Category: Engineering Tools

The Friis transmission equation, as shown below, gives the ratio of received to transmitted power for given antenna gains, ranges, and wavelengths under ideal conditions. The calculator below uses this equation to find any one of the variables, provided all the other variables are known.

Leave the unknown value blank and fill in the remaining values. When one available unit for a value is filled in, the other available units are automatically converted from the entered unit value. Once all but one value is entered in, press Calculate next to the unknown value.

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Transmit Power, Pt	W
	dBm
Transmit Antenna Gain, Gt	dBi
	dBd
Receiver Antenna Gain, Gr	dBi
	dBd
Received Power, Pr	W
	dBm
Range, R	meters
	miles
Frequency	kHz
	MHz
	GHz
Wavelength, λ	meters
	cm
	mm

Pi Attenuator Calculator Sorry, this calculator needs Javascript Either your browser does not support Javascript, you have disabled it or there is a problem with my page. If you suspect the last one, please email me with details of your browser so that I can fix the problem.

Enter values and press Enter or click on the Calculate button
	Attenuation:	dB
	Input Impedance:	Ohm
	output Impedance:	Ohm
Ideal Values R1 Ohm R2 Ohm R3 Ohm

E12 Values		E12 Performance
R1	Ohm	Attenuation	dB
R2	Ohm	Zin	Ohm
R3	Ohm	Zout	Ohm
E24 Values		E24 Performance
R1	Ohm	Attenuation	dB
R2	Ohm	Zin	Ohm
R3	Ohm	Zout	Ohm
E48 Values		E48 Performance
R1	Ohm	Attenuation	dB
R2	Ohm	Zin	Ohm
R3	Ohm	Zout	Ohm
E96 Values		E96 Performance
R1	Ohm	Attenuation	dB
R2	Ohm	Zin	Ohm
R3	Ohm	Zout	Ohm
E192 Values		E192 Performance
R1	Ohm	Attenuation	dB
R2	Ohm	Zin	Ohm
R3	Ohm	Zout	Ohm

 

T Attenuator Calculator

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Either your browser does not support Javascript, you have disabled it or there is a problem with my page. If you suspect the last one, please email me with details of your browser so that I can fix the problem.

Enter values and press Enter or click on the Calculate button
	Attenuation:	dB
	Input Impedance:	Ohm
	Output Impedance:	Ohm
Ideal Values R1 Ohm R2 Ohm R3 Ohm

E12 Values		E12 Performance
R1	Ohm	Attenuation	dB
R2	Ohm	Zin	Ohm
R3	Ohm	Zout	Ohm
E24 Values		E24 Performance
R1	Ohm	Attenuation	dB
R2	Ohm	Zin	Ohm
R3	Ohm	Zout	Ohm
E48 Values		E48 Performance
R1	Ohm	Attenuation	dB
R2	Ohm	Zin	Ohm
R3	Ohm	Zout	Ohm
E96 Values		E96 Performance
R1	Ohm	Attenuation	dB
R2	Ohm	Zin	Ohm
R3	Ohm	Zout	Ohm
E192 Values		E192 Performance
R1	Ohm	Attenuation	dB
R2	Ohm	Zin	Ohm
R3	Ohm	Zout	Ohm

Enter any one of the parameters below and the rest will be calculated automatically.

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Return Loss:		dB
Reflection Coefficient ( S11 ):
VSWR:		:1

When an inductor or capacitor are placed in series or parallel they will have a resonant frequency which is determined by the design equation below. LC resonant circuits are useful as notch filters or band pass filters. They are also found in oscillator circuits.   Design Equation: Enter in any two parameters for a resonant circuit, and this calculator will calculate the third missing parameter.   Frequency: (MHz) Capacitance: (pF) Inductance: (nH)

This calculator converts between watts, dBm, volts and dBmV. Select the Impedance then enter any one of the other parameters below and the rest will be calculated automatically Sorry, this calculator needs Javascript Either your browser does not support Javascript, you have disabled it or there is a problem with my page. If you suspect the last one, please email me with details of your browser so that I can fix the problem. Impedance (Ω):  50Ω Common in RF and Microwave Systems 75Ω Common in TV and Video Systems 600Ω Common in Audio Systems Custom Value   milli Watts (mW): Watts (W):   dBm: dBW:   VRMS: VPeak: Assuming a sine wave VP-P: Assuming a sine wave   dBmV: dB relative to 1mV RMS. Often used in the cable TV industry and only valid in 75Ω systems Most RF engineers will have memorised the following values: dBm mW Notes   0   1 Exact by definition of dBm   3   2 3 dBm is actually 1.995 mW but that’s near enough for most practical purposes  10  10 Exact  +3  X 2 Adding 3 to the power in dBm is the same as multiplying the power in Watts by two (actually 1.995 but that’s near enough for most practical purposes) +10 X 10 Adding 10 the the power in dBm is exactly the same as multiplying the power in Watts by 10