Joe, You have just made my day! I have hoped that this was a case of "Boy with New Toy", and it is. I did not have a proper value for SHIFT, so the radio and the computer were not properly mapped to each other. I can now see and use the entire 4 khz. Thanks to all that spent some time thinking about this!
--- On Thu, 1/8/09, Joe Subich, W4TV <li...@subich.com> wrote: > From: Joe Subich, W4TV <li...@subich.com> > Subject: Re: [Elecraft] Mildly confused - Assumed filter width and what > Iseein waterfall do not match > To: elecraft@mailman.qth.net > Date: Thursday, January 8, 2009, 12:51 AM > > I would like to at least get the 4.2 khz mentioned - > but in > > fact, I do not. > > I don't know why you can't get 4 KHz if you have a > 6 KHz > roofing filter enabled for receive in the DATA modes. I > see 200 Hz to 4200 Hz with my audio spectrum analyzer > software > on the Line Out port (although the Line Out has more low > frequency roll off than I would like between 200 Hz and 500 > Hz). > > Set BW (WIDTH) = 4.00 and FC (SHIFT) = 2.20 and you should > have 200 - 4200 Hz available to your waterfall. I have it > with my FM filter (even when I tell the K3 configuration > the FM filter is 6 KHz wide). > > In the direct e-mail, I've attached a waterfall that > shows two > CW signals (can't hear any PSK31 tonight) one at 1 KHZ > and the > other at 4 KHz with several weaker signals in between. You > can > also see the significant roll-off in the K3 Line Out > response > (-26 dB from 800 Hz to 100 Hz) below 500 Hz. > > 73, > > ... Joe, W4TV > > > > > -----Original Message----- > > From: elecraft-boun...@mailman.qth.net > > [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of > Thomas > > Bingenheimer > > Sent: Wednesday, January 07, 2009 11:01 PM > > To: elecraft@mailman.qth.net > > Subject: Re: [Elecraft] Mildly confused - Assumed > filter > > width and what Iseein waterfall do not match > > > > > > I would like to at least get the 4.2 khz mentioned - > but in > > fact, I do not. My chief concern is that I should at > least be > > able to use the full 4 khz waterfall that I can, in > fact, get > > out of most other radios. > > > > > > --- On Wed, 1/7/09, Joe Subich, W4TV > <li...@subich.com> wrote: > > > > > From: Joe Subich, W4TV <li...@subich.com> > > > Subject: RE: [Elecraft] Mildly confused - Assumed > filter width and > > > what Isee in waterfall do not match > > > To: t...@yahoo.com, elecraft@mailman.qth.net, > "'Bob > > Cunnings'" <bob.cunni...@gmail.com> > > > Date: Wednesday, January 7, 2009, 10:15 PM > > > > I guess my basic answer, is that should be > my choice, > > > not the > > > > radio firmware. If I want to run 4 (or say, > 10khz) > > > into my > > > > computer (and out) that should be my choice. > > > > > > The K3 does not support an audio bandwidth higher > than 4.2 KHz > > > in ANY MODE. If you do some checking you will > find the > > > DSP's > > > digital to analog converter effectively includes > a 4.2 KHz > > > "brickwall" filter ... even in AM mode > with the > > > "bandwidth" > > > set to 5 KHz (10 KHz IF). > > > > > > If you expect audio response above 4.2 KHz, you > will need > > > to > > > convince Wayne and Lyle to relax the upper > frequency limit. > > > > > > HOWEVER, for digital modes I'm not so sure > that is a > > > good > > > idea. With sound cards sampling at 11025 Hz, the > input > > > audio > > > needs to be band limited to 5.5 KHz maximum and > 4.5 KHz > > > offers > > > a fair margin for safety to handle the occasional > > > application > > > that runs at 8 or 9 KHz. > > > > > > For AM - since the digital modes are not a > consideration - > > > it > > > would be nice to have 5.5 or 6.0 KHz response. > > > > > > 73, > > > > > > ... Joe, W4TV > > > > > > > > > > > > > -----Original Message----- > > > > From: elecraft-boun...@mailman.qth.net > > > > [mailto:elecraft-boun...@mailman.qth.net] On > Behalf Of > > > Thomas > > > > Bingenheimer > > > > Sent: Wednesday, January 07, 2009 9:07 PM > > > > To: elecraft@mailman.qth.net; Bob Cunnings > > > > Subject: Re: [Elecraft] Mildly confused - > Assumed > > > filter > > > > width and what Isee in waterfall do not > match > > > > > > > > > > > > I guess my basic answer, is that should be > my choice, > > > not the > > > > radio firmware. If I want to run 4 (or say, > 10khz) > > > into my > > > > computer (and out) that should be my choice. > After > > > all, how > > > > is an SDR all that different. Again, I > suspect this is > > > a > > > > oversight in the firmware, not a design > choice. Why > > > should > > > > such a flexible radio be hobbled in this > manner? > > > (assuming, > > > > of course, that it is actually limited as > such, as > > > opposed to > > > > me setting it up wrong :) ). > > > > > > > > > > > > --- On Wed, 1/7/09, Bob Cunnings > > > <bob.cunni...@gmail.com> wrote: > > > > > > > > > From: Bob Cunnings > <bob.cunni...