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K3 APF Adjustable Q

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Roy Morris-6

K3 APF Adjustable Q

An adjustable Q would be a desirable APF feature. Also the SHIFT control needs to be more responsive. It sometimes doesn't keep up with changes while sweeping the peak frequency. I hope these tweeks can be added in future firmware. Thanks, Roy Morris W4WFB
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juergen piezo

Re: K3 APF Adjustable Q

Hi Morris

The IC7600 has some kind of Q adjustment in its APF feature. The Icom IC7600 has "SOFT" and "SHARP"settings for the APF. This is also combined with the WIDE, MID and narrow settings for the APF. This would be similar in operation to having a dedicated Q control. In all honesty the APF as implemented in the FT1000D works better than that in the IC7600. On any setting of the IC7600's APF control it is not worth engaging most of the time.

APF has to be an instantaneous control that does not require a multiplicity of settings. The one in the FT1000D is a dream on the low bands.

Out of curiosity what radio has a APF filter with a Q control?

I have a old Mizuho AP-1D Audio Processor/peak filter. This APF filter has a fixed bandwidth of 900hz and its variable from 500 to 1000hz. It does not have a Q control however it works better than the one in the Icom 7600.

73
John

--- On Fri, 10/29/10, Roy Morris <[hidden email]> wrote:

> From: Roy Morris <[hidden email]>
> Subject: [Elecraft] K3 APF Adjustable Q
> To: [hidden email]
> Date: Friday, October 29, 2010, 8:08 PM
> An adjustable Q would be a desirable
> APF feature. Also the SHIFT control needs to be more
> responsive. It sometimes doesn't keep up with changes
> while sweeping the peak frequency. I hope these tweeks
> can be added in future firmware. Thanks, Roy
> Morris W4WFB
> ______________________________________________________________
> 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
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alorona

Re: K3 APF Adjustable Q

This was exactly my point the other day. The simpler it is, the more useful it
will be in a variety of circumstances. The more tweaking it requires, the less
useful it will be in a pressure situation.

Al W6LX

> Juergen said:
> APF has to be an instantaneous control that does not require a multiplicity of
>settings.
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Bob K6UJ

Re: K3 APF Adjustable Q

I have a different opinion my ham friends.
I don't mind at all an extra knob turning / button pushing to utilize APF.
You don't need the APF functionality all the time.
It is a tool to be used in the real tough cases where the signal is right down in the noise and you need that extra help to pull him out.
I'm afraid any dumbing down of the circuit to make it more automated and eliminate an extra button push, etc would also reduce its effectiveness.
If we think about what the circuit is trying to accomplish it needs to be as effective as it can be ! That tiny bit of improvement in signal to noise
ratio it provides is critical, lets focus on optimizing it ! Like I said you don't need it all the time but I sure want it in my tool box when needed.
I am excited about the prospect of having it integrated into the K3. There just isn't any better CW radio in my opinion. For me its like having your
cake and eat it to with APF added. I wanted to voice my fear of reducing its effectiveness, thats all.

73,
Bob
K6UJ

On Oct 30, 2010, at 4:30 PM, Al Lorona wrote:

> This was exactly my point the other day. The simpler it is, the more useful it
> will be in a variety of circumstances. The more tweaking it requires, the less
> useful it will be in a pressure situation.
>
> Al W6LX
>
>
>
>
>> Juergen said:
>> APF has to be an instantaneous control that does not require a multiplicity of
>> settings.
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
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Steve Ellington

Re: K3 APF Adjustable Q

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

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Joe Subich, W4TV-4

Re: 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
>
> ______________________________________________________________
> 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
>

Steve Ellington

Re: K3 APF Adjustable Q

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
>>
>> ______________________________________________________________
>> 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]
>
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> Please help support this email list: http://www.qsl.net/donate.html

Roy Morris-6

Re: K3 APF Adjustable Q

In reply to this post by Roy Morris-6

We already have the peak sweep with the SHIFT control. It would be great to have variable Q with the WIDTH control. Varying the amount of Q is desirable so the peak can be adjusted to reduce any ringing that might be present. Roy Morris W4WFB
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Guy, K2AV

Re: K3 APF Adjustable Q

In reply to this post by Steve Ellington

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
>>>
>>> ______________________________________________________________
>>> 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
>
> ______________________________________________________________
> 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
>

Matt Zilmer

Re: K3 APF Adjustable Q

In reply to this post by Steve Ellington

There are also other considerations. In QRQ mode, RIT is N/A. So
other than tuning VFO A to follow the peak, use SHIFT to do it. Also,
SHIFT uses a 10 Hz resolution independent from the VFO tuning rate.
This doesn't leave many of the overloaded controls on the UI for a
PEAK control.

