Outernet cubesat news

kalashnikov · 2015-12-07T14:22:51.479Z

I suppose you know this proyect https://satnogs.org/ …

bmcintosh · 2015-12-07T14:41:41.607Z

Just had a quick peek - this looks very cool. I may need to set one up!

Seasalt · 2015-12-08T13:43:12.866Z

Could / would the above antenna work on a boat at sea with either a Outernet lighthouse getting high speed data (1 GB a day) or connected to a Outernet Lantern getting the 10MB a day satellite data feed.

It looks very easy to build and may work the RTL SDR Dongle I have.

The antenna on the new Outernet Lantern device looks very small and we have been discussing whether it will only function in a stationary position or whether it could be on the roof of a vehicle and still get 10 MB of Data per day from space.

George

branko · 2015-12-08T14:39:45.117Z

Seasalt:

The antenna on the new Outernet Lantern device looks very small and we have been discussing whether it will only function in a stationary position or whether it could be on the roof of a vehicle and still get 10 MB of Data per day from space.

New Lantern is still a stationary device. I’m curious if you actually got L-band reception using RTL SDR, though. How did that go, or are you just planning to do it?

Seasalt · 2015-12-08T15:11:44.129Z

Thanks for the reply Branko I am more just thinking out loud about ideas. I do not want to be the first person to go through the hassle of experimenting on what satellite equipment does work, and what doesn’t work on a tilting sailing boat under way.

But I will be very excited to play with a Lantern and experiment. If it only works in calm situations at anchor that would be fine as well, especially in terms of a $165 device.

I would also like to put a simple antenna up that would allow me to send small APRS data packets etc. up to amateur satellite repeaters as a very basic form of up-link email and possibly have people reply to me using the Outernet $3 per month “twitter” messaging service. Which I imagine is sent almost immediately as priority packets over the Lantern and Lighthouse feed. This would give me a kind of internet chat to the outside world that would be kind of connected to the internet in a kind of real time, depending on how many free to-use satellites go up in the future. ( My feeling is that lots of Cube sats are going to go up.)

Out of interest could you please post the Outernet down-link frequencies or range of frequencies that you expect to use for the Lantern 10 MB per day service.

For the Cubesats what frequencies / Bands do you intend to broadcast on?

What kind of Payload options is Outernet taking on the Cubesats. How much power is available to your payload transmitters.

Are you going to allow APRS repeater function on the Cubesats?

Will the Lantern allow the connection of non dish type antennas i.e flat phased array antennas etc for mobile operation?

I have only used my rtlsdr usb stick to pick up the aircraft ADS-B signals flying over where I live, using a circular DIY half dipole coaxial antenna which allows me to see planes landing 30 km away.

But I see on the internet there are many RTL SDR using them for UHF satellite reception. My feeling was it might allow me to decode some low 1000 ish L-Band . But I am not in a rush, Until you start the 10mb a day Lantern download I am sort of doing other projects first.

George

Syed · 2015-12-08T18:34:29.004Z

Seasalt:

But I will be very excited to play with a Lantern and experiment. If it only works in calm situations at anchor that would be fine as well, especially in terms of a $165 device.

Sadly, the new Lantern will no longer cost $165. Our backers will be getting an OUTSTANDING discount for a really unique satellite terminal. We expect the price of the future version of Lantern to drop to that price, but that is a couple years away. Satcomm is expensive

Seasalt:

Out of interest could you please post the Outernet down-link frequencies or range of frequencies that you expect to use for the Lantern 10 MB per day service.

We will be delivering content between 1525 MHz and 1559 MHz. A simple patch antenna, with gain of about 8 dBi should suffice, but you’ll need a specialized (but still free) software demodulator to turn the signal into actual content.

The cubesats will be transmitting around 403 MHz.

The cubesats will have about 8W of power available. It’s a 1U satellite, so the only payload is the UHF radio.

Since we want to deliver more than just 10MB of content, we had to switch to a proprietary design, so the connector will not be exposed. But for a software-based receiver, you can add any kind of antenna to, similar to how you work with an RTL dongle.

The RTL can pick up L-band, but it get really hot and unstable above 1 GHz. You should be fine for the receiving the cubesats, though.

kenbarbi · 2015-12-09T00:50:44.366Z

Sadly too, Lighthouse with Version 2.0.000 software is receiving data from Galaxy 19, but not displaying it in the Librarian either. Details sent to Branko by e mail. Ken

pradeeka · 2015-12-09T05:16:49.932Z

kenbarbi:

Lighthouse with Version 2.0.000 software is receiving data from Galaxy 19, but not displaying it in the Librarian either

I have a Lighthouse flashed with V2.0.000, pointed to ABS-2 74.9E and it is receiving data and displaying in the Librarian.

Seasalt · 2015-12-09T11:07:54.780Z

If i buy a lighthouse now will I be able to connect a smaller antenna or different antenna in the near future and pick up the 10mb a day feed that the Outernet Lantern will be receiving?

