|This article needs additional citations for verification. (September 2010)|
The Yaesu FR-50 is one of the earlier HF receivers on the commercial market. Both the FR/FL-50 equipment were released together in 1966 by the Japanese Yaesu Musen Corp. In Europe these radios were marketed under the brand name Sommerkamp. The all-metal-cased receiver is only suitable for amateur (HAM) band reception in the AM, CW and SSB modes.
As modern transceivers were not very common on the HAM bands in that days the FR-50 has not only been designed as a stand-alone receiver but it is also suitable for transceiver operation when connected to the FL-50 model Single Side Band transmitter.
In 1969 the follow-on models FR/FL-50B were released with slight optic changes in the frontpanel layout and internal improvements in the mechanical filters. In 1973 the FR/FL-50B production line was closed.
In Europe the sets were sold as FR-50B and FL-50B Sommerkamp.
The FR-50(B) is a double conversion superheterodyne type in which the 1st local oscillator is not crystal controlled but controlled by LC self-oscillation. Its oscillation frequency ranges from 8.5 MHz to 24.0 mHz depending on the used band. This type of construction makes the VFO output frequency very unstable. Two 4kHz mechanical filters are standard equipped for the internal two step IF amplifiers at 455 kHz. A 100kHz x’tal calibrator is incorporated.
- Additional fixed channel circuitboard for 4 fixed x’tal frequencies.
- FV-50B VFO for transceiver use with the FL-50B.
- SP-50 desktop speaker
Lo-tech equipment with easy accessible internal parts and nice looks. If one pops up on the second hand market it will be friendly priced ($50 at the utmost) as such a rig only has some value for collectors.
The FR-50(B) is not comparable anymore with the current electronics standards. In fact it now is a completely outdated type of receiver only suitable for 80, 40, 20, 15 and 10 meter amateur bands and not even for the WARC bands. It has a VFO instability for which is no solution. As the years go by and its tubes are deteriorating this will cause a “sudden deafness” on several frequencies. Inserting new tubes however resolves this problem completely.
- Frequency range: 3.5 - 3.8 / 7 – 7.5 / (10 – 10.5 JJY – WWV option) / 14 – 14.5 / 21 – 21.5 / 28 – 29.2 mHz
- Tubes: 8x (6BZ6 RF amp; 6BE6 product detection; 3x 6BA6 2nd IF amp; 6CB6 2nd mixer; 12AT7 triode 1st mixer and 6BM8 AF amp)
- Transistors: 3x 2SC372 (colpitts osc circuit; buffer amp; 2nd local osc)
- Sensitivity: better than 0.5 muV S/N 10 dB for CW/SSB; better than 1 muV S/N 10 dB for AM
- Selectivity: -50 dB at +/- 5 kHz, -6 dB at +/- 1.5 kHz
- Image Ratio: better than 50 dB
- Audio Output: 1 W for 8 Ohm/ 600 Ohm
- Power Requirements: (AC) / 100; 110; 117V (JPN/US) ; 200; 220; 235V (Export)
- Dimensions: 33.5 x 15.3 x 26 cm
- Weight: 8 kg