September 2022 - pacsat - mailman.amsat.org

Modulation options
by Corey Minyard 07 Oct '22

07 Oct '22

I looked a bit last night at the ax5043; I didn't realize (I should have remembered) that it doesn't just convert to baseband, it actually demodulates the signal. Are current designs just using that for FM demodulation and doing the AFSK modem in the TMS570? I don't see a way it could do both. It does appear to do GMSK. The only concern there is if it can support the polynomial used by G3RUH for randomization, I think. I'd be surprised if it didn't. But I don't have the programmer's guide. And it doesn't matter, I guess, if it can't do FM and GMSK at the same time. For AFSK, you can do a lot better than what a hardware decoder can do. See https://github.com/wb2osz/direwolf/blob/master/doc/A-Better-APRS-Packet-Dem… for details. direwolf can pull signals out of the noise in a way that a hardware decoder can't. The difference is significant. I've done some thing in my modem that can improve things even more. There is a similar situation for 9600: https://github.com/wb2osz/direwolf/blob/master/doc/A-Better-APRS-Packet-Dem… But that's only the receive side, since this would only be transmitting it doesn't matter. You could probably do the AFSK demodulation on a TMS570. Modulation of 9600 can probably be table driven, so that should be doable. Note that there are far better modulation techniques than these. Almost anything being done now is using OFDM of some type. VARA is taking over in the packet world. All modern modulation for cell phones is OFDM. I think digital TV is, too. OFDM is certainly better for fading and multipath and since it's using low-baud subcarriers I'd guess it's better for doppler, too, but that's just a guess. It would affect the orthogonality (?) of the subcarriers though. Not sure. You probably couldn't do OFDM on the TMS570. Certainly not 4 channels. You would probably need one of the TI chips that has a separate DSP. On the ground side, anyone with a sound card modem and a reasonably modern PC could handle it. It would provide better performance, I'd guess singificantly better, than using AFSK and G3RUH. (It would be even better if you could get rid of putting it inside an FM carrier and directly modulate, but that's probably not a practical option.) Also, on the satellite, if you converted to I and Q directly from RF, and you had a DSP or a fast enough processor, you could get rid of the AX5043s and do the FM and modem in the DSP. I remember seeing single chips that could do this, but I would have to hunt to find them. Anyway, since we are just getting started, I wanted to point out that options are available that are better from a pure technical point of view than what is currently being proposed. I know there are other concerns like the availability of current working circuits, power budget, timeframe, etc. -corey - AE5KM

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TMS570 eval kits (Launchpad)
by Burns Fisher (AMSAT) 27 Sep '22

27 Sep '22

To help figure out what eval board to get here is some info: First, the processor on the RT-IHU is a TMS570LS0914 The info about the Launchpad that I used to initially develop Golf software is here (thanks to Hemeir to whom I gave it): The processor model in the dev kit is TMS570LS1224CPGE001. The dev kit's part number is: LAUNCHXL2-TMS57012 ------------------------------------ To be honest, I have not really discovered a table showing the differences among the TMS570 versions. All I know is that this one was adequate. Which one do you have Rich? 73, Burns Fisher, WB1FJ *AMSAT(R) Engineering -- Flight Software*

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Fwd: TMS570 eval kits (Launchpad)
by JIm McCullers 27 Sep '22

27 Sep '22

DigiKey has no evaluation kits in stock. Mouser has 17 of the LAUNCHXL2570LC43 (R5F) kits in stock. They expect 95 of the LAUNXL2-TMS57012 (R4F) kits to be available 11/28/2022. Jim WA4CWI more info... the LC is an R5F and the LS is an R4F. https://training.ti.com/hercules-arm-cortex-r-processor-r4-compared-r5 Should we stick with the LS launchpad? Bill

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Serial line for program loader
by Burns Fisher (AMSAT) 26 Sep '22

