Sony ICF-6800W (white)
Manufactured by Sony Corp., Tokyo.
The Sony ICF-6800W has a special place in the hierarchy of world band receivers from Sony. Due to its performance, it could be classified as a (semi)professional set and get a designation from the CRF series, but in terms of technical construction and pricing, it has its place in the ICF - series of home shortwave radios. After a first series, the ICF-6800W was improved especially with regard to its suboptimal large-signal behaviour and narrower IF filters were installed, the high sensitivity was adapted to the signal strengths in Central Europe:
- ICF-6800W („white“): white lettering below the frequency dial; active preselector, slightly higher sensitivity, poorer dynamic range, Murata filter from CFT / CFU - class.
- ICF-6800WA orange lettering below the frequency dial, serial no.: > 30 001; passive preselector, transistor Q72 has been omitted, improved dynamic range, better Murata filters from the CFU / CFW class.
- Principle: Double conversion superhet, IF AM 19.055 MHz and 455 kHz / FM 10.7 MHz
- Frequency range: FM broadcast band, MW, 30 x SW (1.0 - 30.0 MHz)
- Frequency display: digital display, 1 kHz
- Frequency memory: none
- Features: RF gain, preselector with separate dial.
- Sensitivity: AM (A3) 1.3 - 2 μV, SSB 0.3 - 0.6 μV / Selectivity: 3.1/7.8 kHz, 4.8/xx kHz (WA) resp. 4.5 kHz/ 9 kHz (W) (-6/-46 dB)
- Mains operation: 110, 220 V
- 453 x 184 x 227 mm, weight 6.1 kg
The Sony ICF-6800W and its sister model ICF-6700W have the breadbox shape in the form of an elongated cuboid in common, it is unique to these Sony sets. The anthracite coloured set measures 45.3 x 18.4 x 22.7 cm and has a weight of 6.2 kg. Although it has carrying handles on the side, and a carrying strap can be attached, the Sony has the format of a full-grown tabletop receiver.
The set can be powered from 110 / 220 V mains or by 6 UM-1 batteries, these are inserted into the battery compartment under the hinged cover on the top of the unit, a world time table and a radio band overview is printed on the cover.
The left third of the front panel is taken by the speaker grill, the separate treble and bass controls, the volume control and the headphones jack are located underneath.
In the right part of the front panel, the mains switch is located in the left upper corner, below it are two small push-buttons, one activates the dial illumination and displays the battery voltage on the instrument during battery operation, with the other, the digital frequency display can be switched off to save energy. The large round S-meter is easy to read, but its calibration from 1 - 9 at full scale is not following the usual conventions. Just to the right of it are the pushbuttons for FM broadcast band, MW and shortwave, next to it the rotary switch to switch the two IF filters in AM and both sidebands in SSB mode.
The rotary switch further right selects the shortwave ranges: A small lever switch selects the 0-10, 10-20 or 20-30 MHz ranges, the central rotary knob selects the last MHz digit. I would like to point out this switch in particular: in many ICF-6800Ws that are sold second-hand, one or more of these 10 MHz sections have failed, usually components in the MHz synthesiser circuit have gone out of tolerance, the synthesiser no longer locks and the display shows a frequency around 80000, and the receiver will be inoperative in this range.
In contrast to the encouraging advice on the eBay pages „a drop of contact spray will fix it“, this is not the case, numerous components have to be replaced, and hardly any workshops are left that are confident enough and willing to do this repair. Further right you find the RF gain control.
