Advantage of KBPF3 in K3?
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No response to my earlier question about the usefulness of the KBPF3 posed last week so here goes again;
if one already has an AM filter in one of the K3's slots what does one need a KBPF3 for (in terms of general coverage SWLing)? Does it allow band selection of the popular SWBC bands in addition to the ham bands? Still curious. 73, Jeff, NH7RO K-Line proud assembler/owner since 2011 ______________________________________________________________ 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 Message delivered to [hidden email] |
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> if one already has an AM filter in one of the K3's slots what does one need a KBPF3 for (in terms of general coverage SWLing)?
> > Does it allow band selection of the popular SWBC bands in addition to the ham bands? Hi Jeff, The AM crystal filter is for close-in selectivity (6 kHz) in the I.F. This filter can be used in AM and SSB modes whether in or out of a ham band. The KBPF3 is at a different point in the receive chain: at the front end. It provides band-pass filters several MHz wide to allow copy of SWL ranges between the ham bands. Without a KBPF3, there are a number of places between ham bands where sensitivity would roll off up to 20 dB or so. This is because the K3's normal band-pass filters are very narrow, covering just the ham bands themselves. This is a very good thing from a receive performance standpoint; it removes strong signals that are well out of each ham band that could otherwise cause spurious or image responses. Unlike the K3, most receivers have really wide band-pass filters, leaving them susceptible to such interference in the ham bands. By adding a KBPF3, you'll be able to tune virtually the entire range from 0.5 to 30 MHz (plus 6 meters) with your K3 without significant loss of sensitivity. The K3 automatically selects the KBPF3 filters when you tune a certain distance outside a given ham band. This is how we provide MARS coverage (when enabled). I said "virtually" the entire range because there is one gap: right around the first I.F. (8.215 MHz). In the vicinity of this gap, sensitivity will be quite a bit lower because the K3 has multiple traps at this frequency designed to ensure excellent first-I.F. rejection. Also, the range from 0.5 to 1.5 MHz is gradually attenuated as you go lower in frequency because of a high-pass filter that protects the PIN diodes used in the T/R switch. To get around this, you can bring the signal into the RX ANT jack on the KXV3 option. You might do this is you were doing low-band (AM broadcast) DXing. A KBPF3 can be added to the main receiver, or the sub receiver, or both. 73, Wayne N6KR ______________________________________________________________ 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 Message delivered to [hidden email] |
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OK, guys, I've got it now (makes a ton of sense now that I think about it). I don't do a lot of SWL anymore but I might want to add one to my K3 sometime for the fun of it.
Thanks very much for all of your replies and feel free to close this thread now that it has been answered well. 73, Jeff, NH7RO > Subject: Re: [Elecraft] Advantage of KBPF3 in K3? > From: [hidden email] > Date: Mon, 9 Feb 2015 14:23:10 -0800 > CC: [hidden email] > To: [hidden email] > > > if one already has an AM filter in one of the K3's slots what does one need a KBPF3 for (in terms of general coverage SWLing)? > > > > Does it allow band selection of the popular SWBC bands in addition to the ham bands? > > > Hi Jeff, > > The AM crystal filter is for close-in selectivity (6 kHz) in the I.F. This filter can be used in AM and SSB modes whether in or out of a ham band. > > The KBPF3 is at a different point in the receive chain: at the front end. It provides band-pass filters several MHz wide to allow copy of SWL ranges between the ham bands. > > Without a KBPF3, there are a number of places between ham bands where sensitivity would roll off up to 20 dB or so. This is because the K3's normal band-pass filters are very narrow, covering just the ham bands themselves. This is a very good thing from a receive performance standpoint; it removes strong signals that are well out of each ham band that could otherwise cause spurious or image responses. Unlike the K3, most receivers have really wide band-pass filters, leaving them susceptible to such interference in the ham bands. > > By adding a KBPF3, you'll be able to tune virtually the entire range from 0.5 to 30 MHz (plus 6 meters) with your K3 without significant loss of sensitivity. The K3 automatically selects the KBPF3 filters when you tune a certain distance outside a given ham band. This is how we provide MARS coverage (when enabled). > > I said "virtually" the entire range because there is one gap: right around the first I.F. (8.215 MHz). In the vicinity of this gap, sensitivity will be quite a bit lower because the K3 has multiple traps at this frequency designed to ensure excellent first-I.F. rejection. Also, the range from 0.5 to 1.5 MHz is gradually attenuated as you go lower in frequency because of a high-pass filter that protects the PIN diodes used in the T/R switch. To get around this, you can bring the signal into the RX ANT jack on the KXV3 option. You might do this is you were doing low-band (AM broadcast) DXing. > > A KBPF3 can be added to the main receiver, or the sub receiver, or both. > > 73, > Wayne > N6KR > > ______________________________________________________________ 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 Message delivered to [hidden email] |
Re: Advantage of KBPF3 in K3?
