[Ground-station] Question for ORI:

[Bruce Perens]

The second issue about LORA is that it's a garbage band, and destined to
become a really big garbage band. On the ground that's OK, you have the
square law and obstacles hiding most of those transmitters from each other.
>From space, maybe even from a balloon, I would imagine you would be hearing
a lot of chips on top of each other, or the noise floor would be high with
no intelligible signal. They might all be able to hear you, but not the
other way around.

So, maybe what we want to do from a satellite is downlink or even broadcast
using LORA or some other Part 15 mode. It uses the strengths of a
satellite, not the weaknesses.

Perhaps this is undemocratic :-) But I think it might be better if it took
a little more effort to put together a station that we would be likely to
hear from a satellite, and more difficult for stations intended to be
terrestrial to be heard accidentally. Maybe you should have a ham license,
too.

    Thanks

    Bruce

On Wed, Mar 31, 2021 at 4:40 PM Howie DeFelice <howied231 at hotmail.com>
wrote:

> I’m not a patent expert but it appears the first one listed covers the
> generation of spread spectrum “chirps” using a fractional N synthesizer.
> The other patent covers the  data formatting and modulation scheme.
> Assuming we have to stay away from those two aspects, we could still use
> chirp spread spectrum, just not generated the same way. The biggest
> advantage to chirped spread spectrum from a satellite operations
> perspective is that it’s inherently resistant to doppler issues. As long as
> the signal is in the receiver bandwidth and you can detect the direction of
> the chirp you can decode the signal.  Using a chirp spread spectrum
> physical layer into a an adapted 802.16 mesh network configuration could
> provide a way to have satellite augmented ground networks (or vice versa)
> without having to have a planned constellation of satellites. If every new
> LEO carried the transponder, the network would automatically form and
> grow.  When satellites are visible to each other traffic would also be
> repeated satellite to satellite. If the frequency plan was compatible to
> QO-100 transatlantic relays could be possible into the QO-100 footprint.
>
>
>
> Howie AB2S
>
>
>
>
>
> *From: *Bruce Perens via Ground-Station
> <ground-station at lists.openresearch.institute>
> *Sent: *Wednesday, March 31, 2021 7:13 PM
> *To: *Douglas Quagliana <dquagliana at gmail.com>
> *Cc: *Michelle Thompson via Ground-Station
> <ground-station at lists.openresearch.institute>
> *Subject: *Re: [Ground-station] Question for ORI:
>
>
>
>
>
>
>
> On Wed, Mar 31, 2021 at 3:43 PM Douglas Quagliana <dquagliana at gmail.com>
> wrote:
>
> Bruce writes:
>
> > someone more skilled than me would be sitting down to make an open data
> link implementation built on some cheap microprocessor
>
>
>
> If I understand what you're saying, Phil has already written several
> downlink schemes.
>
>
>
> Yes, but I am not aware of Phil addressing this particular application,
> which is dirt-cheap SS data links between so-far-terrestrial embedded
> microprocessors with a link budget to go miles at the lowest data rate and
> long life on small batteries. I hold out some hope that the functionality
> of their chip can be duplicated with a relatively small number of discrete
> components and a cheap microprocessor. Certainly we have ones that can do
> significant DSP in the $4 range these days, and they idle at microamps
> drain.
>
>
>
>     Thanks
>
>
>
>     Bruce
>
>
>


-- 
Bruce Perens - CEO at stealth startup. I'll tell you what it is eventually
:-)
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