[TangerineSDR] [HamSCI] Re: HamSCI Telecon this Week

Fri Jul 24 09:40:35 EDT 2020

Hi Bob,

  As Tom K3IO knows, of course, this technique is a staple of radio
astronomy applications for decades now.  For a while, it was driven by the
fact that ADCs (Sigma/Delta, whatever architecture) were not that linear at
low bit counts but were much better at high bit counts.  So you traded a
bit less bandwidth (that occupied by the out-of-information-band tone) for
much better quantization / Van Vleck noise.  It could be useful as you say
here.

73
Phil W1PJE

On Fri, Jul 24, 2020 at 9:38 AM McGwier, Bob <rwmcgwi at vt.edu> wrote:

> Sorry, I forgot this.  The trick I was taught early on by Tom Clark, K3IO
> and now used in Kerberos SDR is the introduction of wideband noise at a low
> level into the front end.  This noise allows one to maintain some level of
> phase synchrony and certain more than enough, IMO, for HF measurements.
> In fact, Tom convinced me that in many cases you can allow the noise to
> ride along with the signal and it makes very little difference to the
> measurements of the signal.
>
>
>
> Tom introduced a pulse train which produced a comb of coherent tones.  But
> a noise generator based on some simple circuit like that sold by Elecraft
> and spread by a “corporate feed in reverse” to near the connectors on your
> multiple channel radio.
>
>
>
> Bob
>
>
>
>
>
> *From: *"McGwier, Bob" <rwmcgwi at vt.edu>
> *Date: *Friday, July 24, 2020 at 8:28 AM
> *To: *"hamsci at googlegroups.com" <hamsci at googlegroups.com>
> *Cc: *TAPR TangerineSDR Modular Software Defined Radio <
> tangerinesdr at lists.tapr.org>
> *Subject: *Re: [HamSCI] Re: HamSCI Telecon this Week
>
>
>
> Great talk.
>
>
>
> I disagree on NOT wanted a sky noise limited system, especially with the
> small antenna.  This will allow regular hams to put up < 10w EIRP systems
> that emit in the ham bands and see the ionospheric returns.  We know this
> because the fantastic work done by Dr. Greg Earle’s and my students around
> the eclipse led to a PhD and three Masters degrees.  Along with the
> Tangerine SDR,  and possibly other SDR instruments, this will lead to
> inexpensive major advance in deploying ionospheric mapping tools.
>
>
>
> You and I need to do some propagation work between McGwier Antenna Farm
> near Auburn and the stuff to be deployed at Kentland and your home or even
> the ham station or satellite station.
>
>
>
> Great talk Zach and this work might be submitted to TAPR for kitting and
> distribution.
>
>
>
> So glad you are working on your doctorate. I am very proud of you.
>
>
>
> Bob
>
> N4HY
>
>
>
>
>
> *From: *<hamsci at googlegroups.com> on behalf of "Leffke, Zachary" <
> zleffke at vt.edu>
> *Reply-To: *"hamsci at googlegroups.com" <hamsci at googlegroups.com>
> *Date: *Thursday, July 23, 2020 at 5:30 PM
> *To: *"hamsci at googlegroups.com" <hamsci at googlegroups.com>
> *Cc: *TAPR TangerineSDR Modular Software Defined Radio <
> tangerinesdr at lists.tapr.org>
> *Subject: *RE: [HamSCI] Re: HamSCI Telecon this Week
>
>
>
> I really like this idea (and the WSPR TX one that is underway).  One area
> of interest to me is the ‘data exfil’ problem if running a receiver.  Of
> course there is Iridium and their SMS services, used a lot for things like
> larger high altitude balloons, the MIST magnetometers at the south pole
> (and elsewhere) and tons of other Machine to Machine (M2M) applications…but
> the nerdy Ham in me wants an Amateur Radio solution.
>
>
>
> My knee jerk desire/thought is a ham radio smallsat (cubesat) for store
> and forward services.  Might be able to get higher data rates than the
