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[K3] AM Bandwidth

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Rick Prather

[K3] AM Bandwidth

After installing the 6.0 kHz AM filter I notice the Max DSP b/w is 5.0 and the Shift center is 1.5 kHz.

Is this the normal set up?

TIA,

Rick
K6LE
# 3727
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Matt Zilmer

Re: [K3] AM Bandwidth

If you press and hold the SHIFT control (see NORM on VFO A), it will
reset the Fc and BW to what's normal for that mode.

matt W6NIA
K3 #24

On Mon, 22 Mar 2010 08:57:18 -0700, you wrote:

>After installing the 6.0 kHz AM filter I notice the Max DSP b/w is 5.0 and the Shift center is 1.5 kHz.
>
>Is this the normal set up?
>
>TIA,
>
>Rick
>K6LE
># 3727
>______________________________________________________________
>Elecraft mailing list
>Home: http://mailman.qth.net/mailman/listinfo/elecraft
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>Post: mailto:[hidden email]
>
>This list hosted by: http://www.qsl.net
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Rick Prather

Re: [K3] AM Bandwidth

"Nor" is 3 khz and 1.5 kHz center.

My main question is is it normal for the BW to max out at 5.0?

Probably doesn't matter since there is no audible difference as you advance wider than 3.2 anyway.

Thanks,

Rick
K6LE

On 3/22/2010, at 9:11 , Matt Zilmer wrote:

> If you press and hold the SHIFT control (see NORM on VFO A), it will
> reset the Fc and BW to what's normal for that mode.
>
> matt W6NIA
> K3 #24
>
> On Mon, 22 Mar 2010 08:57:18 -0700, you wrote:
>
>> After installing the 6.0 kHz AM filter I notice the Max DSP b/w is 5.0 and the Shift center is 1.5 kHz.
>>
>> Is this the normal set up?
>>
>> TIA,
>>
>> Rick
>> K6LE
>> # 3727
>> ______________________________________________________________
>> 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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Joe Planisky

Re: [K3] AM Bandwidth

In reply to this post by Rick Prather

Hi Rick,

Yes, that's normal. The displayed bandwidth is audio bandwidth.
Remember that AM uses both sidebands, so the 6 kHz filter passes 3 kHz
above and 3 kHz below the carrier (6 kHz total). Your resulting audio
bandwidth will actually be somewhere around 3 kHz.

You can get more audio bandwidth on AM receive by using the FM filter,
which is about 13 kHz wide, but you can't transmit AM through the FM
filter.

73
--
Joe KB8AP

On Mar 22, 2010, at 8:57 AM, K6LE wrote:

> After installing the 6.0 kHz AM filter I notice the Max DSP b/w is
> 5.0 and the Shift center is 1.5 kHz.
>
> Is this the normal set up?
>
> TIA,
>
> Rick
> K6LE
> # 3727

Matt Zilmer

Re: [K3] AM Bandwidth

In reply to this post by Rick Prather

3.0 / 1.5 *seems* right. If the BW control goes up to 5.0, I think it
tops out at 3.something.

There is something about this that was on the list, last year, but I
can't find it in the huge stack that develops...

73,
matt

On Mon, 22 Mar 2010 09:40:34 -0700, you wrote:

>"Nor" is 3 khz and 1.5 kHz center.
>
>My main question is is it normal for the BW to max out at 5.0?
>
>Probably doesn't matter since there is no audible difference as you advance wider than 3.2 anyway.
>
>Thanks,
>
>Rick
>K6LE
>
>On 3/22/2010, at 9:11 , Matt Zilmer wrote:
>
>> If you press and hold the SHIFT control (see NORM on VFO A), it will
>> reset the Fc and BW to what's normal for that mode.
>>
>> matt W6NIA
>> K3 #24
>>
>> On Mon, 22 Mar 2010 08:57:18 -0700, you wrote:
>>
>>> After installing the 6.0 kHz AM filter I notice the Max DSP b/w is 5.0 and the Shift center is 1.5 kHz.
>>>
>>> Is this the normal set up?
>>>
>>> TIA,
>>>
>>> Rick
>>> K6LE
>>> # 3727
>>> ______________________________________________________________
>>> 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

Rick Prather

Re: [K3] AM Bandwidth

Thanks Matt,

I'll chalk it up to "Normal".