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In reply to this post by wayne burdick
Thank you for a great description.
From: Wayne Burdick <[hidden email]> To: Jeff Cathrow <[hidden email]> Cc: Elecraft Digest <[hidden email]> Sent: Monday, February 9, 2015 5:23 PM Subject: Re: [Elecraft] Advantage of KBPF3 in K3? > if one already has an AM filter in one of the K3's slots what does one need a KBPF3 for (in terms of general coverage SWLing)? > > Does it allow band selection of the popular SWBC bands in addition to the ham bands? Hi Jeff, The AM crystal filter is for close-in selectivity (6 kHz) in the I.F. This filter can be used in AM and SSB modes whether in or out of a ham band. The KBPF3 is at a different point in the receive chain: at the front end. It provides band-pass filters several MHz wide to allow copy of SWL ranges between the ham bands. Without a KBPF3, there are a number of places between ham bands where sensitivity would roll off up to 20 dB or so. This is because the K3's normal band-pass filters are very narrow, covering just the ham bands themselves. This is a very good thing from a receive performance standpoint; it removes strong signals that are well out of each ham band that could otherwise cause spurious or image responses. Unlike the K3, most receivers have really wide band-pass filters, leaving them susceptible to such interference in the ham bands. By adding a KBPF3, you'll be able to tune virtually the entire range from 0.5 to 30 MHz (plus 6 meters) with your K3 without significant loss of sensitivity. The K3 automatically selects the KBPF3 filters when you tune a certain distance outside a given ham band. This is how we provide MARS coverage (when enabled). I said "virtually" the entire range because there is one gap: right around the first I.F. (8.215 MHz). In the vicinity of this gap, sensitivity will be quite a bit lower because the K3 has multiple traps at this frequency designed to ensure excellent first-I.F. rejection. Also, the range from 0.5 to 1.5 MHz is gradually attenuated as you go lower in frequency because of a high-pass filter that protects the PIN diodes used in the T/R switch. To get around this, you can bring the signal into the RX ANT jack on the KXV3 option. You might do this is you were doing low-band (AM broadcast) DXing. A KBPF3 can be added to the main receiver, or the sub receiver, or both. 73, Wayne N6KR ______________________________________________________________ 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 Message delivered to [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 Message delivered to [hidden email] |
Re: Advantage of KBPF3 in K3?
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In reply to this post by NH7RO
I actually run a KBPF in both the receivers.
The K3 works nice on SW From: Jeff Cathrow <[hidden email]> To: Elecraft Digest <[hidden email]> Sent: Monday, February 9, 2015 6:37 PM Subject: Re: [Elecraft] Advantage of KBPF3 in K3? OK, guys, I've got it now (makes a ton of sense now that I think about it). I don't do a lot of SWL anymore but I might want to add one to my K3 sometime for the fun of it. Thanks very much for all of your replies and feel free to close this thread now that it has been answered well. 73, Jeff, NH7RO > Subject: Re: [Elecraft] Advantage of KBPF3 in K3? > From: [hidden email] > Date: Mon, 9 Feb 2015 14:23:10 -0800 > CC: [hidden email] > To: [hidden email] > > > if one already has an AM filter in one of the K3's slots what does one need a KBPF3 for (in terms of general coverage SWLing)? > > > > Does it allow band selection of the popular SWBC bands in addition to the ham bands? > > > Hi Jeff, > > The AM crystal filter is for close-in selectivity (6 kHz) in the I.F. This filter can be used in AM and SSB modes whether in or out of a ham band. > > The KBPF3 is at a different point in the receive chain: at the front end. It provides band-pass filters several MHz wide to allow copy of SWL ranges between the ham bands. > > Without a KBPF3, there are a number of places between ham bands where sensitivity would roll off up to 20 dB or so. This is because the K3's normal band-pass filters are very narrow, covering just the ham bands themselves. This is a very good thing from a receive performance standpoint; it removes strong signals that are well out of each ham band that could otherwise cause spurious or image responses. Unlike the K3, most receivers have really wide band-pass filters, leaving them susceptible to such interference in the ham bands. > > By adding a KBPF3, you'll be able to tune virtually the entire range from 0.5 to 30 MHz (plus 6 meters) with your K3 without significant loss of sensitivity. The K3 automatically selects the KBPF3 filters when you tune a certain distance outside a given ham band. This is how we provide MARS coverage (when enabled). > > I said "virtually" the entire range because there is one gap: right around the first I.F. (8.215 MHz). In the vicinity of this gap, sensitivity will be quite a bit lower because the K3 has multiple traps at this frequency designed to ensure excellent first-I.F. rejection. Also, the range from 0.5 to 1.5 MHz is gradually attenuated as you go lower in frequency because of a high-pass filter that protects the PIN diodes used in the T/R switch. To get around this, you can bring the signal into the RX ANT jack on the KXV3 option. You might do this is you were doing low-band (AM broadcast) DXing. > > A KBPF3 can be added to the main receiver, or the sub receiver, or both. > > 73, > Wayne > N6KR > > ______________________________________________________________ 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 Message delivered to [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 Message delivered to [hidden email] |
Re: Advantage of KBPF3 in K3?
