Design passive and active distributed antenna systems on scaled floor plans, with per band link budgets, cable lengths from the layout and indoor coverage prediction to ITU-R P.1238 and P.2040.
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Walkthrough
Trace walls, openings and rooms over the plan. Walls set the propagation model and wall losses, and rooms define the areas that need coverage.
Place the head end, splitters, couplers, attenuators and antennas, then draw the cable runs along their real routes.
Place a master unit and remote units, run fibre from the master to each remote and coax from each remote to its antennas. The optical budget checks the level reaching each remote.
Coverage is shown as a heat map of the strongest antenna at each point, with downlink level and uplink margin, for the selected level and band.
A summary runs every band through the same coverage calculation and names the weakest.
Check the design against the NSW Public Safety Network in-building coverage criteria in both directions. The verdict names any direction that falls short.
For an off-air amplifier, compare the donor isolation, estimated from the layout or measured on site, with the amplifier gain to avoid oscillation.
Validation reports structural problems such as loops, unterminated ports, out of band parts and fibre runs that miss their optical budget. Each figure shows whether it comes from a datasheet, a derivation or a generic part.
Project library with saved designs.
Overview
A distributed antenna system carries mobile and radio coverage through a building. In a passive system, coax runs from a head end through splitters and couplers to antennas spread across the floors, and every element takes part of the signal. The losses change with frequency, and the cable lengths that dominate the budget depend on how the cable is routed through the building. A spreadsheet can do the arithmetic but loses the geometry.
The In-building DAS Designer keeps both. You import a floor plan for each level, set its scale and place the head end, distribution and antennas at real positions. Cable lengths come from the routed layout, including the vertical distance up a riser between levels, with a slack allowance and the option to enter a measured length. Active systems are also supported, with a master unit feeding remote units over optical fibre for buildings that a passive network cannot reach.
The link budget runs once for every band in the design, because cable loss, passive loss and antenna gain all change with frequency. Coverage is predicted across each floor with the ITU-R P.1238 site-general model, or with free space loss plus ITU-R P.2040 wall losses where walls are drawn, and shown as a heat map of the strongest antenna at each point. The uplink is budgeted as well as the downlink, so a design that a handheld can hear but cannot talk back to is caught.
Each level has its own floor plan and scale, set by aligning the plan to the grid or by marking two points a known distance apart. Equipment is placed at real coordinates, so cable lengths and coverage are measured in the building rather than on a schematic.
Run lengths come from the routed cable path, including the vertical distance between levels. A slack allowance covers dressing and service loops, and a measured length can replace the derived figure where the run has been measured on site.
A passive design feeds splitters, couplers, attenuators and antennas from a source such as an off-air bi-directional amplifier, a small cell or a land mobile repeater. An active design uses a master unit and remote units over optical fibre, with an optical budget for each remote, and both can be mixed in one design.
The budget runs for every band in the design and gives the power at every node and the EIRP at every antenna. Losses are split into cable, passive and connector parts, and the uplink is budgeted back to the head end or through the remote unit on an active branch.
Coverage uses the ITU-R P.1238 site-general model, or free space loss plus ITU-R P.2040 wall losses where walls are drawn, but never both at once. Directional antenna patterns and a shadow fading margin at your chosen confidence are applied, and the tool flags predictions beyond the range the model was fitted over.
The heat map shows the strongest antenna at each point for the selected level and band, with downlink level and uplink margin. When rooms are drawn the statistics cover only those rooms, and a summary of every band names the one that covers worst.
A design can be checked against the NSW Public Safety Network in-building coverage criteria in both directions. For an off-air amplifier, the tool estimates donor isolation from the layout, or uses a measured value, and checks it against the amplifier gain to avoid oscillation.
Each component shows whether its figures come from a datasheet, a vendor design library, a physical derivation or a generic planning part, and a check that relies on missing data reports that it cannot be assessed. Projects save in your browser and to your account, and can be exported as a file.
Inputs and outputs
Inputs 10
Outputs 11
Use cases
Cable loss, passive loss and antenna gain all change with frequency. Coax loss is markedly higher at 2.6 GHz than at 700 MHz, and a wideband indoor antenna does not have one gain figure across its range. A single frequency budget would be wrong by several decibels at one end of the band plan.
It is a planning estimate. The ITU-R P.1238 site-general model is an empirical fit with a published shadow fading spread, which the tool applies as a margin at your chosen confidence, and the tool flags predictions beyond the distance range the model was fitted over. Where walls are drawn, the tool uses free space loss plus ITU-R P.2040 material losses instead. It is not a ray tracing tool.
No. Antennas on a level serve that level. The floor penetration factors needed for through-floor prediction are published mainly for frequencies well above the mobile bands, so the tool does not estimate them. A DAS normally places antennas on the floors they serve.
Yes. A master unit can feed remote units over optical fibre, and each remote outputs its own rated power once the optical level reaching it clears its threshold. On the uplink, the remote amplifier sets the noise figure for its branch. Passive and active branches can be mixed in one design.
They are the in-building coverage requirements published by the NSW Telco Authority for its public safety radio network, covering a minimum received level over a share of the area in both directions. Australia has no national law or standard requiring in-building coverage, so the tool presents these as an operator specification for NSW. Other states have their own requirements.
Catalogue parts load from the noIM₃ component catalogue, and generic planning parts are available for early design. Each part shows whether its figures come from a datasheet, a vendor design library, a physical derivation or a generic planning value, and a check that depends on missing data reports that it cannot be assessed rather than passing.
Yes. Equipment still sits at real coordinates and cable lengths still come from the geometry. The floor plan is a backdrop that makes placement accurate, not a requirement.
Related
Included in the 14-day Pro trial on every new account. No credit card.