Rick
K6LE

On 3/22/2010, at 10:51 , Matt Zilmer wrote:

> 3.0 / 1.5 *seems* right. If the BW control goes up to 5.0, I think it
> tops out at 3.something.
>
> There is something about this that was on the list, last year, but I
> can't find it in the huge stack that develops...
>
> 73,
> matt
>
> On Mon, 22 Mar 2010 09:40:34 -0700, you wrote:
>
>> "Nor" is 3 khz and 1.5 kHz center.
>>
>> My main question is is it normal for the BW to max out at 5.0?
>>
>> Probably doesn't matter since there is no audible difference as you advance wider than 3.2 anyway.
>>
>> Thanks,
>>
>> Rick
>> K6LE

MontyS

Re: [K3] AM Bandwidth

In reply to this post by Matt Zilmer

Those readings are normal. An indicated 3 khz bandwidth requires the 6 khz
filter - 3 khz on each side of the carrier. Since AM is DSB, one has to
double the indicated bandwidth to see what filter is needed.

Monty K2DLJ

> 3.0 / 1.5 *seems* right. If the BW control goes up to 5.0, I think it
> tops out at 3.something.
>
> There is something about this that was on the list, last year, but I
> can't find it in the huge stack that develops...
>
> 73,
> matt
>
> On Mon, 22 Mar 2010 09:40:34 -0700, you wrote:
>
>>"Nor" is 3 khz and 1.5 kHz center.
>>
>>My main question is is it normal for the BW to max out at 5.0?
>>
>>Probably doesn't matter since there is no audible difference as you
>>advance wider than 3.2 anyway.
>>
>>Thanks,
>>
>>Rick
>>K6LE

Joe Subich, W4TV-4

Re: [K3] AM Bandwidth

In reply to this post by Rick Prather

> My main question is is it normal for the BW to max out at 5.0?

Yes. The K3 "width" display represents the audio bandwidth.
In AM the RF bandwidth is twice the audio bandwidth. Note
however, that the bandwidth display is somewhat confusing
in that it represents the larger of 2 * (Fh-Fc) or 2 * (Fc-Fl)
where Fc = center, Fh = Hi cut, and Fl = Low cut. Further the
maximum Fh (high cut) frequency is 4200 Hz in AM, LSB, USB and
2400 Hz in CW.

73,

... Joe, W4TV

> -----Original Message-----
> From: [hidden email]
> [mailto:[hidden email]] On Behalf Of Rick Prather
> Sent: Monday, March 22, 2010 12:41 PM
> To: [hidden email]
> Cc: Elecraft Elecraft
> Subject: Re: [Elecraft] [K3] AM Bandwidth
>
>
> "Nor" is 3 khz and 1.5 kHz center.
>
> My main question is is it normal for the BW to max out at 5.0?
>
> Probably doesn't matter since there is no audible difference
> as you advance wider than 3.2 anyway.
>
> Thanks,
>
> Rick
> K6LE
>
> On 3/22/2010, at 9:11 , Matt Zilmer wrote:
>
> > If you press and hold the SHIFT control (see NORM on VFO
> A), it will
> > reset the Fc and BW to what's normal for that mode.
> >
> > matt W6NIA
> > K3 #24
> >
> > On Mon, 22 Mar 2010 08:57:18 -0700, you wrote:
> >
> >> After installing the 6.0 kHz AM filter I notice the Max DSP b/w is
> >> 5.0 and the Shift center is 1.5 kHz.
> >>
> >> Is this the normal set up?
> >>
> >> TIA,
> >>
> >> Rick
> >> K6LE
> >> # 3727
> ______________________________________________________________
> >> 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: [K3] AM Bandwidth

The 5 kHz dsp bandwidth comes into play when one uses AM synchronous
detection (AM then ALT) where the "shift" is either carrier plus upper
sideband (USB is on in display) or carrier plus lower sideband (LSB).
It actually sounds like 5 kHz bandwidth. What I use all the time
listening to BC up above 40m.

73, Guy.

On Mon, Mar 22, 2010 at 2:54 PM, Joe Subich, W4TV <[hidden email]> wrote:

>
>> My main question is is it normal for the BW to max out at 5.0?
>
> Yes. The K3 "width" display represents the audio bandwidth.
> In AM the RF bandwidth is twice the audio bandwidth. Note
> however, that the bandwidth display is somewhat confusing
> in that it represents the larger of 2 * (Fh-Fc) or 2 * (Fc-Fl)
> where Fc = center, Fh = Hi cut, and Fl = Low cut. Further the
> maximum Fh (high cut) frequency is 4200 Hz in AM, LSB, USB and
> 2400 Hz in CW.
>
> 73,
>
> ... Joe, W4TV
>
>
>> -----Original Message-----
>> From: [hidden email]
>> [mailto:[hidden email]] On Behalf Of Rick Prather
>> Sent: Monday, March 22, 2010 12:41 PM
>> To: [hidden email]
>> Cc: Elecraft Elecraft
>> Subject: Re: [Elecraft] [K3] AM Bandwidth
>>
>>
>> "Nor" is 3 khz and 1.5 kHz center.
>>
>> My main question is is it normal for the BW to max out at 5.0?
>>
>> Probably doesn't matter since there is no audible difference
>> as you advance wider than 3.2 anyway.
>>
>> Thanks,
>>
>> Rick
>> K6LE
>>
>> On 3/22/2010, at 9:11 , Matt Zilmer wrote:
>>
>> > If you press and hold the SHIFT control (see NORM on VFO
>> A), it will
>> > reset the Fc and BW to what's normal for that mode.
>> >
>> > matt W6NIA
>> > K3 #24
>> >
>> > On Mon, 22 Mar 2010 08:57:18 -0700, you wrote:
>> >
>> >> After installing the 6.0 kHz AM filter I notice the Max DSP b/w is
>> >> 5.0 and the Shift center is 1.5 kHz.
>> >>
>> >> Is this the normal set up?
>> >>
>> >> TIA,
>> >>
>> >> Rick
>> >> K6LE
>> >> # 3727
>> ______________________________________________________________
>> >> 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
>