Having a changeable Q would be nice too, but as peaky as it is, it's
probably about optimal. Lyle does good work, and probably agonized
for some time about how high and tight to make it. Really, there's no
control for the Q since WIDTH is left for normal use. Unless one is
"found".

BUT - who knows what the final outcome will be. Elecraft can be full
of surprises.

73,
matt W6NIA

On Sun, 31 Oct 2010 08:58:57 -0400, you 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
>
>______________________________________________________________
>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

Vic K2VCO

Re: K3 APF Adjustable Q

In reply to this post by Guy, K2AV

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
http://www.qsl.net/k2vco/
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Steve Ellington

Re: K3 APF Adjustable Q

By "oscillate" I was thinking of my HQ-150's Q multiplier. It does remind me
of APF but of course is a totally different thing.
As APF now exist in the K3, I choose to use it only when necessary. If it
had variable Q, it would be on constantly and I would adjust Q as needed.
One advantage to an external APF box is how the sidetone is filtered and
ends up sound so sweet. Normally sidetones sound a bit dull but APF can
brighten them up and make them sound so pure and clean.
Steve

----- Original Message -----
From: "Vic K2VCO" <[hidden email]>
To: <[hidden email]>
Sent: Sunday, October 31, 2010 12:25 PM
Subject: Re: [Elecraft] K3 APF Adjustable Q

>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
> http://www.qsl.net/k2vco/
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
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> Post: mailto:[hidden email]
>
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> Please help support this email list: http://www.qsl.net/donate.html

Byron N6NUL

Re: K3 APF Adjustable Q

In reply to this post by Bob K6UJ

On Saturday, October 30, 2010, Robert Harmon <[hidden email]> wrote:

> It is a tool to be used in the real tough cases where the signal is right down in the noise and you need that extra help to pull him out.

Naieve newbie question, because im missing something here: if the
signal you want is that hard to receive, what are the chances the
other station will be able to hear your reply?

Byron KI6NUL

--
- Northern California Contest Club
- CU in the 2011 Cal QSO Party 1-2 Oct 2011
- www.cqp.org
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Vic K2VCO

Re: K3 APF Adjustable Q

Pretty good, if the other station is QRP and you are not, if the other station is DX and
you are a high-power DXer, or if the other station has a K3 too!

On 10/31/2010 10:05 AM, Byron Servies wrote:

> On Saturday, October 30, 2010, Robert Harmon<[hidden email]> wrote:
>
>> It is a tool to be used in the real tough cases where the signal is right down in the
>> noise and you need that extra help to pull him out.
>
> Naieve newbie question, because im missing something here: if the signal you want is
> that hard to receive, what are the chances the other station will be able to hear your
> reply?
>
> Byron KI6NUL
>
>

W2RU - Bud Hippisley

Re: K3 APF Adjustable Q

In reply to this post by Byron N6NUL

If he's running 5 watts to a coat hanger antenna on a remote island, and you're using a 1500-watt amplifier and 3-element beam to go with your beautiful K3, the chances are quite good....:-)

Besides...the APF feature will help us all be able to copy the "/QRP" at the end of his call.

Bud, W2RU

On Oct 31, 2010, at 1:05 PM, Byron Servies wrote:

> Naive newbie question, because im missing something here: if the
> signal you want is that hard to receive, what are the chances the
> other station will be able to hear your reply?

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AC7AC

Re: K3 APF Adjustable Q

In reply to this post by Vic K2VCO

CONTENTS DELETED

The author has deleted this message.

Kok Chen

Re: K3 APF Adjustable Q

In reply to this post by Byron N6NUL

On Oct 31, 2010, at 10/31 10:05 AM, Byron Servies wrote:

> Naieve newbie question, because im missing something here: if the
> signal you want is that hard to receive, what are the chances the
> other station will be able to hear your reply?

Since I use simple antennas, and even though I always run barefooted,
I *always* assume a DXpedition to an isolated island can copy me when
I can barely copy them above the noise.

Although Reciprocity Theory states that if both of you use the same
power, the received power at the two antenna terminals will be the
same independent of what antennas are at each end, other things
determine if he can copy you better than you can copy him.

The obvious factor that influence whether he can copy you is therefore
obviously the amount of power that you use compared to the amount of
power that he uses.

However, another factor, arguably more important, is the antennas'
directivity and where the directivity are aimed at. If his antenna is
more directive than yours by 3 dB, all else being equal, he has a 3 dB
of SNR advantage. If the arrival angle of his signal at your antenna
is 10 dB below where your antenna actually peaks, while your signal
arrives at his antenna where the response of his antenna peaks, you
have yet another 10 dB disadvantage, etc.

