This facility is only available in RLToolNet.

The following data have to be known:

• co-ordinates of all radio sites
• equipment data, incl. interference sensibility
• antenna data, incl. radiation pattern
• all radio frequencies.

Existing sites or networks – not subject to the planning - operating in the planned frequency band(s) may interfere with the planned network. To consider their contributions the corresponding data have to be known.

RLTool feature:

• The radio frequencies can be selected from an ITU-R recommended r.f. channel plan, or selected freely.
• Most of the ITU-R recommended r.f. channel plans are stored in the program-internal database.
• When an ITU-R recommended r.f. channel applies, the frequencies are selected by stating the channel No. RLToolNet will automatically set the correct frequencies for the hops’ go and return direction, thus avoiding errors by mistyping.

Note:
The frequency planning and interference calculation can only be performed, when the site co-ordinates are given and activated.


Interference calculations
All frequencies within the same r.f. band are tested against each other. Hereby, the bandwidth of the disturbed receiver and the spectrum bandwidth of the disturbing transmitter are considered, as these will influence the interference effect. In the first calculation, free-space propagation is assumed for all interference paths. If necessary, additional attenuations due to obstacles in the interfering paths can be inserted before the next run.

If one site contains RL systems operating in the lower (L) and in the upper (U) halfband of an r.f. band , the risk for interference between the antenna of the 1st system and the antenna of the 2nd system is very high. This is also valid if their antennas are placed on different towers, but close to each other. If, furthermore, one of the antennas is inside the nearfield  of the 2nd antenna, the antennas’ REP is not longer valid. In this case, the worst condition is assumed, which is direct interference between the two radiators. If the resulting interference level is harmful, the antenna manufacturer should be consulted about the antenna discrimination for the particular application.

RLTool feature 1:

• RLToolNet facilitates the possibility to perform interference calculations also if one radio site operates both as an L and U station.

RLTool feature 2:

• If a radio path includes a passive repeater, interfering signals reaching a disturbed receiver via this repeater are included in the calculation.

It should be noted, that the calculation of the interfering signal level is based on the r.f. midband frequency.
For each receiver the individual interfering levels and the total interference loading is calculated.


Interference network chart
In addition to the Frequency list and the Cumulative interference calculation report, RLToolNet generates an Interference network chart. This chart shows all individual interference connections with a signal level higher than a selectable threshold.
Clicking an interference path leads one directly to the associated interference report.