Width of AM filter
Locked
 
|
Hello,
I have K3 with KFLA-6K. I can only adjust the width to 5.0 using the width knob on the K3. I use AM to listen to the AM BCB and some SW. I remember getting a wider width in the past ?? Any suggestions ? Thanks Jerry, KE9I ______________________________________________________________ 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 |
|
|
> have K3 with KFLA-6K. I can only adjust the width to 5.0 using the
> width knob on the K3. I use AM to listen to the AM BCB and some SW. I > remember getting a wider width in the past ?? Any suggestions ? Older firmware showed the IF bandwidth when you rotated the WIDTH control. Beginning with MCU firmware release 2.78 it was changed to show the AF bandwidth. 73, Lyle KK7P ______________________________________________________________ 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 |
|
Administrator
|
In reply to this post by Gerard Jendraszkiewicz
Jerry,
The WIDTH control sets the final audio bandwidth, which is limited to 5 kHz in AM mode. But in AM mode, the crystal filter bandwidth needed is 2x the audio bandwidth, or 10 kHz in this case, because it has to pass both sidebands. To obtain this full bandwidth, you'd have to have the 13 kHz FM filter installed. The AM filter is only 6 kHz wide (an industry standard), and if that's the widest filter you have, you're actually getting only a little over 3 kHz of audio bandwidth even if you set the WIDTH control to max (5 kHz). 73, Wayne N6KR On Mar 26, 2009, at 11:23 AM, Gerard Jendraszkiewicz wrote: > Hello, > > I have K3 with KFLA-6K. I can only adjust the width to 5.0 using the > width knob on the K3. I use AM to listen to the AM BCB and some SW. I > remember getting a wider width in the past ?? Any suggestions ? > > Thanks > Jerry, KE9I > > ______________________________________________________________ > 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 > > --- http://www.elecraft.com ______________________________________________________________ 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 |
|
|
Wayne
It seems odd to have to purchase an expensive filter to obtain a wider bandwidth doesn't it? Isn't there some way to just bypass the filter and rely on DSP? I still would appreciate more bandwidth for CW. 2.7khz is far too narrow for comfortable monitoring while working around the shack. I know it takes some programing but from a layman's point of view, it seems like a simple request and it would certainly improve the product. 73 Steve Ellington [hidden email] ----- Original Message ----- From: "wayne burdick" <[hidden email]> To: "Gerard Jendraszkiewicz" <[hidden email]> Cc: <[hidden email]> Sent: Thursday, March 26, 2009 2:39 PM Subject: Re: [Elecraft] Width of AM filter > Jerry, > > The WIDTH control sets the final audio bandwidth, which is limited to 5 > kHz in AM mode. But in AM mode, the crystal filter bandwidth needed is > 2x the audio bandwidth, or 10 kHz in this case, because it has to pass > both sidebands. To obtain this full bandwidth, you'd have to have the > 13 kHz FM filter installed. The AM filter is only 6 kHz wide (an > industry standard), and if that's the widest filter you have, you're > actually getting only a little over 3 kHz of audio bandwidth even if > you set the WIDTH control to max (5 kHz). > > 73, > Wayne > N6KR > > On Mar 26, 2009, at 11:23 AM, Gerard Jendraszkiewicz wrote: > >> Hello, >> >> I have K3 with KFLA-6K. I can only adjust the width to 5.0 using the >> width knob on the K3. I use AM to listen to the AM BCB and some SW. I >> remember getting a wider width in the past ?? Any suggestions ? >> >> Thanks >> Jerry, KE9I >> >> ______________________________________________________________ >> 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 >> >> > > --- > > http://www.elecraft.com > > ______________________________________________________________ > 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 -------------------------------------------------------------------------------- No virus found in this incoming message. Checked by AVG - www.avg.com Version: 8.0.238 / Virus Database: 270.11.29/2024 - Release Date: 03/26/09 07:12:00 ______________________________________________________________ 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 |
|
Administrator
|
> Isn't there some way to just bypass the filter and rely on DSP?
