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Posted by Romy the Cat on
07-12-2010
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fiogf49gjkf0d Guys, I need somebody help me with middle grad school math – I truly can’t do it. I need to calculate if my antenna in the line of sight with my WCRB and if not then what kind elevation I shall have in order to get the line of sight.
The image below is well depicts the situation. My antenna is at 160 feet toll over the sea level and 12 miles away there is 949 feet toll transmitter antenna. 2000 feet away there is a 240 feet tall heal the might or might not cover the line of sight. Who know how to figure it out? I do not remember geometry anymore…
Rgs, The caT
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Posted by oxric on
07-12-2010
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fiogf49gjkf0d Well Romy:
A quick calculation shows that the angle of elevation is 1.24310 degrees (i.e tan inv of (949-160)/36360).
At a horizontal distance of 2000ft from the antenna, this angle of elevation results in an overall height above sea level of 203ft (i.e tan of elevation x 2000= 43 + 160 = 203ft). The 240ft tall heal will therefore be in the way of your line of sight... as you said it may or may not adversely affect your reception.
You could always set fire to it...
All the best
Rakesh
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Posted by Romy the Cat on
07-12-2010
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fiogf49gjkf0d Oxric, thank you very very much. Would you be kind to help me to find out what shall be the elevation of my antenna in order to reach the line of sight clarence over that hill?
The Cat
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Posted by oxric on
07-12-2010
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fiogf49gjkf0d Romy:
My pleasure.
The actual angle of elevation required to clear the summit of the heal is 1.182 degrees (i.e tan inv 709(949-240)/34360(36360-2000)). Using similar triangles (h/2000=709/34360) or simple trig gives an overall antenna height of 198.731ft, so that you need to raise your antenna at least an additional 38.731ft to just clear the heal.
Rakesh
P.S You could move the antenna back if you wanted to maintain a height of 160ft but you would need to move 3877ft from the heal that is a further 1877ft back from the present position of the antenna, not a viable proposition at all I am sure.
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Posted by oxric on
07-13-2010
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fiogf49gjkf0d Romy:
I just suddenly realised that by 'heal' you probably meant 'hill'. For a moment I thought it was some strange geographical feature that I had not come across.
Regards
Rakesh
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Posted by Romy the Cat on
07-13-2010
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fiogf49gjkf0d
Oops, I am sorry. Of cause it was hill, I need to add it to my dictionary
http://www.goodsoundclub.com/Forums/ShowPost.aspx?PostID=3823
The 40 extra feet in addition to my current 35? This would make 75 feet mast. Hm, this is complicate as it will be make the tallest structure in my neighborhood and it will make it very vulnerable to lighting…
The Cat
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Posted by Romy the Cat on
07-15-2010
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fiogf49gjkf0d I raised the antenna on 10 feet. Got extra 8dB of signal, not a lot itself but it a lot from a point of view of signal to noise ratio and I now can get a the specific station that I want with an acceptable level of noise. Oxric, thanks for your help. If you play 24 bit files then I might send you my tomorrow’s recording and it might be something that you might like.
The Cat
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Posted by oxric on
07-18-2010
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fiogf49gjkf0d Hi Romy:
Please don't mention it.
Yes I can play 24 bit files and yes I don't mind trying your recording.
All the best
Rakesh
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