FREEDAS calculator · Indoor signal boosters

Know how much signal reaches every room before you install.

Draw the system as it will be built: outdoor antenna, cable, booster, splitters or couplers and indoor antennas. The calculator gives the level at every point, flags the weak link and tells you what to change.

Open the calculator How it works

Free, no sign-up Opens full screen Interface in Spanish

The “two-storey house” example, calculated and drawn by the calculator itself. Antenna values are the RSRP a phone would see 5 m away.

The signal at every antenna

Every cable, splitter and coupler shows its loss, and every indoor antenna the RSRP a phone would get nearby.

Find the weak link

Booster noise, saturation, isolation and uplink are checked for you, with the fix one click away.

A report for the client

Save the project with a short link and download the results, levels and bill of materials as a PDF.

Capabilities

From the roof to the last room.

Distribution

Splitters or couplers: compare both with one click.

A splitter shares equally, so the antennas at the end of long cables get less. An inline trunk with couplers can give every antenna the same level with less cable. The calculator rebuilds the system both ways and picks the coupling values for you.

Splitters2 to 8 ways
Couplers3 to 30 dB, through and tapped port
Cables5D-FB, RG-6, LMR-400 and more, loss by frequency and length

Two-storey house

Band 3 · −100 dBm outside · RSRP 5 m from each antenna

Parallel

3-way splitter

Living room −89.4

Kitchen −91.3

First floor −93.3

Spread: 3.9 dB
Cable: 48 m
Parts: 14

Inline

Couplers 8 + 5 dB

Living room −92.3

Kitchen −92.4

First floor −91.2

Spread: 1.2 dB
Cable: 36 m
Parts: 19

Inline: 12 m less cable and every room within 1.2 dB.

Booster

What gain alone cannot fix.

A booster fed a weak signal amplifies its own noise; one fed a strong one cuts back its gain. Too little isolation between antennas makes it oscillate, and too much uplink gain disturbs the operator’s cell. Each case gets its own warning and a suggested change.

DownlinkGain, maximum output, ALC and noise figure
UplinkPhone power at the cell and noise added to it
IsolationEstimated from distance and walls, or your measurement

Home tri-band

65 dB · max. 17 dBm · 800/1800/2100 MHz

Input−65.3dBm

+65 dB

Output−0.3dBm

SNR at input33.1 dB

Isolation (est.)≈ 88.8 / 80 dB

ALCnot limiting

4.1 dB lost before the booster

Every dB lost before the booster lowers the signal-to-noise of the whole system.

Use LMR-400 for the downlead

The booster would raise the cell’s noise

Lower the uplink gain a few dB: same coverage, no interference.

Lower uplink gain by 6 dB

Results

Save it, share it, hand it over.

Each project gets a short link that opens it in the calculator. The results page collects the assessment, the level at every component and the parts list, and downloads as a PDF.

Bands700 to 3500 MHz, switch without redrawing
ProjectsIn your browser, as a .json file or as a link
PDFAssessment, levels and bill of materials

The system works well

All 3 antennas get good or excellent signal, no warnings.

Weakest−93.3 dBm

Spread3.9 dB

Cable48 m

1×Yagi outdoor antenna11 dBi

1×Home tri-band booster65 dB

1×3-way splitter5.3 dB

3×Ceiling antenna3 dBi

48 m5D-FB coaxial cable4 runs

Download PDF Share link Edit diagram

How it works

The diagram is the calculator.

Examples

Flat, one antenna

Two-storey house

Office, inline couplers

Warehouse, two systems

Start from an example

A flat, a house, an office or a warehouse. Set the outdoor signal you measured and the band.

Ceiling · 3 dBi Living room PIRE −4.7 dBm −89.4 dBmat 5 m · Good

Gain (dBi)

3↑↓

Cable to it

6 m

Shape the system

Tap any component to change it, add antennas, or switch between splitters and couplers. Levels update as you edit.

4.1 dB lost before the booster

A lower-loss downlead improves the whole system.

Use LMR-400 for the downlead

Download PDF Share link

Fix and export

Apply the suggested fixes, then save the project and download its results as a PDF.

Model

How it is calculated.

A link budget along every path, downlink and uplink, with the same RSRP quality scale as the coverage map.

Path to the first floor

Channel power along the path, dBm

−93.3 dBmRSRP at 5 m

The two-storey house example: gains lift the level, cable and splitter losses lower it.

Outdoor signal

RSRP is the power of one subcarrier; a booster works with the whole channel, about 28 dB more in a 10 MHz LTE channel. The outdoor antenna adds its gain and the downlead subtracts its loss.
Booster

Gain up to its maximum output, with automatic level control when the input is strong and its noise figure when it is weak.
Distribution

Splitters share equally (3 dB in two ways, 4.8 dB in three, 6 dB in four) plus their excess loss. Couplers tap a set fraction and pass the rest along the trunk.
Indoors

RSRP at a reference distance from each antenna, with an indoor path loss for homes, offices or open spaces.

Know the limits

Indoor RSRP, isolation between antennas and the uplink to the operator depend on walls and on the real cell. The calculator estimates them and says so; measure them before signing off an installation.

Use cases

When it is useful.

A flat with one antenna

Check whether a window antenna and a small booster are enough before buying.

A house on several floors

Decide how many indoor antennas you need and where the splitter goes.

Offices and shops

Plan a coupler trunk that gives every room the same level.

Warehouses and farms

Split a large site into two systems, each with its own outdoor antenna.

Installer quotes

Hand the client a PDF with the expected levels and the parts list.

A system that underperforms

Reproduce it and see whether the cable, the booster or the outdoor signal is to blame.

Draw the system before you drill the first hole.

Free and without sign-up. It opens full screen with an example ready to edit.

Open the calculator