RF Tools.

Quick, accurate calculators for everyday RF work. Everything runs in your browser; nothing is uploaded.

Watt ↔ dBm ↔ dBW

Type in any box; the others update instantly.

In readable units–
Quick reference1 W = 30 dBm · 10 W = 40 dBm · 20 W = 43 dBm · 40 W = 46 dBm · 80 W = 49 dBm · 1 mW = 0 dBm · −100 dBm = 0.1 pW

How to use

  1. Type a value in Watt, dBm or dBW; the other two follow.
  2. Negative dBm works too, e.g. −95 for a received level.

Good to know

Radio datasheets usually quote power per port. Every doubling of power, or of the number of ports, adds 3 dB. Values below 1 mW give negative dBm, which is normal for received signal levels.

dBm = 10·log10(P[W]) + 30  ·  dBW = dBm − 30

EIRP / ERP

Radiated power from transmitter power, feeder / jumper loss and antenna gain, plus a dBi ↔ dBd converter.

Inputs

EIRP–
ERP–
Power at antenna port–

Antenna gain: dBi ↔ dBd

Linear gain–× over isotropic
RememberA half-wave dipole has 2.15 dBi = 0 dBd.

How to use

  1. Enter the transmit power per port and pick W or dBm.
  2. Add feeder, jumper and connector loss. Use about 0 dB for an AAU or an RRU mounted next to the antenna.
  3. Enter the antenna gain in dBi for the band you are checking. If the datasheet gives dBd, convert it in the box below.

Good to know

The result is per port. For the total over several MIMO ports add 10·log10(ports), e.g. +3 dB for 2 ports or +6 dB for 4. Many regulators state limits as EIRP; some use ERP, which is 2.15 dB lower.

EIRP = Ptx[dBm] − loss + G[dBi]  ·  ERP = EIRP − 2.15  ·  dBi = dBd + 2.15

Downtilt & beam throw

Where the main beam and the vertical −3 dB edges reach the ground: on flat ground, with a height difference, or along a real terrain profile. Downtilt is positive when pointing down.

Flat ground · earth curvature on

Inner edge (−3 dB)–
Main beam–
Outer edge (−3 dB)–
Footprint depth–outer − inner

Ground

Use a positive value when the site stands on higher ground than the area it serves, negative when the area is higher. Ignored while a terrain profile is loaded.

Real terrain (optional)

Ground heights come from the Copernicus 90 m DEM via Open-Meteo. Only the profile coordinates are sent; buildings and trees are not included.

Reverse: tilt for a target distance

Required total downtilt–

How to use

  1. Enter the antenna height above its own ground (centre of the panel).
  2. Set electrical (RET) and mechanical tilt. Total tilt is the sum.
  3. Take the vertical beamwidth for this band from the antenna datasheet.
  4. Optional: add the height difference, or load the real terrain along the sector azimuth.
  5. Use the reverse box to find the tilt that puts the main beam on a target, e.g. the cell edge.

How far to trust it

This is beam geometry: where the −3 dB edges meet the ground, not a signal-strength prediction. On flat ground the numbers are exact for the inputs given. With terrain it follows a 90 m DEM, which is good for hills and slopes but has no buildings, trees or clutter. It also ignores side lobes, null fill and the real vertical pattern, so use it as a quick sanity check before a planning-tool prediction (Atoll / Planet) or a drive test, not instead of them.

ray: z(d) = hant − d·tan(tilt)  ·  ground: g(d) + hUE + d² / (2·k·R)  ·  inner edge = tilt + BW/2  ·  outer edge = tilt − BW/2  ·  k·R = 4/3 · 6371 km

LTE EARFCN ↔ frequency

3GPP TS 36.101 channel numbering. Enter an EARFCN, or pick a band and type a frequency.

EARFCN → frequency

Downlink–
Paired uplink–

Frequency → EARFCN

DL EARFCN–
UL EARFCN / frequency–

How to use

  1. Left: type any EARFCN, downlink or uplink. The band and the paired channel are found for you.
  2. Right: pick a band and type the downlink centre frequency to get the EARFCN.

