contest reflections on K2 - addendum

[DOUGLAS ZWIEBEL]

Hi all:

I was going to post this privately, but since I've received several
private (direct) comments in addition to the public postings, most
recently by Dave, G3YMC, I'm making it public, using up some
bandwidth, as I think this might benefit others.

1.  QSK.  This is user skill level dependent.  If you do 20 wpm or
less, the K2 QSK may be fine for you.  During contesting, I am going
at least 32-34 wpm, and not uncommonly at 40wpm.  At these speeds and
during a contest, I NEED to hear everything immediately (that is what
top-end contesting is about).  So not hearing between dits at "slow"
contest speeds of 32 wpm is an issue for me.  NOTE that I still used
the K2 despite that deficit because OVERALL, it is a great radio.  But
for someone used to real QSK, this is not real QSK.  Ask other serious
contesters and they will say the same.  For most K2 users, who are
clearly not serious contesters, this is not an issue at all.  Since
the K3 says "very much better QSK than the K2," I would easily assume
that the deficit is real and acknowledged.

2.  Stable power output.  I use multiple antennas PER BAND.  All are
resonant (monoband yagi's, Optibeam tribanders, and quads).  EXAMPLE:
During the WPX contest that took place this weekend I may have been
working Europe on my yagi pointed to EU (about 45 degree from NJ).  If
I hear a potential qso in South America (170 degrees), I simply turn
the antenna switch to my QUAD which is already pointed south.  When I
do that, the power output indicated on the K2 DRAMATICALLY changes.
It might go from 5 watts to 2 watts or to 15 watts!  I am not sure
why, but some of the "technical" guys explained it to me long ago
(something about how the power output is set [calculated] on the K2).
I cannot justify entering the qrp category of a contest if the radio
is running 15 out when qrp is defined as 5 out.  So whenever I change
antennas (which I do a million times during a contest), I have to hit
TUNE to make sure the power stays at qrp (goldie locks syndrome).
NOTE:  I do not have the internal antenna tuner.  I don't know that
would make a difference or not.  IF THIS IS NOT HOW THE RADIO SHOULD
WORK, PLEASE TELL ME!  W3FPR tells me that this IS how it works.

3.  AGC.  Using the K2 S meter, signals here range from zero S units
on the meter (even though atmospheric noise is supposed to be S1) to
40 or even 60 over 9 (all LEDs lit up).  A 40 over 9 signal is VERY
LOUD in the phones while S1 is not.  This has to be real because the
K3 provides tools to address this.  I assume (know) that this is how
the radio was designed.  Many contesters have commented (here) that
they like this aspect because it is easier to pick out the LOUD
signals in a big pileup.  Different strokes....

AND FINALLY....
I have been reminded that the K2 was not designed as contest
radio...that it simply ended up being so good in other aspects, that
it ended up being that way.  Agreed.  My comments were posted in
response to a recent number of reflector posts suggesting
"improvements" for the K2.  I doubt that any of these will be
addressed because the K2 is a fine radio the way it is and being a
serious contester puts me out of the main target market for the K2,
esp now with the K3 on the near horizon (which I have ordered).  But
if Lyle, Eric, Wayne, et all ever catch their breath, and if K2 users
want improvements, I thought I'd add my "contester-centric" dime.

SO IN CONCLUSION
The K2 is an awesome value and for all, including serious contesters.
At US$600 base, nobody expects it to be 100% perfect for all market
niches.  This is clearly the ABSOLUTE BEST VALUE going in ham radio.

de Doug KR2Q
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[Jack Smith-6]

Doug:

You might find my measurements useful in understanding your K2's audio
output with changes in RF input levels.
http://www.cliftonlaboratories.com/receiver_agc_curves.htm

Some receivers have an AGC curve that holds the audio output constant
for 80 dB or more variation in input level, such as the Racal RA6790/GM.
The K2's AGC does not have this flat-top characteristic. Rather, the
audio output increases with RF input, but obviously not at a 1 dB : 1 dB
rate.

Depending on whether you have the pre-amp on or off, the K2's audio
changes as much as 40 dB over an input range from -120 dBm to -20 dBm.
Under those operating conditions, the AGC works at about a 2.5 dB : 1
dB, RF to audio change.

As you say, some folks like the AGC to hold the audio constant and
others a K2-type action.


Jack K8ZOA
www.cliftonlaboratories.com


>
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[Jack Smith-6]

I said:
>
> Depending on whether you have the pre-amp on or off, the K2's audio
> changes as much as 40 dB over an input range from -120 dBm to -20 dBm.
> Under those operating conditions, the AGC works at about a 2.5 dB : 1
> dB, RF to audio change.

I did not mean that statement to imply that the audio output to RF input
transfer ratio remains constant throughout the 100 dB input range. It's
definitely non-linear, as the curves at
http://www.cliftonlaboratories.com/receiver_agc_curves.htm demonstrate.

Jack K8ZOA
www.cliftonlaboratories.com
>
>
>
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[Tim Heasman]

Hi All,

Regarding the K2 qsk; in comparison to my TT Corsair II it sounds almost
like semi break in to me.  However, I bought the K2 for portable operation,
and it beats anything I have used in the past.

Tim

gm4lmh

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[David Cutter]

I find QSK tiring, especially when the incoming audio is loud.  The transmit
period I find restful to my ears.  On the odd occasion I miss an over and
need a repeat, but not often.

David
G3UNA


----- Original Message -----
From: "DOUGLAS ZWIEBEL" <[hidden email]>
To: <[hidden email]>
Sent: Monday, May 28, 2007 5:24 PM
Subject: [Elecraft] contest reflections on K2 - addendum

> Hi all:
>
> 1.  QSK.  This is user skill level dependent.  If you do 20 wpm or
> less, the K2 QSK may be fine for you.  During contesting, I am going
> at least 32-34 wpm, and not uncommonly at 40wpm.  At these speeds and
> during a contest, I NEED to hear everything immediately (that is what
> top-end contesting is about).  So not hearing between dits at "slow"
> contest speeds of 32 wpm is an issue for me.  NOTE that I still used
> the K2 despite that deficit because OVERALL, it is a great radio.  But
> for someone used to real QSK, this is not real QSK.  Ask other serious
> contesters and they will say the same.  For most K2 users, who are
> clearly not serious contesters, this is not an issue at all.  Since
> the K3 says "very much better QSK than the K2," I would easily assume
> that the deficit is real and acknowledged.
>

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