The best use of DSB in ham radio would be for SSTV or some such. You could
have the picture on one side, and voice talking about it on the other. We
used to throw up a DSB signal in transmitting to other government
facilities, with one stream to station A on USB, and another stream of
traffice to station B on LSB.
Danny Douglas N7DC
ex WN5QMX ET2US WA5UKR ET3USA
SV0WPP VS6DD N7DC/YV5 G5CTB all
DX 2-6 years each
.
QSL LOTW-buro- direct
As courtesy I upload to eQSL but if you
use that - also pls upload to LOTW
or hard card.
moderator [EMAIL PROTECTED]
moderator http://groups.yahoo.com/group/DXandTalk
----- Original Message -----
From: "Walt DuBose" <[EMAIL PROTECTED]>
To: <digitalradio@yahoogroups.com>
Sent: Wednesday, January 31, 2007 11:38 PM
Subject: Re: [digitalradio] PSK on AM and you get two sidebands for
diversity
> If you place different data on either sideband, its ISB which is illegal
or if
> not now, may be in the near future.
>
> However, if detecting either sideband independently does not produce
separate
> data streams, then its not ISB.
>
> DSB would only double the information of one sideband so you would want to
use
> the other sideband for more data.
>
> The question you have to answer is which is better...doubling, being
redundant
> as with interleaving or sending characters twice or obtaining a greater
bit rate
> or raw throughput.
>
> Another consideration is what would the bandwidth be with DSB where two
350 Hz
> PSK modes were sent? The bandwidth would be 770+ Hz.
>
> I think that you would still need a raised cos or filter on the transmit
tones
> as well as a brickwall filter on the received signal.
>
> Noticed I said think because I haven't really had time to totally digest
the use
> of DSB but I kinda like the approach. A 100 watt PEP DSB transmitter is
sooooo
> easy to build. Using the FCC-2 oscillator as described in the Feb. QST,
and a
> low level diode balanced modulator and several stages of amplication, you
could
> easily build a 100 watt PEP (50 watts per sideband) transmitter. But the
> problem is finding an ISB receiver which you would need. Perhaps a
direct
> conversion receiver with a Q/I (?) detector and DSP brickwall filter would
work.
>
> Walt/K5YFW
>
> Paul L Schmidt, K9PS wrote:
> > For a simple transmitter, how about a sound card mode that uses the
> > sound card in STEREO mode with I and Q components on L and R channels,
> > feeding two balanced modulators, and build a phasing-type exciter
> > to do J2D type emissions?
> >
> > Maybe not quite as simple as AM, DSB, or NBFM, but probably pretty
> > close.
> >
> > A companion receiver could use the same scheme to produce a simple
> > I and Q output to feed to a sound card.
> >
> > And no crystal filters on either one...
> >
> > - ps
> >
> > kd4e wrote:
> >
> >>>Interesting. Run PSK on AM and you get two sidebands for diversity
> >>>reception and a pilot carrier. This could make building small PSK rigs
> >>>easier...
> >>>Leigh/WA5ZNU
> >>
> >>What about DSB or NBFM, same result?
> >>
>
>
>
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