New K3 owner, couple of questions (APF vs. DUAL PB, NR under the water sound, KPA3 temp)

[Andreas Hofmann-3]

Hi,

I put together my new K3 without any issues. My 8 and 10 year old daughters helped and they really enjoyed it too. Overall I am very happy with its performance.  I do not seem to need PRE on the high bands as much, but I do seem to need ATT on the low bands more...  I guess that is by design. I have a few things I need to figure out and the manual does not seem to help:


1.       DUAL PB, APF. I am not sure I get the APF to work. I do not hear or see the middle peak of the filter. I think I only get DUAL PB, no matter what I set in the config menu.  I am using the latest FW. Any ideas how to verify?

2.       NR:  I like how the noise goes away, but I do not like the under-the-water sound (K2 owner, no DSP experience).  I seem to switch constantly back and forth... I am using the default setting for NR (F1-1). Is there a way to back off the setting slightly to have a better compromise setting?

3.       KPA3 temp: The fans are MUCH quieter as my K2's which is good, but I do worry that I have not setup something right...When I monitor the KPA3 temperature, what is the max value that I should watch out for? I am getting up to 41 C during casual operation.

Thanks in advance and 73,
Andy
KU7T
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[Ian Kahn, KM4IK]

Andy,

Congratulations on the new K3!  I've had mine about three years and love it.
I can only answer one part of one question for you - the Dual PB comes into
play only in RTTY operations.  It shouldn't enabled for other modes.  To
help you learn about your K3, you might consider purchasing Fred Cady's
book, The Elecraft K3:  Design, Configuration, and Operation, from Lulu.com
(http://www.lulu.com/shop/search.ep?keyWords=Fred+Cady&type=Not+Service&site
search=lulu.com&q=).  It will tell you all you need to know, and then some,
about the K3.  And, no, Fred isn't giving me kick-backs for promoting his
book.  I'm just another happy customer with no financial interest (unless
you count knowing how to run the multi-thousands of dollars piece of
equipment at my operating station).

Hope this helps.

73 de,

-- Ian
Ian Kahn, KM4IK
Roswell, GA  EM74ua
[hidden email]
K3 #281, P3 #688, KPA500 #1468
HRD v5.x/6.0 Test Team

-----Original Message-----
From: [hidden email]
[mailto:[hidden email]] On Behalf Of Andreas Hofmann
Sent: Monday, March 10, 2014 1:07 PM
To: '[hidden email]'
Subject: [Elecraft] New K3 owner, couple of questions (APF vs. DUAL PB, NR
under the water sound, KPA3 temp)

Hi,

I put together my new K3 without any issues. My 8 and 10 year old daughters
helped and they really enjoyed it too. Overall I am very happy with its
performance.  I do not seem to need PRE on the high bands as much, but I do
seem to need ATT on the low bands more...  I guess that is by design. I have
a few things I need to figure out and the manual does not seem to help:


1.       DUAL PB, APF. I am not sure I get the APF to work. I do not hear or
see the middle peak of the filter. I think I only get DUAL PB, no matter
what I set in the config menu.  I am using the latest FW. Any ideas how to
verify?

2.       NR:  I like how the noise goes away, but I do not like the
under-the-water sound (K2 owner, no DSP experience).  I seem to switch
constantly back and forth... I am using the default setting for NR (F1-1).
Is there a way to back off the setting slightly to have a better compromise
setting?

3.       KPA3 temp: The fans are MUCH quieter as my K2's which is good, but
I do worry that I have not setup something right...When I monitor the KPA3
temperature, what is the max value that I should watch out for? I am getting
up to 41 C during casual operation.

Thanks in advance and 73,
Andy
KU7T
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[k5oai]

I saved this gem of a post from Jack WA9FVP

====
Re: [Elecraft] [K3]Noise Filter (NF) ADJ

wa9fvp Thu, 27 Dec 2012 16:19:36 -0800

There's no documentation but as far as I can tell--

F1-x through F4-x defines the amount of noise reduction or how aggressive
the filter attacks the I.F. noise.  F5-X through F8-X defines the amount of
reduction and the level that's mixed with the filtered and non-filtered
I.F.
Note that "m" which means "mix" will appear after F5-X and above.