> Iridium service, but obviously lose the coverage they offer, so net
> ‘throughput’ and delays/time lag would be an issue (waiting for the orbit
> to line up, first with the buoy for uplink, then with the command GS for
> downlink).  Also, getting such a system built and launched is no small task
> (probably obvious).  I mention all this as it might make for a fun mission
> analysis style project for interested AOE/ECE students (the O means ocean
> hihi, and the Aerospace students could work the orbits, with the ECEs
> working the comm analysis)……and as far as getting it built and launched,
> its not impossible for educational cubesats to get funding / CSLI slots
> (particularly if the store and forward payload is in addition to other
> science objectives/payloads).
>
>
>
> I wonder if QO-100 might be able to provide some type of capability on
> this front (Amateur GEO bird, roughly covering ITU Region 1, maybe a little
> of region 3).  Not sure of the footprint….its over the equator obviously,
> but not sure what the antenna pattern coverage is and if its focused more
> on land masses and how much ocean it covers (particularly in the southern
> hemisphere).  But it might cover a decent amount of the Indian Ocean and
> Eastern/Southern Atlantic.  Imagine a relay from ocean buoy to QO-100 to a
> station with the right equipment in ITU Region 1, to forward the collected
> data on to the ground network.  Building a 2.4 GHz transmitter for the
> uplink that works reliably in the ‘high seas’ sounds like a pretty tough
> challenge…..then there’s the regulator aspect for remote control of the TX
> per part 97 rules…..also, I’m probably not the first to think of
> this…especially if Phil, KA9Q is involved…..…but it might be feasible and a
> fun project (yet another reason to get a GEO bird over Region 2….and Region
> 3….).
>
>
>
> And while typing this, and letting my mind wander……now I have visions of
> buoy to cubesat to QO-100 to expand the coverage, both in ‘real time’ and
> as store and forward system…..that might actually be ‘easier’ in the sense
> that the buoy antenna wouldn’t need to be as stable if the link can be
> closed with omnis (perhaps at a different band than 2.4 GHz…..like a UHF or
> L-Band uplink to the cubesat and then the cubesat to AO-100 at 2.4 GHz,
> then QO-100 to Region 1 GS at 10 GHz.  All that assumes that the cubesat
> has good attitude control for pointing at QO-100….
>
>
>
> I’m probably thinking up solutions to problems that don’t exist……but hey
> experimenting is fun, and its after 6pm……(and its good fodder for student
> projects).
>
>
>
> -Zach, KJ4QLP
>
>
>
> P.S. Nathaniel, I’m about to send you the link to access the PDF for my
> talk for the HamSCI page (with typos/errors corrected).  Thanks again to
> all for the time/attention!
>
>
>
> --
>
> Research Associate
>
> Aerospace & Ocean Systems Lab
>
> Ted & Karyn Hume Center for National Security & Technology
>
> Virginia Polytechnic Institute & State University
>
> Work Phone: 540-231-4174
>
> Cell Phone: 540-808-6305
>
>
>
> *From:* hamsci at googlegroups.com <hamsci at googlegroups.com> *On Behalf Of *Ward
> Silver
> *Sent:* Thursday, July 23, 2020 5:45 PM
> *To:* hamsci <hamsci at googlegroups.com>
> *Cc:* TAPR TangerineSDR Modular Software Defined Radio <
> tangerinesdr at lists.tapr.org>
> *Subject:* Re: [HamSCI] Re: HamSCI Telecon this Week
>
>
>
> Hi folks,
>
>
>
> Turns out my understanding of the KA9Q-assisted floating platform was
> backwards - it's a WSPR transmitter, not a receiver.  (See
> http://www.arrl.org/news/high-school-marine-buoy-transmitter-now-active-on-20-meter-wspr)
