[Elecraft] K2 and CW

Mon Apr 9 13:05:06 EDT 2007

Based on the emails I have been getting, I apparently didn't state this 
well.  I am VERY happy with the level of filtering that I have been 
getting from the K2 in CW mode.  The ability to turn the AGC off and 
drill down with the filters has been a great improvement over the 718.

That being said, the next time I put the system on spectrogram, I am 
going to have a couple more tools available that I didn't have the first 
time around, and one of things I am going to be looking at is making the 
last two filters a little more narrow.  I hope to do this without 
greatly attenuating the signal.  Neither of these statements is meant to 
be a disparaging remark, merely a statement of what I hope to 
accomplish.  One of the reasons I chose this rig, was because I can 
tailor the filters as I see fit.

I played with the SSB on 80m the other night, and didn't get the level 
of rejection of adjacent signal interference that I would have liked. 
That being said, I have NOT put the rig back on Spectrogram since 
setting up the SSB board.  So my first assumption was that I have not 
done my due diligence, not any deficiencies with the rig.

David Wilburn
dave.wilburn at verizon.net
K4DGW
K2 #5982

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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