[Ground-station] Potential Phase 4 - Gateway interference

[Michelle Thompson]

OK I see what you mean.

In doing a BOE for GEO, the occlusion is longer lasting, because the moon
moves more slowly across the sky than a lower satellite, but the outcome
appears to be the same. It's rare.

If we can put this on a single slide, for that one time someone
with authority requires an answer, then the work to come up with numbers is
worth it. I think Kent is correct in the order of magnitude for LEO and
pretty close numerically.

I am interested in generating a solid number. Does anyone have good
software for this, or want to write up a python script that encapsulates
the problem?

-Michelle W5NYV



On Fri, Feb 14, 2020 at 1:07 PM KENT BRITAIN <wa5vjb at flash.net> wrote:

> Interference would be rare, and momentary.
>
> OK, the bird goes though a 360 deg arc in about 80 minutes.
>
> So in a typical overhead pass that's about 4 deg a min..
> ( Yes, a lot of variables in that equation! )
>
> The antenna beam is 6 deg if we allow for the -10 dB points.
> So 90 seconds would put the 2nd bird well out of the pattern from the
> ground station.
>
> Lots of orbits, a parallel orbit is not impossible, but in most cases they
> would only be in common view of the ground dish for a minute or so.
> I'll let someone else do this calculation.  Take two LEO Birds, and when
> looking from a common point on the ground, how often do they pass within
> 6 deg of each other?    Not often I suspect.    Kent WA5VJB
>
>
>
> On Friday, February 14, 2020, 1:17:53 PM CST, Michelle Thompson <
> mountain.michelle at gmail.com> wrote:
>
>
> Good point on frequency management.
>
> We plan to use (up to) the entire 10MHz amateur allocation.
>
> Gateway appears to be using less.
>
> Given that one can model this as a narrowband interferer to a broader band
> signal, in your opinion, can we accept or ignore the potential interference?
>
> -Michelle W5NYV
>
>
>
>
> On Fri, Feb 14, 2020 at 10:20 AM KENT BRITAIN <wa5vjb at flash.net> wrote:
>
> The typical Direct TV style dish looks at 1/4000 th of the sky.
> Well, we only see 1/2 of the sky at any given time, so even if both birds
> are visible
> at the same time, only 1/2000 of the time would they both be in the same
> beam
> even if on the same frequency.
>
> Yea, can crunch these numbers several ways but with a little frequency
> management
> interference is going to be pretty rare.    Kent WA5VJB
>
>
>
>
> On Friday, February 14, 2020, 12:03:12 PM CST, Michelle Thompson via
> Ground-Station <ground-station at lists.openresearch.institute> wrote:
>
>
> With AREx and Lunar Orbiting Platform Gateway (usually just called
> "Gateway") developing and progressing, Paul KB5MU brought up something we
> need to check on.
>
> If Gateway uses the 10GHz amateur downlink (and they plan to) how much
> impact do other 10GHz payloads present? QO-100, Phase 4X, CatSat, etc.?
>
> I think any interference or outages are going to be very small, but I'd
> like to have an answer before someone like ARISS asks.
>
> If we all use DVB-S2/X, then it would seem that there would be a potential
> for brief interference.
>
> Assuming 10GHz downlinks from Gateway
> 1) how often would potential interference occur for GEO, HEO, LEO?
> 2) is there anything that we (or Gateway) should do about it?
> 3) is there anything that we (or Gateway) could do about it?
>
> Goal: Quantify and document.
>
> -Michelle W5NYV
>
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.openresearch.institute/pipermail/ground-station-openresearch.institute/attachments/20200214/4c173584/attachment.html>