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Roofing filter for CW

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n6fb

Roofing filter for CW

As a prospective buyer of the K3, and a 100 percent CW op, I am wondering which of the roofing filters is the correct choice, assuming I am buying only one?? I usually find that when operating weak sigs with my Pro 3, a bandwidth of about 600 to 800 hz is plenty adequate in normal QRM conditions. With that is mind, am I better off with the 1000 or 500 HZ 8 pole filter???

Bill, N6FB

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AD4C2009

Re: Roofing filter for CW

500 or 400Hz 8 poles (xtals) must be your choice for the narrow roofer when you be on CW.If you are a contester,narrower BW will be even better like 250 Hz but always 8 poles,in my K3 I only use the 500Hz and with the DSP set at 200Hz its a brick,very selective RX.

AD4C

"For a refined ham it is compulsory to own a k3"

--- On Tue, 2/16/10, [hidden email] <[hidden email]> wrote:

From: [hidden email] <[hidden email]>
Subject: [Elecraft] Roofing filter for CW
To: [hidden email]
Date: Tuesday, February 16, 2010, 6:50 PM

As a prospective buyer of the K3, and a 100 percent CW op, I am wondering which of the roofing filters is the correct choice, assuming I am buying only one?? I usually find that when operating weak sigs with my Pro 3, a bandwidth of about 600 to 800 hz is plenty adequate in normal QRM conditions. With that is mind, am I better off with the 1000 or 500 HZ 8 pole filter???

Bill, N6FB

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Bob - W0GI

Re: Roofing filter for CW

I agree that no wider then the 500Hz. If I had umlimited money, I would add a 1000Hz to my 250Hz as it would be nice for tuning, but then tuning with the DSP set to 1000Hz it just fine.

Inrad should have another batch of 1500Hz filters made up next month, and that is a nice filter for CW tuning, and usable on SSB.

Brett Howard

Re: Roofing filter for CW

In reply to this post by n6fb

I do mostly CW but every so often head up and do SSB for contests. I
also wanted the ability to do FM on 2M. So my choices are 13Khz,
2.8Khz, 1.5Khz, 1.0Khz, 250Hz. I have that combination in both
receivers and I'm very happy with the way it works. If I was 100% CW
I'd probably have gotten the 2.7Khz (5Pole), and then add the 1.0Khz
for CW tuning, and 250Hz (8 pole) for pileups. I find that I often
sit around 600 to 800 as well and thus why the 1.0Khz filter works
great. It gives you a nice space to run around in and get what you
want with the DSP while keeping the ADC's exposure fairly confined.
Then when you really want to get in close to someone and pull out a
weak one the 250Hz filter always brings a smile to the face.

~Brett (KC7OTG)

On Tue, Feb 16, 2010 at 10:50 AM, <[hidden email]> wrote:

>
>
>
> As a prospective buyer of the K3, and a 100 percent CW op, I am wondering which of the roofing filters is the correct choice, assuming I am buying only one?? I usually find that when operating weak sigs with my Pro 3, a bandwidth of about 600 to 800 hz is plenty adequate in normal QRM conditions. With that is mind, am I better off with the 1000 or 500 HZ 8 pole filter???
>
> Bill, N6FB
>
>
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Matt Zilmer

Re: Roofing filter for CW

Bill,

I have a very similar filter set (to Brett's as shown below),
including the 250 Hz 8-pole.

I find the 1 KHz is best for casual CW and digital modes, and the 250
Hz filter is best for eliminating strong adjacent signals and in CW
pileups. Would have to say that I'm on the 1 KHz filter 90% of the
time though. The 250 gets put into service when it's contest time, or
the bands *really* open up (like lately).

You can put a lot of energy into a 250 Hz bandpass, so it's also
excellent for weak CW and some digital signals. Because it's so
narrow, you may find tuning with the 250 to be hit-or-miss. If you
tune with the 250 Hz filter, maybe try FINE resolution. Also, with a
narrow filter like this one, you may want to boost the gain to 3 or 4
dB.

Remember that the roofing filter is only part of the equation. The
DSP really provides the ultimate bandpass shaping, so you can still
get down to 50 Hz (I think...) in CW using the WIDTH or HIGH/LOW
controls.

73,
matt W6NIA
K3 #24

On Tue, 16 Feb 2010 12:24:38 -0800, Brett wrote:

>So my choices are 13Khz,
>2.8Khz, 1.5Khz, 1.0Khz, 250Hz. I have that combination in both
>receivers and I'm very happy with the way it works.

==

>> As a prospective buyer of the K3, and a 100 percent CW op, I am wondering which of the roofing filters is the correct choice, assuming I am buying only one?? I usually find that when operating weak sigs with my Pro 3, a bandwidth of about 600 to 800 hz is plenty adequate in normal QRM conditions. With that is mind, am I better off with the 1000 or 500 HZ 8 pole filter???
>>
>> Bill, N6FB
>>
>>
>> ______________________________________________________________
>> 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
>>
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Olli Tuppurainen

Re: Roofing filter for CW

In reply to this post by n6fb

One thing to remeber is that if you get strong signal within your roofing
filter passband you will notice that AGC will go up to protect DSP
overloading. Then you have use for narrower roofing filters.

I have 400Hz but considering to add 200Hz after working couple of CW and
RTTY contest on 40 meters :)

Olli
OH6CT

> -----Alkuperäinen viesti-----
> Lähettäjä: [hidden email]
> [mailto:[hidden email]] Puolesta [hidden email]
> Lähetetty: 16. helmikuuta 2010 20:51
> Vastaanottaja: [hidden email]
> Aihe: [Elecraft] Roofing filter for CW
>
>
>
>
> As a prospective buyer of the K3, and a 100 percent CW op, I
> am wondering which of the roofing filters is the correct
> choice, assuming I am buying only one?? I usually find that
> when operating weak sigs with my Pro 3, a bandwidth of about
> 600 to 800 hz is plenty adequate in normal QRM conditions.
> With that is mind, am I better off with the 1000 or 500 HZ 8
> pole filter???
>
> Bill, N6FB
>
>
> ______________________________________________________________
> 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
>