Roofing Filters

 
   
  OK....
   
  How many roofing filters do you need in a K3?  I would suggest one for SSB and one for CW.  What am I missing here with roofing filters.  Someone with more engineering savy should enlighten us liberal arts majors.
   
  Lee - K0WA
   


In our day and age it seems that Common Sense is in short supply.  If you don't have any Common Sense - get some Common Sense and use it.  If you can't find any Common Sense, ask for help from somebody who has some Common Sense.  Is Common Sense devine?
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[Jeff Stai]

Depends on what you want to do. I ordered the SSB 2.8KHz filter, plus the 250 and 400Hz for RTTY and
  CW contests. I'm not planning on any FM or AM use.

I like having both 250 and 400 for RTTY - sometimes one or the other BW will copy better on my
current rig depending on QRM, etc.

I'm hoping between now and July they will offer a 1.8KHz SSB filter, which I refer to as my
Sweepstakes filter on my current rig...:)

(Sorry - I didn't have time to put all that in iambic pentameter!)

73 - jeff wk6i


Lee Buller wrote:
>
> How many roofing filters do you need in a K3?  I would suggest one for SSB and one for CW.  What
> am I missing here with roofing filters.  Someone with more engineering savy should enlighten us
> liberal arts majors.
>
> Lee - K0WA


--
Jeff Stai               [hidden email]
Twisted Oak Winery      http://www.twistedoak.com/
Winery Blog             http://www.elbloggotorcido.com/

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[dj7mgq]

>  How many roofing filters do you need in a K3?

I belong to the liberal arts faction...

In other words I don't know what I am talking about... ;-)


I ordered my K3 with the secondary RX, 6kHz Filter, FM Filter, 2x
2.7kHz and the CG frontend filter.

As for the other roofing filters, I also am unsure what I should
order - mainly because we do not know yet, when which filters will be
avaidable, and we do not have any hard data on the filters themselves.

If the variable filters have no real disadvantages (factors such as
skirt steepness down to c. -30dB, image rejection for IF to NF,
impulse behaviour, etc.), then I personally would try and cover as
large a bandwidth range as possible with the variable filters.

My dream configuration could look like this:

RX1

1) 200Hz (or 250Hz)
2) 300Hz to 600Hz variable
3) 600Hz to 1.2kHz variable
4) 1.2kHz to 2.4kHz variable
5) 2.7kHz (or 2.8kHz)

RX2+CG

1) 300Hz to 600Hz variable
2) 1.2kHz to 2.4kHz variable
3) 2.7khz (or 2.8kHz)
4) 3kHz to 6kHz variable
5) FM

OTOH, if the A/D and AGC are good enough, we might be able to do with
only few well choosen bandwidths.

I doubt Elecraft will offer a 3kHz to 6kHz, and 600Hz to 1.2kHz is
also not very likely. But maybe the firmware will allow people who
have the right skills to design and build their own filters.

I do think this will become an area for much discussion in months to
come, especially if third parties also start to offer roofing filters
for the K3.


vy 73 de toby
--
DD5FZ, 4N6FZ (ex dj7mgq, dg5mgq, dd5fz)
K2 #885, K2/100 #3248
K3/100 #??? (< #200)
DOK C12, BCC, DL-QRP-AG
 

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[dj7mgq]

> mainly because we do not know yet, when which filters will be
> avaidable, and we do not have any hard data on the filters
> themselves.

If no one else noticed, the web based order form has been updated, and
there is a new roofing filter mentioned: KFL3A-1.0  1 kHz, 8-pole
roofing filter


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[Craig Rairdin]

I miss a 100Hz filter, which I use in the K2 all the time during contests. I
ordered the 200Hz and 400Hz filters for CW and am hoping that's what I want.

Craig

-----Original Message-----
From: [hidden email]
[mailto:[hidden email]] On Behalf Of Toby Deinhardt
Sent: Tuesday, May 01, 2007 3:36 PM
To: Elecraft Reflector
Subject: Re: [Elecraft] Roofing Filters


>  How many roofing filters do you need in a K3?

I belong to the liberal arts faction...

In other words I don't know what I am talking about... ;-)


I ordered my K3 with the secondary RX, 6kHz Filter, FM Filter, 2x
2.7kHz and the CG frontend filter.

As for the other roofing filters, I also am unsure what I should
order - mainly because we do not know yet, when which filters will be
avaidable, and we do not have any hard data on the filters themselves.

If the variable filters have no real disadvantages (factors such as
skirt steepness down to c. -30dB, image rejection for IF to NF,
impulse behaviour, etc.), then I personally would try and cover as
large a bandwidth range as possible with the variable filters.

My dream configuration could look like this:

RX1

1) 200Hz (or 250Hz)
2) 300Hz to 600Hz variable
3) 600Hz to 1.2kHz variable
4) 1.2kHz to 2.4kHz variable
5) 2.7kHz (or 2.8kHz)

RX2+CG

1) 300Hz to 600Hz variable
2) 1.2kHz to 2.4kHz variable
3) 2.7khz (or 2.8kHz)
4) 3kHz to 6kHz variable
5) FM

OTOH, if the A/D and AGC are good enough, we might be able to do with
only few well choosen bandwidths.

I doubt Elecraft will offer a 3kHz to 6kHz, and 600Hz to 1.2kHz is
also not very likely. But maybe the firmware will allow people who
have the right skills to design and build their own filters.

I do think this will become an area for much discussion in months to
come, especially if third parties also start to offer roofing filters
for the K3.


vy 73 de toby
--
DD5FZ, 4N6FZ (ex dj7mgq, dg5mgq, dd5fz)
K2 #885, K2/100 #3248
K3/100 #??? (< #200)
DOK C12, BCC, DL-QRP-AG
 

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[wayne burdick]

Craig Rairdin wrote:

> I miss a 100Hz filter, which I use in the K2 all the time during
> contests. I
> ordered the 200Hz and 400Hz filters for CW and am hoping that's what I
> want.

Hi Craig,

Our 200 Hz or 400 Hz filter, combined with DSP I.F. and A.F. filtering
down to 50 Hz, should handle any CW-mode QRM situation.

73,
Wayne
N6KR


---

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