Receiver Review: ICOM IC-R75

IC-R75

Year Introduced 1999

Power 13.6 Volts DC (AC mains adapter or DC power cord supplied, depending upon receiver version)

Size 241 by 94 by 229 mm (9.5 x 3.75 x 9 in) HWD

Weight 3.0 kg (6 lbs 10 oz)
Price US$600, CAN$1400, A$1440, ú650, €999.

Accessories: OPC-689 12 vDC power cable US$20; UT-102 Speech Module US$55, UT-106 DSP Module US$140, choice of 10 additional filters US$75-170, RS-R75 remote control software US$60.

Coverage 30 kHz – 60 MHz (regional exceptions above 30 MHz, see text)

Value Rating: starstarstarstar

 


This review was compiled independently. The Medium Wave Circle and Radio Netherlands has no financial connection with Icom, the manufacturer of this receiver.


Review by Thomas R. Sundstrom

The durable ICOM IC-R71A (1984-1996) won many fans for being a workhorse receiver. The factory-supplied filters were of superior quality, but some users grumbled about “muffled„ audio quality. More than a decade later, some owners still tout the receiver as “excellent.„ The IC-R72 (1990-1998) was not as a robust receiver as the R71A, but it had its share of followers.

At the start of 1999, ICOM had a vacancy in its product lineup. There was no tabletop communications receiver. Kenwood and Yaesu had also recently discontinued their general coverage tabletop receivers, and these two firms apparently have no intent of returning to the listening market. In North America Drake was virtually alone at the near-US$1000 price point. (Lowe filled the US$600 price point with its popular HF-150 receiver.)

In 1999, ICOM filled the vacancy with the introduction of the IC-R75 communications receiver. The price is less than its predecessors, and less than the Drake R8-series receiver. Comments in the Internet newsgroups and mailing lists asked questions about how the IC-R75 stacked up to the Drake R8B and the IC-R71A and IC-R72.

On December 31, 1999, we purchased an IC-R75, with the serial number 1442. We also added options: an FL-257 3.3 kHz/-6 dB SSB wide filter, the OPC-869 DC power cable, the UT-106 audio DSP unit, the RS-75 remote control Windows software and the UT-102 voice synthesizer unit.

 

Let's open the box

So what do you get in the standard box? In North America the receiver comes with an external "brick" AC power adapter, supplying 13.8 volts DC, and a spare fuse. Depending upon the area of the world and the version of the receiver, you may get a DC power cable instead of the AC power adapter. ICOM states the maximum current drain at full receiver volume is 1.1 A and recommends a power supply capable of 1.5 A.

A 44-page manual completes the package. The manual includes instructions on installing accessories and four pages on the software control command set. Do not lose the manual, as no instructions come with the optional accessories . We rate the clarity of the manual, with numerous illustrations, to be good. Some other manufacturers supply manuals, which have obviously been translated literally from Japanese without the translator understanding the technical terms: but not in this case. We believe the English sentence construction to be quite readable for those who speak English as a second language.

 

So what do you get in the receiver?

In most areas of the world, the receiver covers from 30 kHz to 60 MHz. In Asia, the coverage stops 1 Hz short of 30 MHz. In Denmark, the receiver also stops just short of 30 MHz, but adds 50.0 to 52.0 MHz. In Australia, coverage stops at 30 MHz, then adds 50 to 54 MHz. There may be other regional variations.

We like the coverage of the receiver, especially on the high end of the spectrum. In this solar maximum period, the coverage reminds us of our favourite Hallicrafters 8R40 receiver (1950-55, 0.54-44 MHz, 8 valves) and the spectacular 1957-58's solar maximum. In those days, on the east coast of North America, we listened for European television audio below the 6-metre (50-54 MHz) amateur radio band to determine F2 band openings. Except for the relatively expensive DC-to-daylight receivers that typically lack performance in the HF spectrum, the coverage of the IC-R75 may be unique among the currently produced tabletop receivers capable of tuning continuously above 30 MHz.

