Manufactured by Trio - Kenwood Co.
As successor of the Trio 9R-59 - shortwave receiver, the Japanese company Trio Corp. introduced the 9R-59DE resp. 9R-59DS in 1968. This early „all wave receiver“ from Japanese production was a reliable performer especially in the medium wave range, it's band spread dial limited the useability to the amateur radio bands and soon got a good reputation among medium wave specialists due to its price-performance ratio.
- Mains operation: 110, 220 V
- 380 x 180 x 260 mm, weight 8 kg
The 9R-59DS is a medium-sized tabletop receiver, built in conventional technology according to the state of the art in the mid-sixties. Its grey metal housing has dimensions of 38 x 18 x 26 cm, the weight of the mains-operated 8-tube receiver is 8 kg. The power supply can be switched from 115 to 220 V alternating current. The 9R-59DS does not have an integrated speaker; the SP-5D loudspeaker was the speaker matching the set.
The outer ring of the two-part main tuning knob operates the coarse tuning. The receiver can be tuned from 550 kHz to 30 MHz in four ranges, but in the broadcast bands the readability on the main dial visible in the left-hand scale window is not good enough, to reliably find a station on a known frequency, especially on the high frequencies. Better is the reading on the band spread dial in the amateur radio bands, the fine tuning is set with the inner part of the tuning knob.
For reception in the amateur bands, the main tuning dial must be set to the corresponding marker; in the other frequency ranges, the band spread just serves as a fine-tuning aid. The large analogue S-meter indicates the signal strength, the level can be adjusted with a control on the rear of the set. A rotary switch located at the right of the tuning knob selects the band range, the first covers mediumwaves from 550 kHz - 1.6 MHz, the shortwave ranges are 1.6 - 4.8 / 4.8 - 14.5 / 10.5 - 30 MHz.
The mode switch to the left of the tuning knob also acts as main switch. In AM mode, an noise limiter can be activated in the position AM-ANL. For SSB reception, the BFO pitch control is located on the far left below the company logo, CW and SSB reception is possible with some limitations, especially in the amateur radio bands. The frequency stability is not sufficient for ECSS reception of boradcast stations in single-sideband mose. On the right, one above the other, are the RF gain control, the AF gain for volume control and, at the bottom, the antenna trimmer.
In practical use, the 9R-59DS is distinguished by its narrow-band IF filter, which, however, tends to „ring“ at high signal levels. Even when used with a medium-length long-wire antenna, overmodulation signs with clipping of strong signals on adjacent channels and intermodulation can often be observed - the set is single conversion design. The signal must often be attenuated with sensitive use of the RF gain. The dial calibration is only sufficient to reliably locate a frequency in the medium-wave range. Because the set has not a reduced sensitivity on mediumwaves, the 9R-59D is a quite good performer in the medium-wave range. The German importer Richter / Ricofunk commissioned a fully transistorised version as an improved variant of the 9R-59D, the Minix MR-73 came also with a crystal calibrator. In contrast to the original version, the main and band spread dials were reversed, the MR-55A only covered the amateur radio bands.
Single conversion, analogue technology, band spread useful only in amateur radio bands.
The set is solid state.