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K3 Passband/DSP Filter Display Question ?

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Phil Hystad-3

K3 Passband/DSP Filter Display Question ?

I have had my K3 for four years but rarely make use of the passband tuning features. Today though I was experimenting with APF and the passband controls and learned that I really do not know what I am doing.

In particular, the VFO B display is a mystery to me during passband tuning and APF SHIFT tuning. For example, in passband tuning (APF not enabled), the VFO B display says FC and then a number like 0.70 or whatever. What does "FC" mean (I can guess, but that would not be useful) and what is this number. I scanned all the documents I have and have not found descriptions of the content of the VFO B readout during passband tuning. I know it has something to do with shifting the frequency of center (I think) so maybe FC means Frequency Center. Also, there is an asterisk in the field, like: FC *0.68. Maybe someone can interpret the meaning of that.

If I knew the definition for passband tuning for the VFO B field content I could probably guess at the meaning of the APF enabled display which is similar such as: APF *0.68.

I have found lots of description of passband tuning and that part of the display showing the passband width and position but nothing describing the VFO B contents (not covered in documentation on alternate VFO B displays either).

73, phil, K7PEH

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k5oai

Re: K3 Passband/DSP Filter Display Question ?

yes FC means Frequency Center
the astric * before the number indicates the APF shift is in the center
the .68 sez your center (your cw pitch) set to 680hz

so if you saw .670 or .690
there would be no * and your APF center
would now be 10 hz up .690 or down .670

some have found the ringing they experienced with APF
was fixed by shifting the APF center off by maybe 10-20hz
and using the RIT moved their receive the same amount

On 1/31/2014 12:48 PM, Phil Hystad wrote:

> I have had my K3 for four years but rarely make use of the passband
> tuning features. Today though I was experimenting with APF and the
> passband controls and learned that I really do not know what I am
> doing.
>
> In particular, the VFO B display is a mystery to me during passband
> tuning and APF SHIFT tuning. For example, in passband tuning (APF
> not enabled), the VFO B display says FC and then a number like 0.70
> or whatever. What does "FC" mean (I can guess, but that would not be
> useful) and what is this number. I scanned all the documents I have
> and have not found descriptions of the content of the VFO B readout
> during passband tuning. I know it has something to do with shifting
> the frequency of center (I think) so maybe FC means Frequency Center.
> Also, there is an asterisk in the field, like: FC *0.68. Maybe
> someone can interpret the meaning of that.
>
> If I knew the definition for passband tuning for the VFO B field
> content I could probably guess at the meaning of the APF enabled
> display which is similar such as: APF *0.68.
>
> I have found lots of description of passband tuning and that part of
> the display showing the passband width and position but nothing
> describing the VFO B contents (not covered in documentation on
> alternate VFO B displays either).
>
> 73, phil, K7PEH

--
GB & 73
K5OAI
Sam Morgan
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Don Wilhelm-4

Re: K3 Passband/DSP Filter Display Question ?

In reply to this post by Phil Hystad-3

Phil,

Yes, "FC" means Frequency Center, which is where the passband is
centered. The "*" means it is the default (the same as your sidetone
pitch setting for CW).
You did not ask about the Width display, but it is the width of the
passband and extends half that vale on either side of FC. Those numbers
are much more accurate than the low resolution graphic on the display,
but the display gives you an idea about which part of the ballpark you
are in.

For SSB and other voice modes, the default FC is 1.5 kHz, but I would
suggest you not worry about that, but use Hi-Cut and Lo-Cut instead of
shift and width and directly define the low and high frequency edges of
the passband. You will not be able to cut much more than to 350 or 400
Hz on the low end before loosing intelligibility, but you can cut the
high end substantially and still maintain intelligibility although some
of the voice characteristics become a bit more 'pinched'.

Attempting to use Width and Shift with voice modes will require you to
reposition the Shift each time you change the Width.

