Re: K3 on-channel strong signal overload?

Posted by kd4d on May 04, 2009; 9:10pm
URL: http://elecraft.85.s1.nabble.com/K3-on-channel-strong-signal-overload-tp2785612p2789455.html

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.  :-)

73,

Mark





----- Original Message -----
From: "Randy Downs" <[hidden email]>
To: [hidden email], "Jim Brown" <[hidden email]>
Sent: Monday, May 4, 2009 4:37:01 PM GMT -05:00 US/Canada Eastern
Subject: Re: [Elecraft] K3 on-channel strong signal overload?

40 over is several volts? I thought it was around 5 mili volts. That's what
I am talking about. I've seen this distortion in signals since several fw
revisions ago. If I get time tonight I'll reload some earlier rev's.
Randy
K8RDD
----- Original Message -----
From: "Jim Brown" <[hidden email]>
To: "Elecraft List" <[hidden email]>
Sent: Monday, May 04, 2009 2:34 PM
Subject: Re: [Elecraft] K3 on-channel strong signal overload?

> On Mon, 4 May 2009 14:12:09 -0400, Randy Downs wrote:
>
>>It's on 10 meters. Should I not run 10 meters?
>
> Of course not. Just don't be surprised when several volts of on-
> frequency RF causes overload.
>
> 73,
>
> Jim K9YC
>
>
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