Manufactured by Trio-Kenwood.
After the quite popular Trio - Kenwood 9R-59DS, Kenwood launched the QR-666, a transistorised shortwave receiver with a continuous coverage from medium wave to 30 MHz, optionally also covering the FM broadcast band.
- Frequency range: FM broadcast band (optional), LW (170-410 kHz), MW (525-1250 kHz), 4 x SW (1.25-3 / 3-7.5 / 7.5-18 / 18-30 MHz), spread ham bands 80, 40 20, 15, 10 m.
- Frequency display: Analogue display, not linear, in the MW range with an accuracy of 10 kHz, towards 30 MHz only 100 kHz can be estimated.
- Frequency memory: none
- 360 x 165 x 280 mm, weight 7.3 kg
The Kenwood QR-666 is a fully solid state all wave receiver which, with its dimensions of 36 x 16.5 x 28 (31 with rotary knobs) cm, is one of the larger tabletop receivers. The Kenwood R-1000 is considerably smaller. On the one hand, the frequency tuning is done with a coarse tuning dial, on the other hand, frequencies in the amateur radio bands can be set more precisely on a band spread dial.
In the ranges A - E resp. the ranges from longwave to 18 MHz, the receiver works as a single conversion, only in range F (18 - 30 MHz), which is very susceptible to mirror frequency reception, as a double conversion with a first conversion to an IF of 4.034 MHz and then a second conversion to 455 kHz.
The front panel is dominated by the two horizontal drum dial with the two tuning knobs next to them. On the far left of the front panel, below the S-meter which is calibrated in S units, are the push-buttons for dial illumination and standby, below this the main switch, next to it the BFO control for single sideband reception. At the bottom left, a headphone can be plugged in a 6.3 mm jack plug.
In the middle of the frontpanel, the yellow backlit dials are placed one above the other. The upper dial covers longwave, mediumwave and the entire shortwave range up to 30 MHz without frequency gaps. On the lower dial, the spread amateur radio bands can be set with the fine tuning knob next to it.
To the right of the dial drums is the row of pushbuttons for the operation mode, AM, AM/ANL (AM with activated noise limiter), CW/SSB (for SSB reception a BFO is switched on, the BFO control to the left below the dials is used to set the pitch or the sideband. If the set is equipped with the optional FM broadcast band unit, the latter is activated with the fourth key, the fifth key selects the bandwidth „wide - narrow“ and activates the AFC (automatic frequency control, automatically adjusts to the centre of the frequency when receiving stronger FM stations) for FM reception. At the right of the operating mode buttons, the RF gain control is located; when the button is pulled out, the optional crystal calibrator is activated and can be used to calibrate the frequency dial.
The band switch below the operation mode buttons selects the band segment, longwaves, mediumwaves or one of the four shortwave ranges. To the right of this is an antenna trimmer and at the bottom right is the volume control (referred to as AF Gain, Audio Frequency Gain).
In contrast to the 9R-59D, the QR-666 comes with an inernal loudspeaker on the left side of the cabinet.
At the rear of the unit are the terminal connectors for long-wire antennas, an SO-239 / PL - 50 Ohm antenna input, the connectors for the mains power and for 13.8 V DC for car battery operation. Some adjustment elements are directly accessible from the rear of the unit; similar to the 9R-59DS, the S-meter sensitivity can also be adjusted.
On the right-hand side of the set, there is a large rotary knob with a reduction gear, and on the inner metal ring the numbers 88 - 108, that's right - it's the FM broadcast band tuning knob and the corresponding frequency dial. Here, Kenwood has already anticipated the Sony engineers, who also equipped their ICF-6800W with a simple FM broadcast band tuner with a rudimentary dial, so that you can listen to the evening news on SRF-1 with this „radio“.
Now lets look at the operation: After switching on with the mains switch at the bottom left, the RF gain control is turned up fully clockwise, then the AF gain is set to a medium hiss. To receive Radio Österreich International on 6155 kHz, select Operation mode AM, set the band segment switch to D and set the dial D between the 6.1 and 6.2 MHz marks. When the news from Vienna become audible, the fine tuning dial can be used to tune to signal maximum and, if necessary, the antenna trimmer can be adjusted to maximum signal.
For reception in the amateur radio bands, the upper coarse tuning scale is tuned to the corresponding triangular marker; if the position is correct, the frequency marks on the lower band spread dial should indicate reasonably correct the frequencies in the ham bands. However, if the main tuning is out of tune or if you accidentally turn the upper tuning knob, the frequency indications on the lower dial are completely inaccurate.
Based on my experience so far, I cannot say much about the reception of weak DX stations. Without the crystal calibrator, it is difficult to determine the frequency of a station you are listening to; you have to use a listening guide or wait for the station announcement.
In summary, the Kenwood QR-666 still can be used as a basic all wave receiver for search operation on the shortwave bands and lets you listen to many exotic stations, even radio amateurs can be heard in CW and SSB. Without digital memories and with only rudimentary means of determining the frequency of a received station, a set with digital frequency display is more recommended for the first steps into shortwave reception. The Kenwood QR-666 may appeal more to collectors or enthousiasts of analogue technology to be a witness of a developmental step on the road to modern communications receivers.
Conventional single conversion superhet, only in the highest frequency range 18 - 30 MHz acting as double conversion superhet.
The set is solid state.
The list price was 890.- CHF, plus 150.- CHF for the FM broadcast band option and another 60.- CHF for the crystal calibrator.