10 GHz Noise Measurement for LNB System

In this video I show you how to set up SpectraVue with HDSDR for measuring cold sky, ground, sun and moon noise. Noise measurements can be used to optimize your system and verify its performance.
See also my 10 GHz Notes page:
www.n1bug.com/1...
Link to download SpectraVue:
moetronix.com/s...
Link to download Microsoft Visual C++ Redistributable 2010 x86 (10.0.40219.325):
learn.microsof...
Link to download VB Cable:
vb-audio.com/C...

[@milesprower6641]

noise level from the snow is probably the ground noise reflecting off the clouds, or reflecting off the snow itself; the denser the snow fall the more reflective the clouds or snow. or further, it could be noise power from the snow itself.

[@n1bug]

Thank you. I think what I was seeing that day may have been noise from the "warm" snow itself or the snowflakes reflecting ground noise. I think that because changes in noise level tracked so well with intensity of the snow. It makes sense that clouds would have some influence. It would be interesting to investigate this further.

[@PY1SAN]

Great !

[@stargazer7644]

Objects warmer than absolute zero emit noise. That's what you're measuring. Put your hand in front of the feed and you'll hear noise - your warm hand is emitting 10 GHz. The sky in a snowstorm is warmer than cold sky. Also, the sky isn't uniformly cold as you imply. The plane of the galaxy is warmer than other places in the sky. Just as pointing at the Sun measures noise, pointing at the 400 billion or so stars in the milky way also measures noise. With a big enough dish, that becomes significant.

[@n1bug]

Thank you. This is the first time I have heard that the sky is not uniformly quiet at 10 GHz. I know it is not at lower frequencies such as 144 and 432 MHz where I had prior experience. When I asked about using sky/sun/ground noise measurements to evaluate feedhorn (LNB) placement and performance of this system, everyone said it would not matter as long as I was not pointed at the sun or moon. Maybe they meant "with this size dish"? Now I want to do more experimentation with this, when and if I get a dish on a proper mount where I can more easily steer it and up higher where it can see more of the sky without also seeing trees or my other antenna structures.

[@stargazer7644]

@@n1bug Here's a paper that compares galactic sky maps made at various frequencies from 10 MHz to 94 GHz. It has a section that shows visual images and references to various studies of the energy received from the sky at different frequencies that might be interesting to you. arxiv dot org/pdf/0802.1525.pdf This is a radio continuum map made of the galactic plane at 10 GHz: cade dot irap dot omp dot eu/dokuwiki/doku.php?id=nobeyama

[@stargazer7644]

@@n1bugI'm not sure if the links to those papers are making it through the comment filter or not. Google for "nobeyama 10ghz radio continuum" and you'll get the 10 GHz map of the galactic plane. Google for "arxiv Angelica de Oliveira-costa galactic radio emission" for the paper talking about sky maps at various frequencies. You might find them interesting.