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R: AM on existing Satellites? A better idea



Hi Cliff , K7RR

Early october 1986 an article on ACSSB by Jim Eagleson WB6JNN was
published in Ham Radio magazine and i got from Jim two PCBs for level 1
ACSB compandor kit and i got several nice QSOs via OSCAR-10 with
the only one station operating ACSB via satellite at that time i.e. Vern
Riportella WA2LQQ........nice to remember that AMSAT President !

73" de

i8CVS Domenico

 ----- Original Message -----
From: Cliff Buttschardt <cbuttsch@kcbx.net>
To: G8IFF/KC8NHF Nigel A. Gunn <nigel@ngunn.net>
Cc: Howie <hdefelice@petrexintl.com>; Bob Bruninga <bruninga@usna.edu>;
<amsat-bb@AMSAT.Org>
Sent: Thursday, February 05, 2004 2:13 AM
Subject: Re: [amsat-bb] AM on existing Satellites? A better idea


> Quite a number of years ago there were three voice systems attempting to
retain
> fidelity and limit bandwidth.  High seas telephone service by AT&T used a
SSB
> system in which the carrier was about 12 db down.  The shore station was
to
> lock on to this carrier.  Two problems:  The receiver was rather complex
and
> the transmitters had a devil of time keeping the carrier amplitude
correct.
>      Another system used double sideband and no carrier.  The carrier was
> reconstructed by doubling the DSB signal and inserting it back into the
original.
> It did not work well with atmospheric and other phase changes in the
system.
>      Amplitude Compounded SideBand transmitted a reference tone at ten
percent
> amplitude just higher than voice bandwidth.  This worked rather well and
even
> met with some success in the commercial market.  The hams operated a
transponder
> in the San Francisco Bay area capable of six simultaneous ACSB
conversations
> at one time.  It was ready for satellite packaging but never was
completed.
> Cliff K7RR  AMSAT LM1606
>
>
> "G8IFF/KC8NHF Nigel A. Gunn" wrote:
> >
> > And if you have a small amount of carrier, perhaps 20dB down on peak
> > sideband signal, you can build AFC into your receiver to counteract
doppler.
> >
> > Howie wrote:
> >
> > >".....old fashioned full carrier double sideband AM has no place on
> > > existing OSCAR satellites!....."
> > >
> > >Agreed... however, I belive many HF rigs generate an "AM equivalent"
signal
> > >by inserting a user adjustable amount of carrier into an SSB
transmission.
> > >This could be an interesting mode for LEO operation where doppler is a
> > >factor.  Since the carrier reference is transmitted with the modulated
> > >sideband doppler is tracked, so to speak. Less bandwidth than FM,
similar
> > >power requirements to digital modes, no capture effect to "eliminate"
weaker
> > >uplinks.....or I could be wrong !
> > >
> > >Howie AB2S
> > >
> > >----
> > >Sent via amsat-bb@amsat.org. Opinions expressed are those of the
author.
> > >Not an AMSAT member? Join now to support the amateur satellite program!
> > >To unsubscribe, send "unsubscribe amsat-bb" to Majordomo@amsat.org
> > >
> > >
> > >
> > >
> >
> > --
> > <><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><>
> > Nigel A. Gunn. 59 Beadlemead, Milton Keynes, MK6 4HF, England.
> > Tel +44 (0)1908 604044 or 07774 478270 (mobile)
> > e-mail nigel@ngunn.net   http://www.ngunn.net/cyberworld
> > Amateur radio stations  G8IFF, KC8NHF
> > Member of  AMSAT-NA  LM-1691, AMSAT-UK #182, ARRL, QRPARCI #11644,
> >            Flying Pigs #385, Dayton ARA #2128, Milton Keynes ARC, GQRP
#11396
> > Supporter of MK Lightning and Dayton Bombers Ice Hockey Teams
> > <><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><>
> ----
> Sent via amsat-bb@amsat.org. Opinions expressed are those of the author.
> Not an AMSAT member? Join now to support the amateur satellite program!
> To unsubscribe, send "unsubscribe amsat-bb" to Majordomo@amsat.org




----
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