- 21st January 2005, 16:55 #1

- Join Date
- Nov 2004
- Posts
- 43
- Helped
- 2 / 2
- Points
- 1,670
- Level
- 9

## What is EIRP???

Hello, everybody.

I have a question, that is, what is the definition of EIRP??? and what's the relationship with antenna gain?

Thks in advance.

- 21st January 2005, 16:55

- 21st January 2005, 17:15 #2

- Join Date
- Dec 2002
- Location
- Romania
- Posts
- 735
- Helped
- 41 / 41
- Points
- 9,194
- Level
- 22

## What is EIRP???

Well, one theory could say that EIRP is one of our moderator buddies, but here http://www.csgnetwork.com/antennaecalc.html you can find a more comprehensive definition of Effective Isotropic Radiated Power, and some tools to calculate it from the antenna gain and the actual transmitted output power.

/pisoiu

- 21st January 2005, 18:11 #3

- Join Date
- Jan 2005
- Location
- Asia
- Posts
- 311
- Helped
- 22 / 22
- Points
- 3,276
- Level
- 13

## Re: What is EIRP???

EIRP is a measure of approximate power radiated from an antenna.

The approximation works well as it considers almost all possible factors.

Say an antenna is capable of transmiting P power..(Watts) ,then this P is not actually transmited.

Consider the various losses and we can get actual power radiated.

For simplicity ,EIRP is calculated in Log system as losses can be directly substracted from net power.

EIRP= P - Losses.

EIRP is directly proportional to antenna gain.

EIRP is most important parameter while designing various systems. (say a satellite link )

- 21st January 2005, 18:11

- 21st January 2005, 19:03 #4

- Join Date
- Feb 2002
- Posts
- 50
- Helped
- 4 / 4
- Points
- 4,111
- Level
- 15

## Re: What is EIRP???

Originally Posted by**pisoiu**

- 21st January 2005, 19:03

- 21st January 2005, 20:56 #5

- Join Date
- Dec 2004
- Location
- New England, USA
- Posts
- 4,122
- Helped
- 1130 / 1130
- Points
- 29,592
- Level
- 41

## Re: What is EIRP???

A famous cowboy from the American west, Wyatt Eirp.

- 23rd January 2005, 07:05 #6

- Join Date
- Apr 2004
- Posts
- 204
- Helped
- 6 / 6
- Points
- 2,958
- Level
- 12

## Re: What is EIRP???

You can refer to this docuemnt.

Antenna Pattern Measurement: Theory and Equations

- 27th January 2005, 10:06 #7

- Join Date
- Feb 2004
- Posts
- 29
- Helped
- 0 / 0
- Points
- 1,783
- Level
- 9

## Re: What is EIRP???

The Effective Isotropic Radiated Power (EIRP) of a transmitter is the power that the transmitter appears to have if the transmitter were an isotropic radiator (if the antenna radiated equally in all directions).*

By virtue of the gain of a radio antenna (or dish), a beam is formed that preferentially transmits the energy in one direction.* The EIRP is estimated by adding the gain (of the antenna) and the transmitter power (of the radio).

EIRP = transmitter power + antenna gain – cable loss

[100 mW <=> 20 dBm]

- 28th January 2005, 13:35 #8

- Join Date
- Nov 2004
- Posts
- 43
- Helped
- 2 / 2
- Points
- 1,670
- Level
- 9

## Re: What is EIRP???

thank you for answer my question, except the cable loss, Is the path loss also the important factor for measuring the EIRP????

- 8th February 2005, 12:47 #9

- Join Date
- Dec 2004
- Posts
- 71
- Helped
- 8 / 8
- Points
- 2,197
- Level
- 10

## What is EIRP???

path loss is not included in measuring EIRP, coz EIRP is effective power radiated by antenna, this is transmitter's power(dB) + antenna gain (dB). Path loss is experienced by the radiated power, so path loss is an external factor of lossess.