# Calibration

## Combined revision comparison

Comparing version 20:11, 21 Nov 2014 by Admin with version 20:29, 21 Nov 2014 by Admin.

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This is the power arriving in the flexible wave guide attached to the feed horn behind the dish antenna.
Note that dBm is itself a logarithmic scale, with 0 -> 1 milliwatt, -10 -> 0.1 milliwatt, -20 ->0.01 milliwatt, etc.
To get the incoming power from the target, you need to also calculate the antenna gain factor.  For the 55 cm
dish, this is around 25 or 30 dB (I have an estimate of the value somewhere - bug me.)  So if the usrp.value30dB.
maps to an incoming power of -60 dB, and the antenna has a gain of 25 dB, then incoming power at the antenna,
before focussing (i.e. before the antenna gain comes into play) is -85 dB.

## Version from 20:11, 21 Nov 2014

This revision modified by Admin (Ban)

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## Current version

This revision modified by Admin (Ban)

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This is the power arriving in the flexible wave guide attached to the feed horn behind the dish antenna.
Note that dBm is itself a logarithmic scale, with 0 -> 1 milliwatt, -10 -> 0.1 milliwatt, -20 ->0.01 milliwatt, etc.
To get the incoming power from the target, you need to also calculate the antenna gain factor.  For the 55 cm
dish, this is around 25 or 30 dB (I have an estimate of the value somewhere - bug me.)  So if the usrp.value
maps to an incoming power of -60 dB, and the antenna has a gain of 25 dB, then incoming power at the antenna,
before focussing (i.e. before the antenna gain comes into play) is -85 dB.