[amsat-bb] Re: Arecibo

i8cvs domenico.i8cvs at tin.it
Sat Apr 17 09:00:11 PDT 2010

Hi Nick, K5QXJ

Is your KLM 436 a linearly polarized antenna or a circularly polarized
antenna ?

If it is circularly polarized switch polarization to LHCP because Arecibo
transmit RHCP toward the moon but the moon reflect back isotropically
a signal in LHCP

If your KLM 436 is linearly polarized no matter if it is horizontal or
vertical because Arecibo comes to you circularly LHCP

About the sun-noise supposing that the gain of your antenna is 16 dBi
corresponding to the gain of a dish with diameter of 6.5 feet and that
the sun activity yesterdat 16 April was 75 sfu at 2800 MHz (10.7 cm)
using the program NOISE.EXE with 75 kelvin for your 1 dB of NF
for preamplifier and 70 kelvin for the antenna temperature with the
elevation of the sun 75° it outcomes that the sun-noise you should
receive as a (S+N)/N ratio is 2.8 dB maximum

So you receive the right sun-noise figure from your system no matter
if the antenna is linearly or circularly polarized because the sun-noise
is a uncoherent signal no polarized.

In a separate email I have sent to you the software NOISE.EXE a
very simple but powerful program working in DOS

73" de

i8CVS Domenico

----- Original Message -----
From: "Nick Pugh K5QXJ" <quadpugh at bellsouth.net>
To: <amsat-bb at amsat.org>
Sent: Saturday, April 17, 2010 1:09 PM
Subject: [amsat-bb] Arecibo

> Hi All
> I have a KLM 436 with < 1 db preamp I did not here them yesterday. I have
> about 2 db of sun noise. The question I have for those who copied Arecibo
> yesterday how much sun noise do you have in a 2.4 KHz band with filter?
> Thanks
> nick
> Office   337 593 8700
> Cell      337 258 2527
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