26 Sep '22

Hi Heimir, It has been so long since I did anything with serial ports on the TMS570 that I totally forgot something important. I'm putting this on the software list too to help anyone else remember what is going on, and especially Zach. Also on the pacsat list mainly because of the info about the HET, which some pacsat people may need (my condolences). Pacsat folks, Heimir has written a code loader that loads over the serial port via the satellite umbilical so we can update code after the satellite is assembled. First you need to know that the TMS570 has a gadget called the HET (High End Timer). This is a programmable peripheral that has a fairly high-speed and accurate clock. The "programmable" part is really microcode in the old computer sense. It uses an "assembly language" to do low level things like wait for a clock tick, raise this pin, and branch to one of 3 or so different places depending (and do something else too by the way). I am pretty good at assembly language in several computers, and this is really horrible. TI gives you a special "HET IDE" to write programs in it but I mainly found example programs and modified them slightly. Here is an example of what it looks like: SCITX CNT { next= Lm10, reg = T, max= 64, irq = OFF,data=0} ;****Baud rate writes to max value here! Lm10 BR { next= SCIRX, cond_addr= Lm11, event = ZERO} ;Every BAUD_DIVIDER + 1 LRP, send out one bit ;DJZ checks if any active bits needs to send out Lm11 DJZ { next=SendOverINT,cond_addr=SCIRX,reg=A,irq=OFF,data=0};***set to number of bit to transfer ;CNT is used to generate the interrupt when sending is done SendOverINT CNT { reg=A,irq=ON,max=9,data=0}; ;SHFT out the data to the TX1_PIN Lm12 SHFT { next=SCIRX,smode=OR0,prv=OFF,cond_addr=SCIRX,cond=UNC,pin=TX1_PIN,reg=A,irq=OFF,data=0x0}; **Data goes here Next, the TMS570 has two serial port hardware devices called SCI and SCILIN (LIN has some fancier capabilities that I don't right now remember). However, we needed three serial ports: 1) The console line and code loader. 2) Talk to the SDR (Ettus E310) 3) Talk to the ADAC What I did was assign the 2 and 3 to the SCI and SCILIN, and the console to one of the two HETs. Yes, that HET has firmware to make it emulate a serial port. (The other HET has firmware to emulate an I2c master peripheral because the TMS570 has only one hardware I2c peripheral). So here is the critical thing, Heimir: We either will need to include the HET firmware as part of the flash loader or else use one of the hardware serial lines for the console. And if we do that, it will mean changes to the V2 RT-IHU (the pins for the two hardware serial ports currently go through a bus switch, while the console for each processor has its own set of bus lines). I don't know where you are now, but I'd suggest you get it working with one of the hardware serial lines--probably just what you did with the LaunchPad--and we can decide how we are going to do this a bit later (but before Zach finishes the layout for RTIHU V2). Just remember that when you are using the hardware serial lines, they go through the bus switch and only connect to one of the processors at a time. Sorry to throw this in...I had totally forgotten, as I said before. 73, Burns Fisher, WB1FJ *AMSAT(R) Engineering -- Flight Software*

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GNURadio conference live stream
by Rich Gopstein 26 Sep '22

26 Sep '22

If anyone is interested, you can watch the live stream of the GNU Radio conference on youtube. They request free registration, but it's not required. https://www.youtube.com/watch?v=1jJWfsGeZvE

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Fwd: [FOXTELEM] 3rd Quarter FalconSAT-3 Chicken Little report
by Burns Fisher (AMSAT) 25 Sep '22

25 Sep '22

Looks like March or April is the current predicted demise of Falconsat. 73, Burns Fisher, WB1FJ *AMSAT(R) Engineering -- Flight Software* ---------- Forwarded message --------- From: Alan <wa4sca(a)gmail.com> Date: Sun, Sep 25, 2022 at 5:12 PM Subject: [FOXTELEM] 3rd Quarter FalconSAT-3 Chicken Little report To: Fox Telemetry Analysis <foxtelem(a)amsatfox.org> As of today, 25 September 2022, this is the current predicted lifetime from the NASA DAS program: The calculated reentry date continues to move somewhat earlier, with the current expectation in early April 2023. 73, Alan ----------------------------------- The prospect of domination of the nation’s scholars by Federal employment, project allocations, and the power of money is ever present — and is gravely to be regarded. President Dwight D. Eisenhower ----------------------------------------------- FOXTELEM mailing list -- foxtelem(a)amsatfox.org View archives of this mailing list at https://mailman.amsat.org/hyperkitty/list/foxtelem@amsatfox.org To unsubscribe send an email to foxtelem-leave(a)amsatfox.org Manage all of your AMSAT-NA mailing list preferences at https://mailman.amsat.org

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CAUTION Pacsat and Gmail Spam
by Burns Fisher (AMSAT) 24 Sep '22

24 Sep '22

If you are using gmail, check your spam folder to see if there are any pacsat messages there. I found that there were several in mine. I've added a filter to ensure that they are not put in spam. (Hopefully this is one of the lucky messages that gets through!) 73, Burns Fisher, WB1FJ *AMSAT(R) Engineering -- Flight Software*

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Re: Falconsat-3
by Burns Fisher (AMSAT) 24 Sep '22

