I have to question the use of LoRa on amateur satellite bands. LoRa is a closed, patented, proprietary mode. SDR implementations of it (if they work...) are legally dubious, leaving us to have to use Semtech hardware to receive. Why are we allowing this? I thought amateur radio was meant to be open and free for all to experiment, modify, and learn?

As for TinyGS, they openly support satellites which were *denied* coordination by the IARU, and still use the amateur radio bands anyway. At least SatNOGS makes it quite clear on the satellite page that the sats in question are band intruders, and that we are only monitoring them for space situational awareness purposes...

73 Mark VK5QI

On Wed, Apr 20, 2022 at 5:01 PM nick quadpugh@bellsouth.net wrote:

Hi Pet

The satellite team ant the University of Louisiana is using the RFM96 on its satellite and balloon. What is your group using

nick

Cell 337 258 2527

*Helping UL become a world Class Engineering and Educational School*

*Disagree I Learn*

*From:* vk2pet@internode.on.net vk2pet@internode.on.net *Sent:* Tuesday, April 19, 2022 11:54 PM *To:* 'AMSAT BB' amsat-bb@amsat.org *Subject:* [AMSAT-BB] Tiny GS

Hi All,

Is anyone running Tiny GS ground stations? What hardware & gateways are you using?

Also interested if any used LoRa in weather balloon, again what type of hardware used?

Cheers

Pete

Vk2pet

http://www.avg.com/email-signature?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=emailclient Virus-free. www.avg.com http://www.avg.com/email-signature?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=emailclient <#m_7283341374536914516_DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2>

---

Sent via AMSAT-BB(a)amsat.org. AMSAT-NA makes this open forum available to all interested persons worldwide without requiring membership. Opinions expressed are solely those of the author, and do not reflect the official views of AMSAT-NA. Acceptable Use and Privacy Policies available at https://www.amsat.org/about-amsat/

View archives of this mailing list at https://mailman.amsat.org/hyperkitty/list/amsat-bb@amsat.org To unsubscribe send an email to amsat-bb-leave(a)amsat.org Manage all of your AMSAT-NA mailing list preferences at https://mailman.amsat.org

Can I point at a single-chip device that can do that? Not off the top of my head, no. You'll note that amateur radio operators don't generally have access to silicon foundries, so making this kind of thing is a bit difficult.

However, you are in the right place to ask the question - perhaps the engineers of the Fox-series of sats, or Funcube could comment on their uplink systems. With modulations like BPSK and decent FEC, extremely good performance is definitely possible, but no - we can't make you a single chip to do it. Sorry about that.

As for the specs you quoted, I'd be seriously testing that out on a bench before you trust what is said in the datasheet. Factors like frequency offset (due to doppler shift, or crystal drift) are also going to come into play here. You'll note that the other users of LoRa on sats are running at very wide bandwidths (125 kHz... for maybe a few hundred bit/s throughput... what an efficient use of spectrum!), so I'd be asking why that is the case.

73 Mark VK5QI

On Wed, Apr 20, 2022 at 6:29 PM nick quadpugh@bellsouth.net wrote:

Good morning/afternoon Mark

Good questions. The main reason for choosing LoRa. The main reason for choosing LoRa is its receiver sensitivity which is -148 DBM. This let us a use a $6 device on a LEO satellite close the link with an omni gain antenna on the ground. This can be done in a 10 KHZ channel. I also believe this can be used in part 97 of the FCC rules. It might require a rule waver but I believe it is doable.

The negative is as you point out is it is proprietary however there are 10 of million of the devices in operation globally.

In summary given it sensitivity and low cost it is a good choice.

Can you suggest a better choice ?

nick

Cell 337 258 2527

*Helping UL become a world Class Engineering and Educational School*

*Disagree I Learn*

http://www.avg.com/email-signature?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=emailclient Virus-free. www.avg.com http://www.avg.com/email-signature?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=emailclient <#m_-185372798167113450_DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2>

Hello all,

Apart from all the technological interesting questions, that is something I really enjoy investigating, we seem to miss the point about the fact that it is closed and are violating IARU regulations.

So to the vendors and mission teams share all the data and adhere to regulations, then I will be happy to support this, otherwise move to an other frequency range.

On 20-04-2022 12:22, nick wrote:

Hello again Mark

Good questions. We have tested the sensitivity specs and the frequency offset is very tight . Plus, or minors a few HZ and as best as best we can measure the -148 DBMM is correct. We have a method to achieve to get the frequency offset in specs but it is untested.