Barry N1EU

Re: [K3] AM Bandwidth

In reply to this post by Joe Planisky

Joe Planisky wrote

Yes, that's normal. The displayed bandwidth is audio bandwidth.
Remember that AM uses both sidebands, so the 6 kHz filter passes 3 kHz
above and 3 kHz below the carrier (6 kHz total). Your resulting audio
bandwidth will actually be somewhere around 3 kHz.

Not here. I've consistently measured (with SpectraPLUS) 4Khz audio bandwith on my K3 in AM with 6Khz filter and width control indicating 5Khz. I've always had 4Khz wide rx audio in AM - am I the only one?

73, Barry N1EU

Joe Subich, W4TV-4

Re: [K3] AM Bandwidth

> Not here. I've consistently measured (with SpectraPLUS) 4Khz
> audio bandwith on my K3 in AM with 6Khz filter and width
> control indicating 5Khz. I've always had 4Khz wide rx audio
> in AM - am I the only one?

No you're not. The DSP has a brickwall response at 4200 Hz
(except for the various clock leakage products).

73,

... Joe, W4TV

> -----Original Message-----
> From: [hidden email]
> [mailto:[hidden email]] On Behalf Of Barry N1EU
> Sent: Monday, March 22, 2010 8:53 PM
> To: [hidden email]
> Subject: Re: [Elecraft] [K3] AM Bandwidth
>
>
>
>
> Joe Planisky wrote:
> >
> > Yes, that's normal. The displayed bandwidth is audio bandwidth.
> > Remember that AM uses both sidebands, so the 6 kHz filter
> passes 3 kHz
> > above and 3 kHz below the carrier (6 kHz total). Your
> resulting audio
> > bandwidth will actually be somewhere around 3 kHz.
> >
> Not here. I've consistently measured (with SpectraPLUS) 4Khz
> audio bandwith on my K3 in AM with 6Khz filter and width
> control indicating 5Khz. I've always had 4Khz wide rx audio
> in AM - am I the only one?
>
> 73, Barry N1EU
>
> --
> View this message in context:
> http://n2.nabble.com/K3-AM-Bandwidth-tp4778593p4781621.html
> Sent from the [K3] mailing list archive at Nabble.com.
> ______________________________________________________________
> 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

Barry N1EU

Re: [K3] AM Bandwidth

In reply to this post by Barry N1EU

Barry N1EU wrote

Not here. I've consistently measured (with SpectraPLUS) 4Khz audio bandwidth on my K3 in AM with 6Khz filter and width control indicating 5Khz. I've always had 4Khz wide rx audio in AM - am I the only one?

I should have mentioned that this is in normal AM mode. In sync AM, I see the audio bandwidth reduced from 4Khz to 3Khz.

Barry N1EU

AD4C2009

Re: [K3] AM Bandwidth

Barry,you are not the only one,my K3 "see" a maximun of 4Khz BW(from 40 to 4000Hz) when I am on AM even it show 5Khz on the display and as you I use the Spectralab as spectrum analyzer.

AD4C

"For a refined ham it is compulsory to own a k3"

--- On Tue, 3/23/10, Barry N1EU <[hidden email]> wrote:

From: Barry N1EU <[hidden email]>
Subject: Re: [Elecraft] [K3] AM Bandwidth
To: [hidden email]
Date: Tuesday, March 23, 2010, 1:21 AM

Barry N1EU wrote:
>
> Not here. I've consistently measured (with SpectraPLUS) 4Khz audio
> bandwidth on my K3 in AM with 6Khz filter and width control indicating
> 5Khz. I've always had 4Khz wide rx audio in AM - am I the only one?
>
I should have mentioned that this is in normal AM mode. In sync AM, I see
the audio bandwidth reduced from 4Khz to 3Khz.

Barry N1EU

--
View this message in context: http://n2.nabble.com/K3-AM-Bandwidth-tp4778593p4781739.html
Sent from the [K3] mailing list archive at Nabble.com.
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______________________________________________________________
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