[Elecraft] K2 and CW

Mon Apr 9 18:12:10 EDT 2007

Scott...

I echo previous comments and add a few...

With CW experience, in-the-brain filtering really does develop. It does 
take time, but just as assuredly, it does develop.

I have an FT990 with a 250cps filter that I used pretty much all the time. 
Got use to it. That said, there were still times when adjacent signals 
messed everything up. So, I'm thinking selectivity tends to be as 
subjective as a graph makes it look objective.

I have my K2 #5957 CW filters set for SSB/2.2kc, 800cps, 400cps & 150cps. I 
also have the DSP unit, and I have set those CW filters at BandPass, 
500cps, 250cps & 100cps. I've tried most combinations of these two filter 
sets, but like you, I'm still getting a feel for the radio. That said, 
there's enough selectivity in that combination to narrow things down to the 
point that I sometimes open it up just to make sure the radio is still on <g>.

I have used Spectogram to align the filters, and I'll be doing that again 
with a bit more experience. That made a significant difference in the 
"feel/sound" of the radio. Like you, I intend to do some more "measurement" 
in addition to just setting things up and starting to operate.

Compared to the FT990, a rig that I have really enjoyed for many reasons, 
the K2 is much quieter and more flexible. The FT990 is now on the floor and 
the K2 is at the operating position. At the end of the day, it's a hobby 
and it's about having fun - and providing a service to the emergency 
community. I'm having more "fun" with the K2 than at any point in my 
hamming experience to date. I'm now working a fair amount of QRP "because 
it's there." I do have the 100w amp, and the tube amp is ready when needed. 
So, the K2 has given me a wider hamming experience and for that I'm grateful.

...robert

At 08:46 04/09/2007 -0400, David Wilburn wrote:
>I have an 718 with the 250 Hz filter.  That filter locks down things quite 
>well, but it also allows "blow by" with large nearby signals that make 
>things difficult also. In the short time I have been a CW op, the skill 
>that Ron mentions is just starting to get to me.  I have often been 
>frustrated by other ops nearby.  That is part of what drove me to the K2, 
>was the many choices of filters.
>
>I agree with Scott, in the since, that I am seeking a way to make that 
>last filter have more isolation capability without further attenuating the 
>signal.  Now that I have a little bit better idea what is going on with 
>Spectrogram, after I have all the pieces finished, I plan on making 
>another pass with that while sending some tones through and seeing what 
>kind of tweaking I can accomplish.
>
>Scott, have you put your K2 through the Spectrogram alignments yet?  I was 
>not terribly impressed with the filters after the default settings were 
>installed, but I was amazed after (several tries) I gave the filters a 
>good alignment with Spectrogram.
>
>David Wilburn
>dave.wilburn at verizon.net
>K4DGW
>K2 #5982
>
>
>Ron D'Eau Claire wrote:
>>I can't speak about the 718 or the Elecraft DSP, but in my experience such
>>"brick wall" filtering creates far more problems than solutions. A huge
>>amount of unwanted stuff is produced by signals on the sharp edges of such a
>>filter that appear throughout the passband - much of it is that 'noise' you
>>mention.
>>I work 99% CW and my K2 is seldom set for less than 1.0 kHz bandwidth. My
>>minimum is 0.4 kHz used only when I get a "loudmouth" shouting from almost
>>on top of the signal I'm copying. That occasionally happens during a
>>contest, but that's about it.
>>I do have a skill that a great many experienced CW ops have that might be
>>the difference. We can copy easily with several signals within the passband.
>>It's like listening to one voice in a crowded party; we just "tune out" the
>>other babble going on around us unless it's something we want to follow. It
>>only gets difficult if one nut starts shouting in my ear when I'm trying to
>>listen to someone else, Hi!
>>Ron AC7AC
>>
>>-----Original Message-----
>>Hello
>>I haven't had my K2 (# 5846 ) long enought to fully understand all the
>>different settings that are possible with it , so I have a question. My CW
>>filter setting are FL-1 1.50, FL-2 0.70, FL-3 0.40, and FL-4 is 0.10. 
>>Even FL-4 is no where near as effective as the 250 hz crystal
>>filter in my Icom 718. When I turn on the 250 hz filter in the Icom, it's
>>like building a wall right on each side of the signal that I am listening
>>to. Nothing else is heard except noise and signals that are exactly on the
>>same frequency. Is this kind of selectivity possible with the K2? If I
>>installed the DSP option would that help? And if so, what would the filter
>>settngs need to be? The only options I presently have are the 160 meter
>>option, noise blanker, serial adapter, ssb option, and the KPA100. Thanks
>>Scott N5SM
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Robert G. Strickland PhD ABPH - KE2WY
rcrgs at verizon.net.usa
Syracuse, New York  USA