[Milsurplus] BC-348 series CORRECTION

Tue Jun 27 10:24:07 EDT 2017

RayCan't speculate on why the Navy or any other service would need AC power for the BC-348 but I easily found a photo and schematic of a Hallicrafters made power supply at: http://www.ohio.edu/people/postr/bapix/BC348Q_3.htm
Jim

      From: Ray Fantini <RAFANTINI at salisbury.edu>
 To: "COURYHOUSE at aol.com" <COURYHOUSE at aol.com>; 'Milsurplus' <milsurplus at mailman.qth.net> 
 Sent: Tuesday, June 27, 2017 8:41 AM
 Subject: Re: [Milsurplus] BC-348 series CORRECTION

#yiv0525176721 #yiv0525176721 -- _filtered #yiv0525176721 {panose-1:2 4 5 3 5 4 6 3 2 4;} _filtered #yiv0525176721 {font-family:Calibri;panose-1:2 15 5 2 2 2 4 3 2 4;}#yiv0525176721 #yiv0525176721 p.yiv0525176721MsoNormal, #yiv0525176721 li.yiv0525176721MsoNormal, #yiv0525176721 div.yiv0525176721MsoNormal {margin:0in;margin-bottom:.0001pt;font-size:12.0pt;}#yiv0525176721 a:link, #yiv0525176721 span.yiv0525176721MsoHyperlink {color:blue;text-decoration:underline;}#yiv0525176721 a:visited, #yiv0525176721 span.yiv0525176721MsoHyperlinkFollowed {color:purple;text-decoration:underline;}#yiv0525176721 span.yiv0525176721EmailStyle17 {color:#1F497D;}#yiv0525176721 .yiv0525176721MsoChpDefault {font-size:10.0pt;} _filtered #yiv0525176721 {margin:1.0in 1.0in 1.0in 1.0in;}#yiv0525176721 div.yiv0525176721WordSection1 {}#yiv0525176721 What possible advantage would there be in the Military building an AC power supply for the BC-348? There were plenty of other better suited receivers for ground use during the war like the BC-342 or the SP-200/BC-779 that already had AC power supplies and by the wars end newer and better ground receivers were starting to come on line like the 51J/R-388 family so why waste time and money on a AC version of the 348? In training applications the radios were run from 28 volts just like in the aircraft, perhaps some radios that were repurposed from nonfunctional aircraft were used in unofficial ground roles but beyond that cannot imagine except maybe the one circumstance as being used in a FAC setup where the BC-348 would have been used in a ground role. This is in no way demeaning or disparaging the quality and utility of the radio, it did work in some aircraft as late as the seventies and may have had as long a history of operational use in the ARC-8 configuration as any radio fielded but it is what it is. The problems I see with the idea of the drop in AC power supply replacing the internal Dynamotor deck are first all the primary distribution of the 28 volts to the radio would be wrong for AC power. When doing the Ham modification to convert the set to AC you almost always install a new circuit for the AC primary, fuse and AC power switch. Second, the radio has its filament string wired for 28 volts, in Ham service you always convert the filament string for six volt operation. A drop in supply would have to provide 28 volts for the filament string. If you can show me a picture or other evidence of a factory built drop in AC supply that can address these two issues then I will stand corrected but until that time I tend to think that it never occurred and perhaps there is some weird bias about how some work that has been done by hams in converting is too high a quality as to not have been conducted by Hams. It’s true there are a lot of hacks out there but there are also a lot of Hams that have more than adequate experience and expertise to design and install a AC power system in this receiver that meets or exceeds Mill Standards. Think part of this goes back to the same drum that I am always beating that the history of this radio also includes its long time in service with Ham radio operators and SWL operators that often exceeds its time in military service, including its modifications and adaptions for use in that service. The base radio was a great radio in the ARC-8 package but with the AC power supply and a couple simple audio modifications like a low impedance output transformer it’s a great AM and SWL set that was used by tens of thousands in the Ham community for decades and to ignore that aspect of its history is to ignore reality itself. At least that’s my opinion, have to respect those who insist on wanting the radio to be in pristine condition as to how it appeared in its military role. And I do respect that. But how many of us were introduced to the world of SWL or Ham radio by the hacked and modified BC-348 and will always have a palace in there hart for that hacked 348 with the additional knobs, S meter and vent holes cut in the cabinet?    Ray F/KA3EKH       From: milsurplus-bounces at mailman.qth.net [mailto:milsurplus-bounces at mailman.qth.net]On Behalf Of Ed Sharpe Archivist for SMECC via Milsurplus
Sent: Tuesday, June 27, 2017 12:40 AM
To: kk5f at arrl.net; glennmaillist at bellsouth.net; milsurplus at mailman.qth.net
Subject: Re: [Milsurplus] BC-348 series CORRECTION    Thanks  for this  Mike -   It is  a great reference!   was there any resolve on   the AC power supply  being made at time  of  Mfr  or was it aftermarket? Ed# KF7RWW   www.smecc.org   In a message dated 6/26/2017 8:52:17 P.M. US Mountain Standard Time,kk5f at earthlink.net writes: 
That's an OK but unintended BC-348 link.  Here's the correct URL for Ken's work:

  https://www.nonstopsystems.com/radio/pdf-radio/article-bc348-kf6nur.pdf

Mike / KK5F 
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