Re: [Elecraft] Roofing filters and DSP bandwidth tuning

[Jim Brown]

On 1/27/2021 3:06 PM, David Woolley wrote:
Having the roofing filter too close to the DSP filter is not necessarily 
a good thing, as the roofing filters are likely to have worse passband 
ripples and will have non-linear phase responses, which can compromise 
digital modes.  At least some of the DSP filters are finite impulse 
response, meaning they are also linear phase, which means that pulses 
will not get smeared out.


K1JT strongly urges 3kHz or greater IF bandwidths for his modes, and for 
exactly that reason. And it's why top RTTY contesters have abandoned the 
K3's dual-peak filter in favor of 500 Hz IF bandwidth. My professional 
life in audio system design taught me that speech intelligibility is 
degraded by time/phase distortion and suspected the result would be the 
same with RTTY, but I was derided when I started preaching that to RTTY 
guys. Several years later, author of the 2Tone RTTY software G3YYD said 
the same thing, and folks started believing it. It's also why I find 
that the 2.1 kHz 8-pole provides better speech intelligibility than the 
1.8 kHz filter.


Years ago, I tried using narrow SSB realignments of the K2's CW crystal 
filters in contests. I had carefully tweaked them per the build 
instructions, noting that their amplitude response looked like the 
profile of a mountain range. I wasn't surprised that those settings made 
signals much harder to copy. The SSB TX filter sounded fine on RX.


When I switched from the 2.7 kHz 5-pole filters to the 2.8 kHz filters 
for TX in one of my K3s I noticed considerably less incidental AM on 
RTTY, and immediately converted the other two. I didn't do that in the 
2nd RX, because I only use it for weak signal CW work on the lower bands.


73, Jim K9YC


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Re: [Elecraft] Roofing filters and DSP bandwidth tuning

[Jim Brown]

On 1/27/2021 2:48 PM, j...@kk9a.com wrote:

I have both as well in all my radios. I can clearly hear the difference
when switching between them. I mostly use the 250 Hz filter for CW and
the 500 Hz filter for RTTY.


Sorry, I mis-spoke. I have the 8-pole 250 Hz and 400 Hz filters, but I 
set the DSP IF for 500 Hz for RTTY. I'm well aware how similarly they 
measure -- W0YK and I did that independently in 2008-9 when we first 
installed them.


73, Jim
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Re: [Elecraft] Roofing filters and DSP bandwidth tuning

[Fred Jensen]

True.  Statement was focused on preventing AGC action from signals 
outside the DSP BW and to do that, you'd like the roofing filters to 
include the DSP BW but not much more.  The "effective" BW of the xtal 
filters is also something larger than the 2.5 kHz or 0.5 kHz or 0.25 kHz 
in the name ... more poles = steeper skirts. Phase response is fairly 
irrelevant on CW and almost so on SSB.  If you're operating digital 
modes, phase response [and passband ripple] becomes important if the 
desired signal BW fills the filter BW.


73,

Fred ["Skip"] K6DGW
Sparks NV DM09dn
Washoe County

On 1/27/2021 3:06 PM, David Woolley wrote:

On 27/01/2021 20:35, Fred Jensen wrote:
   It follows that you'd probably like the selection of roofing 
filters to follow the DSP BW as closely as possible.


Having the roofing filter too close to the DSP filter is not 
necessarily a good thing, as the roofing filters are likely to have 
worse passband ripples and will have non-linear phase responses, which 
can compromise digital modes.  At least some of the DSP filters are 
finite impulse response, meaning they are also linear phase, which 
means that pulses will not get smeared out.




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Re: [Elecraft] Roofing filters and DSP bandwidth tuning

[David Woolley]

On 27/01/2021 20:35, Fred Jensen wrote:
   It follows that you'd probably like the selection of roofing filters 
to follow the DSP BW as closely as possible.


Having the roofing filter too close to the DSP filter is not necessarily 
a good thing, as the roofing filters are likely to have worse passband 
ripples and will have non-linear phase responses, which can compromise 
digital modes.  At least some of the DSP filters are finite impulse 
response, meaning they are also linear phase, which means that pulses 
will not get smeared out.


--
David Woolley

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Re: [Elecraft] Roofing filters and DSP bandwidth tuning

[john]

I have 8 pole 400 Hz filters in my K3s's, not 500 Hz as well as 250 Hz.
According to W0YK's presentation linked below the 400 filter has a bandwidth
of 435 and the 250 filter has a bandwidth of 370. This data is for 8 pole
crystal filters made by Inrad, I am not sure what filters Elecraft currently
sells. 

http://www.nccc.cc/archived_meetings/pdf/K3%20Filters,%20Jan%202009.pdf  

John KK9A


Jim Brown K9YC wrote:

On 1/27/2021 12:14 PM, john at kk9a.com wrote:
> FWIW, I have both the 400 and 250 8 pole filters. If money is an issue, 
> I believe that there is very little bandwidth difference between the two.

I have both as well in all my radios. I can clearly hear the difference 
when switching between them. I mostly use the 250 Hz filter for CW and 
the 500 Hz filter for RTTY.

