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Re: AM with FM filter (was: Re: [Elecraft_K3] Re: Close to Ordering)

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KD8NNU

Re: AM with FM filter (was: Re: [Elecraft_K3] Re: Close to Ordering)

Why not go to the confurgation menue and change the filter setting from
13 to 6 khz. I bet it will work.

I dont have the filter so I can not check it out.

I am not sure what effect this would have on the TX width, maybe someone
can check it out.

~73
Don
KD8NNU

On Mon, Nov 7, 2011 at 1:34 PM, Oliver Dröse wrote:

> Hi Joe,
>
> interestingly you CAN transmit AM with the FM filter! But it just
> works for one over. ;-)) Found it out by chance during the last few
> weeks with the nice 10 m conditions when tuning to the AM portion of
> the band. I only have the FM filter fitted (besides CW/SSB filters)
> and running firmware 4.42 beta (not tested with other ones) I can
> transmit in AM. Just AFTER releasing the PTT I will get an TXFILERR on
> the VFOB display and will not be able to transmit anymore. You need to
> power-off and on the radio then to make it work again. As that is no
> good QSO practice and you probably miss a few sentences from your QSO
> partner during "K3 reboot" I just did one QSO that way (and
> furthermore I am not really interested in AM just wanted to try it
> out). ;-))
>
> Just my observations on that topic. Besides I completely agree with
> you, I do not see why you should not be able (or better "allowed") to
> transmit AM through the FM filter ...
>
> 73, Olli - DH8BQA
>
>
>
> ----- Original Message ----- From: "Joe Subich, W4TV"
> <[hidden email]>
> To: <[hidden email]>
> Sent: Monday, November 07, 2011 6:13 PM
> Subject: Re: [Elecraft_K3] Re: Close to Ordering
>
>
>>
>>> If you wish to transmit AM, you'll need a 6 kHz filter.
>>>
>>> If you wish to transmit FM, you'll need a 13 kHz FM filter.
>>
>> This still bugs me ... *WHY* won't Wayne enable AM transmit
>> with the FM filter? I've run multiple tests with a spectrum
>> analyzer and can find no image when I set the bandwidth of
>> the FM filter to 6 KHz to enable AM and generate a test signal
>> with the two-tone generator.
>>
>> I don't want to waste one of the limited filter slots for both
>> AM and FM filters but I want to be able to transmit either mode
>> if so inclined.
>>
>> 73,
>>
>> ... Joe, W4TV
>>
>>
>
> ______________________________________________________________
> 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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Dunc Carter - W5DC

Re: AM with FM filter (was: Re: [Elecraft_K3] Re: Close to Ordering)

On 11/7/2011 5:16 PM, [hidden email] wrote:
>
> Why not go to the confurgation menue and change the filter setting from
> 13 to 6 khz. I bet it will work.
>
That's what you need to do to use the FM filter on AM - lie to the K3.

