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K2: CW passband tuning

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Tom KG3V

K2: CW passband tuning

I am finally getting comfortable with the K2 in CW contests. One thing
I want to do is set up my filters ( I have KDSP2), so I can shift the
passband slightly to either side. I nkow I heard this discussed
before. Does anyone have a good set of filter parameters that have
given good performance in really crowded conditions?

Can I assume that my transmit frequency will stay fixed as I shift the
receiver passband? I think only the sidetone freq. will change.

73,

Tom KG3V
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Bill N2BC

K3: KRC2 interface

Just doing some planning for the eventual arrival of my K3.

The KRC2 needs AUXBUS 8R and ground. Where / what on the K3 AUX I/O
connecter is 8R or it's equivalent?

Thanks!

73, Bill N2BC

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Don Wilhelm-4

Re: K2: CW passband tuning

In reply to this post by Tom KG3V

Tom,

The K2 always uses the FL1 BFO for transmitting, so that must be set
properly for transmit (do not shift that one - for SSB, visually center
that passband between 300 and 2600 Hz on Spectrogram (assuming you have
the 2.4 kHz SSB filter width).

I have found that SSB intelligibility degrades significantly if the low
frequency corner of the passband is set higher than 300 Hz. I typically
align the SSB filters FL2 thru FL4 to progressively more narrow widths
than the FL1 (OP1) filter. Each filter 200 to 300 Hz more narrow than
the previous one. Set the low frequency corner of each filter at 300 Hz
and try it.
By aligning the SSB filters this way, you can tap XFIL to reduce any
QRM/QRN you hear at a high audio frequency and the desired signal will
still be intelligible. If you attempt to cut the low frequency end
significantly, the signal quickly become unintelligible.

73,
Don W3FPR

Tom Z wrote:

> I am finally getting comfortable with the K2 in CW contests. One thing
> I want to do is set up my filters ( I have KDSP2), so I can shift the
> passband slightly to either side. I nkow I heard this discussed
> before. Does anyone have a good set of filter parameters that have
> given good performance in really crowded conditions?
>
> Can I assume that my transmit frequency will stay fixed as I shift the
> receiver passband? I think only the sidetone freq. will change.
>
> 73,
>
> Tom KG3V
>
>

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Don Wilhelm-4

Re: K3: KRC2 interface

In reply to this post by Bill N2BC

Bill,

The KRC2 does not need the 8R input for use with the K2 or K3. Look at
page 20 of the KRC2 manual and you will see that the KRC2 uses 8R only
as an analog input.

The KeyOut signal timing is equivalent to the K2 8R signal.

73,
Don W3FPR

Bill Coleman N2BC wrote:
> Just doing some planning for the eventual arrival of my K3.
>
> The KRC2 needs AUXBUS 8R and ground. Where / what on the K3 AUX I/O
> connecter is 8R or it's equivalent?
>
> Thanks!
>
> 73, Bill N2BC
>
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Bill N2BC

Re: K3: KRC2 interface

Hi Don,

Do you mean the K3 AUX I/O Pin 10 "KEYOUT-LP" line? The purpose of this
line is a bit fuzzy, to me anyway.

I based my KRC2 'needs' list based on page 21 of the KRC2 manual.

The paragraph at the top of the page states that the minimum required for a
K2 are:

W16 - AUXBUS
W18 - 12V (can be provided via external source)
W19 - 8R
W21 - to pass PC serial info to K2 (not needed in K3)
W23 - ditto W21

Table 3 states that the KRC2 uses 8R to determine TX/RX status, I would have
thought to inhibit band changing while transmitting.

I just tried the KRC2 without feeding it 8R from the K2 (W19 pulled). 8R is
indeed not 'needed' to handle the band info from the AUXBUS. Tried changing
bands on the K2 while key down or asserting PTT - it won't change. But the
K2 remembers the band change key press and does change once key down or PTT
is dropped & the KRC2 follows.

Anywho, it looks like the K2 is smart enough to not change bands while in TX
& the KRC2 will follow the AUXBUS as/when ordered. I'm sure the K3 is at
least that smart [ ;-) ] So I amend my KRC2 "needs" list to simply AUXBUS
and ground - GREAT!

73, Bill N2BC

----- Original Message -----
From: "Don Wilhelm" <[hidden email]>
To: "Bill Coleman N2BC" <[hidden email]>
Cc: "elecraft" <[hidden email]>
Sent: Wednesday, January 30, 2008 9:48 AM
Subject: Re: [Elecraft] K3: KRC2 interface

> Bill,
>
> The KRC2 does not need the 8R input for use with the K2 or K3. Look at
> page 20 of the KRC2 manual and you will see that the KRC2 uses 8R only as
> an analog input.
>
> The KeyOut signal timing is equivalent to the K2 8R signal.
>
> 73,
> Don W3FPR
>
> Bill Coleman N2BC wrote:
>> Just doing some planning for the eventual arrival of my K3.
>>
>> The KRC2 needs AUXBUS 8R and ground. Where / what on the K3 AUX I/O
>> connecter is 8R or it's equivalent?
>>
>> Thanks!
>>
>> 73, Bill N2BC
>>
>