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| Reviews Summary for BC-348 WWII MW/SW Receiver |
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Reviews: 2
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Average rating: 3.5/5
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MSRP: $348
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Description: Businesslike wartime reciever used in planes and on the ground, recieves most
of the MW and SW bands in switchable ranges, has a BFO for CW work and an
xtal filter that's very nice for CW and even listening to AM SW broadcasts.
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Product is not in production.
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More info: http://
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write your own review of the BC-348 WWII MW/SW Receiver.
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SWL377
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Rating: 3/5
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Aug 21, 2006 14:42
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Great history, OK performance
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Time owned: more than 12 months
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I like to imagine that my BC 348 flew in a B 17G over Germany in WW II, but I have no proof that it actually served in combat. Mine has a postwar civilian AC PS sited in an external speaker cabinet and an outboard audio amp to give loudspeaker volume. The original dynamotor was removed. I found dial accuracy to be outstanding on all bands. HF sensitivity is OK, not as good as my Hammarlund HQ 180 but good enough for normal listening. It is also a noisier rcvr than my Hammarlund. Stability my my BC 348 is good enough for decent SSB copy without frequent retuning even on 20 meters. I use the BFO for SSB demod and it works fine. I listen to HF USB marine comms in the 8 MHz band with the BC 348 and it does just fine once it has warmed up and stabilized. Sensitivity on LF is decent, I could hears some distant NDBs that are hard to hear in my area. On my set the XTAL FLTR acts only as a high low sensitivity switch and accomplishes nothing useful in narrowing bandwidth and maintaining decent sensitivity in the center of the filter response curve. Maybe it needs work but I cannot find any bad components in that section. I love having a rcvr with such a rich heritage, but I wouldn't depend on it for any serious DXing when I have my HQ 180 at hand. To be fair, it was designed much earlier and withstood a lot of abuse. My BC 348 hasn't had any mods other than the PS and 99% of the caps and resistors are orginal. I love the looks of the set, especially the Art Deco bezel over the main tuning dial. It is pretty amazing that it can deliver the goods over 60 years after it left the production line. I wish it covered BCB. If it did I'd put it in the living room. The BC 348 has looks good enough for a family room while the better performing surplus aircraft HF rcvrs (like my ARR 15)look like they belong in a ham shack or military airplane. BC 348s are still plentiful and not horribly expensive ($60-$150 at most swaps depending on cndx). I suggest buying one while they are still affordable. As a side note, I once saw a 100% solid state BC 348 owned by the late Command Set collector, Henry Engstrom. It looked VERY professional inside, with fiberglass PC boards etc. It didnt work and Henry had no documents on the conversion. I often wonder who has it now and if they restored it to operation.
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AC7ZL
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Rating: 4/5
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Jul 31, 2006 12:40
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Fun to play with
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Time owned: 3 to 6 months
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A while back I was fortunate to stumble across a BC-348-Q at a hamfest. I am partial to vintage electronics and boatanchors, and the BC-348-Q has a certain aesthetic charm to it---maybe it's the "military" look, the illuminated, shuttered dial face, or the tuner crank that requires nearly 100 turns from lock to lock! Whatever the reason, I purchased the radio and took it home.
I'm no old timer, but from what I gather, the BC-348 series of radios enjoyed some popularity as convert-to-ham-use surplus following WWII. For this reason, finding an unmodified BC-348 is somewhat difficult. The radio was originally designed to be powered from a 28 volt DC supply. An internal dynamotor produced the 220 volts for the radio's plates. For these reasons, at the very lease, most BC-348's have been rewired for a 6 volt filament string, and often contain homebrew power supplies mounted in the dynamotor bay.
My own radio contained wiring errors, a bad tube, several weak tubes, and a full set of dried out capacitors. I also found several fractured carbon resistors which lead me to repopulate the entire chassis with new caps and resistors. My radio came with neither a dynamotor nor power supply, so I built and installed my own supply.
Repairing equipment like this is made much easier with proper documentation. Schematics are available at the BAMA site, but the best scans I found were available at www.jamminpower.com/main/bc348.jsp .Note that there are several siblings in the BC-348 family, denoted by a letter extension. In my case, the radio is a BC-348-Q, originally built under contract by Wells Gardner. The revision letter is important, because there can be significant wiring differences from one radio to the next.
The radio offers 6 bands of coverage, from 200 khz to about 18 mhz. The AM broadcast band, unfortunately, is omitted. This probably has to do with the fact that the set uses a 915khz IF. The dial features a shutter mechanism that selectively occludes the tuning dial during band changes, such that only the frequencies associated with the selected band are visible. Mechanically, tuning is very precise. A worm gear drives a zero-backlash gear-train with such reduction that the dial crank has to be turned nearly a hundred times to get from one end of the tuning scale to the other. In addition, the set features an adjustable BFO and crystal filter for CW work.
While the set has great character and I do not for a second regret any effort that went into restoring it to operation, its use as an everyday ham receiver is questionable. Sensitivity seems good. Selectivity is not all that great (though I've been told that this may be due to leaky caps in the IF cans.) Even if it was better, the resolution of the dial markings are such that, at best, you will never know more than your approximate frequency.
Tracking on my set leaves much to be desired. The low band tracks fairly well, but the other bands do not. Without going into excessive detail, alignment adjustments are fairly limited, which leads me to postulate that some of the caps inside of the rf compartments may have drifted. Digging that far into the radio is doable, but something of a mechanical nightmare, and something that I will likely avoid for now.
Some writers have complained about the amount of volume that the radio's audio amp (6K6) will produce. In fact, one of the common radio modifications found is the insertion of additional amplifier stages. This criticism is not entirely fair, in my opinion. A headset of proper impedance will produce more than enough volume for ear damage. If you want to drive a speaker, make sure to use a matching transformer, and if that's not good enough, add a stage of outboard amplification.
The crystal filter, by the way, has significant attentuation when it's switched in. One trick that I discovered to improve the radio's performance was to measure the actual resonant frequency of the filter crystal, then align the IF cans in the set to the measured frequency. For example, my crystal resonated at 914 khz, so I aligned the IF path to 914 khz. The radio works fine and the filter works much better.
For day-to-day useability, selectivity, dial resolution, and features I'd rate this set a 3. On the other hand, a fellow ham noted that the BC-348 was not designed for stellar performance. Rather, it was designed to "...work ok while you were being shot at." It certainly does. Moreover, for charm, charisma, and historical appeal, the radio scores a 5. It is easy to troubleshoot and repair, and it is my expectation that this 60-year-old radio will still be functional in another 60 years. Therefore my composite score is a 4.
Pete, AC7ZL
www.hpfriedrichs.com
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