@gmail.com> > > > > > Subject: Re: [Elecraft] Mildly confused > - Assumed > > > filter width and > > > > > what I see in waterfall do not match > > > > > To: elecraft@mailman.qth.net > > > > > Date: Wednesday, January 7, 2009, 8:59 > PM > > > > > Disabling the AGC in the K3 certainly > does > > > "do the > > > > > trick" in terms of > > > > > preventing strong signals in the > passband from > > > reducing > > > > > receiver gain > > > > > and thus affecting the weaker signal > I'm > > > decoding - > > > > > that's exactly why > > > > > I do it. > > > > > > > > > > As for ADC overload -that's a risk > I'm > > > well aware > > > > > of but most of the > > > > > time it's a non-issue, for me at > least. If it > > > happened > > > > > I would react > > > > > to it, but I rarely encounter signals > in the > > > passband at > > > > anywhere near > > > > > the level to cause trouble of that > sort. > > > > > > > > > > Bob NW8L > > > > > > > > > > On Wed, Jan 7, 2009 at 6:23 PM, Don > Wilhelm > > > <w3...@embarqmail.com> > > > > > wrote: > > > > > > Bob, > > > > > > > > > > > > That will do the trick in an > analog only > > > receiver, but > > > > > a receiver like the > > > > > > K3 has an analog front end > followed by an > > > ADC and DSP > > > > > processor. The trick > > > > > > is to keep from overloading the > ADC - should > > > that > > > > > happen, the copy will be > > > > > > garbage. > > > > > > > > > > > > That situation is not limited to > the K3 - > > > overload of > > > > > the soundcard ADC is > > > > > > also a possibility with equally > bad results. > > > > > > > > > > > > I have to admit that in many > cases, one can > > > operate > > > > > with a wide bandwidth > > > > > > with no problem, but when that > strong signal > > > enters > > > > > the passband, the wide > > > > > > bandwidth possibilities are > "all > > > over". I > > > > > chose to take preventive measures > > > > > > before that happens. > > > > > > > > > > > > 73, > > > > > > Don W3FPR > > > > > > > > > > > > Bob Cunnings wrote: > > > > > >> > > > > > >> I simply disable AGC when I > wish to run > > > a wide > > > > > receive bandwith with > > > > > >> PSK31 for "point and > click" > > > tuning - > > > > > precisely to avoid such a > > > > > >> problem. > > > > > >> > > > > > >> Bob NW8L > > > > > >> > > > > > >> On Wed, Jan 7, 2009 at 5:44 > PM, Don > > > Wilhelm > > > > > <w3...@embarqmail.com> wrote: > > > > > >> > > > > > >>> > > > > > >>> Thomas, > > > > > >>> > > > > > >>> I will not answer your > questions > > > directly, > > > > > >>> BUT > > > > > >>> From an operational > standpoint, > > > using a wide > > > > > bandwidth for data modes > > > > > >>> is *not* the best way to > do it. > > > > > >>> The reason is AGC in the > radio. Any > > > signal in > > > > > the receiver passband can > > > > > >>> activate the AGC - and > that is fine > > > *if and > > > > > only if* the strongest > > > > > >>> station in the receiver > passband is > > > the one > > > > > you are working - usually > > > > > >>> that is not the case. > The strong > > > signal will > > > > > reduce the receiver gain > > > > > >>> due to its AGC action and > the > > > station you are > > > > > trying to QSO with will be > > > > > >>> reduced along with it. > Overload of > > > the DAC by > > > > > the strong signals is > > > > > >>> another similar > consideration - > > > fortunately, > > > > > the K3 employs a hardware > > > > > >>> AGC ahead of the DAC to > avoid just > > > that > > > > > possibility. The DSP ADC can > > > > > >>> handle an S9+20 signal > without > > > overload, but > > > > > there are signals stronger > > > > > >>> than that even in the > sub-bands > > > commonly used > > > > > for digital. > > > > > >>> > > > > > >>> Using a narrow passband > for data > > > modes allows > > > > > one to avoid that > > > > > >>> situation. Yes, one must > tune with > > > the VFO to > > > > > place the desired station > > > > > >>> inside the receiver > passband, but > > > the > > > > > possibility of a QRM free QSO is > > > > > >>> much greater with the > narrow > > > passband. > > > > > >>> > > > > > >>> Just because the software > > > application can > > > > > display a 4 kHz slice of the > > > > > >>> spectrum is not sufficient > reason to > > > use a > > > > > wide receiver passband IMHO. > > > > > >>> > > > > > >>> Elecraft may well consider > it just > > > because > > > > > some folks want to operate > > > > > >>> that way, but it certainly > does not > > > make much > > > > > sense to me. > > > > > >>> > > > > > > > > _______________________________________________ > > Elecraft mailing list > > Post to: Elecraft@mailman.qth.net > > You must be a subscriber to post to the list. > > Subscriber Info (Addr. Change, sub, unsub etc.): > > http://mailman.qth.net/mailman/listinfo/elecraft > > > > Help: http://mailman.qth.net/subscribers.htm > > Elecraft web page: http://www.elecraft.com > > _______________________________________________ > Elecraft mailing list > Post to: Elecraft@mailman.qth.net > You must be a subscriber to post to the list. > Subscriber Info (Addr. Change, sub, unsub etc.): > http://mailman.qth.net/mailman/listinfo/elecraft > > Help: http://mailman.qth.net/subscribers.htm > Elecraft web page: http://www.elecraft.com _______________________________________________ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