The IC-R75 comes with three filters (data supplied by ICOM, not measured by Radio Netherlands):

SSB, CW, RTTY AM, S-AM FM
>2.1kHz/-6 dB
<4.0kHz/-60 dB
> 6 kHz/-6 dB
<20 kHz/-50 dB
> 12 kHz/-6 dB
<30 kHz/-40 dB

 

Setting up the receiver

The connections on the rear of the receiver are intuitive, but there are a few strange configurations. The recorder remote control jack is a mini plug, unlike the usual terminals or lug strips found on other receivers. For receiver control, this ICOM has a DB9 (RS-232C) connector and a connector for the ICOM standard CT-17 CI-V level converter. If you are not controlling multiple ICOM receivers or transceivers, then you do not need to purchase the expensive level converter.

IC-R75 back

Other connectors include an 8-ohm external speaker jack, mute control, a ground connector and connections for high and low impedance antennas.

As the AC mains adapter is rather large, we opted to power the IC-R75 with a regulated 20 A 13.8 Volts DC power supply that is used to power other receivers and accessories on the desktop. The OPC-869 DC power cable has 3A fuses in both leads of the cord, and extra fuses are supplied.

The conventional headphone jack is on the front panel of the receiver, to the lower left near the power switch.

 

Turning on

The front panel is dominated by a large yellowish backlit LCD. The display shows the frequency to 10 Hz (or time) in large digits, a linear s-meter runs along the bottom, and other function and mode indicators – mode, memory, AGC, preamp, noise blanker, tuning step et al – appear around the frequency readout.

IC-R75 front

Tuning is via a large tuning knob or direct keypad entry. Via the keypad, frequencies above 1 MHz are entered as MHz, requiring the user to press the decimal point or entering digits to fill the display to 10 Hz. Mode buttons, filter selection, and the tuning step buttons are above the tuning knob. Modes are AM, synchronous AM, CW, RTTY, SSB (USB and LSB) and CW. The CW and RTTY offsets include a reverse option to move away from an interfering signal. Tuning steps of 01.1, 1, 5, 6.25, 9, 10, 12.5, 20, 25 and 100 kHz are available, independently selectable by mode. Buttons for memory or VFO selection, writing to memories and scanning are beneath the keypad on the right of the panel.

Six small buttons – preamplifier, attenuator, noise reduction, automatic notch filter, noise blanker, and automatic gain control – are placed horizontally along the very bottom of the front panel, under the concentric AF/SQL gain and twin passband tuning controls. We find them a bit awkward to access unless the adjustable stand is used to tilt up the receiver. The tiny lock button – disabling the controls – is also on the bottom edge, but to the right of the tuning knob.

Looking beyond the buttons and knobs, the dual function ANT/SET button provides entry to a menu of not-often-used receiver settings, each displayed in turn with a key press, and the tuning knob selects the desired condition. The settings include the behaviour of the RF/squelch control, confirmation beep and its level, s-meter peak hold for 0.5 seconds, scan resume and speed choices, AM synchronous detection options, CW pitch control, speech (if the optional UT-102 voice synthesiser is installed), clock and the LCD backlight from 0 to 100 percent.

The IC-R75 tends more to the side of separate controls for receiver functions, rather than the nested menu approach of the AOR AR-7030 receiver.

 

IF Filters and Passband Tuning

There are three IF (intermediate frequency) stages. The first is 69 MHz. You can install one additional filter each at the 9 MHz and 455 kHz IF. We opted for a FL-257 3.3 kHz/-6 dB 455 kHz SSB filter (US$160) to fill the gap between 6 and 2.1 kHz.

The twin passband tuning (PBT) controls are concentric knobs, effectively narrowing the lower and upper passbands independently to remove interference. Moving both controls to the same position shifts the IF.

passband tuning

 

DSP

Digital signal processing (DSP) is available with the optional UT-106 DSP unit (US$140). The more expensive receivers like the Kneisner & Doering KWZ-30 and the Japan Radio Company NRD-545 have the DSP circuitry built into the IF stages, a theoretically effective methodology when combating difficult reception conditions. The IC-R75 has DSP functioning in the audio stage, and adds an auto notch function (ANF) (removing stable or moving heterodynes) too. Press and hold the NR button for two seconds enables the tuning knob to set the DSP level; we found a setting of 3 or 4 (out of 16) to be best in the majority of cases. In our opinion, there is no need to purchase an after-market external DSP unit (c.f. "Digital Signal Processing... and a look at two market leaders of post-receiver processing units", World Radio TV Handbook, 1997 edition).

