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1 Khz filter

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john@kk9a.com

1 Khz filter

What is this used for?

John KK9A

From: Ralph Matheny K8RYU
Mon Jul 24 16:30:29 EDT 2017

Anybody got a 1 Khz filter for K3 they wanna sell??

de K8RYU

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Dale Boresz

Re: 1 Khz filter

Hello John,

It's used for CW. I have a pair of them (main and sub rx) and find that CW
sounds more pleasing through this filter. I operate about 90% CW and I use
this filter most of the time, engaging narrower filters only when it
becomes really necessary.

73,

Dale -- WA8SRA

On Tue, Jul 25, 2017 at 3:49 PM, [hidden email] <[hidden email]> wrote:

> What is this used for?
>
> John KK9A
>
> From: Ralph Matheny K8RYU
> Mon Jul 24 16:30:29 EDT 2017
>
>
> Anybody got a 1 Khz filter for K3 they wanna sell??
>
> de K8RYU
>
> ______________________________________________________________
> Elecraft mailing list
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Elecraft mailing list

Re: [DETECTED AS SPAM] Re: 1 Khz filter

Same here, perfect for contesting on CW, I like to be able to hear almost
up to a KC up the band to pick up those who cannot zero beat,
I have 400 and 200 filters also, but only use them for extreme conditions,
Merv K9FD/KH6

> Hello John,
>
> It's used for CW. I have a pair of them (main and sub rx) and find that CW
> sounds more pleasing through this filter. I operate about 90% CW and I use
> this filter most of the time, engaging narrower filters only when it
> becomes really necessary.
>
> 73,
>
> Dale -- WA8SRA
>
> On Tue, Jul 25, 2017 at 3:49 PM, [hidden email] <[hidden email]> wrote:
>
>> What is this used for?
>>
>> John KK9A
>>
>> From: Ralph Matheny K8RYU
>> Mon Jul 24 16:30:29 EDT 2017
>>
>>
>> Anybody got a 1 Khz filter for K3 they wanna sell??
>>
>> de K8RYU
>>
>> ______________________________________________________________
>> Elecraft mailing list
>> Home: http://mailman.qth.net/mailman/listinfo/elecraft
>> Help: http://mailman.qth.net/mmfaq.htm
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>>
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Bill Breeden

Re: 1 Khz filter

I added a 1 kHz filter to my "Field Day" K3 for the same reason, and I
really like it. When calling CQ on CW during Field Day a lot of folks
who answer are using radios they aren't very familiar with and as a
result they aren't zero beat very accurately when they call. I found
that I was missing stations that were calling on the skirts of my 400 Hz
filter, so I added a 1 kHz filter. When I tune the band to answer CQs I
still prefer listen through the 400 Hz filter.

73,

Bill - NA5DX

On 7/25/2017 8:07 PM, Merv Schweigert via Elecraft wrote:

> Same here, perfect for contesting on CW, I like to be able to hear
> almost
> up to a KC up the band to pick up those who cannot zero beat,
> I have 400 and 200 filters also, but only use them for extreme
> conditions,
> Merv K9FD/KH6
>
>> Hello John,
>>
>> It's used for CW. I have a pair of them (main and sub rx) and find
>> that CW
>> sounds more pleasing through this filter. I operate about 90% CW and
>> I use
>> this filter most of the time, engaging narrower filters only when it
>> becomes really necessary.
>>
>> 73,
>>
>> Dale -- WA8SRA
>>
>> On Tue, Jul 25, 2017 at 3:49 PM, [hidden email] <[hidden email]> wrote:
>>
>>> What is this used for?
>>>
>>> John KK9A
>>>
>>> From: Ralph Matheny K8RYU
>>> Mon Jul 24 16:30:29 EDT 2017
>>>
>>>
>>> Anybody got a 1 Khz filter for K3 they wanna sell??
>>>
>>> de K8RYU
>>>
>>> ______________________________________________________________
>>> Elecraft mailing list
>>> Home: http://mailman.qth.net/mailman/listinfo/elecraft
>>> Help: http://mailman.qth.net/mmfaq.htm
>>> Post: mailto:[hidden email]
>>>
>>> This list hosted by: http://www.qsl.net
>>> Please help support this email list: http://www.qsl.net/donate.html
>>> Message delivered to [hidden email]
>>>
>> ______________________________________________________________
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>>
>
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Jim Brown-10

Re: 1 Khz filter

On 7/25/2017 7:11 PM, Bill Breeden wrote:
> I found that I was missing stations that were calling on the skirts of
> my 400 Hz filter, so I added a 1 kHz filter. When I tune the band to
> answer CQs I still prefer listen through the 400 Hz filter.

It's important to remember that IF bandwidth is determined by DSP, and
continuously adjustable. The plug-in filters are ROOFING filters --
their primary function is to protect the DSP from overload by very
strong stations outside the bandwidth of the DSP IF. They have the
secondary function of adding the filtering provided by the DSP, and when
the DSP and the roofing filter are at the same bandwidth, the filter
skirts become steeper (sharper).