> Phil and I talked about a floating receiver in passing and I got the two
> projects mixed up. At any rate, the WSPR buoy is a good thing.  Maybe a
> floating receiver is not so far-fetched.
>
>
>
> 73, Ward N0AX
>
>
>
> On Thu, Jul 23, 2020 at 4:22 PM Dr. Nathaniel A. Frissell Ph.D. <
> nathaniel.frissell at scranton.edu> wrote:
>
> Hi all,
>
>
>
> Great talks today from Ward N0AX and Zach KJ4QLP!
>
>
>
> Here is the Zoom recording:
> https://scranton.zoom.us/rec/share/z-FXc7X60DtOAaeSuW6HaoUdMcPaeaa8hHAX_qYEnh1Bgo3oMRuC9jPT-zsV_m3a
>
> 73 de Nathaniel W2NAF
>
>
>
> *From:* hamsci at googlegroups.com <hamsci at googlegroups.com> *On Behalf Of *Dr.
> Nathaniel A. Frissell Ph.D.
> *Sent:* Thursday, July 23, 2020 8:19 AM
> *To:* hamsci at googlegroups.com
> *Subject:* RE: [HamSCI] Re: HamSCI Telecon this Week
>
>
>
> Thanks, Ben! We look forward to seeing you!
>
>
>
> And this also serves as the friendly reminder to everyone that we are
> meeting today 1900z / 3 PM Eastern. Here is the zoom link:
> https://zoom.us/j/286316405
> <https://www.google.com/url?q=https://zoom.us/j/286316405&sa=D&usd=2&usg=AOvVaw2OnI5H71OLLdu2hNNXq6EO>
>
>
>
> 73 de Nathaniel
>
>
>
>
>
> *From:* hamsci at googlegroups.com <hamsci at googlegroups.com> *On Behalf Of *
> pa5bw.ben
> *Sent:* Thursday, July 23, 2020 8:14 AM
> *To:* HamSCI <hamsci at googlegroups.com>
> *Subject:* [HamSCI] Re: HamSCI Telecon this Week
>
>
>
> I'm very interested in both items, will be there!
>
> (But maybe only the first hour)
>
>
>
> Ben PE5B
>
>
>
> On Tuesday, 21 July 2020 04:07:09 UTC+2, Dr. Nathaniel A. Frissell Ph.D.
> wrote:
>
> Hi everyone,
>
> Please join us this Thursday, July 23nd at 1900z / 3 PM Eastern for our
> bi-weekly HamSCI telecon. This week we have two speakers:
>
>
>
> 1.      Ward Silver N0AX will be giving us an update on the new RBN
> receivers funded by the Yasme foundation.
>
> 2.      Zach Leffke KJ4QLP (Virginia Tech) will present on his crossed
> dipole active antenna design for HF (based on the LWA active balun design).
> He is hoping that his presentation of his RF measurements might help
> provide a strawman for the defining requirements for the PSWS project. Zach
> is also looking for ideas and constructive criticism.
>
>
>
> Have a good week and see you Thursday!
>
>
>
> 73 de Nathaniel W2NAF
>
> ----------------Nathaniel Frissell is inviting you to a scheduled Zoom
> meeting.
> Join Zoom Meeting
> https://zoom.us/j/286316405
> <https://www.google.com/url?q=https://zoom.us/j/286316405&sa=D&usd=2&usg=AOvVaw2OnI5H71OLLdu2hNNXq6EO>
>
> One tap mobile
> +19294362866,,286316405# US (New York)
> +16699006833,,286316405# US (San Jose)
>
> Dial by your location
>         +1 929 436 2866 US (New York)
>         +1 669 900 6833 US (San Jose)
> Meeting ID: 286 316 405
> Find your local number: https://zoom.us/u/atEc8ZDe2
> <https://www.google.com/url?q=https://zoom.us/u/atEc8ZDe2&sa=D&usd=2&usg=AOvVaw1dIz7MR9seRyl-_CEkv7AS>
>
>
>
> -----------------------------------------------
>
> Dr. Nathaniel A. Frissell, Ph.D., W2NAF
>
> HamSCI Lead
> Assistant Professor
> Department of Physics and Electrical Engineering
> University of Scranton
> (973) 787-4506
>
>
>
> --
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> --
> Please follow the HamSCI Community Participation Guidelines at
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>
> --
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>
> --
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>
>
> --
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-- 
----
Phil Erickson
phil.erickson at gmail.com
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