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*Subject*: R: [amsat-bb] System NF Calculations*From*: "i8cvs" <domenico.i8cvs@xxxxxx>*Date*: Mon, 21 May 2001 13:03:09 +0200

Hi Bill, The FT-736 sensitivity in CW/SSB with 2500 Hz bandwidth is -15 dB microvolt for a ratio of (S+N)/N = 12 dB from here: 10 log ( -15/20 ) = 0,177 microvolt 10 This is the applied voltage across the receiver input necessary to obtain an output with a ratio of (S+N)/N = 12 dB (12/10) (S+N)/N =12 dB is equivalent to 10 = 15,84 in factor S+N and S/N = -------- -1 =15,84-1= 14,84 in factor N The noise figure in dB can be readily calculated using the following formula derived from an article published in Ham Radio Magazine April 1980 page 71 and 94 and titled "Noise Figure Relationship" -6 ( 0,177x10 ) x 20 NF (dB) = [ 10 log ----------------------- ] + 174 = 10 2500 x 14,84 = -167,7 + 174 = 6,27 dB In this formula 20 is a constant and 174 is the -174 dBm available thermal noise power density (dBm in 1 Hz at room temperature) and 2500 is the bandwidth in Hz 73 de i8CVS Domenico ----- Original Message ----- From: Bill Hurlock <bill@hurlock.net> To: Scott Townley <nx7u@arrl.net> Cc: Joe Leikhim <jleikhim@nettally.com>; <amsat-bb@AMSAT.Org> Sent: Sunday, May 20, 2001 11:56 PM Subject: Re: [amsat-bb] System NF Calculations > I looked at the manual for the Ft-736R and it says for cw/ssb better than > -15dbu for 12 db S=N:N. What does that make it. > > > ---- > > Via the amsat-bb mailing list at AMSAT.ORG courtesy of AMSAT-NA. > > To unsubscribe, send "unsubscribe amsat-bb" to Majordomo@amsat.org > > ---- > Via the amsat-bb mailing list at AMSAT.ORG courtesy of AMSAT-NA. > To unsubscribe, send "unsubscribe amsat-bb" to Majordomo@amsat.org > ---- Via the amsat-bb mailing list at AMSAT.ORG courtesy of AMSAT-NA. To unsubscribe, send "unsubscribe amsat-bb" to Majordomo@amsat.org

**References**:**Re: System NF Calculations***From:*Scott Townley

**Re: System NF Calculations***From:*Bill Hurlock

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