N8YX
03-20-2016, 12:19 PM
It's been a bit since we did one of these, and my inspiration is a recently acquired FR-101S which actually works as intended.
Which receiver(s) have a special place in your shack (or heart), and why?
My picks, in no specific order:
1) The aforementioned FR-101. No phase noise at all...as the entire signal chain is derived via analog means. In addition to the normal 160-10M amateur bands it also covers the 60-31-25-19-16-13-11M SWBC allocations, the Class D CB band (26.95-27.55) and has 4 AUX bandswitch spots for things like WARC segments or other ranges of interest. With the accessory 6 and 2M receiving converters and the FM Demodulator board installed you can keep track of the gang on the VHF repeaters.
Drawbacks: No selectivity options other than an optional AM and CW filter. The earlier FRDX-400 design offered "Rejection Tuning". For casual amateur band listening or SWBC monitoring this isn't an issue but having a narrow SSB filter option along with a notch filter (and possibly, a variable BFO) would be nice. Yaesu's transceive scheme (with the companion FL-101 transmitter) leaves a bit to be desired.
2) Kenwood R-820. Meant as the mate to the TS-820S. Think of the design as an intermediate step between the TS-820S and the TS-830S receiver sections. 160-10M coverage but no FM and no WARC bands, though I've modified two of my "twins" to include them. Lots of selectivity and QRM-fighting options - variable bandwidth tuning, IF shift, a real (IF) notch filter among them.The receiver also covers the 31, 25, 19 and 16M SWBC segments. Kenwood got the transceive scheme "right" with this one, in that the R-820's HET (1st mixer) oscillator is used to drive a companion TS-820S when the two are run in "Transceive" mode. Yaesu should have done this with the FR/FL setup.
Drawbacks: The same evils which plague any of the Kenwood hybrids of the era. PLL/display failures due to the SIP interconnection headers becoming oxidized or which were cold soldered to begin with, intermittent VFO grounding resulting in frequency jumps...distorted audio and an ever-present low-level whine. These can be fixed with a bit of rework and re-engineering, as can the issues with the FR-101.
3) Drake R7. It's supposedly a little noisier "on the bench" than an R-820 but I can't tell the difference; both use an analog VFO and a synthesizer for the HFO. Drake also got the transceive scheme down with this one when run in conjunction with the TR7. If you tally up the number of filter bandwidths offered by Drake themselves, Sherwood and Inrad you get a grand total of 12 choices and 5 may be installed in the radio at any one time. More AGC speeds than either of the two above, a front panel antenna/receiving converter selector enables you to engage external VHF converters such as the CC-2 and CC-6.
Drawbacks: A drifty PTO and intermittent connectors which join the various circuit boards are usually the biggest gripes which people have with ANY 7-line gear, but fortunately these can be fixed. Most components used in the design were off-the-shelf, so repairs (if required) aren't overly challenging. Some users gripe about the band change procedure with both TR7 and R7, but an AUX-7 board and accompanying band modules makes this as simple as rotating two knobs.
Which receiver(s) have a special place in your shack (or heart), and why?
My picks, in no specific order:
1) The aforementioned FR-101. No phase noise at all...as the entire signal chain is derived via analog means. In addition to the normal 160-10M amateur bands it also covers the 60-31-25-19-16-13-11M SWBC allocations, the Class D CB band (26.95-27.55) and has 4 AUX bandswitch spots for things like WARC segments or other ranges of interest. With the accessory 6 and 2M receiving converters and the FM Demodulator board installed you can keep track of the gang on the VHF repeaters.
Drawbacks: No selectivity options other than an optional AM and CW filter. The earlier FRDX-400 design offered "Rejection Tuning". For casual amateur band listening or SWBC monitoring this isn't an issue but having a narrow SSB filter option along with a notch filter (and possibly, a variable BFO) would be nice. Yaesu's transceive scheme (with the companion FL-101 transmitter) leaves a bit to be desired.
2) Kenwood R-820. Meant as the mate to the TS-820S. Think of the design as an intermediate step between the TS-820S and the TS-830S receiver sections. 160-10M coverage but no FM and no WARC bands, though I've modified two of my "twins" to include them. Lots of selectivity and QRM-fighting options - variable bandwidth tuning, IF shift, a real (IF) notch filter among them.The receiver also covers the 31, 25, 19 and 16M SWBC segments. Kenwood got the transceive scheme "right" with this one, in that the R-820's HET (1st mixer) oscillator is used to drive a companion TS-820S when the two are run in "Transceive" mode. Yaesu should have done this with the FR/FL setup.
Drawbacks: The same evils which plague any of the Kenwood hybrids of the era. PLL/display failures due to the SIP interconnection headers becoming oxidized or which were cold soldered to begin with, intermittent VFO grounding resulting in frequency jumps...distorted audio and an ever-present low-level whine. These can be fixed with a bit of rework and re-engineering, as can the issues with the FR-101.
3) Drake R7. It's supposedly a little noisier "on the bench" than an R-820 but I can't tell the difference; both use an analog VFO and a synthesizer for the HFO. Drake also got the transceive scheme down with this one when run in conjunction with the TR7. If you tally up the number of filter bandwidths offered by Drake themselves, Sherwood and Inrad you get a grand total of 12 choices and 5 may be installed in the radio at any one time. More AGC speeds than either of the two above, a front panel antenna/receiving converter selector enables you to engage external VHF converters such as the CC-2 and CC-6.
Drawbacks: A drifty PTO and intermittent connectors which join the various circuit boards are usually the biggest gripes which people have with ANY 7-line gear, but fortunately these can be fixed. Most components used in the design were off-the-shelf, so repairs (if required) aren't overly challenging. Some users gripe about the band change procedure with both TR7 and R7, but an AUX-7 board and accompanying band modules makes this as simple as rotating two knobs.