Although the manual clearly states the DSP and ANF functions work only in the SSB mode, we note instances on weaker signals where the noise reduction works to some degree in the AM mode.

We should note that in North America there is an ongoing sales promotion that offers the UT-106 DSP module free to purchasers of the receiver before March 30, 2000. After sending in the registration card and coupon, we received the module from ICOM America in two weeks time. It took us about 10 minutes to install the small circuit board and plug in three cables. We cannot determine if there is a similar promotion elsewhere in the world. Check with your dealer.

 

Memories

The IC-R75 has 99 memory positions and two band edge positions for scanning purposes. The memories are tunable (akin to the Japan Radio Company NRD-series receivers), i.e., select a memory and then turn the tuning knob. The entry will not be overwritten unless the memory write button is pressed.

Each memory can store up to 8 alphanumeric characters to label the contents. The process is akin to programming a cell phone, with a lot of button pressing on the keypad to do so. Frankly it was beyond us to do this manually.

The ICOM manual devotes no less than 7 pages to using the memories and scan functions. In our opinion, it will take some study and experimentation to use these functions to their full value.

 

Clock

The built-in 24-hour clock, like so many other radios, only displays the time when the CLOCK button is pressed. Nevertheless, the clock can be used in conjunction with the tape recorder jacks on the receiver rear apron to do timed remote recording.

 

Speech Announcements

So few receivers these days are capable of a voice synthesiser to assist the visually challenged listeners in finding their way around the dial. The optional UT-102 speech module (US$55) uses a woman's voice to announce the signal strength, frequency, mode and time in English or Japanese when one presses the LOCK button for 2 seconds.

We would prefer an easy way – and software control – to adjust the UT-102 playback volume. It sometimes gets buried in the received signal audio.

Additionally, the voice automatically announces the receiver mode when one of the mode buttons is pressed.

We checked to see if the voice synthesizer output is fed out through the line out jack. It is, so it is possible to "stamp" a recording with the voice information. But the key press beeps also appear in a recording, so you may want to turn off the key press beep confirmation. Unfortunately the voice is only activated when pressing the LOCK key; it cannot be activated under the clock timer or software control.

 

Other controls and notes

The noise blanker (NB) works best on impulse noise. It is either on or off, no variable settings here. As with many other receivers, the noise blanker will distort the audio of strong signals. Our impression is that the noise blanker is effective, but in our low-noise environment (with utilities underground) it is difficult to truly evaluate.

The automatic gain control (AGC) has three settings: normal, fast and off. An old trick of medium wave DXers is to turn off the AGC and use the RF gain control when listening to multiple signals on a frequency. It eliminates audio distortion of multiple sub-audible heterodynes pumping the AGC levels so quickly that the receiver cannot keep up. With the AGC off, audio is easier to understand. Simply stated, this technique worked very well.

The preamplifiers are two-fold, and in a quiet band the high-gain "preamp-2" can work very well. Without bench test equipment to perform actual measurements, our impression is that the improvement is quite good and weak or marginal signals, especially in quiet bands. Clearly, even "preamp-1" can be too much for crowded nighttime bands such as 49 and 41 metres.

Apparently there is a mild attenuator in the LW and MW section of the receiver. There is no schematic in the IC-R75 manual, but the ICOM specifications state that AM sensitivity at 0.1 to 1.8 MHz at 10 dB S/N ratio is 5.6 uV compared to above 1.8 MHz and 1.6 uV. (Above 1.8 MHz SSB sensitivity drops to 1.6 uV.)

ICOM states that spurious and image rejection is more than 70 dB, a bit less in the 6 metre band.

Audio output is rated at "more than 2.0 W at 10% distortion with an 8-ohm load." The internal speaker is satisfactory, but an appropriate external speaker is preferable.

