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KAF2 or KDSP2 for K2?

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Millerhill

KAF2 or KDSP2 for K2?

Well going from a rather ancient Ten Tec to a K2 has been a real treat for sure, and as most of us can't seem to be able to leave anything well enough alone, I was thinking about possible options I can add without breaking the bank. Can any of you folks tell me the real life difference between these two options and whether or not either one of them is worth the expense? I do almost no voice...all cw.

Thanks!

Steve
W1SFR

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David Pratt

Re: KAF2 or KDSP2 for K2?

Just my opinion having used both, Steve, but if you are primarily a CW
operator I think you would be better off with the KAF2.

73 DE David G4DMP

In a recent message, Stephen Roberts <[hidden email]> writes
>Well going from a rather ancient Ten Tec to a K2 has been a real treat
>for sure, and as most of us can't seem to be able to leave anything
>well enough alone, I was thinking about possible options I can add
>without breaking the bank. Can any of you folks tell me the real life
>difference between these two options and whether or not either one of
>them is worth the expense? I do almost no voice...all cw.
--
+ - - - - - - - - - - - - - - - - +
| David M Pratt, Kippax, Leeds. |
| Website: http://www.g4dmp.co.uk |
+ - - - - - - - - - - - - - - - - +

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Andrew Moore-3

Re: KAF2 or KDSP2 for K2?

In reply to this post by Millerhill

Steve - situation here was much the same - went from older Ten-Tec to a K2,
do CW only, and wrestled with the KAF2 / KDSP2 choice, spent lots of time
with KAF2 and some time evaluating KDSP2, even in side by side tests (two
rigs). I have some details of the experience which I think are only in
email and never made it to the list, so I'll dig those up for you.

One is no dramatically better overall than the other; the choice is more
about the application.

In the end I decided that for the CW op, the KAF2 wins, but for an all-mode
op (or SSB/data mode op), it's the KDSP2, which provides some flexibility
that the KAF2 doesn't have.

I found the KDSP2 to be a little *too* configurable/fiddly, but keep in
mind that's because as a CW op I didn't have a need for that much control
over sideband cutoffs, bandwidths for data modes, etc... The KAF2 is dead
simple in operation and is very effective.

I'll dig up my notes and send them your way (or to the list).

--Andrew, NV1B
..

On Tue, May 1, 2012 at 12:26 PM, Stephen Roberts <[hidden email]>wrote:

> Well going from a rather ancient Ten Tec to a K2 has been a real treat for
> sure, and as most of us can't seem to be able to leave anything well enough
> alone, I was thinking about possible options I can add without breaking the
> bank. Can any of you folks tell me the real life difference between these
> two options and whether or not either one of them is worth the expense? I
> do almost no voice...all cw.
>
> Thanks!
>
> Steve
> W1SFR
>
>

Guy, K2AV

Re: KAF2 or KDSP2 for K2?

In reply to this post by David Pratt

For serious contest use of the K2 on 160, I found that the extra skirt
depth afforded by the DSP was extremely useful when running as opposed to
search and pounce. On the other hand the easy rolloff of audio off the
center frequency was useful. Like some others what I really wanted was
BOTH.

73, Guy.

On Tue, May 1, 2012 at 12:50 PM, David Pratt <[hidden email]>wrote:

> Just my opinion having used both, Steve, but if you are primarily a CW
> operator I think you would be better off with the KAF2.
>
> 73 DE David G4DMP
>
> In a recent message, Stephen Roberts <[hidden email]> writes
> >Well going from a rather ancient Ten Tec to a K2 has been a real treat
> >for sure, and as most of us can't seem to be able to leave anything
> >well enough alone, I was thinking about possible options I can add
> >without breaking the bank. Can any of you folks tell me the real life
> >difference between these two options and whether or not either one of
> >them is worth the expense? I do almost no voice...all cw.
> --
> + - - - - - - - - - - - - - - - - +
> | David M Pratt, Kippax, Leeds. |
> | Website: http://www.g4dmp.co.uk |
> + - - - - - - - - - - - - - - - - +
>
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Arie Kleingeld PA3A-2

Re: KAF2 or KDSP2 for K2?

