Manufactured by Sony, Tokyo.
After Sony had a great success in 1980 with the ICF-2001 which was the first microprocessor-controlled world band receiver. The ICF-7600D, the first microprocessor-controlled travel radio in small, i.e. pocketbook format, followed in 1983. Two years later, its big brother, the ICF-2001D, was launched.
The silver-coloured plastic cabinet of the ICF-7600D, with the dimensions of 18.4 x 11.8 x 3.2 cm and a weight of 650 g, was smaller than the well-known World Radio TV Handbook, as the well known receiver test author Larry Magne noted in the 1984 World Radio TV Handbook.
The set has a tendency to fall over when it stands upright; as there was no fold out stand at the rear side , many listeners started tinkering with a homemade stand. The telescopic aerial on the top face of the unit can be swivelled, the receiver has also an external aerial jack, in the German version this connector was omitted.
The left half of the front panel is taken up by the speaker grill. With 200 mW output when running on batteries and 400 mW on mains power, the sound volume is sufficient to fill a room, but not to provide sound to a beach party.
At the top right of the front panel, there are three large buttons which switch the receiver on or off and activate the sleep timer. A small slide switch on the top of the unit serves as main switch, preventing the radio from being switched on unintentionally while in a suitcase. The „standby“ button activates the timer mode. Three tiny buttons left of the time display are used to set the time, and the time display of the 7600D can be switched from 12h to 24h format. Below the time display - in contrast to many expensive station receivers, the time and frequency are displayed simultaneously - is the frequency display, which is unfortunately not backlit. The frequency is displayed with an accuracy of 5 kHz; for frequencies in a short-wave broadcast band, the corresponding metre band is also displayed. A small red LED next to the display serves as a field strength indicator and lights up in the event of strong signals.
With the numeric keypad, the operation frequency can be entered directly and is called up with EXECUTE. Before that. The AM or FM key must be used to call up the AM band extending from 153 - 29'995 kHz, which includes long, medium and shortwaves, or the FM broadcast band from 76 MHz (in the international version) or 87.5 MHz (in the German version) to 108 MHz. The key sequence AM - 6 - 1 - 5 - 5 - Exec, for example, calls up Radio Oesterreich International from Vienna. To store a frequency you are listening to, press the ENTER key, which is also in Sony miniature format, and one of the numeric keys at the same time; to recall the stored station, press the corresponding key later. A +/- or up/down switch on the left is used to tune the receiver up and down in 5 kHz steps; if you also press the small Band Select button, the set immediately jumps to the lower limit of the next shortwave radio band. Pressing the Start-Stop button starts a search function; the receiver stops at the next station with a sufficient signal strength, search is continued automatically after 1.5 seconds if the Stop button is not pressed.
Other important controls, which are also to be operated with pointed fingers, are located on both side faces of the set: on the right, the volume slider control, a tone control switch and the operating mode switch. In the normal position, this small switch sets the receiver to tune in 5 kHz steps; in fine tuning mode, the frequency can be adjusted continuously between the 5 kHz points with the knurled fine tuning knob, the frequency display is not changed. So, if there is interference from an adjacent channel, the operation frequency can easily be moved down one or two kHz, making the signal more intelligible. In the SSB position, the BFO is activated, and the small fine-tuning knob must now be used to tune to zero beat.
The small Sony receiver can be operated with a total of 6 UM-3 batteries, two of them for the memory and clock functions, which last a long time. The other 4 batteries for the radio operation operate the set for about 12 hours. To control battery consumption, the supplied mains adapter AC-240 or a special 12V adapter cable for car battery operation can be used. Since reception performance drops when the set is operated from 4.8 V from 4 NiCd batteries, modifications were developed. One trick is to replace the two batteries for the microprocessor with a 3 volt photographic battery, and to put a fifth battery in the microprocessor battery compartment, thus achieving the required 6 volts. When it was released, the Sony 7600D's reception performance was outstanding for such a small receiver; even today, the set the set is a solid performer when travelling. The slightly suboptimal sensitivity is less noticeable in Europe with its high density of transmitting stations and high field strengths than in Africa or the Pacific region. With the built-in IF filter, transmitters in 5 kHz channel spacing can be separated, especially when fine tuning is used to tune 1 - 2 kHz lower or higher. When long-wire antennas are connected, the small Sony tends to overload. From my point of view, broadband active antennas - such as even the Sony AN-1 that was sold together with the set - are less suitable because of the high level wideband signal tend to overload the RF amplifier. I experienced less problems with my 20 m antenna, which is connected over the Yaesu FRT-7700 antenna tuner. The small Sony also copes very well with the Grahn magnetic antenna GS-2. According to reports, the newer Sony active antennas are better adapted to the dynamic range of the travel portable. To dispose of only 10 station memories caused me some trouble during my holidays, but I managed to keep track of the memory contents. The timer/sleep function is practical; if you can do without an illuminated display at nighttime, the Sony ICF-7600D can replace a travel alarm clock.
The price of the Sony 7600D was always a bit higher than the price of sets from competitors. The possibility of fine tuning - a feature not found for a long time with travel receivers with a digital display - and SSB reception, an amazing performance and technically advanced construction always made the 7600D be my favourite travel set.
The set was followed by the technically identical but cheaper ICF-7600DS and then the ICF-SW7600G, which had the same dimensions and functions, but came with a synchronous detector as an additional feature.
Double conversion, digital PLL synthesis circuit.
The set is equipped with semiconductors.