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<div>Quite a few lads in the UK are using the Octagons with the new EsHal bird.</div><div>It was worked well with IF's down to 432 MHz. Some of the more enterprising</div><div>lads are removing the 27 MHz xtals and sending a GPS stabilized signal back up</div><div>the coax externially locking the down converter section. OK on a geo bird,</div><div>but keeping the LO to a few Hz is kind of a waste of time when we will be seeing</div><div>close to 500 kHz of Doppler shift during a full overhead pass.</div><div><br></div><div>Kent WA5VJB<br></div><div><br></div><div><br></div><div><br></div>
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On Friday, January 25, 2019, 5:52:03 PM CST, Ron Economos via Ground-Station <ground-station@lists.openresearch.institute> wrote:
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<p>The standard IF for DVB-S2 receivers is 950 to 2150 MHz.</p>
<p>DB6NT was selling a down-converter from 10489-10500 MHz to
1129-1140 MHz for P4A.</p>
<p><a shape="rect" class="ydpbae0ddeayiv0484140599moz-txt-link-freetext" href="https://shop.kuhne-electronic.com/kuhne/en/shop/new/MKU+LNC+10+OSCAR+P4A/?card=1832" rel="nofollow" target="_blank">https://shop.kuhne-electronic.com/kuhne/en/shop/new/MKU+LNC+10+OSCAR+P4A/?card=1832</a></p>
<p>I'm not sure what decimation has to do with receiving DVB-S2. The
entire 10 MHz signal needs to be demodulated. Individual baseband
frames will be selected for processing, but I call that
de-multiplexing.<br clear="none">
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<p>Ron W6RZ<br clear="none">
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<div class="ydpbae0ddeayiv0484140599yqt9889722016" id="ydpbae0ddeayiv0484140599yqtfd79987"><div class="ydpbae0ddeayiv0484140599moz-cite-prefix">On 1/25/19 15:32, David Vieira via
Ground-Station wrote:<br clear="none">
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<div>Michelle - Thanks for posting. I'll frame some of the
questions.<br clear="none">
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<div>Typical 10 GHz terrestrial contesting rigs are Heterodyne;
that is a Mixer works with a Local Oscillator (LO) to take the
RF down to an IF (Intermediate Frequency).</div>
<div>For an SDR, that IF can be digitized by an Analog-Digital
Converter.</div>
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<div>The most popular IF for contesting/SSB rigs is 144 MHz. </div>
<div>For a data BW of 10 MHz that may or may not be a fast
enough IF carrier. If we can digitize and recover the data,
it would allow a lot of re-use of existing equipment.</div>
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<div>I've heard suggestions/proposals up to the 1.2 GHz Ham
band.</div>
<div>In some sense, the IF carrier could be 144/220/440/915/1200
MHz, or even any Non-Ham frequency in between.</div>
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<div>There are a lot of proof of existence designs for a 10 GHz
Mixed down to an IF; and lots of off the shelf ADC
dev-boards. (catch me off thread for details).</div>
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<div>Some questions I have are: </div>
<div>---from an FPGA side of the SDR, what data rate(s) can the
FPGA absorb in to a decimator? </div>
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<div>Must we decide upfront on a single frequency; or </div>
<div>preferably allow flexibility in the RF front end design
(ie, Mixer, PLL and Local Oscl hardware choices) by allowing a
wide and programmable variety of ADC and decimation rates?</div>
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<div>{This is where RF and Digital folks must communicate across
walls.} ;-)</div>
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<div>Comments welcome.</div>
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<div>regards,</div>
<div>David</div>
<div>KI6CLA</div>
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<div> On Friday, January 25, 2019, 2:41:54 PM PST, Michelle
Thompson via Ground-Station
<a shape="rect" class="ydpbae0ddeayiv0484140599moz-txt-link-rfc2396E" href="mailto:ground-station@lists.openresearch.institute" rel="nofollow" target="_blank"><ground-station@lists.openresearch.institute></a> wrote: </div>
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<div dir="ltr">While we are striving to enable all sorts
of wonderful designs by putting prototypes into GNU
Radio, a central goal is to design our own hardware.<br clear="none">
<br clear="none">
We've had a lot of progress on the protocol and
algorithm front (GSE, LDPC, some of the polyphase). <br clear="none">
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Some fundamental decisions about our own hardware need
to be made.<br clear="none">
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When we receive, we expect to have to decimate. This
is because we are receiving at a relatively high
frequency (10GHz).<br clear="none">
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Our bandwidth is (up to) 10MHz. For DVB-S2/X, we fix
our sampling rate, depending on what bandwidth we want
to support. We have a lot of freedom here.<br clear="none">
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Picking the right frequencies for the receive chain is
therefore important.<br clear="none">
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What are our options? <br clear="none">
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What options make the best sense?<br clear="none">
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I'd like to build and test as soon as possible, so
let's get some discussion going.<br clear="none">
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<div dir="ltr">-Michelle W5NYV<br clear="none">
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