[ARC5] BC-454-B listed in THAT place.

[Dave Merrill]

Two BC-454-E listed currently, one hacked, one might be original.

On Mon, Aug 15, 2016, 3:22 PM Mike Everette via ARC5 <arc5 at mailman.qth.net>
wrote:

> There was a BC-454-E shown on eBay last week.  Only one I've ever seen.
> It was badly hacked, and not (in my opinion) worth whatever the minimum bid
> was.
>
> It had a decal nomenclature tag, and the close-up picture of the tag was
> clear.  I'm 99.999% sure that the mod letter was indeed an E.
>
> FWIW, I have two BC-456-E modulators.
>
> 73
>
> Mike
>
> WA4DLF
>
>
> ------------------------------
> *From:* Mike Morrow <kk5f at earthlink.net>
> *To:* arc5 at mailman.qth.net
> *Sent:* Monday, August 15, 2016 1:27 PM
>
> *Subject:* Re: [ARC5] BC-454-B listed in THAT place.
>
> > OK on the taps, but what determined if the lo-z was used or not?
>
> Every NIB SCR-274-N version B receiver or BC-348-* receiver that I've ever
> owned came out of the box connected for high impedance, which matched the
> impedance of headphones like the HS-23 that were commonly-used by the
> USAAC/F before LOW-Z phones like the HS-33 became common after early WWII.
>
> An aircraft that used low impedance AF output in the SCR-274-N command set
> required the AF tap to be changed to LOW-Z as part of the installation
> process on each receiver output and on the modulator sidetone output.  The
> same had to be done for the BC-348-* receiver and the BC-375-* transmitter
> sidetone adjust switch in the SCR-287-A, the ADF receiver in the SCR-269-*,
> the receiver in the SCR-522-A VHF command set, the marker beacon receiver,
> the BC-733-* VHF ILS localizer, etc.  A sticker in red ink that warns of
> the LOW-Z connection was affixed on the outside of each unit with wiring
> changes.
>
> The USN had historically used LOW-Z headphones, although RU-* receivers
> prior to the 1934 RU-3A could be connected for HIGH-Z or LOW-Z.  Therefore,
> all ARA and AN/ARC-5 receivers and modulators have only LOW-Z AF output.
>
> LOW-Z became the standard everywhere.  If one has a receiver connected for
> HIGH-Z, that's a pretty good indication it was never actually used before
> being surplused.
>
> WRT SCR-274-N receiver nomenclature end-letters, there are only A, B, and
> BM possibilities (not including units radically modified for the UK's
> Standard Beam Approach landing system).
>
> The broadcast band receiver was added late to SCR-274-N for use with the
> AN/ARR-1 VHF homing adapter, and exists only as BC-946-B.  There was never
> a BC-946-A.
>
> A few BC-454-B and BC-455-B receivers were modified for use in the
> AN/CRW-3 remote radio control system for the GB-4 glide bomb.  Those
> receivers have the frequency dial removed and have a paper tag with
> BC-454-BM or BC-455-BM nomenclature.
>
> Mike / KK5F
> ______________________________________________________________
> ARC5 mailing list
> Home: http://mailman.qth.net/mailman/listinfo/arc5
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:ARC5 at mailman.qth.net
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>
>
> ______________________________________________________________
> ARC5 mailing list
> Home: http://mailman.qth.net/mailman/listinfo/arc5
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:ARC5 at mailman.qth.net
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mailman.qth.net/pipermail/arc5/attachments/20160815/75b6cbaa/attachment.html>