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

On 7 Feb, 15:43, "Richard Fry" wrote:
wrote The total distance between the transmitting and receivingantennaof a
microwave link at 10GHz, is 30 Km. the height of the Txantennais
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
transmitterantennawith a height of 80m.

calculate the height of the receiverantennafor 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 receiveantenna, 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

hi

Richard
i have read ur response very carefully and its perfect 142dB Path
loss but problem is that what's the Rx height
if i suppose Tx and Rx install on the same height
then my Rx height after the earth buldge and knife e calculation
i have got 100m Rx
its totally wrong
because
if i increase that (100m) Rx height its mean get the problem at
fresnel Zone

need help

thanks
regard

naqvi

naqvi wrote
i have read ur response very carefully and its perfect 142dB Path
loss but problem is that what's the Rx height if i suppose Tx and Rx
install on the same height then my Rx height after the earth buldge
and knife e calculation i have got 100m Rx its totally wrong
because if i increase that (100m) Rx height its mean get the problem
at fresnel Zone
_________________

Suggest that you print my graphic, and look for different heights of the
transmit and receive antennas that still clear the 80 meter hill by using a
straight edge that always crosses the location of the hill at the elevations
shown in my plot.

It is best to provide more path clearance at the 80 meter hill than I
showed, because some K-factor variations could steer that 10 GHz beam into
that hill, and cause loss of a usable signal for the receiver.

Also remember that this plot was done over a smooth earth. The true
elevations at the endpoints of the path and at the hill could be
considerably different than I showed.

RF