Committee on Radio Astronomy Frequencies

Separation distance required for terrestrial radio stations

This routine calculates the separation distance for land MESs at frequencies between 0.7 and 30 GHz required to protect the Radio Astronomy Service using Recommendation ITU-R P.452 while to estimate the atmospheric attenuation Recommendation ITU-R P.676 is used.

The calculation uses the geographic summation methodology. Since a generic solution is anticipated: no terrain model is included.

The calculation details and assumptions are outlined in ERC Report 26 but generalized for frequencies up to 30 GHz.

The protection criteria for Radio Astronomy are given in Recommendation ITU-R RA.769.

Notes:

  • For distances within 100 km the modified Okomura-Hata model is used (as explained in ERC Report 26)

    transmitting power level per individual station (e.i.r.p.): (in dBW)
    frequency (must be below 30 GHz): (MHz)
    transmitter bandwidth: (MHz)
    density of active users: (km-2)
    maximum permissible spectral power density: (in dB(Wm-2Hz-1))
    height transmitting station: (in meters)
    height radio astronomy antenna: (in meters)
    elevation angle: (in degrees)
    sea-level surface refractivity:
    percentage of time lost due to variable propagation: (this value should be 10% or less)
    initial inner radius of first circle from Radio Astronomy Station (>= 0.001 km): (in km)
    number of rings for calculation:

    Fill in and click to get results
    or click reset to renew all parameters

    Last modified: March 5, 2004