We have flow an AX5043 device that has uses FSK with FEC it is about 10DB short of the LoRa. In the lab we could not get to the published sensitivity of -138 DBM and is very sensitive to frequency offset. The manufacture ON Semiconductors has not been very helpful unless we commit to buy thousands of devices per month. It also requires us to fabricate a filter and baleen that requires ~ 10 capacitors and inductors external to the device. On the positive side it is easily to make this device operate on the standard analog FM mode.

nick

All the best,

Jan PE0SAT

With regards PE0SAT Internet web-page https://www.pe0sat.nl/ irc://chat.freenode.net #Cubesat - Twitter @pe0sat SatNOGS: https://network.satnogs.org/users/PE0SAT/ LSF Core Contributor: https://libre.space/about-us/ DK3WN SatBlog https://www.satblog.info/

Thanks for the feedback do you have any part numbers of those parts?

nick

Cell      337 258 2527   Helping UL become a world Class Engineering  and Educational School Disagree I Learn

-----Original Message----- From: Zach Metzinger zmetzing@pobox.com Sent: Wednesday, April 20, 2022 9:33 AM To: amsat-bb@amsat.org Subject: [AMSAT-BB] Re: Tiny GS

On 4/20/22 05:22, nick wrote:

It also requires us to fabricate a filter and baleen that requires ~ 10 capacitors and inductors external to the device.

Hello Nick,

Please note that the discrete filter/balun topology is recommended by the manufacturer for cost reasons. A transformer-style balun and single-chip low-pass filter would reduce the external component count to just two or three components.

If you're building 10, an extra $2 per device is no big deal. If you're building 1 million, then it matters.

--- Zach N0ZGO

-----------------------------------------------------------

Sent via AMSAT-BB(a)amsat.org. AMSAT-NA makes this open forum available to all interested persons worldwide without requiring membership. Opinions expressed are solely those of the author, and do not reflect the official views of AMSAT-NA. Acceptable Use and Privacy Policies available at https://www.amsat.org/about-amsat/

View archives of this mailing list at https://mailman.amsat.org/hyperkitty/list/amsat-bb@amsat.org To unsubscribe send an email to amsat-bb-leave(a)amsat.org Manage all of your AMSAT-NA mailing list preferences at https://mailman.amsat.org

I would like to add about AX5043 that we have an open hardware COMMS implementation of it published here: https://gitlab.com/librespacefoundation/pq9ish/pq9ish-comms-vu-hw/

~pierros

On Wed, Apr 20, 2022 at 6:35 PM Zach Metzinger zmetzing@pobox.com wrote:

On 4/20/22 10:09, nick wrote:

...

Thanks for the feedback do you have any part numbers of those parts?

Hello Nick,

KF5IDY did some simulation to determine the differential output impedance of the AX5043, given the matching network shown the datasheet. His results are here:

...

Assuming the network is optimized for the frequency specified in the data sheet, the unbalanced impedance that yields minimum loss ranges from 62 Ohms to 149 Ohms, with the middle two entries at 100 Ohms. So, I'm going to assume the IC impedance for the unbalanced pins is 100 Ohms.

He may be persuaded to share his Qucs simulation file with you.

It looks like a straight 1:1 diff-to-unbalanced solution would work. I might look into these parts:

Mini-Circuits NCS1-521+ Johanson Technology 0430BL15A0100 STMicroelectronics BALF-112X-02D3 ( integrated harmonic filter, more research needed to see if it is a reasonable match to the AX5043 output impedance )

The nice thing about the AX5043, versus the little brother part AX5243, is the separate TX and RX paths. One can use the single-ended path with the proper harmonic filter (which has loss) for TX and then use the differential path with a simple balun for RX so that the LPF loss is avoided. The chip has an internal antenna switch for this purpose.

Note that, for full-duplex operation, two ICs will be required. They're cheap, so no problem there. This is what is being done for the GOLF program's RT-IHU design.

--- Zach N0ZGO

---

Sent via AMSAT-BB(a)amsat.org. AMSAT-NA makes this open forum available to all interested persons worldwide without requiring membership. Opinions expressed are solely those of the author, and do not reflect the official views of AMSAT-NA. Acceptable Use and Privacy Policies available at https://www.amsat.org/about-amsat/

View archives of this mailing list at https://mailman.amsat.org/hyperkitty/list/amsat-bb@amsat.org To unsubscribe send an email to amsat-bb-leave(a)amsat.org Manage all of your AMSAT-NA mailing list preferences at https://mailman.amsat.org

Hello, pardon my lengthy article here, I don’t engage regularly. The discussion of use of proprietary, closed comm systems in ham bands, struck a chord, since I am aware of the great efforts by Open Research Institute (US) to bring M17 comm systems for broadband service in the amateur-satellite arena. This is exemplary compared to paying $$$$ for commercial products, or to help commercial companies get footholds into future markets. I question – whether ICOM/Yaesu/others – if the amateur-satellite community gets any benefit from them to use their software/hardware products, such as radios/etc., that may be donated (the company gets a tax credit) or purchased (so they are being paid for this stuff)? I’m from the years of DIY ham radio !

