Igor Sokolov wrote: > Is roofing filter switched out when dual RX is enabled in KX3?
The wider of the two roofing filters (FL2) is usable with dual RX if the distance between VFO A and B is small (about 2 kHz). Beyond this the filters are switched out, leaving the "native" I.F. bandwidth of about 15 kHz (FL1). (The K3, with its true sub receiver, has a definite filtering advantage over the KX3's dual watch feature. But it's also six times bigger :) As mentioned in the manual, this is one of several cases where the roofing filters must be bypassed. The others are AM, FM, ESSB, and with some wide-band noise-blanker settings. > What limits dual RX to +/- 10 kHz? Is it ADC or something else? Sampling rate, mostly, and some existing firmware constraints. +/- 15 kHz may be possible later. Wayne N6KR > > 73, Igor UA9CDC > ----- Original Message ----- From: "Wayne Burdick" <n...@elecraft.com> > To: "Matt Maguire" <vk2...@gmail.com> > Cc: "Elecraft Reflector" <elecraft@mailman.qth.net> > Sent: Thursday, March 08, 2012 10:20 AM > Subject: Re: [Elecraft] Understanding the KX3 Block Diagram > > >> Also keep in mind those roofing filters. This is a substantial >> departure from other SDRs. Wasn't easy, either :) >> >> Wayne >> >> On Mar 7, 2012, at 8:17 PM, Matt Maguire wrote: >> >>> Here is a presentation by G8VOI which talks about some of the >>> concepts used in radios like the KX3. >>> http://www.pe0fko.nl/g8voi/SDR_1.pdf >>> >>> The presentation uses a softrock radio as a concrete example, so >>> where the presentation talks about PCs and soundcards, keep in mind >>> that for the KX3 this corresponds to the A/D & D/A convertors and >>> DSP/microcontroller that are built into the KX3 itself. >>> >>> 73, Matt VK2ACL. >>> >>> >>> On 08/03/2012, at 2:19 PM, David Stratton wrote: >>> >>>> Hoping that I may not be the only Ham puzzled by the block diagram >>>> of the >>>> KX3 I am asking that someone please explain it because it is so >>>> different >>>> from the superheterodyne radio concept I have become accustomed >>>> to in >>>> current amateur radios. I understand direct conversion radios but >>>> what is >>>> all the stuff that's there besides the mixer-oscillator and audio >>>> amplifier >>>> needed by a direct conversion radio? It seems to me the KX3 block >>>> diagram >>>> looks a lot like radios put forth some time ago by Rick Campell >>>> KK7B. Pardon >>>> my saying so but the KX3 radio looks like it has a weak front end >>>> and a >>>> heavy back end that hopes to make up for the weak front end! >>>> >>>> Dave - KO4KL >>>> >>>> >>>> >>>> ______________________________________________________________ >>>> Elecraft mailing list >>>> Home: http://mailman.qth.net/mailman/listinfo/elecraft >>>> Help: http://mailman.qth.net/mmfaq.htm >>>> Post: mailto:Elecraft@mailman.qth.net >>>> >>>> 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:Elecraft@mailman.qth.net >>> >>> 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:Elecraft@mailman.qth.net >> >> 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:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
