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Kenwood / Trio - Kenwood Communications, Tokyo

9R - 59 DS

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überarbeitet am 21.10.2010

In 1968, the japanese Trio Corporation presented the 9R-59DE and 9R-59DS as successors for their 9R-59 set. This early "All Wave Receiver" from japanese production covers the whole shortwave range, only in the amateur radio bands and on mediumwaves, the dial accuracy is sufficient for reasonable DXing. But amongst mediumwave specialists, the 9R-59DS had a very good reputation due to it's mechanical IF filters and it's reasonable price tag.

Single conversion, IF 455 kHz

Analog dial non linear, accuracy 10 kHz in the mediumwave range and around 200 kHz in the 30 MHz range, bandspread tuning in the 80, 40, 20, 15, 10m amateur bands.

AM, CW/SSB with BFO

Sensitivity AM around 2 uV

Selectivity -6/-60 dB
4-6/ 10 kHz

S meter, RF gain, Noise limiter, Antenna trimmer

The 9R-59DS is a medium sized desktop receiver; the dimensions of the metal cabinet are 380 x 180 x 260 mm, the 8 tubes hollow state set weighs 8 kg. The power supply can be set to 115 or 220 V AC mains. The 9R-59DS has no internal speaker, the SP-5D is the matching optional speaker.

The main tuning knob is a double concentric knob: the outer ring activates the coarse or main tuning. The receiver has continuous coverage from 550 kHz to 30 MHz. The dial accuracy of the main tuning dial is acceptable in the mediumwave band, on the high frequency bands, the dial calibration is almost useless. The inner knob activates the bandspread dial at the right of the signal strength meter: when the Main Tuning dial is set to one of the Amateur band calibration marks, You can read the amateur band frequency directly from the right bandspread dial. The big analog S meter indicates the signal level, You can adjust it's level using a control at the rear of the receiver.
A rotary knob at the right of the main tuning knob let's You select one of the band ranges mediumwaves 550 kHz - 1,6 MHz, or shortwaves 1,6 - 4,8 / 4,8 - 14,5 or 10,5 - 30 MHz.
The FUNCTION switch at the left of the main tuning knob will switch the receiver on, select AM or AM-ANL to activate the Noise Limiter. For CW or single sideband reception, You find the BFO control at the left hand of the set below the TRIO logo, You can use the BFO for CW and SSB reception. You can use the receiver to monitor amateur radio traffic, but it's stability is not sufficient for ECSS reception of weak shortwave stations.
At the right hand of the front panel, You find the RF and AF gain (volume) control andan antenna trimmer control.

In practical use, one of the peculiarities of the receiver is the narrow IF filter: with high signal strengths, it tends to ringing effects, but it has an excellent selectivity for mediumwave DXing. With longer antennas, the receiver can suffer from intermodulation effects and appearing "ghost signals" due to it's single conversion design.
As the dial accuracy is suffient only in the low frequency mediumwave band, the set has had a good reputation for mediumwave DXing. Today it's considered as beeing a collector's item.

As an improvement and successor of the set, the German importer Richter / Ricofunk ordered a solid state version of the set to be made from a japanese manufacturer. The Minix MR-73 features an internal crystal calibrator, it's small brother, the MR-55A, covers only the amateur radio bands.

further reading:
d / e: Trio 9R-59DS at www.radiomuseum.org
d: Trennscharf und empfindlich: Trio 9R-59DS, Nils Schiffhauer, Oldie- KW- Empfänger

© Martin Bösch 7.1.2009