K2 receiver issues during contest?

[Darwin, Keith]

Hey folks,
 
I did not operate during the big contest this weekend but spent a bit of
time listening.  I just got my KAF2 audio filter built and installed and
was anxious to see how it did.  While tuning around I noticed some
"problems" that are probably just characteristics of the rig.
 
On 40 CW, there were some strong signals to my 28' vertical.  30-40 dB
over S9 was not uncommon.  I noticed with one of these stations, I could
hear "clicks" up and down the band for +/- several KHz.  I though he had
key clicks.  Then I found a 2nd signal that produced the same results.
Then a 3rd and a 4th.  I suppose it is possible that all of them had
issues with key clicks but it is also possible that I've hit a limit in
the K2's ability to handle strong signals close in.
 
All of the signals were strong.  K2 doesn't do this as a rule on S9
signals.  In fact, this is the first time I've noticed it so I'm going
to say that signals 20 dB over S9 don't produce it (I'd have to double
check that though).  This makes me think it is an issue with only very
strong signals.
 
Narrowing the IF filter helped.  Engaging the attenuator helped.
Kicking in the audio filter helped but through it all, the clicks were
still there.  I have no NB so it wasn't being generated by that circuit.
 
So does this sound like normal fare for the K2 or does it sound like an
issue?
 
- Keith KD1E -
- K2 5411 -
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[n3drk]

----- Original Message -----
From: "Darwin, Keith" <[hidden email]>
 some
On 40 CW, there were some strong signals to my 28' vertical.  30-40 dB
over S9 was not uncommon.  I noticed with one of these stations, I could
hear "clicks" up and down the band for +/- several KHz.  I though he had
key clicks.  Then I found a 2nd signal that produced the same results.
Then a 3rd and a 4th.  I suppose it is possible that all of them had
issues with key clicks but it is also possible that I've hit a limit in
the K2's ability to handle strong signals close in.

All of the signals were strong.  K2 doesn't do this as a rule on S9
signals.  In fact, this is the first time I've noticed it so I'm going
to say that signals 20 dB over S9 don't produce it (I'd have to double
check that though).  This makes me think it is an issue with only very
strong signals.
------------------------------------------------------------------------------------------
Keith, just for clarification, You say 30-40dB over S9 for 4 stations caused
key clicks.
Then in the second paragraph you say that signals 20dB over S9 don't produce
it.
I think you are saying that before you installed the KAF2 the 20dB over S9
signals
did not have key clicks. Is that correct? If so why not take the KAF2 out of
the
circuit and see if that was the case?

73
john-n3drk

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[Brendan Minish]

On Tue, 2006-05-30 at 10:10 -0400, Darwin, Keith wrote:
> Hey folks,
 

>  I noticed with one of these stations, I could
> hear "clicks" up and down the band for +/- several KHz.  I though he had
> key clicks.  Then I found a 2nd signal that produced the same results.
> Then a 3rd and a 4th.  I suppose it is possible that all of them had
> issues with key clicks but it is also possible that I've hit a limit in
> the K2's ability to handle strong signals close in.


Some popular rigs in use by contesters (in particular the 1000MP series)
have very bad keyclicks unless modified
http://www.w8ji.com/keyclicks.htm

Unfortunately it is not uncommon at all to hear bad keyclicks during
major contests

The K2 receive performance is certainly up to contesting, I use my K2 in
preference to my 756PRO2 for CW contesting as it hears better

.brendan EI6IZ

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[Darwin, Keith]

 
Oh GREAT John, you want me to apply logic and problem solving to the
issue :-)

I did not spend much time chasing the issue down at all.  Yes, the AF is
a new addition to the rig and I suppose I could (should) remove it just
to confirm that it is not adding to the issue.

Now that I've seen it, I'll be keeping an eye (ear) out for the issue.
I'll specifically go looking for those S9 + infinity signals.  I'll
switch things in and out and see what happens.  I'll try it with the AGC
off and the RF gain backed down, etc.

