Info on K3 "IF OUT"
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Aside from the frequency, I can find nothing about the characteristics
of the K3 "IF OUT" feed. Could some kind person provide info about bandwidth, levels, etc...? John Ragle -- W1ZI ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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It is a wideband, low-level signal. The bandwidth is just limited by the
front-end filters in the K3. The level is about 7 dB less than the level at the K3 antenna input (preamp and attenuator off). On older K3s that don't have the IF OUT modification the level is less than that, by about 8-10 dB as I recall. Alan N1AL > Aside from the frequency, I can find nothing about the characteristics > of the K3 "IF OUT" feed. Could some kind person provide info about > bandwidth, levels, etc...? > > John Ragle -- W1ZI > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[hidden email] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > > ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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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 ===== On 4/23/2011 11:44 AM, [hidden email] wrote: > It is a wideband, low-level signal. The bandwidth is just limited by the > front-end filters in the K3. The level is about 7 dB less than the level > at the K3 antenna input (preamp and attenuator off). On older K3s that > don't have the IF OUT modification the level is less than that, by about > 8-10 dB as I recall. > > Alan N1AL > > >> Aside from the frequency, I can find nothing about the characteristics >> of the K3 "IF OUT" feed. Could some kind person provide info about >> bandwidth, levels, etc...? >> >> John Ragle -- W1ZI >> ______________________________________________________________ >> Elecraft mailing list >> Home: http://mailman.qth.net/mailman/listinfo/elecraft >> Help: http://mailman.qth.net/mmfaq.htm >> Post: mailto:[hidden email] >> >> This list hosted by: http://www.qsl.net >> Please help support this email list: http://www.qsl.net/donate.html >> >> > > > > > ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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In reply to this post by John Ragle
> 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 ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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In reply to this post by John Ragle
John,
Something is confusing in your post. If you want to sample IF directly, you would need ADC with sampling rate of at least 18MHz or so. (more than twice the 8.215MHz IF of K3). Your 192kHz doesn't make sense. P3 digitizing at 60 MHz because they want to allow using it with other rigs with IF up to 21 MHz or so. Maybe you can explain your setup in more detail. 73, Igor, N1YX -----Original Message----- From: [hidden email] [mailto:[hidden email]] On Behalf Of John Ragle Sent: Saturday, April 23, 2011 12:11 PM To: [hidden email] Cc: [hidden email] Subject: Re: [Elecraft] Info on K3 "IF OUT" 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 ===== On 4/23/2011 11:44 AM, [hidden email] wrote: > It is a wideband, low-level signal. The bandwidth is just limited by the > front-end filters in the K3. The level is about 7 dB less than the level > at the K3 antenna input (preamp and attenuator off). On older K3s that > don't have the IF OUT modification the level is less than that, by about > 8-10 dB as I recall. > > Alan N1AL > > >> Aside from the frequency, I can find nothing about the characteristics >> of the K3 "IF OUT" feed. Could some kind person provide info about >> bandwidth, levels, etc...? >> >> John Ragle -- W1ZI >> ______________________________________________________________ >> Elecraft mailing list >> Home: http://mailman.qth.net/mailman/listinfo/elecraft >> Help: http://mailman.qth.net/mmfaq.htm >> Post: mailto:[hidden email] >> >> This list hosted by: http://www.qsl.net >> Please help support this email list: http://www.qsl.net/donate.html >> >> > > > > > ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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In reply to this post by John Ragle
I am using the LP-Pan on the K3 IF and its clock runs at
8.215x4. Actually, the later models of the LP Pan run at (8.215-.006)x4 = 8.209x4 = 32.836 MHz. LP-Pan set up for radios other than the K3 have a different LO to suit those radio's IF. Minimum sampling rate needs to be >2x the IF frequency. ------------------------------ Message: 4 Date: Sat, 23 Apr 2011 13:27:15 -0400 From: "Igor Kosvin" <[hidden email]> Subject: Re: [Elecraft] Info on K3 "IF OUT" To: <[hidden email]>, <[hidden email]> Cc: [hidden email] Message-ID: <006e01cc01db$b2a38bf0$17eaa3d0$@[hidden email]> Content-Type: text/plain; charset="us-ascii" John, Something is confusing in your post. If you want to sample IF directly, you would need ADC with sampling rate of at least 18MHz or so. (more than twice the 8.215MHz IF of K3). Your 192kHz doesn't make sense. P3 digitizing at 60 MHz because they want to allow using it with other rigs with IF up to 21 MHz or so. Maybe you can explain your setup in more detail. 73, Igor, N1YX 73, Ed - KL7UW, WD2XSH/45 ====================================== BP40IQ 500 KHz - 10-GHz www.kl7uw.com EME: 50-1.1kW?, 144-1.4kw, 432-100w, 1296-testing*, 3400-? DUBUS Magazine USA Rep [hidden email] ====================================== ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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In reply to this post by John Ragle
I'm not familiar with a "Winloe" detector. I assume you are using some
kind of quadrature downconverter, such as LP-PAN, to convert the K3's 8.215 MHz IF to an I/Q baseband signal to feed to the stereo input of a sound card connected to a personal computer. In that case, the IF bandwidth should be somewhat less than the sample rate of the sound card. With a typical 192 ksps sound card, you should get 180 kHz or so bandwidth. If you're only getting 44 kHz RF bandwidth, that sounds like the sample rate may be only 48 kHz. Your 192 ksps sound card may have accidentally been set to 48 kHz. I would read your sound card documentation to figure out how to check for that. BTW, the P3 works differently. It samples the IF directly at a high rate (60 MHz) and does the quadrature downconversion digitally. The advantage is much greater accuracy (for example, no "images" on the other side of the center frequency) and the ability to work with different IF frequencies without any change to the hardware. Alan N1AL On Sat, 2011-04-23 at 12:10 -0400, John Ragle wrote: > 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 > > ===== > > On 4/23/2011 11:44 AM, [hidden email] wrote: > > It is a wideband, low-level signal. The bandwidth is just limited by the > > front-end filters in the K3. The level is about 7 dB less than the level > > at the K3 antenna input (preamp and attenuator off). On older K3s that > > don't have the IF OUT modification the level is less than that, by about > > 8-10 dB as I recall. > > > > Alan N1AL > > > > > >> Aside from the frequency, I can find nothing about the characteristics > >> of the K3 "IF OUT" feed. Could some kind person provide info about > >> bandwidth, levels, etc...? > >> > >> John Ragle -- W1ZI > >> ______________________________________________________________ > >> Elecraft mailing list > >> Home: http://mailman.qth.net/mailman/listinfo/elecraft > >> Help: http://mailman.qth.net/mmfaq.htm > >> Post: mailto:[hidden email] > >> > >> This list hosted by: http://www.qsl.net > >> Please help support this email list: http://www.qsl.net/donate.html > >> > >> > > > > > > > > > > > ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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