Manufactured by Sony, Tokyo.
When Sony introduced the first microprocessor-controlled shortwave receiver in 1980, it triggered a revolution in the design and concept of travel shortwave receivers. The fact that it was no longer necessary to carry around a 6 - 10 kg suitcase sized receiver with protective brackets and a large handle, but a small box that looked like a large pocket calculator, also helped to facilitate shortwave reception among travellers.
The ICF-2001 was the first portable receiver to implement direct frequency input via a numbered keyboard. The ICF-2001D was a further improvement of the immensely successful set, with which the new Sony only had the cabinet dimensions in common. As an innovation, Sony introduced automated ECSS reception with the synchronous detector for the first time. The 2001D was and remained one of the most successful and best performing portable shortwave receivers.
The versions can be identified by the missing AIR BAND button and by the frequency band information above the clock display.
The travel receiver, which has a weight of 1.75 kg and dimensions of 29 x 16 x 5.5 cm, can be powered by an external 4.5 V (!) mains adapter or 3 UM-1 batteries. With a special adapter, it can also be operated from a car battery. A recessed main switch, which effectively prevents unintentional switching on during flight in luggage, activates the power supply so that the set can be switched on with the switch located above the large speaker grill. The error message ERROR3 indicates that either mains power or batteries are missing - or that the main switch is not in the ON position.
A small pushbutton below the switch activates the illumination of the two displays on the right for a few seconds. On the left, the current time (or, if applicable, the timer time or remaining operating time in sleep mode) is displayed, on the right, the LCD display shows the frequency with an accuracy of 0.1 kHz, the Operation mode and IF filter width. The signal strength meter is designed as a chain of ten small LEDs and indicates the relative signal or battery strength from 0 - 10, two small LEDs mark whether the upper or lower sideband is selected in synchronous detector mode. At the top right, slightly recessed on the right face of the cabinet, the smooth-running tuning knob, which sets the frequency and also the time; to change the time, simply press the TIME SET button and turn the tuning knob. The next switch is used to change the tuning speed from fast to fine tuning used for sync mode and SSB reception, and in the LOCK position it blocks the tuning knob completely. The volume control is designed as a slider control. Further sliders on the right face control the RF gain and the tone control.
The large keypad initially led to some criticism to the Sony 2001D; I will try to explain the most basic functions. Direct frequency entry is child's play, as with the old 2001, 6 - 1 - 5 - 5 - Execute and you hear RÖI Vienna from the speaker, if a frequency outside the covered frequency range is entered, the 2001D reports an ERROR1; for visually impaired listeners, the „5“ key is provided with a small nub. The keypad with the 32 keys in four rows is used for memory access; pressing the small black enter key and simultaneously one of the memory keys saves the frequency incl. operation mode and IF filter width. I like the idea to recall the station by simply pressing a single button. I have assigned the four rows to different station groups (tropical band 90m, 60m and „Brazilian“) and can keep track of the stations; other listeners prefer to enter numbers to select memory locations…
Pressing the blue shift key gives access to the secondary function, for example, the Sony ICF-2001D allows direct access to the 25m broadcast band with shift-c3. The three white keys to the left of the memory keys start and stop the scan functions, also the upper and lower frequencies and other functions are called up with the blue shift key as a second function. The three white keys above the memory key field switch between AM, FM(VHF) and AIR band (aeronautical communications band 116 - 136 MHz, AM). Next to them are the keys for activating wide and narrow IF filters in AM, USB, LSB and synchronous detector. The small keys in the row underneath the display are used to set the four timer programmes.
On the left face are the antenna inputs (3.5 mm jack), the switch for the attenuator, the line output for the tape recorder, the earphone and the power supply socket, and underneath the main power switch already discussed.
In practical use, the Sony ICF-2001D has an already impressive performance with the telescopic antenna. In terms of sensitivity, it is one of the best in the portable class and receives the international broadcasting services and also some tropical band stations in a similar quality like tabletop receivers. A long-wire antenna simply connected to the antenna jack leads not only to an increase in signal level but usually to overloading with a mishmash of mixed products, so that the desired station cannot be picked up better.
