I agree that we should not give up the tunable APF. For one thing, RIT is not available if QRQ CW is on. I like the option to set the DSP bandwidth to say, 1 kHz, and then use the APF tune to pick out the guy I want to copy. This might be useful when running in a contest: set the DSP to kill the loud guys on either side of you and then use the APF to peak your caller.
Variable Q might be desirable in some circumstances, but I wouldn't want to give up either the APF tuning or the DSP width adjustment to make it possible. Somebody mentioned being able to adjust the Q 'just below the point of oscillation'. While I like the nostalgic reference to the Heath Q Multiplier and the National Select-o-ject, I suspect that Lyle is quaking in his boots about the possibility of allowing the DSP to oscillate! On 10/31/2010 9:03 AM, Guy Olinger K2AV wrote: > I'd say for variable Q, the tightest setting should be just what is > there now. So no one is losing anything. > > What I have been trying to point out is that there is a general > benefit for a milder shape, that one MAY leave on all the time, and > tweak to tight as needed. MP's EDSP, 450 Hz sidetone, NR=D, Contour= > 11 oclock as an example of a mild contour that is really helpful. > > Being able to tune the APF tight setting around allows me to match the > "tone" of the almost ring to the remembered tone of the weak station > and have it come up when I hit it. > > If the choice is sharp or no APF and no APF tune, I have to RIT the > station to sidetone. This has a couple of disadvantages. > > First, if running in a contest, and there are very loud stations up > and down (aren't there always?), RIT up and down is going to let the > co-channel guys in under the roofing filter and into pre-APF digital > space. That can't be useful. Second, continuing to tune the station > in becomes hard if the station stops or fades out because there is > nothing to "calibrate" the completion of RIT twiddle other than > hearing the tone from the station move to sidetone, and now it's > stopped or faded. > > The presence of APF tune, or variable Q does not disadvantage anyone > who doesn't need them, the same way all the really neat digital stuff > does not disadvantage the straight CW operators. The current setting > and shape of APF is definitely the right max Q setting, and does very > well for me. > > I just want a mild Q setting to imitate the shape I had with the MP > all those years. Those who hear it will get it, just like those that > hear the sharp APF for the first time and try it, get it. I think a > lot of people will leave a mild Q on ALL THE TIME for general > operating. It lowers the level of the stuff up and down a little > without any ringing, but still allows one to hear up and down for off > frequency callers. For me it's an EASIER listen for hours on end. > > 73, Guy. > > On Sun, Oct 31, 2010 at 10:47 AM, Steve Ellington<[email protected]> > wrote: >> If the caller is off frequency I would just use RIT to center him in my >> passband as usual and let APF do it's thing. >> Having used outboard APFs for years, the ability to adjust it's selectivity >> is very important. If the band is quiet and the signal is very weak, I would >> adjust the APF nearly to the point of oscillation then back it off a tad. If >> the signal is weak but there is a lot of QRN, I would back off the >> selectivity a bit further but still take advantage of some extra peaking >> capability. >> >> N4LQ >> Steve >> >> ----- Original Message ----- >> From: "Joe Subich, W4TV"<[email protected]> >> To:<[email protected]> >> Sent: Sunday, October 31, 2010 10:27 AM >> Subject: Re: [Elecraft] K3 APF Adjustable Q >> >> >>> >>>>> however the fixed Q has a bit of ring and at times I would like to >>>>> back it off (widen) it just a tad. >>> >>> This is the same mistake Yaesu made in the FT-1000D; de-Qing the >>> original APF made it useless in later radios. This is the very >>> reason not to add adjustable Q or reduce the Q of the APF currently >>> in field test. If you want a less aggressive filter that is centered >>> on the sidetone, use Dual PB ... that's exactly what it is designed >>> to do (and it does a very good job when used as designed). >>> >>> Adjustable center frequency is very important ... particularly when >>> PB CTRL is set for Shift=.05 (to allow LO-CUT-HI to function) as >>> the 50 Hz increments too course to tune APF using the VFO. The user >>> also needs the ability to adjust the peak independently in order to >>> peak up an off frequency caller and not "chase them up the band." >>> >>> 73, >>> >>> ... Joe, W4TV >>> >>> >>> On 10/31/2010 8:58 AM, Steve Ellington wrote: >>>> If I had a choice between variable center frequency and adjustable Q, I >>>> would choose adjustable Q. >>>> >>>> My logic is: The center frequency automatically follows the sidetone >>>> frequency so I have no need to adjust it however the fixed Q has a bit of >>>> ring and at times I would like to back it off (widen) it just a tad. >>>> >>>> Otherwise it's a HUGE improvement, sounds great and I wish to thank those >>>> who made it possible. >>>> >>>> 73 >>>> N4LQ >>>> Steve -- Vic, K2VCO Fresno CA http://www.qsl.net/k2vco/ ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