In reply to this post by Andrew Moore-3

My K2 had the DSP.

I programmed the DSP in a way that it tracked the IF filter settings. I
had that both in CW (4 settings) and SSB.
This way the DSP worked great as a combo with the IF filtering. More or
less as in the K3.

The DSP auto notch worked reasonable well.
Never got the NR configured in a way that it could increase my copy so
never used that.

Good luck.

73
Arie PA3A
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daleputnam

Re: KAF2 or KDSP2 for K2?

In reply to this post by Guy, K2AV

And I too have found many applications/times that would be nice to have both.In fact, I have an outboard unit that I am going to make work so I can have two in one... well.. sorta.
that takes care of the digi/analog.. now how to do the analog/digi?
--... ..---
Dale - WC7S in Wy

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John Huggins, kx4o

Re: KAF2 or KDSP2 for K2?

In reply to this post by Guy, K2AV

One question I have about the choice between the KAF2 and KDSP2 is what
about having neither.

How would one describe the receiver/filter capabilities of the bare K2?

Thanks.

John, kx4o

On 5/1/12 1:29 PM, Guy Olinger K2AV wrote:
> For serious contest use of the K2 on 160, I found that the extra skirt
> depth afforded by the DSP was extremely useful when running as opposed to
> search and pounce. On the other hand the easy rolloff of audio off the
> center frequency was useful. Like some others what I really wanted was
> BOTH.
>
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Guy, K2AV

Re: KAF2 or KDSP2 for K2?

Bluntly, as clever as the CW filter scheme was for both cost and
effectiveness, the DSP for me really put the finishing touches on the
performance. But that is a contesting analysis. No contesting, maybe I
don't care.

I have the four CW widths and I have the DSP filters set to exactly match
the skirts. A bit of a pain getting that right, but when I'm out working
on an antenna somewhere running battery, I don't have an issue that I wish
I had my K3 out there for hearing.

And when I've got something matched by the auto tuner, I know the network
values being used to do it.

73, Guy.

On Tue, May 1, 2012 at 7:46 PM, John <[hidden email]> wrote:

> One question I have about the choice between the KAF2 and KDSP2 is what
> about having neither.
>
> How would one describe the receiver/filter capabilities of the bare K2?
>
> Thanks.
>
> John, kx4o
>
> On 5/1/12 1:29 PM, Guy Olinger K2AV wrote:
> > For serious contest use of the K2 on 160, I found that the extra skirt
> > depth afforded by the DSP was extremely useful when running as opposed to
> > search and pounce. On the other hand the easy rolloff of audio off the
> > center frequency was useful. Like some others what I really wanted was
> > BOTH.
> >
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
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> Post: mailto:[hidden email]
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Don Wilhelm-4

Re: KAF2 or KDSP2 for K2?

In reply to this post by John Huggins, kx4o

John,

The IF filter response of the K2 filter can be quite good by itself, but
cascaded filters are better, particularly the DSP straight sided filter
responses. To optimize the IF filters, I would encourage all to use
Spectrogram (or something equal) and a wideand noise generator ( or
atmospheric band noise on a dead band) to determine the actual width and
positioning of each filter. See part 3 of the K2 Dial Calibration
article on my website www;.w3fpr.com for more information.

I would like to point out that most K2 filters are not set for optimum
response - the settings in the manual will produce working filters, but
certainly not optimum. I have described the process for achieving not
only good dial calibration, but also good filter response in the K2 Dial
Calibration article on my website www.w3fpr.com.

73,
Don W3FPR

On 5/1/2012 7:46 PM, John wrote:
> One question I have about the choice between the KAF2 and KDSP2 is what
> about having neither.
>
> How would one describe the receiver/filter capabilities of the bare K2?
>
>
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Guy, K2AV

Re: KAF2 or KDSP2 for K2?

