[amsat-bb] Re: e: Satellite technical question

[i8cvs]

Hi Nick ,

The equivalent noise temperature of an antenna do not depends by it's
phisical temperature but only by the noise temperature emitted by the
object that the main lobe of the antenna is looking.

The equivalent noise temperature of the antenna radiation resistance
do not depends by the phisical temperature of the antenna but only
by the noise temperature emitted by the object that the main lobe of
the antenna is looking.

As an example, if you install a parabolic dish on the Nort Pool at very low
temperature and a similar parabolic dish in the desert at the equator at
high temperature and you point both the antennas toward the Sun than the
received Sun Noise will be the same no matter the structural temperature
of  both dishes will be.

Of coarse only the phisical temperature of the antenna preamplifiers and
all the associated receivers phisical temperature must be the same.

73" de

i8CVS Domenico

----- Original Message -----
From: "Nick Pugh" <quadpugh at bellsouth.net>
To: "'Nick Pugh'" <quadpugh at bellsouth.net>; <amsat-bb at amsat.org>
Sent: Sunday, September 09, 2012 8:15 PM
Subject: [amsat-bb] Re: e: Satellite technical question


I am sorry I did not mean the physical temperature What I wanted is the
equivalent noise temperature.

Thanks for those who replied

nick

-----Original Message-----
From: amsat-bb-bounces at amsat.org [mailto:amsat-bb-bounces at amsat.org] On
Behalf Of Nick Pugh
Sent: Sunday, September 09, 2012 10:07 AM
To: amsat-bb at amsat.org
Subject: [amsat-bb] e: Satellite technical question

e: Satellite technical question

Assume a cubesat with a monopole ¼ wave antenna at 400 mhz. The satellite is
in full sun with a 500km orbit. What is the antenna temperature in full sun
and in eclipse?

TNX in advance

Nick CAPE Team