A lot of Hams own the BC-348 receiver. The radio does have the better dual RF amp tube design. The BC-348 test at a very respectable for a tube receiver 106dB 20KHz Blocking dynamic range and 86dB two tone 20KHz dynamic range. It is actually better than a Hallicrafters SX-88 or Collins 75A-4. The IF selectivity is not though. But, the bands are not crowded.
The BC-348 uses a 1 to 5 ohm antenna input though, not 50 ohms as stated in this US Gov't manual: .
https://bama.edebris.com/download/military/bc348/AN%2008-10-209.pdf Place 9 to 1 unun (unbalanced) in the antenna with 9 unun ratio on the antenna input and the 1 unun ratio on the radio antenna input. A unun can be built or a receiver type small 9 to 1 ununs are available on ebay at times or at Palamar Engineers model #SKU BA-9-1000 for $27.95 .
If your BC-348 has an antenna tuner, the antenna tuner makes little difference where tuned. After the unun installation the antenna tuner will have distinct peak providing better receive.
(I made some corrections since first posted- not 4 to 1, 9 to 1 and not balun, but unun). I also listed this modification on eham BC-348 receiver reviews 6 years ago.