Bottom line -- we don't need to buy a 1 kHz filter to get 1 kHz IF
bandwidth, because the DSP already provides that. This is not your
grandfather's radio! :)

73, Jim K9YC

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Vic Rosenthal

Re: 1 Khz filter

In reply to this post by john@kk9a.com

I am a CW operator and I have 2.8kHz, 1kHz, 400Hz and 200Hz filters in
my K3. I think this is serious overkill (especially since I have another
similar set in the subreceiver).

The function of the crystal filters is to allow you to operate closer
than (roughly) the filter bandwidth to a signal that is S9+20 dB or more
without the interfering signal having any effect on the desired signal.
The continuously adjustable DSP filter is a brick wall for undesired
signals weaker than that. But stronger signals can activate the hardware
AGC in the K3 or K3S and cause desensitization even though the QRM is
outside the DSP bandpass.

The optimum situation is to have a filter whose bandwidth is close to or
slightly wider than the DSP bandwidth that you are using. So if you
often operate with the DSP bandwidth set to, say, 900Hz, having a 1kHz
filter would be convenient. If you only had the stock 2.7 kHz filter,
then an undesired S9+20 dB signal 1 kHz away from the signal you are
listening to might cause the sensitivity of the receiver to vary and
thus interfere with your ability to copy, even though you wouldn't hear
the interfering signal.

So it depends on your operating habits. Since I am in the habit of
listening to CW with the DSP set to 400Hz or below, the 1kHz filter
doesn't do anything for me. I also think the value of the 200 Hz filter
is marginal, although it has been helpful at times (like when a
super-strong station one hop away from me is trying to deliberately QRM
a DX station but is not exactly on the DX frequency).

73,
Victor, 4X6GP
Rehovot, Israel
Formerly K2VCO
http://www.qsl.net/k2vco/
On 25 Jul 2017 22:49, [hidden email] wrote:

> What is this used for?
>
> John KK9A
>
> From: Ralph Matheny K8RYU
> Mon Jul 24 16:30:29 EDT 2017
>
>
> Anybody got a 1 Khz filter for K3 they wanna sell??
>
> de K8RYU

Bill Breeden

Re: 1 Khz filter

In reply to this post by Jim Brown-10

Jim,

I think most K3 owners understand that. Those who call CQ during
crowded band conditions also understand that their ears will take less
of a beating when using a 1 kHz DSP bandwidth in conjunction with a 1
kHz roofing filter instead of the next wider roofing filter, which, in a
K3 is often a 2.7 or 2.8 kHz filter. That's the wonderful thing about a
K3, the owner can equip it according to his or her personal preference.
My ears have taking enough beatings over the years from stations outside
of the filter bandwidth pumping the AGC while using lesser receivers to
know that I prefer a tight roofing filter bandwidth so that the stations
outside of my DSP bandwidth have minimal effect on what I am hearing.
I have used my "Field Day" K3 to call CQ during crowd banded conditions
before and after I added the 1 kHz filter and have found the improvement
well worth the price of the filter. Your mileage may vary.

73,

Bill - NA5DX

On 7/25/2017 10:08 PM, Jim Brown wrote:

> On 7/25/2017 7:11 PM, Bill Breeden wrote:
>> I found that I was missing stations that were calling on the skirts
>> of my 400 Hz filter, so I added a 1 kHz filter. When I tune the band
>> to answer CQs I still prefer listen through the 400 Hz filter.
>
> It's important to remember that IF bandwidth is determined by DSP, and
> continuously adjustable. The plug-in filters are ROOFING filters --
> their primary function is to protect the DSP from overload by very
> strong stations outside the bandwidth of the DSP IF. They have the
> secondary function of adding the filtering provided by the DSP, and
> when the DSP and the roofing filter are at the same bandwidth, the
> filter skirts become steeper (sharper).
>
> Bottom line -- we don't need to buy a 1 kHz filter to get 1 kHz IF
> bandwidth, because the DSP already provides that. This is not your
> grandfather's radio! :)
>
> 73, Jim K9YC
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
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Jim Brown-10

Re: 1 Khz filter

On 7/26/2017 9:09 AM, Bill Breeden wrote:
> I have used my "Field Day" K3 to call CQ during crowd banded
> conditions before and after I added the 1 kHz filter and have found
> the improvement well worth the price of the filter. Your mileage may
> vary.

While this is certainly a matter of operating preferences, my preference
is not to bother with callers more than a few hundred Hz off frequency
for at least three reasons. First, I've tried to protect my CQ frequency
by keeping it active. If I work someone widely displaced, my frequency
is unprotected while they're transmitting. Second, if they're that far
off frequency, they're likely to be getting QRMed by a station on their
frequency, which makes them hard to copy. Third, if they're that far off
frequency, they're more likely to be lids, and thus more likely to take
forever to finish a QSO.

For the same reasons, I won't respond to someone signing /QRP. Not
because I don't want to take the time to work a weak station, but
because that station signing /QRP is likely to be a lid. Indeed, by
sending /QRP he/she is wasting time doing so by sending un-necessary
information. I work a LOT of QRP, especially during DX contests, with
more than 160 countries confirmed, but I've never signed /QRP.

73, Jim K9YC

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