The same SNR argument applies to how noisy his local RF environment is
compared to your environment.

And of course, how optimal and easy to use the filtering at his end is
to pull your signal out of the noise, which is what the APF is all
about for CW (and correspondingly, the use of matched filters for
digital modes).

73
Chen, W7AY

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Bill VanAlstyne W5WVO

Re: K3 APF Adjustable Q

So yes, there are a BUNCH of variables that determine whether the DX station
is going to hear your signal.

My approach -- though this has been confined to 6 meters up until recently,
when I got back on HF CW and digital modes with a VERY small footprint --
has always been to do whatever I can to make sure the other guy CAN hear me.
That means the best antennas and the most power I can put together, in
combination of course with the smartest operating practices I can learn and
master. The QRO part of that, well, that's just me. A lot of guys love the
thrill of beating their heads against a brick wall -- sorry, I mean, the
thrill of working DX with QRP and small antennas. :-)

Notwithstanding big differences in things like power and antennas, however,
I think the two principle reasons for assuming the DX station will
eventually be able to copy you are:

(1) Their locations are probably quieter than yours -- sometimes (as in an
island DXpedition location) a LOT quieter, maybe as much as 10 dB or more
quieter.

(2) Guys who run DXpeditions or who run their home stations from rare
entities are usually very, very good operators -- probably better than you
are, for sure better than I am.

Since I've been back on HF CW chasing DX with my puny little sloper and 100
watts, I've seen many, many DX stations go to extreme efforts to pull
through a complete QSO with a weak W/K station (like me) that they
absolutely do NOT need to work for any pragmatic reason, other than personal
pride in operating skills. And some of these guys' skills are just amazing.

Bill W5WVO

-----Original Message-----
From: Kok Chen
Sent: Sunday, October 31, 2010 18:44
To: Elecraft Reflector
Subject: Re: [Elecraft] K3 APF Adjustable Q

On Oct 31, 2010, at 10/31 10:05 AM, Byron Servies wrote:

> Naieve newbie question, because im missing something here: if the
> signal you want is that hard to receive, what are the chances the
> other station will be able to hear your reply?

Since I use simple antennas, and even though I always run barefooted,
I *always* assume a DXpedition to an isolated island can copy me when
I can barely copy them above the noise.

Although Reciprocity Theory states that if both of you use the same
power, the received power at the two antenna terminals will be the
same independent of what antennas are at each end, other things
determine if he can copy you better than you can copy him.

The obvious factor that influence whether he can copy you is therefore
obviously the amount of power that you use compared to the amount of
power that he uses.

However, another factor, arguably more important, is the antennas'
directivity and where the directivity are aimed at. If his antenna is
more directive than yours by 3 dB, all else being equal, he has a 3 dB
of SNR advantage. If the arrival angle of his signal at your antenna
is 10 dB below where your antenna actually peaks, while your signal
arrives at his antenna where the response of his antenna peaks, you
have yet another 10 dB disadvantage, etc.

The same SNR argument applies to how noisy his local RF environment is
compared to your environment.

And of course, how optimal and easy to use the filtering at his end is
to pull your signal out of the noise, which is what the APF is all
about for CW (and correspondingly, the use of matched filters for
digital modes).

73
Chen, W7AY

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Joe Subich, W4TV-4

Re: K3 APF Adjustable Q

In reply to this post by Guy, K2AV

>> 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.

If you want a "milder" shape, use Dual PB filter with a 400 - 500 Hz
background and 100 Hz foreground. That can certainly be left on
all the time and the APF switched on when needed ... at least once
all of the controls have been programmed.

73,

... Joe, W4TV

On 10/31/2010 12:03 PM, Guy Olinger K2AV wrote:

Steve Ellington

Re: K3 APF Adjustable Q

Joe
What you describe is not 'variable'.
N4LQ
Steve

----- Original Message -----
From: "Joe Subich, W4TV" <[hidden email]>
To: "Guy Olinger K2AV" <[hidden email]>
Cc: <[hidden email]>
Sent: Sunday, October 31, 2010 4:47 PM
Subject: Re: [Elecraft] K3 APF Adjustable Q

>
>>> 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.
>
> If you want a "milder" shape, use Dual PB filter with a 400 - 500 Hz
> background and 100 Hz foreground. That can certainly be left on
> all the time and the APF switched on when needed ... at least once
> all of the controls have been programmed.
>
> 73,
>
> ... Joe, W4TV
>
>
> On 10/31/2010 12:03 PM, 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
>>>>>
>>>>> ______________________________________________________________
>>>>> 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
>>>
>>> ______________________________________________________________
>>> 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
>>>
>>
> ______________________________________________________________
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>
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> Please help support this email list: http://www.qsl.net/donate.html

123