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Re: Re: SNR measurements



Hi all,

I have made sun noise measurements using my FT-736.  I was under the
impression that turning down the rf gain control with the audio wide open
would effectively disable the AGC.  Am I wrong?  Any comments?

73 de Ken - K5GUU
----- Original Message -----
From: "i8cvs" <domenico.i8cvs@tin.it>
To: "AMSAT-BB" <amsat-bb@amsat.org>; "Ronald Long" <rlong3@columbus.rr.com>
Sent: Wednesday, February 19, 2003 4:14 PM
Subject: R: [amsat-bb] Re: SNR measurements


> Hi Ron W8GUS,
>
> Your suggestion to use the output transformer in the audio
> circuit loaded as you describes is exactly what i do even using an old
> DRAKE R-4C HF tube receiver with an additional  144-146 to
> 28-30 MHz additional conversion to take the advantages of
> the AGC switching ON and OFF facility.
>
> 73" de i8CVS Domenico
>
> ----- Original Message -----
> From: Ronald Long <rlong3@columbus.rr.com>
> To: <amsat-bb@AMSAT.Org>
> Sent: Wednesday, February 19, 2003 9:17 PM
> Subject: [amsat-bb] Re: SNR measurements
>
>
> > NX7U wrote:
> > Once again, Domenico is right on the money--the key is a constant
> bandwidth
> > measurement that includes the noise in the bandwidth.
> > ------------------------------------------
> > One other possible source of error is the fact that the output impedance
> of
> > modern receivers is not constant or accurately known. An article I read
> > suggested connecting an output transformer in reverse to the speaker
> > terminals, say 8 ohms to a known value, R. Connect a 1W resistor of
value
> R
> > across the R winding and connect the audio voltmeter across R.
> >
> > ron w8gus.
> >
> > ----
> > Sent via amsat-bb@amsat.org. Opinions expressed are those of the author.
> > Not an AMSAT member? Join now to support the amateur satellite program!
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>
>
> ----
> Sent via amsat-bb@amsat.org. Opinions expressed are those of the author.
> Not an AMSAT member? Join now to support the amateur satellite program!
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----
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