 

Software

The optional RS-R75 remote control software, version 1.00, is on a CD-ROM and includes a DB-9 serial cable (US$55). The Microsoft« Visual Basic« version 5 application requires Microsoft« Windows« 95 or 98 (it should run on Windows« 2000 as well), and ICOM recommends a Pentium« 100 MHz or faster, 10 MB of free disk space and 16 MB of memory. Obviously a faster PC and more memory will improve program performance. The recommended display size is 600x800 pixels, 16-bit high colour. The CD-ROM additionally contains a "read-me" file and an 18-page PDF-format manual; the free Adobe Reader is included.

The program defaults to a serial port connection speed of 19200 bps, so sending and receiving data is quick. Other port speeds – 300, 1200, 4800 and 9600 bps – are also supported. But the "automatic" setting that sets the rate according to the connected controller (or remote controller) is not recognized by the RS-75 software. So, if you are also using third-party software that communicates at a rate other than 19200 bps, you'll have to use the receiver's SET button to change the connection speed to that same, specific, rate and change the RS-75 software settings to make all communication rates alike.

Launching the application may require you to first choose 1 of 4 COM ports if you do not use COM port 1. Thereafter, the program launch turns on the receiver. The software emulates the front panel of the receiver. Click on the various buttons to set modes or functions, mouse-click on the keypad buttons or use the numeric keypad on the PC's keyboard to enter frequencies, and click on the UP and DOWN buttons to step through the memories. Pressing and holding the left and right mouse buttons adjust the analogue AF, RF/SQL and PBT controls, a nice touch.

An unlimited number of memory files may be prepared, each holding 99 entries (frequency, mode, attenuator, preamp, antenna, and a comment field) and the two program scan limit memories. The comma-delimited text files may be edited or prepared within the program itself or in any ASCII text editor such as Notepad. Up to eight alphanumeric characters, labelling the memory channel, are displayed on the LCD screen, but the software file window can show additional characters.

IC-R75 software

The memory file management makes it easy to swap out data in the receiver's memories. If you manually store stations in the receiver's memories, the software can poll the receiver memories and save the entries in a data file.

Scanning is two-fold: (1) memory scans or (2) program scans, setting upper and lower limits, scan speed and delay. A "bandscope" function graphically shows frequency occupancy around the centre frequency. Click on a "signal" and the receiver tunes to the frequency.

An options screen gives access to most of the receiver settings described above, including the LCD backlight display level, settings for CW pitch and RTTY baud and shift. And there is a nice touch to mute the receiver… no reaching for a knob when the phone rings.

This is version 1.00, and we like the software. Documentation tells us that software upgrades will be on line at the USA ICOM Web site.

We would like to see some minor improvements in future versions of the software:

* Add a data import capability so that frequency data files may be prepared in a spreadsheet (Excel«) or database (Access«) or from other popular data sources provided by third parties.
* The memory files display the frequencies in significant digits, e.g., "6.165MHz", "10.0MHz". We would prefer a fixed length format to align the decimal point to improve readability.
* Add the capability to sort a memory file by the frequency at a minimum. To reorder a list, now the only practical way is to edit the file with an ASCII text editor.
* When in the memory mode, within the receiver front panel display we would like to see more than the eight characters displayed.
* The LOCK button functionality – locking controls and speech – is missing. We would like to see this control added to the software.

 

First Impressions on Tuning In

The IC-R75 is very sensitive, so much so that to quote sensitivity specifications is meaningless. Using an RF Systems SP-2 Signal Splitter to share a 25-metre (80 feet) vertical wire with a Lowe HF-150 receiver/PR-150 preamplifier, the IC-R75 wins hands down. No surprise here.

In New Jersey, USA, our first test was the antipodal Voice of Indonesia (RRI) on 15149.8 kHz, using the USB filter. When we turned on "preamp-1" and applied a bit of noise reduction to reduce the hiss from solar noise, the signal was outstanding. The signal was marginally acceptable on the HF-150.

Other bench test signals include polar path signals to the Far East, including those from the two Koreas. The results were good. Other tests of receiver performance are the 60-metre band Africans before local sunset and after transmitter sunrise. Ghana, very strong on 4915, is no test for a receiver, but we also heard Uganda on 4976 and Kenya on 4935 kHz. In January and February 2000, we could hear Africans starting two hours before sunset and at least an hour after transmitter sunrise. The receiver also nicely passed our test of USA east coast mid-afternoon reception of the Africans and Iran in the 9.0 to 9.2 MHz range and India on 7410 and 11620 kHz.

