K3 AM filter (on receive) question
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I have the KFL3A-6K 6 kHz AM/ESSB, 8-pole filter installed and working.
In AM mode, I tap XFIL and VFO B display says FL2 6.00 I hold SHIFT in and see <--NOR--> I tap WIDTH and see BW 3.00 -or- HI 3.00 I tap SHIFT and see *FC 1.50 -or- LO 0.00 when I turn WIDTH clockwise to it's maximum, I see BW 5.00 1st question I thought I would be seeing BW 6.00 to match the settings of the AM filter I realize the SHIFT and WIDTH refer to the DSP (I think) and the XFIL refers to the IF filter but does what I'm seeing mean I am not utilizing the full 6khz of the filter and in AM Mode due to the DSP I will never be able to actually have the full 6khz bandwidth? 2nd question If I were to install the KFL3B-FM 13 kHz FM filter I would then tap XFIL and see FLx 13.00 would I still see the same dsp results as I'm seeing now: (meaning.... I would hold SHIFT in and see <--NOR--> I would tap WIDTH and see BW 3.00 -or- HI 3.00 I would tap SHIFT and see *FC 1.50 -or- LO 0.00 .....) again would this mean I would still not be getting anything more than 5.00 bandwidth? color me confused... -- GB & 73 K5OAI Sam Morgan ______________________________________________________________ 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 |
Re: K3 AM filter (on receive) question
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Sam,
Nothing inconsistent as long as you understand what is being displayed. The display is showing you the audio bandwidth, not the IF bandwidth. An AM signal has two sidebands extending on either side of the carrier, and if the width of an AM signal is 6 kHz, it would demodulate to a maximum of 3 kHz of audio (assuming a roofing filter with very steep skirts). With the 6 kHz filter, if you want to hear substantially greater than 3 kHz audio, you can use synchronous AM, or you can install the 13 kHz filter and increase the width control to 5 kHz (the maximum). 73, Don W3FPR On 8/14/2011 1:42 PM, Sam Morgan wrote: > I have the KFL3A-6K 6 kHz AM/ESSB, 8-pole filter installed and working. > In AM mode, I tap XFIL and VFO B display says FL2 6.00 > I hold SHIFT in and see<--NOR--> > I tap WIDTH and see BW 3.00 -or- HI 3.00 > I tap SHIFT and see *FC 1.50 -or- LO 0.00 > > when I turn WIDTH clockwise to it's maximum, I see BW 5.00 > > 1st question > I thought I would be seeing BW 6.00 > to match the settings of the AM filter > I realize the SHIFT and WIDTH refer to the DSP (I think) > and the XFIL refers to the IF filter > > but does what I'm seeing mean > I am not utilizing the full 6khz of the filter > and in AM Mode due to the DSP > I will never be able to actually have the full 6khz bandwidth? > > > > 2nd question > If I were to install the KFL3B-FM 13 kHz FM filter > I would then tap XFIL and see FLx 13.00 > would I still see the same dsp results as I'm seeing now: > (meaning.... > I would hold SHIFT in and see<--NOR--> > I would tap WIDTH and see BW 3.00 -or- HI 3.00 > I would tap SHIFT and see *FC 1.50 -or- LO 0.00 > .....) > > again would this mean > I would still not be getting anything more than 5.00 bandwidth? > > color me confused... > 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 |
Re: K3 AM filter (on receive) question
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> With the 6 kHz filter, if you want to hear substantially greater than > 3 kHz audio, you can use synchronous AM, or you can install the 13 > kHz filter and increase the width control to 5 kHz (the maximum). No matter what (roofing) filter you use, the K3 will not reproduce more than 4.5 KHz audio. The DSP has a maximum high frequency cut-off of 4.2 KHz (the highest one case set "HI") and has a skirt selectivity of approximately 0.10 dB/Hz (10 dB/100 Hz). In addition to the DSP selectivity, current production units have an additional 4.5 KHz analog audio low pass filter following the digital to analog converter. 73, ... Joe, W4TV On 8/14/2011 1:59 PM, Don Wilhelm wrote: > Sam, > > Nothing inconsistent as long as you understand what is being displayed. > > The display is showing you the audio bandwidth, not the IF bandwidth. > > An AM signal has two sidebands extending on either side of the carrier, > and if the width of an AM signal is 6 kHz, it would demodulate to a > maximum of 3 kHz of audio (assuming a roofing filter with very steep > skirts). > > With the 6 kHz filter, if you want to hear substantially greater than 3 > kHz audio, you can use synchronous AM, or you can install the 13 kHz > filter and increase the width control to 5 kHz (the maximum). > > 73, > Don W3FPR > > On 8/14/2011 1:42 PM, Sam Morgan wrote: >> I have the KFL3A-6K 6 kHz AM/ESSB, 8-pole filter installed and working. >> In AM mode, I tap XFIL and VFO B display says FL2 6.00 >> I hold SHIFT in and see<--NOR--> >> I tap WIDTH and see BW 3.00 -or- HI 3.00 >> I tap SHIFT and see *FC 1.50 -or- LO 0.00 >> >> when I turn WIDTH clockwise to it's maximum, I see BW 5.00 >> >> 1st question >> I thought I would be seeing BW 6.00 >> to match the settings of the AM filter >> I realize the SHIFT and WIDTH refer to the DSP (I think) >> and the XFIL refers to the IF filter >> >> but does what I'm seeing mean >> I am not utilizing the full 6khz of the filter >> and in AM Mode due to the DSP >> I will never be able to actually have the full 6khz bandwidth? >> >> >> >> 2nd question >> If I were to install the KFL3B-FM 13 kHz FM filter >> I would then tap XFIL and see FLx 13.00 >> would I still see the same dsp results as I'm seeing now: >> (meaning.... >> I would hold SHIFT in and see<--NOR--> >> I would tap WIDTH and see BW 3.00 -or- HI 3.00 >> I would tap SHIFT and see *FC 1.50 -or- LO 0.00 >> .....) >> >> again would this mean >> I would still not be getting anything more than 5.00 bandwidth? >> >> color me confused... >> > ______________________________________________________________ > 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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