>
>
> I dont have the filter so I can not check it out.
>
> I am not sure what effect this would have on the TX width, maybe someone
> can check it out.
>
> ~73
> Don
> KD8NNU
>
> On Mon, Nov 7, 2011 at 1:34 PM, Oliver Dröse wrote:
>
> > Hi Joe,
> >
> > interestingly you CAN transmit AM with the FM filter! But it just
> > works for one over. ;-)) Found it out by chance during the last few
> > weeks with the nice 10 m conditions when tuning to the AM portion of
> > the band. I only have the FM filter fitted (besides CW/SSB filters)
> > and running firmware 4.42 beta (not tested with other ones) I can
> > transmit in AM. Just AFTER releasing the PTT I will get an TXFILERR on
> > the VFOB display and will not be able to transmit anymore. You need to
> > power-off and on the radio then to make it work again. As that is no
> > good QSO practice and you probably miss a few sentences from your QSO
> > partner during "K3 reboot" I just did one QSO that way (and
> > furthermore I am not really interested in AM just wanted to try it
> > out). ;-))
> >
> > Just my observations on that topic. Besides I completely agree with
> > you, I do not see why you should not be able (or better "allowed") to
> > transmit AM through the FM filter ...
> >
> > 73, Olli - DH8BQA
> >
> >
> >
> > ----- Original Message ----- From: "Joe Subich, W4TV"
> > <[hidden email] <mailto:lists%40subich.com>>
> > To: <[hidden email] <mailto:Elecraft_K3%40yahoogroups.com>>
> > Sent: Monday, November 07, 2011 6:13 PM
> > Subject: Re: [Elecraft_K3] Re: Close to Ordering
> >
> >
> >>
> >>> If you wish to transmit AM, you'll need a 6 kHz filter.
> >>>
> >>> If you wish to transmit FM, you'll need a 13 kHz FM filter.
> >>
> >> This still bugs me ... *WHY* won't Wayne enable AM transmit
> >> with the FM filter? I've run multiple tests with a spectrum
> >> analyzer and can find no image when I set the bandwidth of
> >> the FM filter to 6 KHz to enable AM and generate a test signal
> >> with the two-tone generator.
> >>
> >> I don't want to waste one of the limited filter slots for both
> >> AM and FM filters but I want to be able to transmit either mode
> >> if so inclined.
> >>
> >> 73,
> >>
> >> ... Joe, W4TV
> >>
> >>
> >
> > __________________________________________________________
> > Elecraft mailing list
> > Home: http://mailman.qth.net/mailman/listinfo/elecraft
> > Help: http://mailman.qth.net/mmfaq.htm
> > Post: mailto:[hidden email]
> <mailto:Elecraft%40mailman.qth.net>
> >
> > This list hosted by: http://www.qsl.net
> > Please help support this email list: http://www.qsl.net/donate.html
>
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Joe Subich, W4TV-4

Re: AM with FM filter (was: Re: [Elecraft_K3] Re: Close to Ordering)

In reply to this post by KD8NNU

> I bet it will work.

Yes, it works. That's how I was able to transmit through the FM filter
to test with the spectrum analyzer.

> I am not sure what effect this would have on the TX width, maybe
> someone can check it out.

Since modulation is performed in DSP, there is no change in the TX
width.

73,

... Joe, W4TV

On 11/7/2011 7:16 PM, [hidden email] wrote:

> Why not go to the confurgation menue and change the filter setting from
> 13 to 6 khz. I bet it will work.
>
> I dont have the filter so I can not check it out.
>
> I am not sure what effect this would have on the TX width, maybe someone
> can check it out.
>
>
> ~73
> Don
> KD8NNU
>
>
> On Mon, Nov 7, 2011 at 1:34 PM, Oliver Dröse wrote:
>
>> Hi Joe,
>>
>> interestingly you CAN transmit AM with the FM filter! But it just
>> works for one over. ;-)) Found it out by chance during the last few
>> weeks with the nice 10 m conditions when tuning to the AM portion of
>> the band. I only have the FM filter fitted (besides CW/SSB filters)
>> and running firmware 4.42 beta (not tested with other ones) I can
>> transmit in AM. Just AFTER releasing the PTT I will get an TXFILERR on
>> the VFOB display and will not be able to transmit anymore. You need to
>> power-off and on the radio then to make it work again. As that is no
>> good QSO practice and you probably miss a few sentences from your QSO
>> partner during "K3 reboot" I just did one QSO that way (and
>> furthermore I am not really interested in AM just wanted to try it
>> out). ;-))
>>
>> Just my observations on that topic. Besides I completely agree with
>> you, I do not see why you should not be able (or better "allowed") to
>> transmit AM through the FM filter ...
>>
>> 73, Olli - DH8BQA
>>
>>
>>
>> ----- Original Message ----- From: "Joe Subich, W4TV"
>> <[hidden email]>
>> To:<[hidden email]>
>> Sent: Monday, November 07, 2011 6:13 PM
>> Subject: Re: [Elecraft_K3] Re: Close to Ordering
>>
>>
>>>
>>>> If you wish to transmit AM, you'll need a 6 kHz filter.
>>>>
>>>> If you wish to transmit FM, you'll need a 13 kHz FM filter.
>>>
>>> This still bugs me ... *WHY* won't Wayne enable AM transmit
>>> with the FM filter? I've run multiple tests with a spectrum
>>> analyzer and can find no image when I set the bandwidth of
>>> the FM filter to 6 KHz to enable AM and generate a test signal
>>> with the two-tone generator.
>>>
>>> I don't want to waste one of the limited filter slots for both
>>> AM and FM filters but I want to be able to transmit either mode
>>> if so inclined.
>>>
>>> 73,
>>>
>>> ... Joe, W4TV
>>>
>>>
>>
>> ______________________________________________________________
>> 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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Guy, K2AV

Re: AM with FM filter (was: Re: [Elecraft_K3] Re: Close to Ordering)

In reply to this post by KD8NNU

What will happen the most is that the RX bandwidth will be handled
entirely by the DSP filter width, and stuff in the extra bandwidth
will be in the IF when you are listening. This is the same thing as
listening to CW without a CW roofing filter. For casual stuff, and
since it is a K3, you may not notice.