73, Jim K9YC

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Re: [Elecraft] Roofing filters and DSP bandwidth tuning

[Jim Brown]

On 1/27/2021 12:14 PM, j...@kk9a.com wrote:
FWIW, I have both the 400 and 250 8 pole filters. If money is an issue, 
I believe that there is very little bandwidth difference between the two.


I have both as well in all my radios. I can clearly hear the difference 
when switching between them. I mostly use the 250 Hz filter for CW and 
the 500 Hz filter for RTTY.


73, Jim K9YC
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Re: [Elecraft] Roofing filters and DSP bandwidth tuning

[Fred Jensen]

NJ Mike:  If I understand your question, the answer is "Yes, as you 
narrow the DSP BW with the 'WIDTH" knob, the roofing filters will switch 
such that the narrowest filter that still includes the DSP BW will be 
selected".


To your second question, the ultimate BW is set by the DSP, and on my 
K3, that's 50 Hz.  It doesn't really matter what roofing filter is 
selected.  The xtal filters are in the 1st IF [8 MHz] and their primary 
[maybe only] purpose is to suppress strong signals outside the DSP BW 
that would activate the AGC and affect the level of the desired signal 
inside the DSP BW, even though you can't hear them.  It follows that 
you'd probably like the selection of roofing filters to follow the DSP 
BW as closely as possible.  You won't see any difference between your 
Rigs A, B, and C.


73,

Fred ["Skip"] K6DGW
Sparks NV DM09dn
Washoe County

NJ Mike wrote:

If I understand it correctly, as you turn the bandwidth knob
counterclockwise, the filter narrows.  At some point, it hits the next
roofing filter and thennarrows more?  Just trying to understand so 
I can

get the right filters.  Rig A (below) is what Elecraft recommends for my
operating profile.

What would be the difference between the following three examples, as 
far as

how narrow the bandwidth could actually be adjusted?

Rig A with 2.8, 2.1, 400, 250, 200 filters
Rig B with 2.8, 2.1, 400, 250 filters
Rig C with 2.8, 2.1, 400, 200 filters


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Re: [Elecraft] Roofing filters and DSP bandwidth tuning

[john]

These are roofing filters, they do not effect how narrow the bandwidth  
can be adjusted.  FWIW, I have both the 400 and 250 8 pole filters. If  
money is an issue, I believe that there is very little bandwidth  
difference between the two.


John KK9A


NJ Mike wrote:

If I understand it correctly, as you turn the bandwidth knob
counterclockwise, the filter narrows.  At some point, it hits the next
roofing filter and thennarrows more?  Just trying to understand so I can
get the right filters.  Rig A (below) is what Elecraft recommends for my
operating profile.

What would be the difference between the following three examples, as far as
how narrow the bandwidth could actually be adjusted?

Rig A with 2.8, 2.1, 400, 250, 200 filters
Rig B with 2.8, 2.1, 400, 250 filters
Rig C with 2.8, 2.1, 400, 200 filters

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[Elecraft] Roofing filters and DSP bandwidth tuning

[NJMike]

If I understand it correctly, as you turn the bandwidth knob
counterclockwise, the filter narrows.  At some point, it hits the next
roofing filter and thennarrows more?  Just trying to understand so I can
get the right filters.  Rig A (below) is what Elecraft recommends for my
operating profile.

What would be the difference between the following three examples, as far as
how narrow the bandwidth could actually be adjusted?

Rig A with 2.8, 2.1, 400, 250, 200 filters
Rig B with 2.8, 2.1, 400, 250 filters
Rig C with 2.8, 2.1, 400, 200 filters



--
Sent from: http://elecraft.365791.n2.nabble.com/
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Re: [Elecraft] Roofing Filters

[j...@kk9a.com]

That explains it, thanks.

John KK9A

Sent via the Samsung Galaxy 7 edge, an AT 4G LTE smartphone.


On Tue, Jun 18, 2019 at 1:12 PM Nr4c  wrote:

> The old 400Hz filter was a 8 pole variety. It’s been replaced by a new and
> probably better 6 pole filter. As have several others.
>
> Sent from my iPhone
> ...nr4c. bill
>
>
> > On Jun 18, 2019, at 12:04 PM, "j...@kk9a.com"  wrote:
> >
> > So does Elecraft no longer sell this filter:
> > http://www.inrad.net/product.php?productid=150=140
> >
> > John KK9A
> >
> > Sent via the Samsung Galaxy 7 edge, an AT 4G LTE smartphone.
> >
> >
> >> On Tue, Jun 18, 2019 at 11:34 AM Wayne Burdick 
> wrote:
> >>
> >> The KFL3A is an 8-pole filter.
> >>
> >> The KFL3C is a 6-pole filter. In a 400 Hz bandwidth, performance will be
> >> virtually indistinguishable from the 8-pole.
> >>
> >> 73,
> >> Wayne
> >> N6KR
> >>
> >>
> >>
> >>
> >>> On Jun 18, 2019, at 8:21 AM, j...@kk9a.com wrote:
> >>>
> >>> The new Elecraft site is a little vague regarding roofing filters so I
> am
> >>> going by memory.  I have two filters in my cart KFL3A-2.8K-IR  and
> >> KFL3C-400
> >>> for my third K3S. Before I hit the purchase button I want to be sure
> that
> >>> these are both 8 pole filters.
> >>>
> >>> John KK9A
> >>>
> >>> Sent via the Samsung Galaxy 7 edge, an AT 4G LTE smartphone.
> >>> __
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> >>> Message delivered to n...@elecraft.com
> >>
> >>
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Re: [Elecraft] Roofing Filters

[Conrad PA5Y]

Hello John is that not from Inrad who are a different vendor to Elecraft? Or 
did Elecraft supply Inrad filters at one time? I have no idea I've only just 
started looking.