One thing I have noticed since going to the K2.  The bands don't seem so
crowded.  The overall noise level has come down and the amount of space
between signals has gone up.  Even during the big contest I didn't get
the feeling that things were really all that crowded.  Instead of a
"room full of shouting voices" as I tuned across the band, I found one
QSO after another, each rather neatly packaged into their own almost
private space.  It was weird.  In a way it took some of the excitement
and energy out of it.

73 & thanks all!

- Keith KD1E -
- K2 5411 -

-----Original Message-----
From: John - n3drk [mailto:[hidden email]]

... why not take the KAF2 out of the circuit and see if that was the
case?

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[Leigh L. Klotz Jr WA5ZNU]

I believe it is the TX side.  Here's why:

The SoftRock series of SDR kits are fun for looking at this.  The
receiver is extremely wide, on the order of 50KHz to 100KHz, depending
on your version and sound card quality, so there really isn't anything
analogous to the filtering artifacts you might see (though of course you
can run out of dynamic range).  At least I think this is the case.

I have a SoftRock 40 and the Rocky software (sadly Windows only) offers
a large waterfall display.

You can read the CW as it scrolls horizontally.  I see some signals with
clicks, which show up as vertical bars on the CW signals, and some
without.  The vertical axis is frequency extent, so you can see just how
wide they are, at a glance.

Recent versions of the Rocky software include a visual key-click filter,
which you can to turn on to clean up the waterfall.

Leigh/WA5ZNU
On Tue, 30 May 2006 8:09 am, Brendan Minish wrote:

> On Tue, 2006-05-30 at 10:10 -0400, Darwin, Keith wrote:
>>  Hey folks,
>
>
>>   I noticed with one of these stations, I could
>>  hear "clicks" up and down the band for +/- several KHz.  I though he
>> had
>>  key clicks.  Then I found a 2nd signal that produced the same results.
>>  Then a 3rd and a 4th.  I suppose it is possible that all of them had
>>  issues with key clicks but it is also possible that I've hit a limit
>> in
>>  the K2's ability to handle strong signals close in.
>
>
> Some popular rigs in use by contesters (in particular the 1000MP
> series)
> have very bad keyclicks unless modified
> http://www.w8ji.com/keyclicks.htm
>
> Unfortunately it is not uncommon at all to hear bad keyclicks during
> major contests
>
> The K2 receive performance is certainly up to contesting, I use my K2
> in
> preference to my 756PRO2 for CW contesting as it hears better
>
> .brendan EI6IZ
>
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[Bill Coleman-2]

On May 30, 2006, at 10:10 AM, Darwin, Keith wrote:

> On 40 CW, there were some strong signals to my 28' vertical.  30-40 dB
> over S9 was not uncommon.  I noticed with one of these stations, I  
> could
> hear "clicks" up and down the band for +/- several KHz.

It is quite possible that this guy had clicks. The K2, as designed,  
has excellent rejection of adjacent signals. Sure, you'll have some  
cross-over from nearby adjacent signals, but the results are way down  
from radios costing thousands more.

> All of the signals were strong.  K2 doesn't do this as a rule on S9
> signals.  In fact, this is the first time I've noticed it so I'm going
> to say that signals 20 dB over S9 don't produce it (I'd have to double
> check that though).  This makes me think it is an issue with only very
> strong signals.

You'll definitely notice more of this adjacent signal problem on  
really, really strong signals.

> Narrowing the IF filter helped.  Engaging the attenuator helped.

If turning off the preamp or adding the attenuator eliminates the  
clicks, most likely the are being generated by overloads within the  
K2. These must be EXTREMELY strong signals to do this.

> So does this sound like normal fare for the K2 or does it sound  
> like an
> issue?

I didn't have this problem with my K2 this weekend, but I may not  
have tuned across the same signals you did.

Bill Coleman, AA4LR, PP-ASEL        Mail: [hidden email]
Quote: "Not within a thousand years will man ever fly!"
             -- Wilbur Wright, 1901

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