AOR 7030 Chapter Two

THE AOR AR7030: A BOLD NEW RECEIVER FROM BRITAIN

Guy Atkins

CONSTRUCTION AND DESIGN

The all-metal front panel and case are excellently finished and extremely robust. Only the built-in speaker's grill is less sturdy than I'd like to see. The front panel is at least 5/16" thick, and the large main tuning knob is solid anodized metal and comfortable for bandscanning (it has very effective and "seamless" variable-rate tuning, also). The two smaller rotary controls are not as comfortable, being rather tiny knobs attached to mechanical encoders with quite "stiff" click-stops. It helped to refasten the knobs a bit further out on their 1/4" diameter shafts.

Aesthetics are mostly a personal matter, but in my opinion the AR7030 is quite good looking. The overall appearance resembles current British audio equipment. It does not have that "military-industrial" look common to many shortwave receivers.

The AR7030's compact size and bunker-like construction will be appreciated by anyone taking it along for DXpeditions. At approximately 9-1/2" X 9-1/2", the receiver's "footprint" is very modest for situations where space is at a premium. The top-quality fit and finish is rarely seen these days in receivers in the AR7030's price range.

INFRARED REMOTE CONTROL

 

This is a standard item supplied with the AR7030, not an extra cost option as with ICOM's R71A and Lowe's HF-250 receivers. Most major settings and adjustments can be done with the remote, although changing the AGC time constants and turning the receiver on or off is not possible. These must be done from the AR7030 front panel.

The remote control has the "intelligence" we've come to expect from today's microprocessor-based receivers. Frequencies can be entered in kilohertz or megahertz. No leading zeroes or excess keystrokes are needed. Simply tap in the frequency, press the "kHz" or "MHz" key, and you're there. Frequencies can be entered from the keypad in increments as small as 1.4 Hz (handy for utility monitors). Tuning frequency step size can also be entered and tuned from the remote.

The remote control is handicapped with small rubbery rectangles masquerading as pushbuttons (common practice on many remotes). Initially I did not care for the feel or size of this unit, but I've now warmed up to it. Rather than use the remote from across the room, I place it on the desk in front of my receiver shelf. I had a small "angle bracket" machined from black plastic and attached it to the back of the remote with heavy-duty Velcro fasteners. Two hidden lead strips (for extra weight) and small rubber feet (non-skid) complete the modification. This angles the remote towards the receiver and keeps it in a comfortable position. In this fashion I can change frequencies, filters, memories, passband shift, etc. with the remote at my left hand, while leaving my right hand free to control the AR7030 normally at the front panel. While actively DXing I tend to use the remote controller half of the time, and it's very handy to have its keypad available.

The bracket is not needed if the receiver sits directly on the desk, as the infrared sensor has sufficient field-of-view. There is even a second infrared "eye" on the back panel of the radio to help catch reflected beams. All told, the remote is a fine addition to the AR7030 and adds to the radio's versatility. Larry Magne, in his Media Roundup review on Radio Japan and writing in Monitoring Times, spoke of a review model AR7030 that did not always register the remote's keystrokes. This is not a problem with my receiver; 100% of the keystrokes "take" if the remote is aimed anywhere in the general vicinity of the sensor.

During the dawn-enhancement period of a recent DXpedition, I again encountered that heady experience of trans-Pacific MW stations appearing up and down the band with audio or strong hets. In a situation like this, the AR7030's infrared remote is essential for efficient DXing. A quickly changing DX opening is not the time to use a cumbersome receiver! Casual DXing can be done from the AR7030's front panel alone, but be forewarned that the remote is truly a necessity when you need to fly up and down the band (keypad frequency or memory entry) in the heat of battle. The receiver does have a Fast Tune button on the front panel, and it works well.

LAB MEASUREMENTS

 

The following are measurements on my AR7030, serial# 100067. Many thanks to Craig Siegenthaler, President of Kiwa Electronics for taking the time to perform these independent tests. Kiwa uses the test methods described by the ARRL (same as used by Willem Bos for the R. Netherlands Media Network review). The results are very close to AOR specs, with testing at the AOR-specified frequency the key factor. Test data on other AR7030 receivers and full details on the Premium Filter Modules are found on Kiwa's internet world wide web page: http://www.wolfe.net/~kiwa

Noise Floor Noise Figure LSB -130.5 dBm USB -130.5 dBm (preamp ON) Preamp OFF 19.5 dB Preamp ON 11.8 dB LSB -123 dBm USB -123 dBm (preamp OFF) Preamp OFF but using Kiwa SW Preamp 10.3 dB

Phase Noise 5 kHz spacing -126.5 dBc/Hz 10 kHz spacing -133.5 dBc/Hz 20 kHz spacing -144.5 dBc/Hz 50 kHz spacing -155 dBc/Hz 100 kHz spacing <-156 dBc/Hz Note: -156 dBc/Hz is the limit of the measurement system.

2nd Order Intercept measured at frequencies similar to those in the AR7030 specifications list (23 MHz): +80 dBm

2nd Order Intercept measured at 4 MHz: +67 dBm. Note discrepancy between 23 and 4 MHz with IP2.

3rd Order Intercept measured at frequencies similar to those in the specifications list (12 MHz, Preamp OFF): 200 kHz spacing: +34 dBm 100 kHz spacing: +33.75 dBm 50 kHz spacing: +33 dBm 20 kHz spacing: +32.25 dBm

3rd Order Intercept measured at 12 MHz with the Preamp ON: +9.75 dBm 3rd Order Intercept measured at 12 MHz with the Kiwa SW Preamp: +19.5 dBm

3rd Order Intercept measured at 2 MHz - Preamp OFF 200 kHz spacing: +11.5 dBm 100 kHz spacing: +11.5 dBm 50 kHz spacing: +10.8 dBm 20 kHz spacing: +10.8 dBm. Note discrepancy between the IP3 at 12 and 2 MHz.

As shown above, Kiwa Electronics performed their IP3 tests at 12 MHz which resulted in measurements very close to AOR's specifications. However, IP3 performance was reduced at 2 MHz. After investigation, John Thorpe has determined that surface-mount components for the 1.7 MHz input filter do not have sufficient intermodulation performance to ensure high levels of IP3 around this frequency. A modification exists to retrofit leaded components (a few capacitors and inductors) in place of the surface-mount devices. The resulting IP3 is a nearly flat response from 500 kHz to 30 MHz. AOR indicated on August 19th that the change is now incorporated into the next revision of the main PCB, which is being manufactured now. I have made this modification to my own AR7030 (see comments below), and Kiwa Electronics has retested the IP3 performance.

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