Have to vote for Don's article on his web page. Did it that way and got
the splendid results right off, first time. Huge help. Many thanks, Don.

Oh and probably that is why I saw such a difference adding the DSP. Got
maximum results to start with. I wasn't comparing the K2 after DSP to the
K2 before. I was evaluating the K2 in contest conditions and comparing
results with other rigs. If one is going to do CW contesting then you do
need the DSP and the good procedure for adjustment.

73, Guy.

On Tue, May 1, 2012 at 9:46 PM, Don Wilhelm <[hidden email]> wrote:

> John,
>
> The IF filter response of the K2 filter can be quite good by itself, but
> cascaded filters are better, particularly the DSP straight sided filter
> responses. To optimize the IF filters, I would encourage all to use
> Spectrogram (or something equal) and a wideand noise generator ( or
> atmospheric band noise on a dead band) to determine the actual width and
> positioning of each filter. See part 3 of the K2 Dial Calibration
> article on my website www;.w3fpr.com for more information.
>
> I would like to point out that most K2 filters are not set for optimum
> response - the settings in the manual will produce working filters, but
> certainly not optimum. I have described the process for achieving not
> only good dial calibration, but also good filter response in the K2 Dial
> Calibration article on my website www.w3fpr.com.
>
> 73,
> Don W3FPR
>
> On 5/1/2012 7:46 PM, John wrote:
> > One question I have about the choice between the KAF2 and KDSP2 is what
> > about having neither.
> >
> > How would one describe the receiver/filter capabilities of the bare K2?
> >
> >
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
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>
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> Please help support this email list: http://www.qsl.net/donate.html
>

Bill W4ZV

Re: KAF2 or KDSP2 for K2?

In reply to this post by John Huggins, kx4o

John Huggins, kx4o wrote

One question I have about the choice between the KAF2 and KDSP2 is what
about having neither.

How would one describe the receiver/filter capabilities of the bare K2?

John neither is a valid response for some situations...it all depends on your operating modes. I use my QRP K2 exclusively for field operating so take my comments with that in mind. I used the rig for several years with no filtering besides the XFIL (set for 1000/700/400/100 BWs). I then decided to add a KAF2 thinking it might add some capability, but in fact I seldom use it. I even modified the AF2 setting for low ringing per KI6WX's analysis (BTW the KI6WX link on LA3ZA's mod site no longer works).

This past weekend in the QRPTTF event, conditions were such that nearly all QRP signals were at or below the very low noise floor. Very few signals would light ANY meter bars even with the preamp on. I found my best copy was using the 1000 Hz BW and no AF filtering. I tried both the KAF2's AF1 and AF2 settings several times but always returned it to off for best copy.

For copying weak signals in white noise, I find my ears usually beat any DSP (e.g. K3) or analog filtering with the sole exception of the K3's APF, which can help in some situations. My ears need wide bandwidth to help discriminate weak signals from noise and the fact that APF allows this (a very sharp AF filter with gain superposed on a much wider IF bandwidth) makes it helpful in certain situations.

Anyway, the K2 without additional AF filtering works well for me when copying weak signals if that's your primary operating mode. I did rediscover this weekend how much I hate (i.e. worse than dislike!) the very high distortion in the K2's sidetone which makes it difficult to match signals when zero-beating. TF3MA's mod for that is next on my K2 list:

http://www.raunvis.hi.is/~matti/TF3MA/sidetone_tf3ma.html

73, Bill W4ZV

Mike Harris

Re: KAF2 or KDSP2 for K2?

In reply to this post by John Huggins, kx4o

In my opinion the KAF2 is essential. The always in-line low pass filter
significantly reduces the high frequency audio hiss and makes SSB in
particular much nicer to listen to. Assuming that your hearing extends
above 3kHz.

Note that there is a daughter board add on for earlier versions of the
K3 which does the same thing. This filter was incorporated into the DSP
board in a later revision. See the Elecraft web site for info.

