Listener's Guide

The AR7030 From AOR

Table-top Receiver of the Year award 1996/97 by the World Radio TV Handbook, it has also been awarded five stars by Passport to World Band Radio.

The AR7030 stunned the world when first released due to exceptionally high performance, indeed the AR7030 still wins the analogue-DSP battle in respect of high dynamic range and low noise, a testimony to the successful project between internationally acclaimed UK designer John Thorpe and AOR.

High performance coupled to enhanced microprocessor features and facilities forms the cornerstone of its success. Frequency coverage is from 0 - 32 MHz all mode, AM, Synchronous AM, USB, LSB, CW, DATA and NFM. Four 455 kHz IF filters are provided as standard with provision for a further two (including Collins mechanical filters), all of which are self-aligned by the receiver for optimum performance and passband symmetry; this plus the standard fitted TCXO makes the AR7030 ideal for ECSS applications. The self tuning variable bandwidth synchronous detector is a pleasure to use and hangs on to the weakest of signals, audio quality is superb.

Where good strong signal handling, high performance and transportability are of great importance, the AR7030 is the solution offering an IP3 greater than +30dBm (typical +35dBm reduced by 10dB with the preamp on). Intermodulation free dynamic range with the 2.2kHz filter is typically 105dB at 100/200kHz spacing, 104dB at 20/40kHz and still better than 90dB at 5kHz. This fantastic strong signal handling is aided by the innovative configuration of a lateral DMOS FET QUAD first mixer running at 15V, relay switching in the front end (not diodes) and the use of shielded inductors throughout the signal path. All this and GREAT SENSITIVITY better than 0.5uV for 10dB S/N in AM mode and better than 0.3uV for 10dB S/N in SSB.

Selectivity too is razor sharp typically offering greater than 90dB at 5kHz SSB, almost 100dB at 10kHz and greater than 100dB at 20kHz, these excellent figures are achieved by the implementation of a remarkably low phase noise local oscillator <-158dBc/Hz at 100kHz.

The receiver is built around a TCXO frequency standard which provides the reference for all circuitry ensuring the ultimate in stability and optimum alignment. Single loop DDS provides the clean local oscillator reference essential for low reciprocal mixing levels and seamless tuning in 2.655Hz steps (10.62Hz in AM and NFM modes) with no tuning "plops" at regular intervals. The receiver is a double conversion superheterodyne with intermediate frequencies of 45MHz and 455kHz.

Enhanced features include pass band tuning ±4.2kHz, variable audio pitch tune on CW & data modes and a "variable bandwidth synchronous detector" for AM listening to eliminate the effects of transmitter / receiver drift as well as reducing distortion from selective fading. The pass band tuning may be used in synchronous AM mode to select synchronous USB, LSB, DSB or anything in between. A specially developed AGC release characteristic has been developed to provide very smooth SSB. Noise spike compression has also been included to reduce the effects of noise pulses. A built-in six level attenuator provides levels of sensitivity from +10dB to -40dB.

Assignable controls enable you to place the functions YOU want at your fingertips. It is also possible to save a few of your favourite receiver setups for later retrieval. Twin VFOs are provided in addition to the 100 memory channels (400 with the 'features CPU' fitted) with versatile scanning facilities including independent squelch settings for each memory and VFO. Virtually every aspect of the AR7030 is controllable via the standard REMOTE port for straight forward computer connection, optional PC Windows based software is available.

The tape recorder configurable outputs and slave relay may be programmed to operate from the built-in clock timer or from the squelch control. Mute input is available for use with transmitters.

The AR7030 features a stylish custom CNC machined solid aluminium front panel with extruded aluminium shaped sides, metal top, bottom & rear panels. The front panel finish is brushed and anodised with the sides and other surfaces toned in a matching textured paint. Smooth lines, detailed front panel, domed top mounted speaker grille and ergonomically placed controls spell out the attention to detail of the robust cabinet. An internal battery option adds the possibility of transportable operation. An infrared remote controller is supplied as standard along with a low noise power supply and comprehensively illustrated operating manual.

