[Boatanchors] Short Wave Broadcasts

[Richard Knoppow]

-----Original Message-----
>From: Jim Haynes <jhhaynes at earthlink.net>
>Sent: Apr 19, 2014 9:07 AM
>To: Richard Knoppow <1oldlens1 at ix.netcom.com>
>Cc: Sheldon Daitch <SDAITCH at bbg.gov>, Rob Atkinson <ranchorobbo at gmail.com>, Boat Anchors List <boatanchors at mailman.qth.net>
>Subject: Re: [Boatanchors] Short Wave Broadcasts
>
>speaking of detection of DSB with or with carrier also brings up the work
>of John Costas at G.E.
>
>Synchronous Communications, Proc. I.R.E. December 1956 p. 1956.  Reprinted
>in Proc. I.E.E.E. august 2002, p. 1461 and in I.R.E. Transactions on
>Communications Systems, March 1957, p. 99
>
>Also Synchronous Detection of AM Signals, Tele-Tech, July 1952, p. 55.
>
>Also Poisson, Shannon and the Radio Amateur, Proceedings of the I.R.E.
>December 1959, p. 2058.
>
>Apparently G.E. was trying to sell the military on DSBSC when Collins
>was selling them on SSB.  While DSBSC uses twice the bandwidth of
>SSB the two sidebands can be added coherently so you get the same
>power saving either way, and perhaps some jam resistance.
>
>jhhaynes at earthlink dot net

    Theoretically, DSB with synchronous detection has the advantage of some frequency diversity.