--- On Mon, 5/4/09, [email protected] <[email protected]> wrote:
> From: [email protected] <[email protected]>
> Subject: Re: [Elecraft] K3 on-channel strong signal overload?
> To: [email protected]
> Date: Monday, May 4, 2009, 3:10 PM
> Good day:
>
> I can't help myself. :-)
>
> The "usual" definition of an S9 signal is 50
> uVolts, or -73 dBm (assuming a
> 50 Ohm load).
>
> The "S-Meter" unit is a 6 dB change in VOLTAGE,
> not power. To get one VOLT,
> we need 2000 times 50 uVolts, or S9 + about 86dB (86 dB
> over S9).
>
> 40 over is about 5 mVolts...
>
> The formula for the dB difference for two voltages,
> assuming you want a power
> and have the same load, is
>
> 20 * log (V2/V1). If you want dB's "over"
> S9, let V1 be 50 uV, (50E-6 Volts).
>
> Now, let's hope I managed to get this right. :-)
You got the right answer (86 dB) but when using your slide rule you didn't keep
track of the decimal point. One volt is 20,000 * 50 uV.
Wes Stewart, N7WS
______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[email protected]
This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