X defines the delay.  Delay is the amount of time it takes for the filter to
converge on a non-sinusoidal signal or the noise.   The higher the number,
the longer it takes for the noise to reduce to a low level.

I hope this helps.

Jack WA9FVP

F1-x through F4-x are for CW
F5-x through F8-x are for SSB
====

On 3/10/2014 12:06 PM, Andreas Hofmann wrote:

> Hi,
>
> I put together my new K3 without any issues. My 8 and 10 year old daughters helped and they really enjoyed it too. Overall I am very happy with its performance.  I do not seem to need PRE on the high bands as much, but I do seem to need ATT on the low bands more...  I guess that is by design. I have a few things I need to figure out and the manual does not seem to help:
>
>
> 1.       DUAL PB, APF. I am not sure I get the APF to work. I do not hear or see the middle peak of the filter. I think I only get DUAL PB, no matter what I set in the config menu.  I am using the latest FW. Any ideas how to verify?
>
> 2.       NR:  I like how the noise goes away, but I do not like the under-the-water sound (K2 owner, no DSP experience).  I seem to switch constantly back and forth... I am using the default setting for NR (F1-1). Is there a way to back off the setting slightly to have a better compromise setting?
>
> 3.       KPA3 temp: The fans are MUCH quieter as my K2's which is good, but I do worry that I have not setup something right...When I monitor the KPA3 temperature, what is the max value that I should watch out for? I am getting up to 41 C during casual operation.
>
> Thanks in advance and 73,
> Andy
> KU7T

--
GB & 73
K5OAI
Sam Morgan
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[Phil Wheeler-2]

Regarding the APF there are a couple of notes (in
the KX3 area!) which may help:

http://www.elecraft.com/KX3/tips/Using%20APF%20for%20weak%20signal%20CW%20work%20the%20K3%20and%20KX3.pdf

http://www.elecraft.com/KX3/tips/Using%20APF%20with%20the%20K3%20and%20KX3.pdf

Phil

On 3/10/14, 10:06 AM, Andreas Hofmann wrote:
> Hi,
>
> I put together my new K3 without any issues. My 8 and 10 year old daughters helped and they really enjoyed it too. Overall I am very happy with its performance.  I do not seem to need PRE on the high bands as much, but I do seem to need ATT on the low bands more...  I guess that is by design. I have a few things I need to figure out and the manual does not seem to help:
>
>
> 1.       DUAL PB, APF. I am not sure I get the APF to work. I do not hear or see the middle peak of the filter. I think I only get DUAL PB, no matter what I set in the config menu.  I am using the latest FW. Any ideas how to verify?

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[Phil Wheeler-2]

And in the Config Menu you need to set DUAL PB to
APF vs. nor

Phil

On 3/10/14, 11:38 AM, Phil Wheeler wrote:

> Regarding the APF there are a couple of notes
> (in the KX3 area!) which may help:
>
> http://www.elecraft.com/KX3/tips/Using%20APF%20for%20weak%20signal%20CW%20work%20the%20K3%20and%20KX3.pdf 
>
>
> http://www.elecraft.com/KX3/tips/Using%20APF%20with%20the%20K3%20and%20KX3.pdf 
>
>
> Phil
>
> On 3/10/14, 10:06 AM, Andreas Hofmann wrote:
>> Hi,
>>
>> I put together my new K3 without any issues. My
>> 8 and 10 year old daughters helped and they
>> really enjoyed it too. Overall I am very happy
>> with its performance.  I do not seem to need
>> PRE on the high bands as much, but I do seem to
>> need ATT on the low bands more...  I guess that
>> is by design. I have a few things I need to
>> figure out and the manual does not seem to help:
>>
>>
>> 1.       DUAL PB, APF. I am not sure I get the
>> APF to work. I do not hear or see the middle
>> peak of the filter. I think I only get DUAL PB,
>> no matter what I set in the config menu.  I am
>> using the latest FW. Any ideas how to verify?
>
>
>

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[Richard Ferch]

Hi Andy,

1. The Dual PB/APF button has multiple functions. First of all, it is
different in CW than in RTTY, and it doesn't do anything in other modes
(SSB, DATA A, etc.).