Hi Steve, We convert directly from our 1st I.F. of 8215 down to a 15 kHz 2nd I.F. (DSP). Without a narrow filter at the first I.F., you'd have an image response at 8215 + 15*2 = 8245 kHz that would pass through unimpeded. So you really do need a wide filter if you wish to copy AM at high fidelity, or to use FM at all. Other transceivers incorporate wide filtering by default because they up-convert to a very high first I.F. where it's easy to make such filters. But this results in major compromises in receive performance. We have the opposite strategy -- down converting to a low first I.F., which provides far better receive performance (by 10s of dB in some parameters). But this does require that each K3 user to determine whether they want to use wider-bandwidth modes, and the filters aren't cheap, because they're very high quality, requiring custom, matched sets of crystals. I feel that we made the right tradeoff. > I still would appreciate more bandwidth for CW. 2.7khz is far too > narrow for comfortable monitoring while working around the shack. I > know it takes some programing but from a layman's point of view, it > seems like a simple request and it would certainly improve the > product. I agree, and this is on the MCU firmware list. 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 |
|
|
In reply to this post by Steve Ellington
On Thu, 26 Mar 2009 15:08:32 -0400, Steve Ellington wrote:
>I still would appreciate more bandwidth for CW. 2.7khz is far too narrow for >comfortable monitoring while working around the shack. I know it takes some >programing but from a layman's point of view, it seems like a simple request >and it would certainly improve the product. >73 >Steve Ellington >[hidden email] Yes, a wider maximum CW b/w will be very nice to have. 73, Drew AF2Z ______________________________________________________________ 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 |
|
|
In reply to this post by wayne burdick
I hope I am not stepping on any toes - but I found someone who had designed a 13Khz +/- filter with some toroids and caps - incl variables to adjust and built two and they work great in main KRX3 -
just confirmed again they give nice fidelity on AM - and I can hear the 6khz filter click in when I reduce BW to 3... low cost - fair bit of labour :-) 73 John VE3NFK
|
|
|
I was going to suggest an LC filter for non-critical work. If Elecraft would supply "replacement" carrier boards with the pin sockets either mounted or available it would be nice. --- On Thu, 3/26/09, VE3NFK <[hidden email]> wrote: > From: VE3NFK <[hidden email]> > Subject: Re: [Elecraft] Width of AM filter > To: [hidden email] > Date: Thursday, March 26, 2009, 7:42 PM > I hope I am not stepping on any toes - but I found someone > who had designed a 13Khz +/- filter with some toroids and > caps - incl variables to adjust and built two and they work > great in main KRX3 - > just confirmed again they give nice fidelity on AM - and I > can hear the 6khz filter click in when I reduce BW to 3... > low cost - fair bit of labour :-) > > 73 John VE3NFK > > > Jerry, > > The WIDTH control sets the final audio bandwidth, which is > limited to 5 > kHz in AM mode. But in AM mode, the crystal filter > bandwidth needed is > 2x the audio bandwidth, or 10 kHz in this case, because it > has to pass > both sidebands. To obtain this full bandwidth, you'd > have to have the > 13 kHz FM filter installed. The AM filter is only 6 kHz > wide (an > industry standard), and if that's the widest filter you > have, you're > actually getting only a little over 3 kHz of audio > bandwidth even if > you set the WIDTH control to max (5 kHz). > > 73, > Wayne > N6KR > > On Mar 26, 2009, at 11:23 AM, Gerard Jendraszkiewicz wrote: > > > Hello, > > > > I have K3 with KFLA-6K. I can only adjust the width to > 5.0 using the > > width knob on the K3. I use AM to listen to the AM BCB > and some SW. I > > remember getting a wider width in the past ?? Any > suggestions ? > > > > Thanks > > Jerry, KE9I > > > > > ______________________________________________________________ > > 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 > > > > > > --- > > http://www.elecraft.com > > ______________________________________________________________ > 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 > > > > -- > View this message in context: > http://n2.nabble.com/Width-of-AM-filter-tp2540204p2542146.html > Sent from the Elecraft mailing list archive at Nabble.com. > > ______________________________________________________________ > 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 |