On transmit, the bandwidth of the signal is made in the CPU. The
roofing filter is NOT used to restrict the bandwidth of the
transmitted signal. That is entirely accomplished in the workings of
firmware, and is all done when the TX digital to analog converter
inserts the fully formed TX signal in the 15 kHz IF. There is no
analog modulation anywhere in the TX string. Signal generation via
algorithm.

73, Guy.

On Mon, Nov 7, 2011 at 7:16 PM, <[hidden email]> wrote:

> Why not go to the confurgation menue and change the filter setting from
> 13 to 6 khz. I bet it will work.
>
> I dont have the filter so I can not check it out.
>
> I am not sure what effect this would have on the TX width, maybe someone
> can check it out.
>
>
> ~73
> Don
> KD8NNU
>
>
> On Mon, Nov 7, 2011 at 1:34 PM, Oliver Dröse wrote:
>
>> Hi Joe,
>>
>> interestingly you CAN transmit AM with the FM filter! But it just
>> works for one over. ;-)) Found it out by chance during the last few
>> weeks with the nice 10 m conditions when tuning to the AM portion of
>> the band. I only have the FM filter fitted (besides CW/SSB filters)
>> and running firmware 4.42 beta (not tested with other ones) I can
>> transmit in AM. Just AFTER releasing the PTT I will get an TXFILERR on
>> the VFOB display and will not be able to transmit anymore. You need to
>> power-off and on the radio then to make it work again. As that is no
>> good QSO practice and you probably miss a few sentences from your QSO
>> partner during "K3 reboot" I just did one QSO that way (and
>> furthermore I am not really interested in AM just wanted to try it
>> out). ;-))
>>
>> Just my observations on that topic. Besides I completely agree with
>> you, I do not see why you should not be able (or better "allowed") to
>> transmit AM through the FM filter ...
>>
>> 73, Olli - DH8BQA
>>
>>
>>
>> ----- Original Message ----- From: "Joe Subich, W4TV"
>> <[hidden email]>
>> To: <[hidden email]>
>> Sent: Monday, November 07, 2011 6:13 PM
>> Subject: Re: [Elecraft_K3] Re: Close to Ordering
>>
>>
>>>
>>>> If you wish to transmit AM, you'll need a 6 kHz filter.
>>>>
>>>> If you wish to transmit FM, you'll need a 13 kHz FM filter.
>>>
>>> This still bugs me ... *WHY* won't Wayne enable AM transmit
>>> with the FM filter? I've run multiple tests with a spectrum
>>> analyzer and can find no image when I set the bandwidth of
>>> the FM filter to 6 KHz to enable AM and generate a test signal
>>> with the two-tone generator.
>>>
>>> I don't want to waste one of the limited filter slots for both
>>> AM and FM filters but I want to be able to transmit either mode
>>> if so inclined.
>>>
>>> 73,
>>>
>>> ... Joe, W4TV
>>>
>>>
>>
>> ______________________________________________________________
>> 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

Guy, K2AV

Re: AM with FM filter (was: Re: [Elecraft_K3] Re: Close to Ordering)

In reply to this post by Joe Subich, W4TV-4

On Mon, Nov 7, 2011 at 8:23 PM, Joe Subich, W4TV <[hidden email]> wrote:

> Since modulation is performed in DSP, there is no change in the TX
> width.

DSP modulation is an oxymoron of sorts.

Since modulation involves imposing one signal on a second signal to
obtain the wanted third signal, technically there is no modulation in
a K3. The desired signal is directly formed digitally via algorithm
and placed without further processing into the linear TX string at the
15 kHz IF via a DAC. And we don't normally refer to up-conversion to
the TX frequency as "modulation." So there is no modulation. The K3
uses firmware directed direct signal generation.