Never Leave The House Without A Radio

I am sitting at the Millfields end of Carsington Reservoir in Derbyshire.

For our readers abroad, this is a favourite part of the English Midlands, twenty minutes from the AOR HQ. Just me, this PC and a large flask of coffee.

And I'm cursing because I forgot the radio. Not that I expect to hear more due to the high elevation around here. I know the real DX will have been reflected down from the ionosphere, so my height will have little effect.

All this water will help with ground wave propagation and if I were to go mad and set up a one-man DX-pedition, receiver grounding would be fantastic in the damp soil. The book for the AR7030 says its performance is down a bit if I run it on the car's 12v battery.

To keep that linearity up and the 3rd-order products down, the mains PSU delivers some 15 volts. We need current in the front-end for performance and less of it for good battery life. It's trade off with the AR7030 coming down on the side of performance. More coffee.

As the nominal terminal voltage of a well maintained car battery is some 13.8 volts, the compromise, in real listening terms, is small. And no supply noise problems.

OK, save this copy and watch the sunset. As usual - all this coffee and the toilets are on the far horizon. Suppose that now I've filed copy, I could do a tour-guide of all the on-site conveniences, a Who's Loo. I thought Reservoir Bogs is a good working title...

Is It Worth Listening To Music On Short-Wave?

In an article written for AOR UK, the DX session has gone on through dawn and you are sitting there in the early bright with a well-earned cup of coffee.

GW3COI's impression of the writer, in the dark as usual

The logbook needs updating and you must QSL that Peruvian rare DX who was running three watts into a dummy load when you heard him.

Can you find a little light music for background to the task? The idea of listening to music on short-wave with its fade and phase is not such a good idea. Or is it?

The new generation of synchronous detectors in the AOR AR7030 not only tune the radio for you but cancel out the worst effects of the ionosphere. What you hear is what was transmitted.

Out of Morocco, try Medi One on 9575 where East meets West in a blend of Eurotrash and Moroccan Roll. Germany gave us SWF 3 on 7265 during the day. Listen for the RDS pulses that switch a million car radios to SWF for traffic updates in a mix of music we don't get over here. And we miss it...

Out of Africa, test the north-south path around midday with Africa Number 1 from Gabon on 17630. Another interesting propagation indicator is All India Radio. Evenings on 7410, daytime on 11620 and check if the 10MHz Ham Band is open by checking for the Domestic Service on 10330. Listen for the evening ragas - long improvised sitar pieces. I can't afford a full-size instrument, mine's a baby sitar.

AM Audio Quality

In an article written for AOR UK, they have gone overboard to get the best audio quality.

But all AM broadcasters are now using some form of audio processing to improve the signal-to-noise ratio. There was a time when the quality of the sound from your radio was determined by how much you were prepared to pay for it. Now, in world radio, audibility is the key. And, to be honest, it can sound dreadful - even on an AOR.

The problem lies in the audio processing that has slowly changed the sound balance since Abba were in the charts. It started with wide-band compression. The BBC lead the field with a limiter that gently reduced the dynamic range of all audio frequencies present by the same amount, giving an overall impression of loudness enough to counter reasonable domestic noise. Then came the active systems.

A bank of filters carve up the audio into anything up to six pass-bands. These are then compressed at different rates pre-set by the broadcaster, the reconstituted audio then going for transmission. As processing has no musical analogy, it can lead to listener fatigue simply due to the saturation of the sound.

Engineers say processing is here to stay. Radio marketing men will tell you that he who shouts loudest gets the largest audience and so gets to keep the money. That's fine up to a point but with the CD and Digital Audio Mass Storage setting new standards for source programming and radios improving markedly with each generation - this must be the time for the broadcasters to reassess their use of processing to allow the final level of fidelity to align with the listeners level of investment in equipment.

In other words, you'll get what you pay for. With the 7030, you'll hear what they are sending.