The tuning of the preselector to signal maximum must be done carefully with the knob below, a small auxiliary dial provides information about the preselector setting. Next to the preselector dial, you find the red LED digits of the digital frequency display, which can be difficult to read when the set gets light from the front. Like some tabletop receivers from the early 1980s, the ICF-6800W not only has a digital frequency display with an accuracy of 1 kHz, but also an analogue drum dial with frequency marks every 5 kHz, so the frequency can be determined to around to 2.5 kHz. The pointer line can be moved with a knurled wheel according to the digital display or the frequency announcement of a received station. On the left hand below the S-meter is the auxiliary dial for a rough determination of the FM broadcast band frequency and the switch for the AFC (automatic frequency correction). And finally, an almost unique feature of the ICF-6800W must be mentioned: behind a small cover on the underside of the front panel, there is a small light to illuminate the logbook of the DXer still awake at night time…
In practical use, the ICF-6800 W requires sensitive adjustment of the preselector. Even when operating from its telescopic antenna, the ICF-6800W is a very sensitive set. If a long-wire antenna is connected to the terminals, intermodulation phenomena caused by strong signals on nearby frequencies may occur due to the limited dynamic range. With the preselector, only a selected narrow segment of the entire short-wave spectrum that is present at the antenna input is given to the first mixer. The setting must be done manually with the ICF-6800W, the signal can be „peaked“ with the preselector knob, the preselector auxiliary dial helps to avoid tuning to the signal maximum of a „mirror station“.
This trick gives the ICF-6800W an acceptable large-signal behaviour despite its high sensitivity, but on long antennas on winter evenings in crowded shortwave bands, occasionally signal attenuation by means of the RF gain control must be used. The earlier „white“ version of the ICF-6800W showed even more of these large-signal problems, but has an even slightly higher sensitivity with an active amplifier in the preselector stage. Since there is no fine tuning control, a steady hand is needed for SSB reception when using the main tuning knob, but SSB and ECSS reception, where the unit's internal subcarrier is used to replace the faint carrier of AM stations, are possible thanks to the very good frequency stability, and the performance is above average for a portable receiver. The „orange“ version uses narrower IF filters, which are very practical; the original wide IF filter of the „white“ version was unsuitable to separate stations with 5 kHz channel spacing.
In the FM range, the set left a good impression on testers in the USA with low station density, for FM DX in Europe, other receivers with narrower IF filters and digital frequency display are preferable, but for listening to the local stations on FM, it's certainly enough. The Sony ICF-6800W is a „bare bone“ shortwave receiver, it has neither a digital clock nor electronic memory options and also no advanced signal post-processing options like passband tuning or notch filter. Even Sony's best shortwave receivers never had such additional features known from sets used in the amateur radio segment or professional equipment.
A negative point is the complicated mechanical construction, which makes servicing extremely tedious, and the fact that, in contrast to professional sets, fifteen to twenty year old sets very often have technical problems with the range switching. Very often, one or more 10 MHz ranges of second hand sets are no longer useable, if a range is affected, you only hear a slight hiss and the display shows a number around 80000… This defect is probably caused by out-of-tolerance components that no longer allow the MHz synthesiser to lock onto the corresponding harmonic of the oscillator determining the 10 MHz or MHz digits. The repair is costly and has not been carried out by Sony itself for a long time. Only a few experts dare to repair this defect of the frequency-band synthesiser. Before buying a second-hand device, all functions should be checked thoroughly (best is to ask for pictures showing the digital display working correctly in all 10 MHz ranges - unless you are a service expert yourself. However, an ICF-6800W in good condition remains an excellent DX receiver that can also be used well in the tropical band range and has a very pleasant audio without digital circuitry hiss.
After the preselector and the RF gain control, the radio frequency signal hass to pass through an amplifier stage and is converted to the first intermediate frequency of 19.055 MHz. After conversion to the second intermediate frequency of 455 kHz and the IF filters, the signal is fed to the AM and SSB product detectors, where the subcarrier of the BFO is also mixed for CW reception. After a further amplifier and tone control stage, the signal is fed to the output stage.
In the FM broadcast band, the ICF-6800W works as a single conversion set with an intermediate frequency of 10.7 MHz. With separated signal paths, only the audio signal processing is shared.
The set is equipped with semiconductors.
- Sony ICF-6800W Service Manual, 1978 version