Documentation sections

Parabolic Dish Antenna Calculator

POSThttps://rftools.io/api/py/v1/calculate

Slug parabolic-dish-antenna. Calculate parabolic dish gain, HPBW and effective aperture. Design satellite and microwave dish antennas. Free, instant results.

Inputs

Send every one of these in inputs, in the units shown. Most are required: a call without one is refused (400) and costs nothing; one the calculator can do without takes the default shown. An input outside its range is still computed and flagged in the provenance.

Inputs of parabolic-dish-antenna
Name	Unit	Range	Default	Description
frequencynumber	GHz	at least 0.1	12	Operating frequency in GHz
diameternumber	m	0.01 … 500	1.2	Reflector diameter in meters
efficiencynumber	%	1 … 100	55	Typical values: 50–65% for commercial dishes

Outputs

Returned in values, by key. A value that is unbounded or undefined is null.

Outputs of parabolic-dish-antenna
Field	Unit	Description
gainheadline	dBi	Antenna Gain
hpbw	degrees	Half-Power Beamwidth
effectiveArea	m²	Effective Aperture Area

Calling it

Calculate: one call, the request and response in full, and its errors.
Batch: this calculator with others, or a sweep, in one request.
Solve for a target: the value of one input that brings an output to a target.

curl -X POST https://rftools.io/api/py/v1/calculate \
  -H "X-API-Key: $RFTOOLS_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "slug": "parabolic-dish-antenna",
    "inputs": {
      "frequency": 12,
      "diameter": 1.2,
      "efficiency": 55
    }
  }'

import rftools

client = rftools.Client()  # reads RFTOOLS_API_KEY, or the key `rftools login` saved

result = client.calculate("parabolic-dish-antenna", {"frequency": 12, "diameter": 1.2, "efficiency": 55})
print(result.values)
print(result.warnings, result.provenance.formula_ref)

const response = await fetch("https://rftools.io/api/py/v1/calculate", {
  method: "POST",
  headers: {
    "X-API-Key": process.env.RFTOOLS_API_KEY,
    "Content-Type": "application/json",
  },
  body: JSON.stringify({
    "slug": "parabolic-dish-antenna",
    "inputs": {
      "frequency": 12,
      "diameter": 1.2,
      "efficiency": 55
    }
  }),
});
console.log(response.status, await response.json());

package main

import (
	"bytes"
	"fmt"
	"io"
	"net/http"
	"os"
)

func main() {
	body := []byte(`{
	  "slug": "parabolic-dish-antenna",
	  "inputs": {
	    "frequency": 12,
	    "diameter": 1.2,
	    "efficiency": 55
	  }
	}`)
	req, err := http.NewRequest("POST", "https://rftools.io/api/py/v1/calculate", bytes.NewReader(body))
	if err != nil {
		panic(err)
	}
	req.Header.Set("X-API-Key", os.Getenv("RFTOOLS_API_KEY"))
	req.Header.Set("Content-Type", "application/json")
	res, err := http.DefaultClient.Do(req)
	if err != nil {
		panic(err)
	}
	defer res.Body.Close()
	out, _ := io.ReadAll(res.Body)
	fmt.Println(res.Status, string(out))
}

application/json

{
  "slug": "parabolic-dish-antenna",
  "values": {
    "gain": 40.97746013217156,
    "hpbw": 1.4573244486111112,
    "effectiveArea": 0.6220353454107791
  },
  "warnings": [],
  "errors": [],
  "provenance": {
    "method": "calculator:parabolic-dish-antenna",
    "version": "api@3f2c1a9b04de",
    "formulaRef": "Antenna Theory: Analysis and Design, 4th ed., Constantine A. Balanis (2016), Chapter 15 — Reflector antennas and parabolic dish gain",
    "assumptions": [
      {
        "code": "no-antenna-temperature",
        "text": "No antenna noise temperature is reported: it depends on the elevation angle, the sky brightness temperature (ITU-R P.372) and the spillover onto ground, none of which is an input."
      }
    ],
    "validRange": {
      "status": "inside",
      "bounds": {
        "frequency": {
          "min": 0.1,
          "max": null,
          "unit": "GHz"
        },
        "diameter": {
          "min": 0.01,
          "max": 500,
          "unit": "m"
        },
        "efficiency": {
          "min": 1,
          "max": 100,
          "unit": "%"
        }
      },
      "outside": [],
      "model": null
    },
    "computedAt": "2026-09-24T14:05:11.003Z",
    "inputs": {
      "frequency": 12,
      "diameter": 1.2,
      "efficiency": 55
    },
    "seed": null,
    "elapsedSeconds": 0.003
  }
}

{
  "detail": [
    {
      "type": "float_parsing",
      "loc": [
        "body",
        "inputs",
        "frequency"
      ],
      "msg": "Input should be a valid number, unable to parse string as a number",
      "input": "abc"
    }
  ]
}

An input sent as text. Nothing was counted.

{
  "detail": "More than 120 requests in 60 seconds from this address.",
  "errorKind": "rate_limited",
  "limit": 120,
  "windowSeconds": 60,
  "upgradeUrl": "https://rftools.io/pricing/"
}

Too many requests in a minute, with Retry-After.

Same inputs on the calculator pageParabolic Dish Antenna Calculator, at these values