http://elecraft.85.s1.nabble.com/K3-APF-Adjustable-Q-tp5688670p5691718.html
By "oscillate" I was thinking of my HQ-150's Q multiplier. It does remind me
As APF now exist in the K3, I choose to use it only when necessary. If it
ends up sound so sweet. Normally sidetones sound a bit dull but APF can
>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<
[hidden email]>
>> 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"<
[hidden email]>
>>> To:<
[hidden email]>
>>> 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
>
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