We have SUCH a hard time walking away from our analog roots. It's
comforting to call that voltage scalar pot plus an ADC the "RF" gain.
But it's real hard to find the RF gain lead going to the CPU, cause
the digital variable gain advice is time division multiplexed with a
bunch of other stuff sent on a single lead to the CPU. It's "advice"
because it has no direct affect on anything unless the firmware and
CPU want it to, in very severe contrast to our daddies' analog radios.

73, Guy.
______________________________________________________________
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

Joe Subich, W4TV-4

Re: AM with FM filter

> Since modulation involves imposing one signal on a second signal to
> obtain the wanted third signal, technically there is no modulation in
> a K3. The desired signal is directly formed digitally via algorithm
> and placed without further processing into the linear TX string at the
> 15 kHz IF via a DAC.

I don't know how Lyle does it but one "DSP Modulation" technique is
simply to convert the incoming audio to digital create a quadrature
version of the digital audio stream, multiply each of those streams
with either an in phase or quadrature version of the "carrier" and
combine (add) the resulting data streams. In this case the "modulator"
is identical to a phasing SSB modulator only in the digital domain.

> The K3 uses firmware directed direct signal generation.

It's still nothing more than doing mathematically what was previously
done in circuitry.

> It's comforting to call that voltage scalar pot plus an ADC the "RF"
> gain. But it's real hard to find the RF gain lead going to the CPU,
> cause the digital variable gain advice is time division multiplexed
> with a bunch of other stuff sent on a single lead to the CPU. It's
> "advice" because it has no direct affect on anything unless the
> firmware and CPU want it to, in very severe contrast to our daddies'
> analog radios.

Again, it's simply doing in mathematics what our fathers' radios did
in circuitry. Simply because we can no longer point to a specific
diode and capacitor that converts a series of RF waves of varying
amplitudes into an audio frequency doesn't mean there isn't an envelope
detector (or an AGC detector depending on the size of the capacitor).

73,

... Joe, W4TV

On 11/7/2011 9:37 PM, Guy Olinger K2AV wrote:

> On Mon, Nov 7, 2011 at 8:23 PM, Joe Subich, W4TV<[hidden email]> wrote:
>
>> Since modulation is performed in DSP, there is no change in the TX
>> width.
>
> DSP modulation is an oxymoron of sorts.
>
> Since modulation involves imposing one signal on a second signal to
> obtain the wanted third signal, technically there is no modulation in
> a K3. The desired signal is directly formed digitally via algorithm
> and placed without further processing into the linear TX string at the
> 15 kHz IF via a DAC. And we don't normally refer to up-conversion to
> the TX frequency as "modulation." So there is no modulation. The K3
> uses firmware directed direct signal generation.
>
> We have SUCH a hard time walking away from our analog roots. It's
> comforting to call that voltage scalar pot plus an ADC the "RF" gain.
> But it's real hard to find the RF gain lead going to the CPU, cause
> the digital variable gain advice is time division multiplexed with a
> bunch of other stuff sent on a single lead to the CPU. It's "advice"
> because it has no direct affect on anything unless the firmware and
> CPU want it to, in very severe contrast to our daddies' analog radios.
>
> 73, Guy.
>

Guy, K2AV

Re: AM with FM filter

Not all DSP processing, by any stretch of the imagination, is merely a
digital "analog" of an analog technique. Some stuff simply CANNOT be
done in analog circuits of any kind. It is true that back a ways, the
way we got started was simply digitizing analog techniques and saving
chip count by doing that, but these days there is so much digital
without any analog "analog," that there is no going back, and no
convenient nearby analog version to use as a mental image of what is
going on. Like someone really learning a language, you know you are
there when you both speak and DREAM in digital.

One such K3 process is Wayne's proprietary TX voice amplitude
management scheme as a replacement for compression by RF clipping.

Some of this stuff got no analog daddy to point back at.

73, Guy.