73,
Don W3FPR

On 1/31/2014 1:48 PM, Phil Hystad wrote:
> I have had my K3 for four years but rarely make use of the passband tuning features. Today though I was experimenting with APF and the passband controls and learned that I really do not know what I am doing.
>
> In particular, the VFO B display is a mystery to me during passband tuning and APF SHIFT tuning. For example, in passband tuning (APF not enabled), the VFO B display says FC and then a number like 0.70 or whatever. What does "FC" mean (I can guess, but that would not be useful) and what is this number. I scanned all the documents I have and have not found descriptions of the content of the VFO B readout during passband tuning. I know it has something to do with shifting the frequency of center (I think) so maybe FC means Frequency Center. Also, there is an asterisk in the field, like: FC *0.68. Maybe someone can interpret the meaning of that.
>
> If I knew the definition for passband tuning for the VFO B field content I could probably guess at the meaning of the APF enabled display which is similar such as: APF *0.68.
>
> I have found lots of description of passband tuning and that part of the display showing the passband width and position but nothing describing the VFO B contents (not covered in documentation on alternate VFO B displays either).
>
>

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Phil Hystad-3

Re: K3 Passband/DSP Filter Display Question ?

In reply to this post by k5oai

Sam,

Thanks a lot for your answer. It would be nice if this sort of information were
documented. If it is then I missed it even though I did a full document search
for the letters FC.

phil

On Jan 31, 2014, at 11:23 AM, Sam Morgan <[hidden email]> wrote:

>
> yes FC means Frequency Center
> the astric * before the number indicates the APF shift is in the center
> the .68 sez your center (your cw pitch) set to 680hz
>
> so if you saw .670 or .690
> there would be no * and your APF center
> would now be 10 hz up .690 or down .670
>
> some have found the ringing they experienced with APF
> was fixed by shifting the APF center off by maybe 10-20hz
> and using the RIT moved their receive the same amount
>
> On 1/31/2014 12:48 PM, Phil Hystad wrote:
>> I have had my K3 for four years but rarely make use of the passband
>> tuning features. Today though I was experimenting with APF and the
>> passband controls and learned that I really do not know what I am
>> doing.
>>
>> In particular, the VFO B display is a mystery to me during passband
>> tuning and APF SHIFT tuning. For example, in passband tuning (APF
>> not enabled), the VFO B display says FC and then a number like 0.70
>> or whatever. What does "FC" mean (I can guess, but that would not be
>> useful) and what is this number. I scanned all the documents I have
>> and have not found descriptions of the content of the VFO B readout
>> during passband tuning. I know it has something to do with shifting
>> the frequency of center (I think) so maybe FC means Frequency Center.
>> Also, there is an asterisk in the field, like: FC *0.68. Maybe
>> someone can interpret the meaning of that.
>>
>> If I knew the definition for passband tuning for the VFO B field
>> content I could probably guess at the meaning of the APF enabled
>> display which is similar such as: APF *0.68.
>>
>> I have found lots of description of passband tuning and that part of
>> the display showing the passband width and position but nothing
>> describing the VFO B contents (not covered in documentation on
>> alternate VFO B displays either).
>>
>> 73, phil, K7PEH
>
>
> --
> GB & 73
> K5OAI
> Sam Morgan

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Phil Hystad-3

Re: K3 Passband/DSP Filter Display Question ?

In reply to this post by Don Wilhelm-4

Don,

Thanks for your description. I didn't mention the Width control and display because I understood those. Just was not sure of the interpretation of the 0.68 -- now knowing it is the sidetone pitch makes sense but this sort of thing was not found in the documentation that I could find.

phil

On Jan 31, 2014, at 11:26 AM, Don Wilhelm <[hidden email]> wrote:

> Phil,
>
> Yes, "FC" means Frequency Center, which is where the passband is centered. The "*" means it is the default (the same as your sidetone pitch setting for CW).
> You did not ask about the Width display, but it is the width of the passband and extends half that vale on either side of FC. Those numbers are much more accurate than the low resolution graphic on the display, but the display gives you an idea about which part of the ballpark you are in.
>
> For SSB and other voice modes, the default FC is 1.5 kHz, but I would suggest you not worry about that, but use Hi-Cut and Lo-Cut instead of shift and width and directly define the low and high frequency edges of the passband. You will not be able to cut much more than to 350 or 400 Hz on the low end before loosing intelligibility, but you can cut the high end substantially and still maintain intelligibility although some of the voice characteristics become a bit more 'pinched'.
>
> Attempting to use Width and Shift with voice modes will require you to reposition the Shift each time you change the Width.
>
> 73,
> Don W3FPR
>
>
>
> On 1/31/2014 1:48 PM, Phil Hystad wrote:
>> I have had my K3 for four years but rarely make use of the passband tuning features. Today though I was experimenting with APF and the passband controls and learned that I really do not know what I am doing.
>>
>> In particular, the VFO B display is a mystery to me during passband tuning and APF SHIFT tuning. For example, in passband tuning (APF not enabled), the VFO B display says FC and then a number like 0.70 or whatever. What does "FC" mean (I can guess, but that would not be useful) and what is this number. I scanned all the documents I have and have not found descriptions of the content of the VFO B readout during passband tuning. I know it has something to do with shifting the frequency of center (I think) so maybe FC means Frequency Center. Also, there is an asterisk in the field, like: FC *0.68. Maybe someone can interpret the meaning of that.
>>
>> If I knew the definition for passband tuning for the VFO B field content I could probably guess at the meaning of the APF enabled display which is similar such as: APF *0.68.
>>
>> I have found lots of description of passband tuning and that part of the display showing the passband width and position but nothing describing the VFO B contents (not covered in documentation on alternate VFO B displays either).
>>
>>
>

Don Wilhelm-4

Re: K3 Passband/DSP Filter Display Question ?

Phil,

It will only be equal to the sidetone pitch if the "*" is present.

73,
Don W3FPR

On 1/31/2014 4:05 PM, Phil Hystad wrote:

> Don,
>
> Thanks for your description. I didn't mention the Width control and display because I understood those. Just was not sure of the interpretation of the 0.68 -- now knowing it is the sidetone pitch makes sense but this sort of thing was not found in the documentation that I could find.
>
> phil
>
> On Jan 31, 2014, at 11:26 AM, Don Wilhelm <[hidden email]> wrote:
>
>> Phil,
>>
>> Yes, "FC" means Frequency Center, which is where the passband is centered. The "*" means it is the default (the same as your sidetone pitch setting for CW).
>> You did not ask about the Width display, but it is the width of the passband and extends half that vale on either side of FC. Those numbers are much more accurate than the low resolution graphic on the display, but the display gives you an idea about which part of the ballpark you are in.
>>
>> For SSB and other voice modes, the default FC is 1.5 kHz, but I would suggest you not worry about that, but use Hi-Cut and Lo-Cut instead of shift and width and directly define the low and high frequency edges of the passband. You will not be able to cut much more than to 350 or 400 Hz on the low end before loosing intelligibility, but you can cut the high end substantially and still maintain intelligibility although some of the voice characteristics become a bit more 'pinched'.
>>
>> Attempting to use Width and Shift with voice modes will require you to reposition the Shift each time you change the Width.
>>
>> 73,
>> Don W3FPR
>>
>>
>>
>> On 1/31/2014 1:48 PM, Phil Hystad wrote:
>>> I have had my K3 for four years but rarely make use of the passband tuning features. Today though I was experimenting with APF and the passband controls and learned that I really do not know what I am doing.
>>>
>>> In particular, the VFO B display is a mystery to me during passband tuning and APF SHIFT tuning. For example, in passband tuning (APF not enabled), the VFO B display says FC and then a number like 0.70 or whatever. What does "FC" mean (I can guess, but that would not be useful) and what is this number. I scanned all the documents I have and have not found descriptions of the content of the VFO B readout during passband tuning. I know it has something to do with shifting the frequency of center (I think) so maybe FC means Frequency Center. Also, there is an asterisk in the field, like: FC *0.68. Maybe someone can interpret the meaning of that.
>>>
>>> If I knew the definition for passband tuning for the VFO B field content I could probably guess at the meaning of the APF enabled display which is similar such as: APF *0.68.
>>>
>>> I have found lots of description of passband tuning and that part of the display showing the passband width and position but nothing describing the VFO B contents (not covered in documentation on alternate VFO B displays either).
>>>
>>>
> ______________________________________________________________
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