Re: [amsat-bb] Using AO-40 XLS (AO40_S2.xls)

["John Stephensen, KD6OZH" <kd6ozh@xxxxxxx>]

If you have a calibrated signal generator or noise source and an RMS audio
voltmeter you can measure the minimum discernable signal in CW or SSB modes
and calculate the noise figure.

    NF = 174 - 10*log10(BW) - MDS

BW is the bandwidth in Hertz
MDS is the signal level in dBm that gives a 3 db increase in audio output

The ARRL measures MDS in most product reviews. See
http://www.arrl.org/members-only/prodrev/bymfg.html.

73,

John
KD6OZH

----- Original Message -----
From: "Gerald Payton" <n5gpc@earthlink.net>
To: "AMSAT-BB" <amsat-bb@AMSAT.Org>
Sent: Monday, 04 June 2001 00:43 UTC
Subject: [amsat-bb] Using AO-40 XLS (AO40_S2.xls)


> How does one determine his receiver's NF?  Is the 15dB an average figure?
>
> I have an IC-820H, but the specs. give no NF or bandwidth figures.
>
> Tnx.
>
> Jerry
>
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