24 Sep '22

Thanks, Bob. I have seen Mark saying he was turning on FalconSat, but it may have been on the bulletin board and not twitter. I'm not sure I saw anything from Corey about modulation. Was it a private message? 73, Burns Fisher, WB1FJ *AMSAT(R) Engineering -- Flight Software* On Sat, Sep 24, 2022 at 2:22 PM Bob Stricklin via pacsat <pacsat(a)amsat.org> wrote: > > > > ---------- Forwarded message ---------- > From: Bob Stricklin <bstrick(a)n5brg.com> > To: James McCullers <wa4cwi(a)bellsouth.net> > Cc: "pacsat(a)amsat.org" <pacsat(a)amsat.org> > Bcc: > Date: Sat, 24 Sep 2022 18:21:54 +0000 > Subject: [pacsat] Re: Falconsat-3 > > I sent emails to some of the folks watching for Falconsat-3 and got this > nice feedback from Christy Hunter which is interesting to our efforts; > > > hi Bob, Falconsat-3 is on its final life. Probably will decay in the next > couple of months. its fuel storage has been spent and so aiming is not > working such that its batteries run low. Mark, N8MH is the control > operator and tries to turn it on and posts that action on the AMSAT twitter > page. but I see he last did this on the Sept 22. he sometimes lets it stay > off so that the batteries can charge. > also need to update keps often on this sat, I use celstrak.org. since its > orbit is decaying. > it uses the 9600bd packet and was fun while it was active. but not sure > when or if it will be active again. > too bad, I hope someone comes up with another one. > 73 Christy KB6LTY > > I just looked at twitter and don’t see anything from Mark. > > Corey’s comments were good on modulation. We may need to think more about > data rates and modulation. Reading some of the old posting reminds me about > the difficulties of getting much data through the earlier > Satellites. In the early days everything was done on bulletin boards even > AMSAT development. That is until some of us got on the DARPA mail feed. We > were also working with VITA and there really was a goal of feeding > information to remote areas in Africa. At 1220 baud we were not going to > move much information but it was a big step forward at the time. People may > expect more today. > > Bob > > > > > On Sep 24, 2022, at 8:51 AM, James McCullers <wa4cwi(a)bellsouth.net> wrote: > > According to Mark L. Hammond (N8MH) by the way of Rich, Falconsat-3 has to > be switched on for use and that last only a short period of time which > would explain the lack of reports and interest. > I believe someone said it only had a few months to live. > Hopefully Bill and I can get set up for packet and make a contact or two > before dies. > Hands on experience would be beneficial. > > I’ve been studying the Pacsat links of AC2CZ’s site as well as his ground > station code. > You are correct. Some of the terminology and assumptions reflect a bygone > era. > > While cleaning out a storage closet a year or so ago I threw away an > original 8 inch IBM floppy from about 1975. > It truly flopped! > > Jim McCullers > WA4CWI > > > > All, > > Here is an interesting Pacat link maintained by Chris Thompson AC2CZ. You > will see copies of some of the original papers by Harold Price and Jeff > Ward and others. It's a trip back though history. > Harold mentions the IBM PC and I can remember I had a S100 system at this > time with 8 inch floppies. > > https://g0kla.com/pacsat/ > > Looking at the AMSAT activity tracker I see Falconsat-3 has no heard > reports in a while and a few people are looking. > > > Bob N5BRG > ----------------------------------------------- > pacsat mailing list -- pacsat(a)amsat.org > View archives of this mailing list at > https://mailman.amsat.org/hyperkitty/list/pacsat@amsat.org > To unsubscribe send an email to pacsat-leave(a)amsat.org > Manage all of your AMSAT-NA mailing list preferences at > https://mailman.amsat.org > > > > > > ---------- Forwarded message ---------- > From: Bob Stricklin via pacsat <pacsat(a)amsat.org> > To: James McCullers <wa4cwi(a)bellsouth.net> > Cc: "pacsat(a)amsat.org" <pacsat(a)amsat.org> > Bcc: > Date: Sat, 24 Sep 2022 18:21:54 +0000 > Subject: [pacsat] Re: Falconsat-3 > ----------------------------------------------- > pacsat mailing list -- pacsat(a)amsat.org > View archives of this mailing list at > https://mailman.amsat.org/hyperkitty/list/pacsat@amsat.org > To unsubscribe send an email to pacsat-leave(a)amsat.org > Manage all of your AMSAT-NA mailing list preferences at > https://mailman.amsat.org >

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Falconsat-3
by James McCullers 24 Sep '22

24 Sep '22

According to Mark L. Hammond (N8MH) by the way of Rich, Falconsat-3 has to be switched on for use and that last only a short period of time which would explain the lack of reports and interest. I believe someone said it only had a few months to live. Hopefully Bill and I can get set up for packet and make a contact or two before dies. Hands on experience would be beneficial. I've been studying the Pacsat links of AC2CZ's site as well as his ground station code. You are correct. Some of the terminology and assumptions reflect a bygone era. While cleaning out a storage closet a year or so ago I threw away an original 8 inch IBM floppy from about 1975. It truly flopped! Jim McCullers WA4CWI All, Here is an interesting Pacat link maintained by Chris Thompson AC2CZ. You will see copies of some of the original papers by Harold Price and Jeff Ward and others. It's a trip back though history. Harold mentions the IBM PC and I can remember I had a S100 system at this time with 8 inch floppies. https://g0kla.com/pacsat/ Looking at the AMSAT activity tracker I see Falconsat-3 has no heard reports in a while and a few people are looking. Bob N5BRG

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Pacsat Link
by Bob Stricklin 24 Sep '22

24 Sep '22

All, Here is an interesting Pacat link maintained by Chris Thompson AC2CZ. You will see copies of some of the original papers by Harold Price and Jeff Ward and others. It's a trip back though history. Harold mentions the IBM PC and I can remember I had a S100 system at this time with 8 inch floppies. https://g0kla.com/pacsat/ Looking at the AMSAT activity tracker I see Falconsat-3 has no heard reports in a while and a few people are looking. Bob N5BRG

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