[amsat-bb] Re: ICOM 910H
domenico.i8cvs at tin.it
Thu Aug 9 10:33:32 PDT 2007
Hi Scott, NX7U
Your calculation is correct.
Just for information if 0.11 uV is the applied voltage across an input
impedance of 50 ohm to get the sensitivity for 10 dB S/N the following
formula is very useful to calculate the corresponding NF in dB
( Vin x 10 ) x 20
NF = [ 10 log ------------------------ ] + 174
dB 10 BW x S/N
Vin = applied voltage in uV over 50 ohm
BW = Bandwidth in Hz
S/N = 10 dB Signal to Noise ratio expressed in factor = 10
In fact if you put in the above formula Vin = 0.11 uV ; BW = 3000 Hz
S/N = 10 ,then you get a NF = 3.06 dB
If the receiver sensitivity is given in uV for a ratio of (S/N)/N instead of
a ratio S/N the conversion formula is
S/N = ------- - 1 (in factor and not dB)
(12 / 10 )
Example: (S/N) / N = 12 dB = 10 = 15.84 (in factor)
S/N = 15.84 - 1 = 14 .84 (in factor)
For more detais about the above formula see Ham Radio Magazine April 1980
page 71 " Noise Figure Relationship" by I.L. McNally, K6WX
----- Original Message -----
From: "Scott Townley" <nx7u at cox.net>
To: <amsat-bb at amsat.org>; "ubong ukommi" <uukommi at yahoo.com>
Sent: Wednesday, August 08, 2007 10:05 PM
Subject: [amsat-bb] Re: ICOM 910H
> The RX specifications are
> SSB/CW 0.11uV for 10dB S/N
> ...if the noise bandwidth is around 3kHz then that's a 3dB noise figure
> FM 0.18uV for 12dB SINAD
> ...if the noise bandwidth is around 5kHz then that's a 3.4dB noise figure
> Scott Townley NX7U
> Gilbert, AZ DM43di
> ---- ubong ukommi <uukommi at yahoo.com> wrote:
> > Hello,
> > Please could you help me with the Noise figue of the receiver 910H. I
want to use it for a link budget analysis.
> > I have tried available sources but no solution.
> > Thanks.
> > Ubong (M3UIU)
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