On Mon, Nov 7, 2011 at 10:16 PM, Joe Subich, W4TV <[hidden email]> wrote:

>
>> Since modulation involves imposing one signal on a second signal to
>> obtain the wanted third signal, technically there is no modulation in
>> a K3. The desired signal is directly formed digitally via algorithm
>> and placed without further processing into the linear TX string at the
>> 15 kHz IF via a DAC.
>
> I don't know how Lyle does it but one "DSP Modulation" technique is
> simply to convert the incoming audio to digital create a quadrature
> version of the digital audio stream, multiply each of those streams
> with either an in phase or quadrature version of the "carrier" and
> combine (add) the resulting data streams. In this case the "modulator"
> is identical to a phasing SSB modulator only in the digital domain.
>
>> The K3 uses firmware directed direct signal generation.
>
> It's still nothing more than doing mathematically what was previously
> done in circuitry.
>
>> It's comforting to call that voltage scalar pot plus an ADC the "RF"
>> gain. But it's real hard to find the RF gain lead going to the CPU,
>> cause the digital variable gain advice is time division multiplexed
>> with a bunch of other stuff sent on a single lead to the CPU. It's
>> "advice" because it has no direct affect on anything unless the
>> firmware and CPU want it to, in very severe contrast to our daddies'
>> analog radios.
>
> Again, it's simply doing in mathematics what our fathers' radios did
> in circuitry. Simply because we can no longer point to a specific
> diode and capacitor that converts a series of RF waves of varying
> amplitudes into an audio frequency doesn't mean there isn't an envelope
> detector (or an AGC detector depending on the size of the capacitor).
>
> 73,
>
> ... Joe, W4TV
>
>
> On 11/7/2011 9:37 PM, Guy Olinger K2AV wrote:
>>
>> On Mon, Nov 7, 2011 at 8:23 PM, Joe Subich, W4TV<[hidden email]> wrote:
>>
>>> Since modulation is performed in DSP, there is no change in the TX
>>> width.
>>
>> DSP modulation is an oxymoron of sorts.
>>
>> Since modulation involves imposing one signal on a second signal to
>> obtain the wanted third signal, technically there is no modulation in
>> a K3. The desired signal is directly formed digitally via algorithm
>> and placed without further processing into the linear TX string at the
>> 15 kHz IF via a DAC. And we don't normally refer to up-conversion to
>> the TX frequency as "modulation." So there is no modulation. The K3
>> uses firmware directed direct signal generation.
>>
>> We have SUCH a hard time walking away from our analog roots. It's
>> comforting to call that voltage scalar pot plus an ADC the "RF" gain.
>> But it's real hard to find the RF gain lead going to the CPU, cause
>> the digital variable gain advice is time division multiplexed with a
>> bunch of other stuff sent on a single lead to the CPU. It's "advice"
>> because it has no direct affect on anything unless the firmware and
>> CPU want it to, in very severe contrast to our daddies' analog radios.
>>
>> 73, Guy.
>>
>

Don Wilhelm-4

Re: AM with FM filter

In reply to this post by Joe Subich, W4TV-4

Joe and all,

BUT, doing it mathematically can produce an ideal waveform. That is
something difficult to accomplish with analog components which have
inherent non-linearity and harmonic generation that is absent in the
pure mathematical treatment. The downside of doing it mathematically is
in the conversion from the continuous analog stream to the "number soup"
that must occur and then back again to analog.

The one opposing argument is that the digital treatment has finite bin
sizes and moves stepwise from one bin to an adjacent bin - analog covers
the same ground in a continuous manner with no steps.
The more bits in the ADC (or DAC), the closer the digital can be to an
analog signal, but there still will be stepwise changes in the (number
represented by the amplitude) in any digital transformation - digital
smoothing helps a great deal, but is never perfect.

Which is better depends on the listener's ears - most listeners cannot
determine the difference. Consider the "better" audio quality of CDs as
opposed to vinyl disks (I know there are some that will differ and
consider the analog "better", but digital can preserve the full dynamic
range and impulses where the analog can squash the peaks). Also give
consideration to the fact that MP3s have been touted by some as "more
Hi-Fi" than CD quality! (Yes, I have seen those claims). That is
perception alone - a compressed signal cannot carry the full information
of the original content no matter what the advertizing hype may
indicate. Many such things are only in the ears and mind of the
listener - same goes with analog modulation vs. digitally generated
signals - (yes, even CW is a form of modulation although not usually
thought of as such).

73,
Don W3FPR

On 11/7/2011 10:16 PM, Joe Subich, W4TV wrote:
> It's still nothing more than doing mathematically what was previously
> done in circuitry.
>
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