antenna hight
 

The total distance between the transmitting and receiving antenna of
a microwave link at 10GHz, is 30 Km. the height of the Tx antenna is
above ground level is 20 m. the maximum acceptable total path loss is
169 dB.
Furthermore there is hill located 10 km away from the transmitter (Tx)
antenna with a height of 80m.

calculate the height of the receiver antenna for the path loss to be
just equal to the maximum acceptable value?

Whats the height of the receive antenna? (required)

Is the hill directly in the line of sight of the receive antenna?
yes it is b/w the LOS

antenna hight
 

wrote
The total distance between the transmitting and receiving antenna of a
microwave link at 10GHz, is 30 Km. the height of the Tx antenna is
above ground level is 20 m. the maximum acceptable total path loss is
169 dB. Furthermore there is hill located 10 km away from the
transmitter antenna with a height of 80m.

calculate the height of the receiver antenna for the path loss to be
just equal to the maximum acceptable value?
_____________

The height above mean sea level of the tx and rx sites, and the terrain
profile for the path would be necessary to answer this ~ accurately. But
for a smooth earth model, the graphic at the link below will give some
insight.

It shows that a height of around 270 meters would be needed for the receive
antenna, using a K-factor of 1.33 and 0.6 fresnel clearance for an 80 m hill
10 km downrange. The path loss then would be about 142 dB.

http://i62.photobucket.com/albums/h8.../10GigPath.gif

RF

antenna hight
 

antenna hight
 

wrote in message
oups.com...
hello
Jeff
i am very thank full to your help, i have got Rx height 101.2

Regards
naqvi

Who is right, you or Jeff? You are more than 100% off from each other.

In truth, i could receive that signal holding a hand held 10GHz receiver
while sitting on the ground. The 80m hill is nothing from an observer 10KM
away...only .006 degree from the top of the transmitter tower. It is part of
the horizon. I love it when you guys talk like you are sol knowledgeable yet
lack the common sense to conceptualize the problem as it really exists.

antenna hight
 

wrote in message
oups.com...
hello
Jeff
i am very thank full to your help, i have got Rx height 101.2

Regards
naqvi

Please show your work.

antenna hight
 

"Stefan Wolfe" wrote in message
...

wrote in message
oups.com...
hello
Jeff
i am very thank full to your help, i have got Rx height 101.2

Regards
naqvi

Please show your work.


Hi Stephan

Your posts seem to inply that the receive antenna will "see" the 20 meter
high transmitting antenna when the receiver antenna is in the shadow of the
80 meter hill. It seems that the receiver needs to be out of the shadow of
the hill unless you are able to estimate refraction from the hill.

But, your aparent confidance in the statement "0 feet" makes me wonder if
I have this problem wrongly analyzed. I have so much confidance in Richard
Fry's data that I had accepted his estimation of 270 meters to be as close
as you can estimate.

Do I misunderstand your post about what minimum height is needed?

Jerry

antenna hight
 

"Jerry Martes" wrote in message
news:iLuyh.5336$384.156@trnddc05...

"Stefan Wolfe" wrote in message
...

wrote in message
oups.com...
hello
Jeff
i am very thank full to your help, i have got Rx height 101.2

Regards
naqvi

Please show your work.


Hi Stephan

Your posts seem to inply that the receive antenna will "see" the 20
meter high transmitting antenna when the receiver antenna is in the shadow
of the 80 meter hill. It seems that the receiver needs to be out of the
shadow of the hill unless you are able to estimate refraction from the
hill.

But, your aparent confidance in the statement "0 feet" makes me wonder if
I have this problem wrongly analyzed. I have so much confidance in
Richard Fry's data that I had accepted his estimation of 270 meters to be
as close as you can estimate.

Do I misunderstand your post about what minimum height is needed?

Jerry
Hi Jerry,

how many shadows have you seen that are 20Km long?

antenna hight
 

From: "Stefan Wolfe"
how many shadows have you seen that are 20Km long?
______________

Can we count the shadow of the moon on the earth during a
fully-eclipsed sun?

If so, that's a bit more than 20 km.

RF

antenna hight
 

"Stefan Wolfe" wrote in message
...

"Jerry Martes" wrote in message
news:iLuyh.5336$384.156@trnddc05...

"Stefan Wolfe" wrote in message
...

wrote in message
oups.com...
hello
Jeff
i am very thank full to your help, i have got Rx height 101.2

Regards
naqvi

Please show your work.


Hi Stephan

Your posts seem to inply that the receive antenna will "see" the 20
meter high transmitting antenna when the receiver antenna is in the
shadow of the 80 meter hill. It seems that the receiver needs to be out
of the shadow of the hill unless you are able to estimate refraction from
the hill.

But, your aparent confidance in the statement "0 feet" makes me wonder
if I have this problem wrongly analyzed. I have so much confidance in
Richard Fry's data that I had accepted his estimation of 270 meters to be
as close as you can estimate.

Do I misunderstand your post about what minimum height is needed?

Jerry
Hi Jerry,

how many shadows have you seen that are 20Km long?


Hi Stephan

Tell me where I have misunderstood the problem. I assumed the
transmitting antenna was Lower than the top of the hill. But, you seem to
imply that the transmitter can be seen even when the hill is blocking the
"view" to it.

I have actually never measured a shadow longer that a few feet, but I
assumed they continued to exist to infinity when an object blocks them from
view.

Jerry

antenna hight
 

"Jerry Martes" wrote in message
news:2Yvyh.37369$5U4.35764@trnddc07...

"Stefan Wolfe" wrote in message
...

"Jerry Martes" wrote in message
news:iLuyh.5336$384.156@trnddc05...

"Stefan Wolfe" wrote in message
...

wrote in message
oups.com...
hello
Jeff
i am very thank full to your help, i have got Rx height 101.2

Regards
naqvi

Please show your work.


Hi Stephan

Your posts seem to inply that the receive antenna will "see" the 20
meter high transmitting antenna when the receiver antenna is in the
shadow of the 80 meter hill. It seems that the receiver needs to be out
of the shadow of the hill unless you are able to estimate refraction
from the hill.

But, your aparent confidance in the statement "0 feet" makes me wonder
if I have this problem wrongly analyzed. I have so much confidance in
Richard Fry's data that I had accepted his estimation of 270 meters to
be as close as you can estimate.

Do I misunderstand your post about what minimum height is needed?

Jerry
Hi Jerry,

how many shadows have you seen that are 20Km long?


Hi Stephan

Tell me where I have misunderstood the problem. I assumed the
transmitting antenna was Lower than the top of the hill. But, you seem
to imply that the transmitter can be seen even when the hill is blocking
the "view" to it.

I have actually never measured a shadow longer that a few feet, but I
assumed they continued to exist to infinity when an object blocks them
from view.

Well you see Jerry, the reason you only see it for a few feet is because the
attenuation of the light varies inversely with the distance from the object
that blocks the light. I think you have done a good job in making my point.
Thanks,