In regard of the suboptimal large signal behaviour, an antenna matching set or an external preselector is simply mandatory when operating with an longer external antenna. For example, the PRE-1 from the ADDX can be used, I experienced best results with the FRT-7700 from Yaesu. Then a 20 m antenna is tolerated, the receiver is quiet and I with these combination I could enjoy again and again excellent receptions from the NBC, Australian local stations in the tropical band, from RN del Paraguay to R.Record in the 19 m band and I could log several weak stations. The ICF-2001D also works very well with the magnetic loop from Grahn with its low signal levels, at least much better than with the original broadband high-gain AN-1 antenna supplied with the set. - With the Sony active antenna, I hardly ever experienced an improvement in the intelligibility of a signal, but repeatedly overload symptoms. Regarding the overload phenomena, it should be mentioned that the front-end transistor can be destroyed in the vicinity of strong local stations with high signal levels on a long-wire antenna; in American articles it was recommended to get a ten-pack of replacement transistors right away…
By the way, the attenuator active in the medium wave range can be bypassed with a trick, the antenna plug is not fully inserted, as the full sensitivity to MW-DX is maintained, double caution is in place with long antennas with high signal levels.
The selectivity is not sufficient with the wide AM filter to cleanly separate stations in 5 kHz channel spacing, to do this you have to switch to the narrow AM filter. To improve reception, however, the ICF-2001D has another jewel, the synchronous detector, which I still consider to be the best I have ever had to deal with. The ICF-2001D was the first set to feature automatic ECSS reception. An auxiliary carrier is generated in the set and mixed with one sideband of the AM signal. To avoid adjacent channel interference, select the less affected sideband. ECSS reception is possible manually with any good SSB receiver; with the Sony, the whole thing happens at the push of a button. If you slightly tune below the operation frequency, the other sideband is demodulated.
If, for example, Radio Globo is disturbed on 11805 from a splatter from adjacent 11800 kHz, tune to 11805.1 in sync mode, the receiver locks in after a short whistle and the USB LED lights up, reception is then possible even with the wide filter, as the next adjacent channel on 11810 kHz is free. If you tune down, the receiver switches to LSB at 11804.9 and the interference whistle from the adjacent channel becomes very annoying. The sync detector on my set even locks on weak signals and improves intelligibility a great deal. The fact that the USB-LSB change does not always take place exactly on the transmitting frequency has to do with the fact that, according to reports, Sony's sets were not always perfectly aligned. With the narrow AM/SSB filter and the sync mode, the Sony ICF-2001D copes with some difficult situations even in the tropical bands. The SSB reception is good in itself, but the smallest frequency steps of 100 Hz are sometimes too wide for radioteletype reception with decoders, this small shortcoming was fixed in the successor SW-77.
With the memory, scan and clock functions the operation of the ICF-2001D is really comfortable, these possibilities were further refined in the successor with the memory management in groups that can be labelled alphanumerically. But in contrast to many tabletop receivers, the ICF-2001D can display the time and the frequency at the same time! On the way to becoming a great station receiver, the ICF-2001D still lacks some additional features to improve the signal like passband tuning and notch filters, but Sony has omitted these features from all shortwave receivers designed for the home market - something must be reserved for the professionals.
The Sony ICF-2001D or ICF-2010 as it was called in the USA, was still sold until the end of the nineties, but unfortunately the stocks at Universal Radio have been exhausted in the meantime. In my personal opinion, it is superior to its successor ICF-SW77 in terms of sensitivity, synchronous detector and intelligibility. American DXers have already suggested that one should buy a brand-new '2010 as a second set „for the cupboard“, in case your beloved set ever goes out of service… Fortunately, some listeners do part with their ICF-2100D from time to time, so that the set is still available on the second-hand market as probably the best DX-compatible travel receiver.
Double conversion, PLL synthesis
The set is equipped with semiconductors.