In CW, the Dual PB button has two functions, depending on whether
CONFIG:DUAL PB is set to APF or NOR.

In the APF configuration in CW, it is a very narrow audio peaking
filter. Tuning of signals is touchy - even a 10-20 Hz change can make
the difference between copy and no copy on a weak signal. The APF
doesn't do much for strong signals - it's for pulling very weak CW
signals out of the noise.

In the NOR configuration in CW, the dual PB filter gives you a "stepped"
filter bandpass, with a 150 Hz center portion set within a broader
"context" bandpass about 20 dB down from the central bandpass; the width
of the broader "context" bandpass is controlled by the WIDTH control.
The effect is most obvious when WIDTH is set wide, say to 700-1000 Hz.
Without the DUAL PB, signals several hundred Hz away but within the
bandpass are strong; with DUAL PB, they are attenuated but still
audible, although not as strong as signals within the narrower central
bandpass; when WIDTH is narrowed down, with or without DUAL PB signals
that far away become inaudible. When WIDTH is at, say, 400 Hz or so, the
effect of the DUAL PB setting is not quite as obvious - the stepped
response is not all that different from what you may be used to using
normal crystal filtering without DSP.

In RTTY (FSK D or AFSK A), the Dual PB button gives you a dual peak
filter peaked on the two tones of the RTTY signal. In theory, this
actually degrades the performance of a well-designed demodulator, so you
might be better off not using it routinely, but in the situation where
there are two overlapping RTTY signals with the mark or space of the
interfering signal in between the mark and space of the one you are
trying to work, it may help reduce the interference.

2. I can't help with NR.

3. KPA3 temp: at 41C, from a thermal point of view your PA is loafing.
In heavier use (RTTY or heavy CW contesting use), it will climb up into
the 50s or even the low 60s (depends on the ambient temperature, of
course), and the fans will speed up. You can hear what the fans sound
like at the different speed levels by using the CONFIG:KPA3 menu and
changing it temporarily from NOR to FN1, FN2, FN3 or FN4. I don't think
I have ever gotten my PA temp high enough to switch to the FN4 level
automatically (somewhere around 65-70C, perhaps?), but I have reached
the FN2 and FN3 levels during contests (FN3 mostly in RTTY). The KPA3 is
supposed to protect itself by shutting off at 84C, but I've never seen
anything approaching that level.

You may see the PA TEMP indication change slightly during transmit as
compared to receive. I believe this is caused by the voltage difference
between TX and RX (if for no other reason than resistive losses in the
power cable). You can set the PA TEMP display to RX-only if necessary to
avoid this effect.

73,
Rich VE3KI
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[W6NF]

Not using the dual pass-band mode, due to the degradation Rich notes, is
the consensus of some of the best RTTY contest operators of our
acquaintance.

Jack, W6NF/VE4SNA
Shelley, K7MKL

On 3/10/2014 1:21 PM, Richard Ferch wrote:

>
>
> In RTTY (FSK D or AFSK A), the Dual PB button gives you a dual peak
> filter peaked on the two tones of the RTTY signal. In theory, this
> actually degrades the performance of a well-designed demodulator, so
> you might be better off not using it routinely, but in the situation
> where there are two overlapping RTTY signals with the mark or space of
> the interfering signal in between the mark and space of the one you
> are trying to work, it may help reduce the interference.
>
>
> 73,
> Rich VE3KI
>

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