Nighttime signals in the 49-metre band are always a test for a receiver at this location. One sky hop from the high-powered transmitters at Sackville, Antigua and Bonaire test the mettle of the receiver with intermodulation products superimposed on adjacent signals and spurious signals 910 kHz removed. In the AM mode, we had some minor problems with the former but no problems with the latter. The built-in –20 dB attenuator required some additional help with the attenuator on the external SP-2 signal splitter.

We also enjoyed consistent reception of a number of low-powered stations from Peru in the 60- and 49-metre bands.

We didn't do a full bandscan but it appears that a 50 kW day (1 kW night) medium wave station on 640 kHz 6 km (4 miles) from us causes no problems.

 

Spot the Difference with the Sync

What is the singular failing of this receiver? In our opinion, there is virtually no difference between synchronous AM and AM reception. The synchronous mode includes both sidebands; there is no option to choose the lower or upper sideband. The Lowe HF-150 synchronous modes and performance are far superior. We urge that ICOM correct the synchronous performance in future models and make available a retrofit ROM available to current customers.

Fortunately all is not lost here. As the receiver's SSB reception is quite good, in difficult or crowded band conditions, we simply tune in the appropriate sideband of the desired signal and, if necessary, adjust the PBT controls.

 

Digital signals

We also tested digital signal reception on fax and teletype (RTTY) signals, using the Windows« software WXSat and TruRTTY. Signals were easy to tune in and the receiver is stable; no retuning was required even after several hours on. Reception was best by toggling the USB filter setting to "narrow." The problem of proper frequency readout persists, as it does with most other communications receivers. The display – both on the receiver and the software screen – shows the tuned frequency rather than the nominal carrier frequency.

Let's take CFH (Canadian Forces, Halifax) as an example. CFH transmits both RTTY and fax on 6496.4 kHz.

For fax signals, one must do the math to subtract 1.9 kHz from the nominal carrier frequency and tune in USB mode. For fax reception, in our CFH example, one must tune to 6494.5 kHz. To decode the teletype weather reports at 75 baud and an estimated 500 Hz shift, we were required to change to the RTTY mode. The frequency remains the same, i.e., 6494.5 kHz. Optionally, we could tune the RTTY signal in USB mode by dialing in 6494.97 kHz.

Fixed RTTY shift widths of 170, 200 and 425 Hz may be selected in the SET options mode. We wonder why the shift width standard of 850 Hz was not additionally included.

We would prefer to have a variable width shift control. For example, CFH was transmitting with on a non-standard shift and it took careful tuning on the TruRTTY display to get the signal to decode.

 

Conclusions

In the USA, the base price is 30 percent less than the Drake R8B. Add options to the IC-R75 and the price difference against the R8B decreases, as the latter includes all filters (but no audio DSP or speech capability). In the USA, the IC-R75 is more than 40 percent less than the British-made AOR AR-7030 PLUS but the latter's strong signal handling is better.

Elsewhere in the world, the R8B is even more expensive. The AR-7030 PLUS in Australia is twice as expensive as the IC-R75, 50 percent more in the UK.

Percentages are approximate as prices, coupled with special offers, are subject to change. Prices were last checked in late February 2000.
We believe the IC-R75 is at an attractive price point and, in our opinion, clearly replaces and outperforms the discontinued Yaesu FRG-100B in this price range. The IC-R75 costs more than the Lowe HF-150 but there is a clear performance gain (though, in our opinion, not necessarily in audio) for the money. We perceive the IC-R75's main competition to be the higher-end R8B and AR-7030 PLUS receivers, but the IC-R75's lower cost means making a choice depends upon your listening habits or desires. We do not recommend trading out an R8B or an AR-7030 PLUS; these receivers and the Japan Radio Company NRD-545 are the choices for DXers digging out the weakest signals.

We rate the IC-R75 to be of good value and give the receiver 4 stars.

Special Note: A copy of the manufacture's manual for this receiver is included on Vol 51 of our archive CD's.

This review first appeared on the Radio Netherlands website.