A new, high-end receiver has been released from AOR, the AR-ONE with continuous 10 kHz-3.3 GHz frequency coverage. While hobby monitoring enthusiasts might wonder why some familiar features are missing from this high-end product, the fact that AOR is constantly out of stock on this receiver would indicate that the intended market is well satisfied.
The AR-ONE is a compact (6-1/4"W x 2-1/2"H x 9”D), mobile-styled receiver weighing 4.5 lbs. Operating power is a nominal 13.5 VDC at 2 amps (max.), available from the user’s mobile battery (cable connector provided) or an optional 120 VAC power supply. One single antenna connector (N style) is provided for the entire tuning range. For compact, portable deployment, AOR recommends their SA-7000 wideband antenna.
While the receiver does offer some remarkable perks, its few shortcomings will be discussed throughout this review.
The AR-ONE’s incredible frequency range is the widest on the general market, covering more than 99% of all the listening targets that one would normally monitor throughout the spectrum, including wideband 802.11B allocations. But this receiver also scans cellular telephone frequencies, making it unavailable to the general public, and it has a substantial price tag – $4495.
So who is the intended market? The receiver is directed to government, military, and other professional monitoring organizations as well as non-U.S. clients conducting signal surveillance.
Its frequency stability (0.1 ppm -10 to +50 C.) is lab quality, assuring drift-free reception; for even closer tolerances, a rear-panel input jack allows connection to an external 10 MHz reference oscillator. An optional spectrum display unit (SDU) like AOR’s SDU5600 or AVCOM’s SDM42A or B can be attached to its 10.7 MHz IF output jack. For more detailed signal analysis, a 455 kHz output is also provided.
The receiver can scan 1000 memory channels as well as search between frequency limits, and there are 10 separate VFOs. Modes include AM, NFM, WFM, USB, LSB, CW and data, but no synchronous AM detection. But users wishing to have the benefit of narrow-band SSB detection of full-carrier AM may do it the old-fashioned way: choose USB or LSB for minimum interference, and adjust the remarkably-stable fine tuning for natural sound (“zero beat”).
The receiver may be operated as a stand-alone system, or remotely operated via two RS-232C ports. Up to 99 separate receivers may be controlled by one PC. No OEM software is available, but the operating manual contains a command set for all functions.
The receiver is designed with triple-conversion architecture, and has a third-order intercept of +2 dBm up to 2.5 GHz (-1 dBm above). Dynamic range is 90 dB or better. Sensitivity is specified as 0.5 microvolts at VHF/UHF NFM. Signal strengths are displayed in either dBm or S units.
Standard frequency steps are 1, 10, 50, 100 and 500 Hz, as well as 1, 2, 5, 6.25, 9, 10, 12.5, 25, 50 and 100 kHz. The user may also configure any step in 1 Hz increments up to 1 MHz to assist in automatic tracking of band plans while tuning, searching or scanning. An on-screen menu also permits automatic determination of appropriate frequency steps and modes for the bands selected.
Intermediate Frequency -6dB selectivity and -60 dB rejection points are: 0.5 kHz @ <2 kHz; 3 kHz @ <6 kHz; 6 kHz @ <20 kHz; 8.5 kHz @ <30 kHz; 16 kHz @ <40 kHz; 30 kHz @ <70 kHz; 100 kHz @ <450 kHz; 200 kHz @ <600 kHz; and 300 kHz @ <900 kHz.
When switched on, it takes a full five seconds to observe anything happening, leading some initial users to suspect something’s wrong. But after the initialization period, the radio is fully awake and ready to go. And once you’ve done this, you won’t be concerned about the waiting period next time you turn it on!
Although the LCD is edge-lighted and allows user-adjustable contrast, the user must look at it nearly straight-on, as characters disappear rapidly with increased viewing angle. Rubber-bumper feet invite desktop listening, but there is no tilt bail to prop the receiver up toward the user so he can see the readout. Of course mobile mounting at an angle is a cinch, and the receiver can be elevated to or suspended from a shelf, rack mounted, or tilted with a block for fixed use.
Attaching the receiver’s single N connector to an appropriate antenna system for its full frequency range means either externally switching antennas, or using an external multicoupler. Our test antennas were a GAP Titan vertical below 30 MHz, and a CREATE log-periodic above. The A/B test was measured against an ICOM R8500 wide-coverage receiver.
Sensitivity was now virtually identical to that of the ICOM, although we had to return our first test unit which had profoundly-deficient sensitivity below about 200 MHz that worsened the lower in frequency it was tuned. The replacement unit performed as it should.
Spurious signal rejection was better on the AOR. SSB detection was very good, but strong signals pumped the AGC noticeably, and no setting of the AGC timing configuration made any difference. The only way to stop the distortion from the pumping was to reduce the RF gain. The factory has been notified of this apparent deficiency.
Audio power is a substantial 2 watts, certainly enough to drive the internal 2” speaker to distortion (although sound is good at reasonable listening levels). An external speaker jack allows the full output to drive a larger speaker. An on-screen menu prompts custom contouring of the audio passband, as well as massaging of other options.
The volume control has a peculiar characteristic of suddenly coming alive as it is rotated clockwise, then incrementally shifting levels of audio rather than smoothly gliding. This is most noticeable on background hiss.
The AR-ONE has no noise-reduction circuitry, making its intended mobile installation, or even a fixed/portable application in a noisy location, questionable without the use of an ancillary noise-canceling system.
The illuminated, rubberized keypad is small, but easy to see and use; the tuning knob is also small, but it is rubberized, making it quite manageable.
So do the wide frequency coverage, high intermod rejection, PC control flexibility, small size, and available IF outputs justify the cost? Apparently so, if current government and military sales are any indicator.
Available accessories (not included): 120 VAC Adapter, MM8600 mobile mounting kit.
The AOR AR-ONE is available from Grove Enterprises for $4495 plus shipping.
The Grove Catalog and Buyer's Guide