Re: Info on K3 "IF OUT"

Posted by Bruce Beford-2 on Apr 23, 2011; 4:25pm
URL: http://elecraft.85.s1.nabble.com/Info-on-K3-IF-OUT-tp6299452p6299707.html

> In part, my reason for asking is the following...

> I am feeding the K3 IF Out into a fast ADC at 192 kHz, followed by a
> Winloe detector, etc. for panoramic viewing, but despite the 192 kHz
> sampling frequency I am only getting about 44 kHz TOTAL spectral width.
> Thus, there seems to be a front-end bandwidth of about +/- ~25 kHz. Is
> this true? Or am I doing something wrong?

> The P3 comes up with a TOTAL spectral width of ~200 kHz. Where does it
> pick its signal from?

> John Ragle -- W1ZI

John,
It sounds as though there is something amiss with your setup. The K3 IF
output is indeed quite wide (wider than 200 KHz). It is tapped off before
the roofing filters, but after the BPFs, I believe. This is the same output
the P3 uses.

In answer to your previous question, it is centered on the K3 IF frequency.
As Al, N1AL (Mr. P3) mentioned in his post, signal Levels are less than at
the antenna input. I believe the conversion gain is somewhwere around -7-10
dB, depending on whether or not the IF amp gain mod was performed.

GL,
Bruce, N1RX




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