Re: K3 FSK power transients

Posted by Joe Subich, W4TV-4 on Sep 28, 2009; 2:12pm
URL: http://elecraft.85.s1.nabble.com/K3-FSK-power-transients-tp3712691p3729639.html



> I'm surprised I can see a difference between the two tones
> through the flatter filter 8-pole filter. It's just enough
> to see on the 200W scale of an old (pretty much uncalibrated)
> Daiwa CN-520.

With the 8 pole filter I see 2 watts difference on the N8LP
LP-100 wattmeter.  However, in AFSK A or DATA A modes for
PSK I see as much as 15 watts (0.7 dB) difference (maximum
to minimum) as the tone frequency varies from 200 Hz to 2800
Hz in DATA A (FC=1500 Hz) or 1000 Hz to 3500 Hz in AFSK
(FC=2210 Hz).

73,

   ... Joe, W4TV
   

> -----Original Message-----
> From: [hidden email]
> [mailto:[hidden email]] On Behalf Of Randy Farmer
> Sent: Sunday, September 27, 2009 7:57 PM
> To: [hidden email]
> Subject: Re: [Elecraft] [K3] K3 FSK power transients
>
>
> The roofing filter IS offset to put the RTTY tones (Data |
> Pitch) in the center of the filter.
>
> Good to know. That's how I would have done it I were the designer.
> I'm surprised I can see a difference between the two tones through
> the flatter filter 8-pole filter. It's just enough to see on the 200W
> scale of an old (pretty much uncalibrated) Daiwa CN-520.
>
> 73...
> Randy, W8FN
>

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