K3 and AM RX

[Jan Erik Holm]

When tuning across an AM station there are
clicks and cracks, seems to be on even kHz.
On my radio it has been from day one. Is
this normal or is my radio faulty?
I use latest FW.
/ Jim
______________________________________________________________
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

[pd0psb]

It is normal.
K3 isn't the "smoothest" bandtuner.
(but the upside is a very clean LO signal, once the VFO is settled)

73'
Paul
PD0PSB

[N5GE]

On Sun, 21 Mar 2010 20:01:10 +0100, Jan Erik Holm <[hidden email]>
wrote:

K3 #806 does not do that.

>When tuning across an AM station there are
>clicks and cracks, seems to be on even kHz.
>On my radio it has been from day one. Is
>this normal or is my radio faulty?
>I use latest FW.
>/ Jim
[snip]

Tom, N5GE

K3 #806 with SUB RX, PR6,
KRC2 and K144XV
K3 #1055 with PR6 and XV432
W1, 2 W2's and other small kits

http://www.n5ge.com
http://www.swotrc.net

______________________________________________________________
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

[pd0psb]

So you don't have VCO "relock" chirps every few kHz ??
(at least I think that's what Jim experiences...)

73'
Paul
PD0PSB

[Guy, K2AV]

VCO relock chirps every few kHz is not normal.  Best open a
correspondence with [hidden email].

On Mon, Mar 22, 2010 at 11:48 AM, pd0psb <[hidden email]> wrote:

>
> So you don't have VCO "relock" chirps every few kHz ??
> (at least I think that's what Jim experiences...)
>
> 73'
> Paul
> PD0PSB
> --
> View this message in context: http://n2.nabble.com/K3-and-AM-RX-tp4774105p4778512.html
> Sent from the Elecraft 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
>

______________________________________________________________
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

[W8JI]

> So you don't have VCO "relock" chirps every few kHz ??
> (at least I think that's what Jim experiences...)
>

I seem to have some faint ones on my K3 if I tune in big
steps, but not in small steps. Either way if I have them
they are very difficult to hear.

I can hear them very easy on my Yaesu though.  :-)


______________________________________________________________
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

[pd0psb]

Jim will probably tune in big steps for AM.
With more low frequency content in the audio/carriers of AM signals the VCO interval cross-over points may be more evident.

73'
Paul
PD0PSB

[Jan Erik Holm]

Yes I suppose that´s what it is. Well it´s been like that
from day one, think I have SNR 1594 so it´s been a while.
I always been upset about it since IMO a high performance
radio shouldn´t behave like this. However I just haven´t
had time to look in to it further. Maybe it´s faulty after
all.
In any case so far I know about two units that got it and
one that doesn´t, don´t know about K2AV´s unit.

Jim SM2EKM
------------
On 2010-03-22 16:57, Guy Olinger K2AV wrote:

> VCO relock chirps every few kHz is not normal.  Best open a
> correspondence with [hidden email].
>
> On Mon, Mar 22, 2010 at 11:48 AM, pd0psb<[hidden email]>  wrote:
>>
>> So you don't have VCO "relock" chirps every few kHz ??
>> (at least I think that's what Jim experiences...)
>>
>> 73'
>> Paul
>> PD0PSB
>> --

______________________________________________________________
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

[Jan Erik Holm]

When tuning for example across an AM band (like 49m band)
it does not happen on all stations. Might be that it
happens on some certain frequency interval but still
quite frequent.

I have not done experiments with different tuning steps,
maybe I should. Will try it when I get back home next
weekend.

Jim SM2EKM
-------------
On 2010-03-22 17:03, Tom W8JI wrote:

>> So you don't have VCO "relock" chirps every few kHz ??
>> (at least I think that's what Jim experiences...)
>>
>
> I seem to have some faint ones on my K3 if I tune in big
> steps, but not in small steps. Either way if I have them
> they are very difficult to hear.
>
> I can hear them very easy on my Yaesu though.  :-)
>
>

______________________________________________________________
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

[pd0psb]

Can be correct Jim,
If I remember correctly VCO "jump" intervals are larger than 5kHz SWBC raster.

(have you tried reducing RX EQ band 1 ? That might make this symptom less obvious)

73'
Paul
PD0PSB

[Jan Erik Holm]

No I have the RX EQ flat at 0, will test when I
get back home.

Jim
----
On 2010-03-22 17:38, pd0psb wrote:

>
> Can be correct Jim,
> If I remember correctly VCO "jump" intervals are larger than 5kHz SWBC
> raster.
>
> (have you tried reducing RX EQ band 1 ? That might make this symptom less
> obvious)
>
> 73'
> Paul
> PD0PSB

______________________________________________________________
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]

Hi Eric,

Do you have the mod

http://www.elecraft.com/K3/mods/ELECRAFT_Application_Note_KSYN3_ALC_Rev_A.pdf

in your rig?

I don't have the phenomena you describe in mine.  I do have the above
mod.  I realize it was for another reason, but wonder if it corrected
other stuff as well.

73, Guy.

On Mon, Mar 22, 2010 at 12:54 PM, Jan Erik Holm <[hidden email]> wrote:

> No I have the RX EQ flat at 0, will test when I
> get back home.
>
> Jim
> ----
> On 2010-03-22 17:38, pd0psb wrote:
>>
>> Can be correct Jim,
>> If I remember correctly VCO "jump" intervals are larger than 5kHz SWBC
>> raster.
>>
>> (have you tried reducing RX EQ band 1 ? That might make this symptom less
>> obvious)
>>
>> 73'
>> Paul
>> PD0PSB
> ______________________________________________________________
> 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

[wayne burdick]

> When tuning across an AM station there are clicks and cracks, seems  
> to be on even kHz. On my radio it has been from day one. Is this  
> normal or is my radio faulty? I use latest FW. / Jim

Jim,

When tuning near a very strong continuous carrier, you may hear a  
small AF artifact at points where the PLL divider switches. This  
occurs at different intervals depending on the band. On 20 meters the  
interval averages about 15 kHz. We minimize the effect by introducing  
a small amount of DSP limiting during the switching window (~10 ms).

This is not avoidable with the present synth design, which was  
optimized for extremely low phase noise. There are two contributing  
factors. First, we follow the DDS with a very narrow crystal filter to  
dramatically clean up this signal; frequency shifts through the filter  
are subject to a small amount of group delay. (Other rigs using DDS  
use either no filtering, or very wide filtering, leaving them  
susceptible to DDS spurs.) Second, the VCO control bandwidth is low,  
improving close-in phase noise, but again causing a small re-lock  
delay when the PLL dividers are switched. (Most rigs use a wider VCO  
control bandwidth, and thus suffer from greater phase noise at small  
offsets that are important to ham operation, i.e. < 2 kHz from the  
carrier.)

We feel that this was the right design tradeoff, and I think most  
customers would agree. Dynamic range is greatly improved with a low-
noise synthesizer, both on transmit and receive.

73,
Wayne
N6KR





______________________________________________________________
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