Message-ID: <XFMail.010310164846.cla.po@tiscalinet.it>
Content-Type: text/plain; charset=us-ascii; format=flowed
Content-Transfer-Encoding: 8bit
MIME-Version: 1.0
In-reply-to: <3.0.1.16.20010307120313.08b7191a@mail.cc.kuleuven.ac.be>
Date: Sat, 10 Mar 2001 16:48:46 +0100 (CET)
From: "Claudio" <cla.po@tiscalinet.it>
To: rsgb_lf_group@blacksheep.org
Subject: Re: LF: <TECH>Transatlantic modes - what next?
Precedence: bulk
Reply-To: rsgb_lf_group@blacksheep.org
Sender: <majordom@post.thorcom.com>

Hello LF group,

I agree with Rik arguments about BPSK and I add some more considerations.
 
On 07-Mar-01 Rik Strobbe wrote:
> Hello Jim & group,
> 
> Excellent paper from Jim, it seems a good starting point for an open
> discussion.
> 
> SNIP

> 
> An additional difference occurs at the RX side. QRSS/DFCW are received
> 'wideband', this means you can observe a rather big part of the spectrum
> for DFCW/QRSS signals. This has the advantage that, even at signal
> bandwidths of 0.01Hz, there is nor problem to 'hit' the transmitted signal.
> One can even 'decode' more that one signal at the same time. Opposite to
> this all receiving software for BPSK / WOLF is 'narrowband'. This means
> that you have to 'hit' the transmitted signal very accurate and you can
> receive only 1 signal at a time.
> 
> SNIP
> So far my contribution,
> 
> 73, Rik  ON7YD

BPSK modulation is very sensitive to carrier frequency shift or difference
between transmitter and receiver. The receiver must be frequency locked to the
carrier, if the difference between TX and RX frequency is more that one tenth
of the bit rate you must add some circuit to scan the RX frequency and lock the
receiver local oscillator (do it in hardware or software, doesn't matter) to
the carrier (kiked oscillator ;-) ). After the carrier is locked, the receiver
does lock the data bit clock, this require a training sequence (some data bits
that doesn't carry useful informations) and synchronize the RX side data rate
clock with the transmit side. Those bits are lost and add some time to QSO time.
In general BPSK is easy to implement for hight bit rate

I think that you can ask more to some OSCAR satellite guru about the BPSK
modulation.

73 de Claudio, ik2pii

----------------------------------------------------------------------
Claudio Pozzi       http://www.qsl.net/ik2pii       happy Linux user
E-Mail: Claudio <cla.po@tiscalinet.it> <ik2pii@amsat.org>
Date: 10-Mar-01   Time: 16:26:23
This message was sent by XFMail
----------------------------------------------------------------------