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<p><font face="Comic Sans MS">It was the Scare Crow in the Wizard of
Oz. He spouted it off after he got his brain.</font><br>
</p>
<div class="moz-cite-prefix">On 3/22/2021 5:44 PM, Jacek Radzikowski
wrote:<br>
</div>
<blockquote type="cite"
cite="mid:CAA2oDvbUW4=yR6nvnL9bEjKQg2MBLdzPt6mbe3RvxmHzxvQMQw@mail.gmail.com">
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<div class="gmail_default" style="font-family:tahoma,sans-serif">Aaaaand
the forgotten link: <a
href="https://dspguru.com/files/QuadSignals.pdf"
moz-do-not-send="true">https://dspguru.com/files/QuadSignals.pdf</a></div>
<div class="gmail_default" style="font-family:tahoma,sans-serif"><br>
</div>
<div class="gmail_default" style="font-family:tahoma,sans-serif">Jacek</div>
<div class="gmail_default" style="font-family:tahoma,sans-serif">kw4ep</div>
<div class="gmail_default" style="font-family:tahoma,sans-serif"><br>
</div>
</div>
<br>
<div class="gmail_quote">
<div dir="ltr" class="gmail_attr">On Mon, Mar 22, 2021 at 5:36
PM Jacek Radzikowski <<a
href="mailto:jacek.radzikowski@gmail.com"
moz-do-not-send="true">jacek.radzikowski@gmail.com</a>>
wrote:<br>
</div>
<blockquote class="gmail_quote" style="margin:0px 0px 0px
0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
<div dir="ltr">
<div class="gmail_default"
style="font-family:tahoma,sans-serif">If someone wants to
dig deeper into the mathematical side of SDR, Lyons'
"Complex, But Not Complicated" is a very good starting
point.</div>
<div class="gmail_default"
style="font-family:tahoma,sans-serif"><br>
</div>
<div class="gmail_default"
style="font-family:tahoma,sans-serif">jacek</div>
<div class="gmail_default"
style="font-family:tahoma,sans-serif">kw4ep</div>
<div class="gmail_default"
style="font-family:tahoma,sans-serif"><br>
</div>
</div>
<br>
<div class="gmail_quote">
<div dir="ltr" class="gmail_attr">On Mon, Mar 22, 2021 at
5:06 PM n4tlf <<a href="mailto:n4tlf@wb4jfi.com"
target="_blank" moz-do-not-send="true">n4tlf@wb4jfi.com</a>>
wrote:<br>
</div>
<blockquote class="gmail_quote" style="margin:0px 0px 0px
0.8ex;border-left:1px solid
rgb(204,204,204);padding-left:1ex">
<div>
<p>I've built many of the Softrock kits, including this
one (starting around 2006 or so). Most of the ones I
did were the 80/40 variety. These days, they are
rather old SDR technology, but still work. There may
have been articles on them in back issues of the AMRAD
Newsletter. A Google search on Softrocks, QSD SDR,
etc should help.<br>
</p>
<p>This info is not precise, but it gives you an idea.
While Softrocks are an early SDR entry, most of the
"better" SDRs these days use direct sampling instead.
The hardware is only half the radio in this case, the
software is just as (or maybe more) important.<br>
</p>
<p>The Softrocks are a QSD/QSE design, the software on
the connected computer must be able to handle audio
I/Q signals. An early software was/is "Rocky" by Alex
VE3NEA (I think). It was simple but worked pretty
well. There are a LOT of other SDR programs that
drive these QSD/QSE radios. PoweSDR (originally from
Flex Radio) is another popular SDR software package -
among many.<br>
</p>
<p>The QSD (Quadrature Sampling Detector or Decoder) for
receive basically creates two audio frequency signals
(I and Q) from the RF carrier, which are 90 degrees
out of phase, and requires the software to combine
them properly. The QSE (Quadrature Sampling Encoder
or Exciter) hardware does the reverse, it takes in
audio I/Q samples, and puts out a hopefully clean RF
signal.</p>
<p>The main issue with QSDs and especially QSEs is that
they must be fine tuned so the I/Q signals are of
exactly phased and amplitude level combined to reduce
images and carrier leakage. The Softrock hardware is
rather marginal on these problems. I would NOT plan
to run a Softrock rig into a high powered transmit
amplifier, it will be very marginal on both carrier
leakage and multiple images, possibly failing FCC
rules.<br>
</p>
<p>For a more in-depth discussion of QSD/QSE hardware,
look for a series of four articles in QST in 2002/2003
or so, by Gerald Youngblood of Flex Radio Systems (A
Software Defined Radio For the Masses). That's a good
start.<br>
</p>
<p>73, Terry, N4TLF</p>
<p><br>
</p>
<div>On 3/22/2021 4:15 PM, Alex Fraser wrote:<br>
</div>
<blockquote type="cite"> <font face="Comic Sans MS">Has
anyone had experience with one of these? Building
or hearsay reports appreciated...</font><br>
<h1
id="gmail-m_-7454032134335659790gmail-m_7373941281919369394productName">SoftRock
RXTX Ensemble Transceiver Kit</h1>
<h2
id="gmail-m_-7454032134335659790gmail-m_7373941281919369394productPrices">
<span>$89.00</span></h2>
The SoftRock RXTX Ensemble Transceiver Kit provides a
1 watt SDR transceiver that can be built for one of
the following five band groups: <br>
<br>
<ul>
<li>160m</li>
<li>80m/40m</li>
<li>40m/30m/20m</li>
<li>30m/20m/17m</li>
<li>15m/12m/10m</li>
</ul>
<p>This is the web site where you buy 'em <a
href="http://fivedash.com/index.php?main_page=product_info&products_id=7"
target="_blank" moz-do-not-send="true">http://fivedash.com/index.php?main_page=product_info&products_id=7</a></p>
<p>There are links to the schematics on the above
page.<br>
</p>
<br>
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<br clear="all">
<br>
-- <br>
<div dir="ltr">Given a choice between two theories, take the
one which is funnier </div>
</blockquote>
</div>
<br clear="all">
<br>
-- <br>
<div dir="ltr" class="gmail_signature">Given a choice between two
theories, take the one which is funnier </div>
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