Anyway, I published around 2011-2012 technical articles about multi-hop interplanetary relay communications. I studied Ka-band service based upon the published specs of the Mars Rec. Orbiter, which was then already on-mission. My target data rate was 1 Gbps full du-lex, persistent, across planetary orbit geometries whether from a ground station or from a orbiter or in between, including flyers. Then I discovered CubeSats, and made designed, developed and delivered a propulsion system for CubeSats (BRICSAT-P, CANYVAL-X missions).

But I was surprised that communications systems for small satellites were (in my opinion) relegated to an after-thought – even though, in the commercial VSAT industry small form IDU/ODU/SSPA/HPA and compact stowable antennas have been around for quite a while, and they are becoming smaller and smaller! So we could also use the parts – as we like.

I was also impressed with my late mentor Bob Bruninga’s PSAT / APRS comm relay experiments and experience, and the simplicity of what he showed, that it can be done – ground to space to space to ground relay ! which I studied ..

I do see very expensive hardware being offered for sale on various websites for “high bit-rate” communications – that do require a matching ground station and coverage. In a past technical analysis for university near El Paso, TX, I calculated that the slew rate of the antenna for the projected high eccentricity orbit of a satellite would have literally torn the bearings off the king post for a parabolic dish. So electrical steering would be better of in that case, but then it doesn’t solve all of the problems. All for a few kilobits of power constrained communication from beyond the radiation belt.

** Would there be a community interest in having a forum-style panel discussion on better/modern/practical high bit-rate, deep space comms architecture for ham purposes – global in scope, not only US – that the community could propose for developers to test/study/learn and adopt?

** Perhaps even a virtual AMSAT-sponsored technical forum inviting open-practitioners? Perhaps even considering innovation in multi-hop relay comms architectures, better coding mechanisms (open-source, open-licensed but allowing commercial levels of support for the developers if they provide continuing maintenance for long duration) and better prototype reference designs (again, allowing commercial levels of support for the design maintenance)?

I say the “commercial levels of support” because there are plenty of software / hardware projects that have been abandoned due to lack of proper support after they have been released, or as the developer has moved on/passed away – e.g., EZNEC style programs, many shareware products, many prototype software products, many schematics that have never been able to be updated after the technology was obsoleted. And oh by the way:

(my thoughts) How many times do we have to reinvent the wheel? Students have four years in undergraduate, 1.5 years in MS programs, and by the time they attempt a Ph.D., they are industry/academia bound and we can’t rely upon their interest/support to maintain healthy R&D activity in the amateur-satellite field – they join industry and we end up with having to explain to managers at various companies, “Have you heard of AMSAT, those people who design satellites .. ?”

And lastly I would like to volunteer to help in the architecture definition of a multi-hop amateur=satellite radio/optical network for long duration missions and innovation in space.

73 de Samuda N3RDX

From: David G0MRF via AMSAT-BB amsat-bb@amsat.org Sent: Saturday, April 23, 2022 8:50 AM To: vk5qi@rfhead.net; quadpugh@bellsouth.net Cc: vk2pet@internode.on.net; amsat-bb@amsat.org Subject: [AMSAT-BB] Re: Tiny GS

HI Mark.

Only just spotted this. The 4 Funcube satellites have not used FEC or fast data rates on their command uplink. We only need to send fairly simple commands or the odd 256 character text message for educational outreach etc. Also, the ground stations can run as much power as we like.....So no problems with the uplinks.

The downlink is a completely different story. All the satellites (UKube-1 now QRT) use a modified version of Phil Karns error correcting code originally developed for AO-40. As Phil has told us, this is not an ideal solution, but it does work very well and it is documented. The satellites transmit telemetry continuously. We wanted to get away from the troublesome short burst of data every few minutes that can be difficult to track. Instead The satellites use BPSK generated in a passive mixer....A mini Circuits RMS-1 from memory. 400mW can be received with a simple turnstyle, the low power 50mW or even 30mW can be received without problem using a typical LEO pack type antenna. Bit rate is 1200bps. Telemetry is generated in and 'old' 8 bit processor. TX band is 2m which helps with the path loss.

If you watched any of the AMSAT-UK colloquium presentations last October, you may have seen that a couple of very capable students from Surrey University have produced a modern version using a low power STM32 processor. They managed to increase the bit rate upto 100kb/s and incorporate the whole thing into a real time operating system.

