[Ground-station] Potential Phase 4 - Gateway interference

[KENT BRITAIN]

 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 theground station.
Lots of orbits, a parallel orbit is not impossible, but in most cases theywould 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 whenlooking from a common point on the ground, how often do they pass within6 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 visibleat the same time, only 1/2000 of the time would they both be in the same beameven if on the same frequency.
Yea, can crunch these numbers several ways but with a little frequency managementinterference 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


  
  
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