receiver, it also offers things like synchronous AM detection to enhance AM broadcast enjoyment by ameliorating the effects of multipathing and fading. It also incorporates superb dual passband tuning to combat interfering signals, plus the possibility to add optional crystal filters for enhanced selectivity. Simply push the FIL button to set the narrow filter for the mode you've selected (if installed).
You'll find CW, CW-R (reverse) and RTTY mode settings. Another nice touch: it offers adjustable CW pitch, via the menu.
This triple conversion design has IFs at 69 MHz, 9 MHz and 455 kHz. While it only draws about 1 A at full volume, the AF stage delivers a healthy 2 W or so to the front-firing speaker.
The LF capabilities of this receiver are something to keep in mind in terms of the pending request by the ARRL to allocate bands at 136 kHz and at 160-190 kHz. Experimenters and QRP enthusiasts who enjoy building transmitters might find an able companion for their endeavors in the R75.
But from my point of view, the coolest feature of the IC-R75 is its ability to truly integrate itself into a ham shack. Own an IC-706 or one of the other later-model ICOM transceivers with a computer REMOTE jack? With a simple connecting cable you can make up yourself, the IC-R75 becomes a main or auxiliary receiver—each unit controlling the other and letting you share the best features of each.
Hook it up to your '706 and you can share the IC-R75's ability to punch in frequencies on the keypad or even the receiver's stored memories. For ham radio use, you'll need to add a T/R switching system. It's a great opportunity to resurrect that old Dow-Key relay you've got in the junk box from your "separate-receiver" Novice days.
An Accessible Receiver
The IC-R75 suggests a cross between the IC-706 and IC-746 transceivers—a bit closer to the latter in terms of size, styling, and front-panel layout, but more compact and without the large LCD screen. The R75's sizeable display offers big numbers (or channel names—it's your call) and yellow-orange backlighting. There's a multisegment LED S meter that reads out up to 60 dB over S9. Numerals almost as large as the frequency display tell you which memory you've got dialed up. Other important icons are clear and prominent.
Like the "original" IC-706, there's no band switch. You can directly enter a new frequency or set the tuning step to the correct display digit and dial away. Up and down buttons let you page swiftly through memories—all 99 of them.
The front-panel layout is sensible and accessible. This is a piece of gear you literally can get your hands on without your fingers getting in the way of what you're trying to do. There's a nice large knob with a decently sized dimple on it. The knob incorporates a rubber grip ring. It has a nice "feel" to it. The drag is adjustable.
You can lock the settings with a push of the LOCK button on the front panel. A metal bail is easily deployed from the bottom of the set to angle up the front panel for better viewing.
The right-hand frequency keypad (which also functions to enter memory channel names) is terrific. All buttons and knobs are substantial and clearly labeled. There's a 1/4-inch phone jack on the front panel. Much of being able to operate this little receiver I learned from my experiences with other ICOM gear.
You can connect two separate antennas to the IC-R75 and select either from a front panel button. I'd have preferred to see two 50-Q SO-239 connectors, but the IC-R75 offers an SO-239 for ANT 1 and snap-on connectors for ANT 2 to wire a 500-Q (or other high impedance) antenna, such as a longwire.
The receiver powers from 13.8 V dc via the supplied—and sizeable—ac adapter. Fortunately, it's wired with a plug on the end of a cord so you don't have to figure out where to plug in the hefty cube.
A Capable Receiver
The R75 packs a lot of performance into its compact frame. Keep in mind that ICOM was able to concentrate on simply producing a decent-performing receiver here; they didn't have to worry about what was happening on the transmitter side.
With the R75, you've got a receiver that not only covers a huge chunk of the known HF spectrum plus the low end of the VHF (the only thing that would have made it better would be to have included coverage comparable to the IC-706, but that's for the next version), but also has ample sensitivity over its coverage range. ARRL Lab testing showed the preamp-off sensitivity hovered around -130 dBm—right up there with the big boys—but it includes two preamp stages to boost sensitivity by as much as 10 dB. These really can come in handy!
A few words on dynamic range: This is an aspect of receivers that, while important, often gets less than a full discussion in the typical transceiver review. It's also something that many amateurs......
Copyright © 2000 by the American Radio Relay League Inc.