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In reply to this post by wayne burdick
>>> A KBPF3 can be added to the main receiver, or the sub receiver, or both. <<<
What would be the advantage of adding KBPF3 to both the Main and the Sub? ((((73)))) Milverton / W9MMS From: Wayne Burdick <[hidden email]> To: Jeff Cathrow <[hidden email]> Cc: Elecraft Digest <[hidden email]> Sent: Monday, February 9, 2015 4:23 PM Subject: Re: [Elecraft] Advantage of KBPF3 in K3? > if one already has an AM filter in one of the K3's slots what does one need a KBPF3 for (in terms of general coverage SWLing)? > > Does it allow band selection of the popular SWBC bands in addition to the ham bands? Hi Jeff, The AM crystal filter is for close-in selectivity (6 kHz) in the I.F. This filter can be used in AM and SSB modes whether in or out of a ham band. The KBPF3 is at a different point in the receive chain: at the front end. It provides band-pass filters several MHz wide to allow copy of SWL ranges between the ham bands. Without a KBPF3, there are a number of places between ham bands where sensitivity would roll off up to 20 dB or so. This is because the K3's normal band-pass filters are very narrow, covering just the ham bands themselves. This is a very good thing from a receive performance standpoint; it removes strong signals that are well out of each ham band that could otherwise cause spurious or image responses. Unlike the K3, most receivers have really wide band-pass filters, leaving them susceptible to such interference in the ham bands. By adding a KBPF3, you'll be able to tune virtually the entire range from 0.5 to 30 MHz (plus 6 meters) with your K3 without significant loss of sensitivity. The K3 automatically selects the KBPF3 filters when you tune a certain distance outside a given ham band. This is how we provide MARS coverage (when enabled). I said "virtually" the entire range because there is one gap: right around the first I.F. (8.215 MHz). In the vicinity of this gap, sensitivity will be quite a bit lower because the K3 has multiple traps at this frequency designed to ensure excellent first-I.F. rejection. Also, the range from 0.5 to 1.5 MHz is gradually attenuated as you go lower in frequency because of a high-pass filter that protects the PIN diodes used in the T/R switch. To get around this, you can bring the signal into the RX ANT jack on the KXV3 option. You might do this is you were doing low-band (AM broadcast) DXing. A KBPF3 can be added to the main receiver, or the sub receiver, or both. 73, Wayne N6KR ______________________________________________________________ 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 Message delivered to [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 Message delivered to [hidden email] |
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Diversity reception in the SWL ranges, but that's hard core. ;o)
Rick wa6nhc On 2/9/2015 7:11 PM, Milverton M. Swire via Elecraft wrote: >>>> A KBPF3 can be added to the main receiver, or the sub receiver, or both. <<< > What would be the advantage of adding KBPF3 to both the Main and the Sub? > > ((((73)))) Milverton / W9MMS ______________________________________________________________ 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 Message delivered to [hidden email] |
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In reply to this post by Elecraft mailing list
> What would be the advantage of adding KBPF3 to both the Main and the Sub?
You can put the main and sub on different bands (when CONFIG:VFO IND = YES). So having a KBPF3 in the sub would let you use a ham band with the main RX/TX while using the sub RX to monitor an the AM broadcast band, a MARS channel, WWV at 2.5 MHz or 5 MHz, a favorite SWL station, etc. Having KBPF3s in both receivers adds some versatility, including diversity mode, which is especially useful for lower-band DXing. 73, Wayne N6KR ______________________________________________________________ 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 Message delivered to [hidden email] |
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In reply to this post by NH7RO
One more use for the KPBF3 is for use on the 600m band (not yet a ham
band but one can obtain an experimental license - see link, below). The K3 will tune down to 490-KHz with pretty good sensitivity if you have the KBPF3 and KXV3 transverter option to connect Rx ANT in. I have run under WD2XSH/45 using the K3 in TEST mode to transmit at 0.1mw thru the XVTR connections to a surplus NDB transmitter (100w) on 495-KHz using a 43x122 foot base-loaded inverted-L. http://www.500kc.com/ 73, Ed - KL7UW http://www.kl7uw.com "Kits made by KL7UW" Dubus Mag business: [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 Message delivered to [hidden email] |
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