All we need now is some time on 'Funcube Next' and we may be able to get it into space.

73

David G0MRF However, you are in the right place to ask the question - perhaps the engineers of the Fox-series of sats, or Funcube could comment on their uplink systems. With modulations like BPSK and decent FEC, extremely good performance is definitely possible, but no - we can't make you a single chip to do it. Sorry about that.

-----Original Message----- From: Mark Jessop <vk5qi@rfhead.netmailto:vk5qi@rfhead.net> To: nick <quadpugh@bellsouth.netmailto:quadpugh@bellsouth.net> CC: Pete (vk2pet) <vk2pet@internode.on.netmailto:vk2pet@internode.on.net>; AMSAT BB <amsat-bb@amsat.orgmailto:amsat-bb@amsat.org> Sent: Wed, 20 Apr 2022 9:52 Subject: [AMSAT-BB] Re: Tiny GS Can I point at a single-chip device that can do that? Not off the top of my head, no. You'll note that amateur radio operators don't generally have access to silicon foundries, so making this kind of thing is a bit difficult.

However, you are in the right place to ask the question - perhaps the engineers of the Fox-series of sats, or Funcube could comment on their uplink systems. With modulations like BPSK and decent FEC, extremely good performance is definitely possible, but no - we can't make you a single chip to do it. Sorry about that.

As for the specs you quoted, I'd be seriously testing that out on a bench before you trust what is said in the datasheet. Factors like frequency offset (due to doppler shift, or crystal drift) are also going to come into play here. You'll note that the other users of LoRa on sats are running at very wide bandwidths (125 kHz... for maybe a few hundred bit/s throughput... what an efficient use of spectrum!), so I'd be asking why that is the case.

73 Mark VK5QI

On Wed, Apr 20, 2022 at 6:29 PM nick <quadpugh@bellsouth.netmailto:quadpugh@bellsouth.net> wrote: Good morning/afternoon Mark

Good questions. The main reason for choosing LoRa. The main reason for choosing LoRa is its receiver sensitivity which is -148 DBM. This let us a use a $6 device on a LEO satellite close the link with an omni gain antenna on the ground. This can be done in a 10 KHZ channel. I also believe this can be used in part 97 of the FCC rules. It might require a rule waver but I believe it is doable.

The negative is as you point out is it is proprietary however there are 10 of million of the devices in operation globally.

In summary given it sensitivity and low cost it is a good choice.

Can you suggest a better choice ?

nick

Cell 337 258 2527

Helping UL become a world Class Engineering and Educational School Disagree I Learn

[https://ipmcdn.avast.com/images/icons/icon-envelope-tick-green-avg-v1.png]http://www.avg.com/email-signature?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=emailclient Virus-free. www.avg.comhttp://www.avg.com/email-signature?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=emailclient

-----------------------------------------------------------

Sent via AMSAT-BB(a)amsat.org. AMSAT-NA makes this open forum available to all interested persons worldwide without requiring membership. Opinions expressed are solely those of the author, and do not reflect the official views of AMSAT-NA. Acceptable Use and Privacy Policies available at https://www.amsat.org/about-amsat/

View archives of this mailing list at https://mailman.amsat.org/hyperkitty/list/amsat-bb@amsat.org To unsubscribe send an email to amsat-bb-leave(a)amsat.org Manage all of your AMSAT-NA mailing list preferences at https://mailman.amsat.orghttps://mailman.amsat.org/

On 4/20/22 03:06, Mark Jessop wrote:

I have to question the use of LoRa on amateur satellite bands. LoRa is a closed, patented, proprietary mode. SDR implementations of it (if they work...) are legally dubious, leaving us to have to use Semtech hardware to receive. Why are we allowing this? I thought amateur radio was meant to be open and free for all to experiment, modify, and learn?

Hello Mark,

I share your concerns with the use of LoRa for Part 97 operations. As you have mentioned, it is closed, patented, and proprietary, and has no place in our service. I feel similarly about AMBE, the voice codec used in many of the digital voice modes.

LoRa's claim to fame is resistance to interference, being a frequency-chirped spread-spectrum mode. There is no technical reason that another device or purpose-built hardware could not achieve the same sensitivity on a coordinated frequency for a given bandwidth and data rate.

Nick is correct: Individual support from large silicon vendors will be lacking until we're buying 100k+ units per year.

We need amateurs interested in using commodity hardware (ON AX5043, ADI ADF7021, etc) to step forward and start experimenting. This "new frontier" requires the combined efforts of both those experienced in RF and those comfortable in the digital/programming world to step forward and cooperate.

If this sounds like something anyone is interested in, please contact me and/or visit https://www.amsat.org/volunteer-for-amsat/

--- Zach N0ZGO