Inhaltsverzeichnis
AR7030
Manufactured by AOR Ltd., Tokyo.
At the beginning of 1996, AOR introduced the AR7030: this receiver quickly caused a sensation despite its inconspicuous appearance - some critics were enthusiastic, others found its operation scheme useless…
The set was designed by John Thorpe, who had previously developed the receivers of the English company Lowe, and it was produced by AOR U.K., the English branch of the Japanese manufacturer known primarily for its scanner receivers. The Lowe receivers were already distinguished by their unique operating philosophy with few control elements that give access to many functions through combinations - the AR7030 is a microprocessor-controlled receiver with ultimate performance and developed based on this operating scheme.
Technical data
- Frequency range: 10 KHz - 32 MHz
- Frequency display: digital display, resolution 10 Hz
- Frequency memories: 100 (optionally 400) memories, (optionally alphanumeric labelling)
- Signal strength indicator: LCD bar
- Features: RS232 interface, remote control
- Sensitivity: AM (A3) < 0.35 μV, SSB 0.2 μV / Selectivity: 2.3/3.3 kHz, 5.5/9.1 kHz, 7/11.6 kHz kHz (-6/-60 dB)
Power supply
- Mains operation: 15 V DC from external mains power supply 110, 220 V
Dimensions
- 240 x 90 x 255 mm, weight 2.2 kg
Accessories
- Infrared remote control
Operation
The black metal cabinet of the receiver with the dimensions of 24 x 9 x 22.5 cm, which has a weight of 2.2 kg, has no space for the power supply, which comes separate from the receiver and supplies it with 15 V DC. When operated on a car battery with 12 - 15 V, the specifications are not fully met at lower operation voltages. An 8 cm loudspeaker radiates upwards, the audio response can be changed with separate treble and bass controls.
The front panel is dominated by the tuning knob which is made from metal and has a diameter of 4 cm, above it are the pushbuttons for changing the operating mode and for selecting the tuning speed arranged in a semi-circular way. The dot matrix LC display is backlit green-yellow; the 4 menu buttons and a rotary control to be used for different functions are located below it.
These control elements can operate different functions depending on the operating sequence, which is the crux of the operation. Depending on the settings, two buttons can be used to select the filter bandwidths and the rotary control serves as a PBT shift control, the buttons control memory functions and the rotary control selects the different memories or the buttons switch AGC and noise blanker and the rotary control serves to set the RF gain. On the far left, one above the other, are the volume control, the basic menu button and the on/off switch, which must be pressed twice to switch off the AR7030. The S-meter is displayed as an LCD bar during operation.
On the rear of the unit, the switchable connectors for long-wire antennas and 50 Ohm antenna input are located to the left, loudspeaker, power supply and computer control sockets to the right, other jacks feed the AF signal to auxiliary equipment and RTTY decoders and connect to the relay contacts of the timer. The infrared remote control is indispensable for direct frequency input via a numeric keypad, direct selection of the operation mode AM/AM-SYNC/SSB and for filter selection / PBT control; sensors are mounted on the front and rear of the set.
The frequency-determining quartz oscillator is temperature-controlled, the IF filters are automatically calibrated when the set is switched on for the first time or on command. If the original set is equipped with a 2.2 kHz, 5.5 Khz, 7 kHz and 10 kHz filter (the measured bandwidths result in slightly different values in each case), the retrofitting of a 3.5 - 4 kHz IF filter is strongly recommended for serious DX reception, which fortunately is not difficult thanks to the auto-calibration function active after installation. With a minimum tuning step of 2.7 Hz, SSB reception is no problem, an automatic synchronous detector automatically locks onto the carrier after activation, as if by magic the frequency display is changed and shows slight deviations of tropical band stations from the nominal frequency.
The passband tuning allows the filter's passband to be shifted by 4.2 kHz, and interfering adjacent channel stations can be eliminated very well thanks to the perfectly designed PBT. The notch filter, available as an option or in the extended version, suppresses interfering whistling tones by 50 dB on the AF level, this process is also automatic; the notch frequency is automatically increased by the receiver until the interfering tone disappears, then the receiver locks to the frequency. The speed of the AGC can be adjusted as needed for AM or SSB reception.
In the basic version, the AR7030 has 100 memory channels which can be freely assigned, in the AR7030-plus version with the „enhanced features CPU“ FPU-7030 over 400 memory channels are available, in addition alphanumeric labels can be added to each channel. If the set is tuned to a previously stored frequency when scanning a band, the alphanumeric station identifier is displayed (as with the Drake R-8A). Of course the microprocessor - controlled receiver comes with various clock and timer functions; via relay contacts a tape recorder can be controlled for unattended recording. A control software for Windows 3.1 & 95 is also available from AOR as an option.
Due to the circuitry designed for European conditions with its high signal levels and crowded shortwave bands, the AR7030s a large-signal behaviour leaves hardly anything to be desired in terms of signal processing and can rival semi-professional receivers in terms of sensitivity. If you are comfortable with the „few buttons - many functions“ operating concept that is a characteristic of receivers developed by John Thorpe, and if you find the remote control a welcome convenient addition rather than an annoying gimmick, the AR7030 is one of the first-choice shortwave receivers suitable for DX. It is priced lower than the Drake R-8A/B or the NRD-535/545; these receivers, with their „one function - one button“ concept, provide quicker access to spcial features, they are easier to operate in the eyes of many.
Technical principle
After a switchable attenuator / preamplifier (the latter is used for operation from the telescopic antenna). The signal is passed via a high-pass (>1.7 MHz) and low-pass filter (<32 MHz) after an HF amplifier stage to the first mixer, the first intermediate frequency of 45 MHz is converted to 455 kHz in the second mixer, the signal then passes through one of 6 selectable IF filters, is amplified again and fed to the product detector or narrowband FM demodulator.
Components
The set is equipped with semiconductors.