Regards,

Mike VP8NO

On 01/05/2012 20:46, John wrote:
> One question I have about the choice between the KAF2 and KDSP2 is what
> about having neither.
>
> How would one describe the receiver/filter capabilities of the bare K2?
>
> Thanks.
>
> John, kx4o
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K1FFX

Re: KAF2 or KDSP2 for K2?

In reply to this post by John Huggins, kx4o

For my operating style (DX-ing, contesting that serious contesters would consider "casual",
mostly CW), the filtering capabilities of the basic K2 are way more than adequate. Using the
N-GEN + Spectrogram procedure for filter setup works extremely well and I almost never found
myself wishing for "more filtering" during recent ARRL CW DX and CQWW CW contests. The K2 is
already so much quieter than its predecessor (a Kenwood TS850) that I don't really feel the
need to add the noise quieting benefits of either the KDSP2 or KAF2.

- Bruce

Bruce Rosen
K1FFX
K2/100 6982 KSB2 KAT100-1 KAF2 KIO2

John Huggins, kx4o

Re: KAF2 or KDSP2 for K2?

In reply to this post by Mike Harris

Thanks to everyone for the comments and thoughts.

I'll start with the bare K2 (I really don't have a choice at the moment)
and see how it goes.

Later I will refer to your comments again in the archives for the next step.

73
John, kx4o

On 5/2/12 8:45 AM, Mike Harris wrote:

> In my opinion the KAF2 is essential. The always in-line low pass filter
> significantly reduces the high frequency audio hiss and makes SSB in
> particular much nicer to listen to. Assuming that your hearing extends
> above 3kHz.
>
> Note that there is a daughter board add on for earlier versions of the
> K3 which does the same thing. This filter was incorporated into the DSP
> board in a later revision. See the Elecraft web site for info.
>
> Regards,
>
> Mike VP8NO
>
>

Johnny Siu

KAF2 or KDSP2 for K2?

Hello John,

From time to time, there are used KAF2 available for sale in this reflector at a much lower price. I got mine at US$49.

I don't like the KDSP2. The artifact of the sound is just annoying to me. This topic was well discussed in the past and you can find it from the archive.

TNX & 73,

Johnny VR2XMC

寄件人︰ John <[hidden email]>
收件人︰ [hidden email]
傳送日期︰ 2012年05月3日 (週四) 8:24 AM
主題︰ Re: [Elecraft] KAF2 or KDSP2 for K2?

Thanks to everyone for the comments and thoughts.

I'll start with the bare K2 (I really don't have a choice at the moment)
and see how it goes.

Later I will refer to your comments again in the archives for the next step.

73
John, kx4o

On 5/2/12 8:45 AM, Mike Harris wrote:

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Andrew Moore-3

Re: KAF2 or KDSP2 for K2?

In reply to this post by John Huggins, kx4o

For most CW work, the K2 is fine without either, in my experience. I got
the KAF2 to give me an extra edge in tough conditions, QRP, etc. but most
of the time I just use XFIL1-4. That's not to say the KAF2 isn't useful in
some conditions; I still love having it.

--Andrew, NV1B
..

On Tue, May 1, 2012 at 7:46 PM, John <[hidden email]> wrote:

Wayne Conrad

Re: KAF2 or KDSP2 for K2?

In reply to this post by Millerhill

On 05/01/12 09:26, Stephen Roberts wrote:
> Can any of you folks tell me the real life difference between these
two options and whether or not either one of them is worth the expense?

If you live in the city, I wonder if you might prefer either the KDSP2
or the KNB2 over the KAF2. I live on a busy intersection in a big city,
so 've got pulse noise more often than not. The KNB2 takes it out
pretty well. I think the KDSP2 will deal with pulse noise, also, but
the KAF2 alone won't do any more than dull the high frequency component
of pulse noise.

Also (but this is probably just me), I find that the KAF2 blurs the
edges of the dits and dahs, making signals harder to copy rather than
easier.

Regards,
Wayne Conrad KF7QGA
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