simple Question please Guys about rain attenuation

[other-side-of-d-moon]

Hi All, may *** bless you.

Guys i am in the first semester undergraduate student. and i hv question, can any one explain to me what is the best signal path in presence and absence the rain and/ or clouds For HAPS or satellite .

tnx

 

[jiripolivka]

I possibly know well about the rain attenuation but what is HAPS?

 

[other-side-of-d-moon]

I possibly know well about the rain attenuation but what is HAPS?

HAPS is high altitude platform stations

Tq, i appreciate that

 

[other-side-of-d-moon]

hi all. i think some of you did't understand me well, i mean what is the best signal path in presence and absence the rain and/ or clouds for Ku band

 

[karthiprime]

What is the best signal path in presence of rain?
What is the best signal path in absence of rain?
What is the best signal path in presence of clouds?
What is the best signal path in absence of clouds?

Is that ur question?

 

[other-side-of-d-moon]

what is the best signal path in presence of rain?
What is the best signal path in absence of rain?
What is the best signal path in presence of clouds?
What is the best signal path in absence of clouds?

Is that ur question?

yes this is my question... Is it pretty difficult ????????????????

 

[jiripolivka]

yes this is my question... Is it pretty difficult ????????????????

First I would like to state that the rain and cloud effects upon microwave signals belong to a developing science field. Do not expect "definitive" answers.

Second all atmospheric effects are frequency dependent; there are frequency bands where water, oxygen, and other gases absorb electromagnetic waves. To communicate or to work in remote sensing, a good knowledge of the sate of art is essential. Updated data on atmospheric effects are being published in ITU Reference books (e.g. ITU-R, Rec. ITU-R PN 837-1, Rec. 838, 839, 1992-94, for satellite-communication applications) as they are being collected by researchers.

There are many good books presenting data on rain/cloud attenuation, for planning microwave radios and satellite links. See e.g. Morgan.WL, Gordon,GD, Communication Satellite Handbook, J,Wiley 1989. Now the study extends to terahertz spectrum.

I have studied rain attenuation in 12 and 18 GHz bands by water emission, using microwave radiometers quite successfully. Others use satellite beacons. Depolarization effects have been calculated and confirmed by long-term tests.

 

[other-side-of-d-moon]

tnx jiri, any body else would like to help me. i asked my question in term of the propagation path and the elevation angle.

Pls check the attached image

 

[jiripolivka]

tnx jiri, any body else would like to help me. i asked my question in term of the propagation path and the elevation angle.

Pls check the attached image

Please read again what I wrote. For Ku-band, ITU-R recommendations offer a lot of useful data; rain intensity and rain-cell size differs over territory around the globe. In addition to rain attenuation, there is the depolarization. Your question can stimulate a full Ph.D. thesis to conduct a good research.

I would recommend the book by Gomez, J.M.: Satellite broadcast systems engineering, Artech House 2002, with a good analysis of a satellite Ku-band downlink.