# [amsat-bb] Re: ICOM 910H

i8cvs domenico.i8cvs at tin.it
Thu Aug 9 10:33:32 PDT 2007

```Hi Scott, NX7U

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

-6   2
( Vin x 10    )    x 20
NF     = [ 10 log       ------------------------  ]  + 174
dB                  10        BW  x  S/N

Where:

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)
S/N = -------  - 1     (in factor and not dB)
N
(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

73" de

i8CVS Domenico

----- 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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```