900mhz & 1800mHz downtilt coverage radius formula

[nron3]

Hi All,

Do u know how to calculate 900mhz & 1800mHz downtilt coverage radius?
Highly appreciate if you can share with me.

Many thank.

[zeldalcl]

Hi!
u should clearly your question
1. Calculate Downtilt
2. Calculate coverage radius
3. tilts 900-1800 to have same coverage


BRs

[nron3]

if ant height 45m, M-tile=2, E-tilt=2, what is the coverage radius with:
1. 900Mhz
2. 1800 Mhz
3. 2100 Mhz

Thank you.

[apo7]

Can try this website:


http://www.proxim.com/products/knowledge-center/calculations/calculations-downtilt-coverage-radius


Regards.

[nron3]

From my experience, different Band have different coverage radius.
It should not be same.
Need to find out the formula..

[zeldalcl]

Hi!
- I only guide u how to calculate but can not give exactly value for it because it depend the morphology
- You can use tool and your propagation model to make prediction
- You try more tilt to find out the radius and compare to know the same coverage

hope it helpful for u

[chefo2068]

The cell radius can be calculated as follows:

L=h/tan(Teff), where:

L=cell radius [m];
h=Antenna phase center height [m];
Teff=effective upper half-power tilt angle [degrees]:

Teff = Mt+Et-Vbw/2, where:
Mt-mech. tilt;
ET-electr tilt;
Vbw=half-power vertical beamwidth of the antenna for the calculated frequency.

Note that if Teff is negative, this means you're shooting over the horizon.

[srilasitha]

The cell radius can be calculated as follows:

L=h/tan(Teff), where:

L=cell radius [m];
h=Antenna phase center height [m];
Teff=effective upper half-power tilt angle [degrees]:

Teff = Mt+Et-Vbw/2, where:
Mt-mech. tilt;
ET-electr tilt;
Vbw=half-power vertical beamwidth of the antenna for the calculated frequency.

Note that if Teff is negative, this means you're shooting over the horizon.

Thanks for sharing the equation,seems useful for initial calculation

[chefo2068]

keep in mind that this is just rough tilt calculation, it is valid for flat terrain and doesn't take into account clutter type or height.

[hoangtuna]

The cell radius can be calculated as follows:

L=h/tan(Teff), where:

L=cell radius [m];
h=Antenna phase center height [m];
Teff=effective upper half-power tilt angle [degrees]:

Teff = Mt+Et-Vbw/2, where:
Mt-mech. tilt;
ET-electr tilt;
Vbw=half-power vertical beamwidth of the antenna for the calculated frequency.

Note that if Teff is negative, this means you're shooting over the horizon.

More than these formular, I think the coverage of cell base on pathloss too(so we have difference between 900 and 1800).

I think we have to calculate where the rxlev down to -100dBm to define the coverage of cell. In practical, we used to set 0-2 at rural, 2-4 at urban and 4-10 at dense urban, depend on terrain and user distribution.

Some results from simulation tool:

if ant height 45m, M-tile=2, E-tilt=2, what is the coverage radius with:
1. 900Mhz
2. 1800 Mhz
3. 2100 Mhz

Thank you.

GSM900; Anten 42m; P = 43dBm (with combiner), Total tilt +4,
Distance from BTS to -75dBm/-95dBm
Urban: 1.72km/5.69km
Subrural: 1.79km/7.02km
Rural: 2.41km/10.35km

[nron3]

Hi All,

Thank a lot for your guideline.
According to 1 of my senior, he recommend me to study Hata Model, Okumura-Hata Model and so on.....
Those may provide accurate coverage radius according different frequency.