[Elecraft] Just how good is the K2?

[Brendan Minish]

At 02:12 20/01/2004, George,  W5YR wrote:
>Brendan, unless you add the internal audio DSP module or use an external
>processor such as the NIR-12 or 599XXX, how on CW do you deal with
>heterodynes without a notch filter?
>  With no IF shift available, how do you
>deal with adjacent channel QRM other than narrowing the IF or audio filter

I have added the internal DSP but my ears with a combination of narrowing 
the filter and the often forgotten about CW-R feature. In the worst cases 
using a narrow filter along with narrow DSP and tuning so the wanted signal 
is at the edge of the passband

>(if used) bandwidth? Ditto for SSB?

the DSP in my opinion makes the K2 a useful SSB rig, I don't do much ssb 
operating other than some local nets.

>but for main
>station use, I just don't understand . . .

Well the eyeopener for me was using both rigs (pro2 & K2) in a CW contest 
on top band, yes the Pro2 had better tools for digging them out of the 
noise, however it also had more noise...

With the K2 I had to do less work to hear the same signals and there were a 
few that I could not hear at all on the Pro2.
With my setup I can put any antenna on either radio with the flick of a 
switch and I have yet to hear a single CW signal that the PRO2 could hear 
better than the K2.
On crowded bands the K2's Higher 5 Khz Blocking dynamic range and better 
3rd order IMD performance over the pro2 may have something to do with what 
I hear

http://www.elecraft.com/K2_perf.htm#Main

My K2 has been carefully built, I have done all the elecraft mods to it and 
I have aligned it very carefully using good test gear, it performs about as 
well as a K2 is able to.


>I can hear on the PRO2 or 746PRO any station that I can hear on the K2. The
>exception is that with either PRO I can take that weak "hearable" signal and
>work on it with the IF and audio tools in the PROs and turn it into a
>readable/workable signal. I have found that either PRO will handle strong
>signals as well or better than the K2.


I have never found the noise reduction any use whatsoever, however I am a 
sound engineer and have an excellent ability to hear detail, my job 
requires it. I suspect that as a result I find it easier than many to use 
my brain as a CW filter ( DSP in wetware?) The K2 easily allows my ear to 
pick out a weak signal  very close to a much stronger signal. I don't find 
the audio of the pro2 as transparent in this regard.


>The K2, with the wider filters and higher shape factors, does have a more
>pleasing sound on CW, but when the chips are down, the 50 or 100 Hz IF DSP
>filters in the PROs remove the QRM and QRN at the loss of some of the
>pleasant sound - I can accept that trade-off.


I find that a 120 Hz setting on the k2 (yes the shape factor isn't as good 
as the pro2) along with the DSP module set to around 100 hz is a formidable 
weapon but I almost always run at around 600 or 450 Hz and let the ears do 
the work, it's less tiring that way.


>I am not knocking the K2 for what I think it was designed for and the
>purposes for which I personally use it. The part I don't understand - based
>upon over 57 years of hamming, mostly CW - is why and how it has become
>regarded by so many as superior to the PROs and other high-end rigs with
>more capabilities. Perhaps my serial no. 489 has not kept up with the
>attainments of the latest production units.

I like the pro2 I really do, I owned a pro before the pro2. I use the pro2 
regularly and it is a top notch performer, however for CW (where I don't 
need the pro2's extra features) I can hear better under tough conditions 
with the K2. I also prefer the k2's (admittedly slower) Full break in 
because it's smoother, even after i modified it to go faster ;-)

My k2 is # 1642 and I have done all the post 3000 mods along with a few 
others. The biggest improvement was the closer matched xtals for the filter 
along with the mod to improve de-coupling between the xtals and the varicap 
control line
see
http://home.pacbell.net/johngreb/Mod_To_Improve_K2_CW_Filter_Rejection.pdf

there's full list of mods here
http://www.qsl.net/la3za/K2/mod.html

For my operating style and habits I find the k2 better than the pro2 
although I definitely consider the PRO2 a keeper .


73
Brendan