<div dir="ltr"><div>Hi Michelle, <br></div><div><br></div><div>I would be super interested in being involved with this.</div><div><br></div><div>I think it's fairly straightforward to do this off the shelf:</div><div><br></div><div>USRP -> Low Power Filter -> Amplifier -> High Power Filter -> Antenna<br></div><div><br></div><div>Low Power Filter: <a href="https://www.minicircuits.com/WebStore/dashboard.html?model=VLF-5500%2B">https://www.minicircuits.com/WebStore/dashboard.html?model=VLF-5500%2B</a></div><div>Amplifier: <a href="https://www.minicircuits.com/WebStore/dashboard.html?model=ZHL-100W-63%2B">https://www.minicircuits.com/WebStore/dashboard.html?model=ZHL-100W-63%2B</a></div><div>High Power Filter: TBC<br></div><div><br></div><div>However, where's the fun in that? It would be much more interesting to design it ourselves. What is the Skyworks part you have been evaluating?</div><div><br></div><div>Also, would you be able to provide a link to the
Gateway (LOP-G) architecture and requirements please?<br></div><div><br></div><div>Cheers,</div><div>Thomas<br></div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Tue, Nov 5, 2019 at 6:02 PM <ground-station-request@lists.openresearch.institute> 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">Send Ground-Station mailing list submissions to<br>
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Today's Topics:<br>
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1. LDPC VHDL decoder review progress - need solid 5GHz RF<br>
prototype by late summer 2020 (Michelle Thompson)<br>
<br>
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----------------------------------------------------------------------<br>
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Message: 1<br>
Date: Tue, 5 Nov 2019 08:06:14 -0800<br>
From: Michelle Thompson <<a href="mailto:mountain.michelle@gmail.com" target="_blank">mountain.michelle@gmail.com</a>><br>
To: Michelle Thompson via Ground-Station<br>
<ground-station@lists.openresearch.institute><br>
Subject: [Ground-station] LDPC VHDL decoder review progress - need<br>
solid 5GHz RF prototype by late summer 2020<br>
Message-ID:<br>
<CACvjz2Ui=dBAhMHM1x=<a href="mailto:5w-0HRXCw%2B4x2f76bvL8qfmqAC%2B4PJA@mail.gmail.com" target="_blank">5w-0HRXCw+4x2f76bvL8qfmqAC+4PJA@mail.gmail.com</a>><br>
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<br>
-=-=-=-=-=-=-=-= LDPC VHDL =-=-=-=-=-=-=-=-=-=-<br>
<br>
The LDPC VHDL decoder code review and video report is progressing fast.<br>
Draft video report shared on Slack. Codebase on github is here:<br>
<a href="https://github.com/aicodix/cnp" rel="noreferrer" target="_blank">https://github.com/aicodix/cnp</a><br>
<br>
Huge thanks to Ahmet for the codebase and the explanations. Current focus<br>
of Ahmet's work is the check node processor. Decoder organically growing<br>
out from there!<br>
<br>
-=-=-=-=-=-=-=-= 5GHz RF =-=-=-=-=-=-=-=-=-=-<br>
<br>
After three or so attempts to get a good prototype 5GHz transmit chain, we<br>
don't have one today. Skywave parts looked promising last year and we got<br>
some results in the lab.<br>
<br>
We need something that hooks up to something like the USRP x310 or<br>
equivalent, and provides enough power to close the link up to GEO.<br>
<br>
How much power is that? As much as we can get away with. Our link budgets<br>
have numbers up to 10W on 5GHz.<br>
<br>
Uplink signal is FDMA 4-ary minimum shift keying (modulation selected to<br>
keep the RFs happy).<br>
<br>
Forward error correction can obviously help. Re-using the work that we have<br>
going on for the receiver (BCH and LDPC) makes the most sense.<br>
<br>
Looking at the architecture and requirements for Gateway (LOP-G) LDPC<br>
occurs over and over again. I'm in favor of selecting something that is<br>
already specified in CCSDS/Gateway docs.<br>
<br>
So, bottom line - we need a solid open-source RF transmit design by late<br>
summer 2020.<br>
<br>
We have *plenty* of funding to buy parts and PCBs. We need a solid design.<br>
If you can help then step up and let's get this identified, designed,<br>
documented, built, tested, and ordered.<br>
<br>
We have 10MHz of uplink bandwidth to cover. We have channelization with 96<br>
channels as the baseline 2020 demonstration. This is about 100kHz per<br>
uplink channel.<br>
<br>
Is there something off the shelf that can work? Is this something a student<br>
can use for credit?<br>
<br>
-Michelle W5NYV<br>
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</blockquote></div>