|
|
Inrad has supplied these blank boards at a reasonable price ($10?) in the past for various radios. Barry N1EU (if this message shows up in html format, it's Nabble's fault) |
|
|
In reply to this post by Gerard Jendraszkiewicz
Last time I looked at one of the filter boards there seemed to be a substantial quantity of components....not a simple carrier as
in the Inrad boards or those for the Kenwood plug-in filters. The components' function, I think, is to tell the radio that the appropriate filter is installed for the desired (AM or FM) operating mode. As a result, any "blank" board for one of those operating modes would need to have a certain minimum component population to serve that purpose. It would, as a result, not be a $10.00 (only) board. I trust I will be corrected if I am wrong here. Regards John, N6AX K3 # 567 On Fri Mar 27 4:48 , Barry N1EU sent: > > > >I was going to suggest an LC filter for non-critical work. If Elecraft would supply "replacement" carrier boards with the pin sockets either mounted or available it would be nice. > > >Inrad has supplied these blank boards at a reasonable price ($10?) in the past for various radios. > >Barry N1EU > >(if this message shows up in html format, it's Nabble's fault) > >-- >View this message in context: http://n2.nabble.com/Width-of-AM-filter-tp2540204p2543885.html >Sent from the Elecraft mailing list archive at Nabble.com. > >______________________________________________________________ >Elecraft mailing list >Home: http://mailman.qth.net/mailman/listinfo/elecraft >Help: http://mailman.qth.net/mmfaq.htm >Post: [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 |
|
|
In reply to this post by VE3NFK
Hoping for a 8 MHz LC filter with a BW of 13 KHz and good mirror rejection is like hoping to run a car with a few AA batteries.
A similar idea: the inside of the radio can be "hardened" by applying 117V to random circuits for a second! <quote author="VE3NFK"> I hope I am not stepping on any toes - but I found someone who had designed a 13Khz +/- filter with some toroids and caps - incl variables to adjust and built two and they work great in main KRX3 - just confirmed again they give nice fidelity on AM - and I can hear the 6khz filter click in when I reduce BW to 3... low cost - fair bit of labour :-) 73 John VE3NFK |
|
|
Is that "hardening" voltage AC or DC? :-) (I just *had* to ask -
ROTFL). Afterward I would expect the radio to be very hard (of hearing). - Don't try this with your K3! 73, Don W3FPR Ignacy wrote: > Hoping for a 8 MHz LC filter with a BW of 13 KHz and good mirror rejection is like hoping to run a car with a few AA batteries. > A similar idea: the inside of the radio can be "hardened" by applying 117V to random circuits for a second! > > ______________________________________________________________ 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 |
|
|
In reply to this post by John Klewer
Er, no, or we wouldn't have to configure the filters by mode manually
(or use the K3 utility). A glance at the filter schematic for the KFL3A reveals only filter components. Bob NW8L On Fri, Mar 27, 2009 at 6:08 AM, <[hidden email]> wrote: > Last time I looked at one of the filter boards there seemed to be a substantial quantity of components....not a simple carrier as > in the Inrad boards or those for the Kenwood plug-in filters. > > The components' function, I think, is to tell the radio that the appropriate filter is installed for the desired (AM or FM) > operating mode. As a result, any "blank" board for one of those operating modes would need to have a certain minimum component > population to serve that purpose. It would, as a result, not be a $10.00 (only) board. > > I trust I will be corrected if I am wrong here. > > Regards > > John, N6AX > K3 # 567 > 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 |
|
|
In reply to this post by Gerard Jendraszkiewicz
For those who wish to listen AM/SW broadcast, researching the
Reflector is required to find out that the "FM" filter is the way to go. I suggest an addition to the 13 kHz filter product description, and other discussions of filter choice, to say that it is also recommended for full-bandwidth AM reception. That will help prevent people from ordering the AM filter on the wrong assumption. Windy KM5Q ______________________________________________________________ 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 |
«
Return to Elecraft
|
1 view|%1 views
| Free forum by Nabble | Edit this page |