Good to know

LTE uses a 100 kHz channel raster, so the centre frequency must be a multiple of 0.1 MHz from the band edge. TDD bands use the same channel for uplink and downlink. Covers the bands in common use; others show as not supported.

FDL = FDL_low + 0.1·(NDL − NOffs-DL)  ·  FUL = FUL_low + 0.1·(NUL − NOffs-UL)

NR-ARFCN ↔ frequency

3GPP TS 38.104 global frequency raster, with the common NR bands that contain the frequency.

NR-ARFCN → frequency

Frequency–
Common bands–by frequency range

Frequency → NR-ARFCN

NR-ARFCN–
Common bands–

How to use

  1. Left: type an NR-ARFCN to get the frequency and the common bands that contain it.
  2. Right: type a frequency in MHz to get the nearest NR-ARFCN.

Good to know

NR-ARFCN is the absolute reference point on the global raster. Each band also has its own channel raster (often 15 or 30 kHz), and the SSB position uses GSCN, which is a different number. Overlapping bands such as n77 and n78 are both listed.

FREF = FREF-Offs + ΔFGlobal·(NREF − NREF-Offs)  ·  0–3000 MHz: 5 kHz · 3–24.25 GHz: 15 kHz · 24.25–100 GHz: 60 kHz

Timing Advance ↔ distance

Convert a TA index to UE distance and back. One LTE TA step is 16·Ts ≈ 0.52 µs round trip, about 78 m.

TA → distance

Distance–
Step size–per TA index

Distance → TA

TA index–
Round-trip delay–

How to use

  1. Choose the numerology: LTE and 15 kHz NR use the first option, most mid-band NR uses 30 kHz.
  2. Type the TA index from a trace or counter to get the UE distance.
  3. Or type a distance to see which TA index to expect.

Good to know

TA measures the round trip, so the result is the one-way distance, with a resolution of half a step either side. In non-line-of-sight areas the signal travels further than the straight line, so TA tends to read slightly long. TA beyond the planned cell range usually means overshooting.

d = TA · (16·64·Tc / 2μ) · c / 2  ·  Tc = 1 / (480 000 · 4096) s  →  ≈ 78.07 m / 2μ (78.12 m with c = 3·108)

Free-space path loss

Line-of-sight loss, plus the first Fresnel zone radius at mid-path for link clearance.

Path loss–
1st Fresnel radius at mid-path–keep at least 60 % clear
Wavelength–

How to use

  1. Enter the frequency in MHz and the distance in km.

Good to know

Free space is the best case: open, unobstructed line of sight. Real urban and suburban loss is much higher, which is why planning tools use models such as COST-231 Hata or 3GPP 38.901. The Fresnel radius is for point-to-point links: keep at least 60 % of the first zone clear of obstacles.

FSPL[dB] = 20·log10(d[km]) + 20·log10(f[MHz]) + 32.44  ·  rF1 = 17.32·√(d[km] / (4·f[GHz])) m

CSV → KML sectors

Paste or drop a site list and get a Google Earth file with one folder and colour per band. Columns are detected by name.

Input CSV

Drop a .csv file here, or click to choose

Detected columns

Waiting for data.

How to use

  1. Paste the site list, drop a CSV file, or press Load sample to try it.
  2. Check the detected columns. Missing radius or beamwidth uses the defaults.
  3. Press Download KML and open the file in Google Earth or QGIS.

Good to know

Comma, semicolon and tab separated files all work. Each band gets its own folder and colour, and every sector shows its azimuth, beamwidth and radius when clicked. The file is built in your browser; nothing is uploaded.

Recognised columns: cell / name / site, lat / latitude, lon / lng / longitude, azimuth / az, beamwidth / bw / hbw, radius, band / layer / tech. Rows without coordinates or azimuth are skipped.