If so I will not wait for a Lantern but buy a Lighthouse today and start playing with a large C Band antenna and when the Mobile Lantern service starts I will change over to a smaller mobile antenna and pick up the 10 MB feed as I go to different places.

George

branko · 2015-12-09T12:12:24.456Z

Seasalt:

If i buy a lighthouse now will I be able to connect a smaller antenna or different antenna in the near future and pick up the 10mb a day feed that the Outernet Lantern will be receiving?

No, Lighthouse only has standard DVB-S/S2 tuners.

Seasalt · 2015-12-10T06:29:04.681Z

Branko I think we need some kind of Capability Matrix to simplify this.

Here is my very rough understanding. Please Jump in and advise accordingly.

The Lighthouse can Only pick up KU and C Band but not L Band , VHF and not the UHF of the Cubesats.

The Outernet Lantern can receive KU, C, L-Band and UHF (Cubesat) but not VHF?

George

branko · 2015-12-10T10:54:24.742Z

I’m definitely not an expert on radio so @syed will fill you in on the details. I think the new Lantern will only be L-band (but, as I said, I’m not dealing with that part of the product so I’m not sure).

Syed · 2015-12-12T06:33:17.355Z

Yes, we do need a matrix. I need to update this page:

https://wiki.outernet.is/wiki/Outernet_Receivers

You assumed correctly that Lighthouse receives Ku and C band, through an LNB. Without getting too technical, Lighthouse actually demodulates at L-band, because that is what an LNB downconverts to. But I’ve probably only confused you with that additional piece of information, so to clarify, Lighthouse receives DVB-S2.

Lantern’s design has shifted a bit, but has now stabilized to L-band. Specifically, 1525 MHz - 1559 MHz. The satellites in use are from LightSquared and Thuraya (Thuraya-2 and Thuraya-3).

The cubesats will be transmitting over UHF, specifically 401 MHz. The receiver for those signals will be an RTL-dongle, which can be obtained for about $10.

pradeeka · 2015-12-12T06:39:22.990Z

Syed:

The receiver for those signals will be an RTL-dongle, which can be obtained for about $10

is this a correct one?
http://www.amazon.com/RTL-SDR-DVB-T-Stick-RTL2832U-R820T/dp/B00C37AZXK

Syed · 2015-12-12T06:44:05.078Z

Yes, that’s correct. All of those tv dongles use the same demodulator chip from Realtek. For SDR applications, the chip is not actually used as a demodulator, but as an analog to digital converter with a USB interface. The digital bits are then sent to the processor (whatever the dongle is plugged into) for decoding into files.

pradeeka · 2015-12-12T06:46:28.732Z

Thanks, Syed

Seasalt · 2015-12-12T13:12:40.779Z

Syed thanks for the reply.

As a sometimes mobile user the Lantern and cube sat options have a lot of appeal.

I assume the Lantern will use Clark Belt Geostationary Satellites to beam down a L Band signal that can be picked up 24 hrs a day for those in the satellite footprint.

The data will came on a 15xx Mhz L Band and be around 10mb? a day of data to the Solar powered lanterns.

The cubesats on the other hand will be a much lower orbit and not geostationary. So the satellite will be closer to earth and have a smaller transmission footprint and be moving across the earth.

Here in the Philippines we get the International space station a couple of times a day. The ability to get a clear radio receive from the ISS VHF and UHF transmitters is limited to a few minutes of the satellite approaching and a few minutes after it goes overhead.

Extrapolating that to 3 Cubesats on similar orbits and I would ball park summarize we could get possibly a total 2 to 3 hours a day of cubesat UHF data transmissions. What data rate are you expecting into The RTL-SDR receivers?.

George

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Syed · 2015-12-12T21:08:40.641Z

The data should be at least 20MB a day–that is one of the benefits of our new partnership. Yes, the cubesats will be at an altitude of about 500km. We expect about 7 minutes of contact time with each pass. I would say that two hours per day is being generous. The radios that Clyde Space are using have a target data rate of 9600 bps.

barleyguy · 2016-01-07T20:25:11.970Z

My guess would be that NADIR passes, when the satellite is directly overhead of the target, would be around 7 minutes, but OFF-NADIR passes, when the satellite passes out on the horizon, would be less than 7 minutes. To visualize, draw a circle, then draw a line through the middle of the circle, and draw a line out closer to the edge of the circle. You can see that the line on the edge of the circle is shorter.

Unless you’re only going to use the NADIR passes, which lessens your passes per day, the software will need to be able to handle data increments as low as about 2 minutes.

If you run sun synchronous to keep your solar cells powered, you’ll get two NADIR passes per day per satellite, and 8 off NADIR passes per day per satellite. (One off by a single pass and one off by 2 passes both to the east and west). As a rough guess, that would mean:

72 + 44 + 4*2 = 14+16+8 = 38 minutes per day per satellite

$.02.

Syed · 2016-01-10T19:51:08.738Z

I don’t think your calculations are far off. Let’s run with 38-minutes and see what happens against 9600 bits per second:

9600 * (60second * 38minutes) = 21,888,888 bits per day.