73

Conrad PA5Y

-Original Message-
From: elecraft-boun...@mailman.qth.net  On 
Behalf Of j...@kk9a.com
Sent: 18 June 2019 18:04
To: Wayne Burdick 
Cc: Elecraft Reflector 
Subject: Re: [Elecraft] Roofing Filters

So does Elecraft no longer sell this filter:
http://www.inrad.net/product.php?productid=150=140

John KK9A

Sent via the Samsung Galaxy 7 edge, an AT 4G LTE smartphone.


On Tue, Jun 18, 2019 at 11:34 AM Wayne Burdick  wrote:

> The KFL3A is an 8-pole filter.
>
> The KFL3C is a 6-pole filter. In a 400 Hz bandwidth, performance will 
> be virtually indistinguishable from the 8-pole.
>
> 73,
> Wayne
> N6KR
>
>
>
>
> > On Jun 18, 2019, at 8:21 AM, j...@kk9a.com wrote:
> >
> > The new Elecraft site is a little vague regarding roofing filters so 
> > I am going by memory.  I have two filters in my cart KFL3A-2.8K-IR  
> > and
> KFL3C-400
> > for my third K3S. Before I hit the purchase button I want to be sure 
> > that these are both 8 pole filters.
> >
> > John KK9A
> >
> > Sent via the Samsung Galaxy 7 edge, an AT 4G LTE smartphone.
> > __
> > Elecraft mailing list
> > Home: http://mailman.qth.net/mailman/listinfo/elecraft
> > Help: http://mailman.qth.net/mmfaq.htm
> > Post: mailto:Elecraft@mailman.qth.net
> >
> > This list hosted by: http://www.qsl.net Please help support this 
> > email list: http://www.qsl.net/donate.html Message delivered to 
> > n...@elecraft.com
>
>
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Re: [Elecraft] Roofing Filters

[Nr4c]

The old 400Hz filter was a 8 pole variety. It’s been replaced by a new and 
probably better 6 pole filter. As have several others. 

Sent from my iPhone
...nr4c. bill


> On Jun 18, 2019, at 12:04 PM, "j...@kk9a.com"  wrote:
> 
> So does Elecraft no longer sell this filter:
> http://www.inrad.net/product.php?productid=150=140
> 
> John KK9A
> 
> Sent via the Samsung Galaxy 7 edge, an AT 4G LTE smartphone.
> 
> 
>> On Tue, Jun 18, 2019 at 11:34 AM Wayne Burdick  wrote:
>> 
>> The KFL3A is an 8-pole filter.
>> 
>> The KFL3C is a 6-pole filter. In a 400 Hz bandwidth, performance will be
>> virtually indistinguishable from the 8-pole.
>> 
>> 73,
>> Wayne
>> N6KR
>> 
>> 
>> 
>> 
>>> On Jun 18, 2019, at 8:21 AM, j...@kk9a.com wrote:
>>> 
>>> The new Elecraft site is a little vague regarding roofing filters so I am
>>> going by memory.  I have two filters in my cart KFL3A-2.8K-IR  and
>> KFL3C-400
>>> for my third K3S. Before I hit the purchase button I want to be sure that
>>> these are both 8 pole filters.
>>> 
>>> John KK9A
>>> 
>>> Sent via the Samsung Galaxy 7 edge, an AT 4G LTE smartphone.
>>> __
>>> Elecraft mailing list
>>> Home: http://mailman.qth.net/mailman/listinfo/elecraft
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>>> This list hosted by: http://www.qsl.net
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>>> Message delivered to n...@elecraft.com
>> 
>> 
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Re: [Elecraft] Roofing Filters

[j...@kk9a.com]

So does Elecraft no longer sell this filter:
http://www.inrad.net/product.php?productid=150=140

John KK9A

Sent via the Samsung Galaxy 7 edge, an AT 4G LTE smartphone.


On Tue, Jun 18, 2019 at 11:34 AM Wayne Burdick  wrote:

> The KFL3A is an 8-pole filter.
>
> The KFL3C is a 6-pole filter. In a 400 Hz bandwidth, performance will be
> virtually indistinguishable from the 8-pole.
>
> 73,
> Wayne
> N6KR
>
>
>
>
> > On Jun 18, 2019, at 8:21 AM, j...@kk9a.com wrote:
> >
> > The new Elecraft site is a little vague regarding roofing filters so I am
> > going by memory.  I have two filters in my cart KFL3A-2.8K-IR  and
> KFL3C-400
> > for my third K3S. Before I hit the purchase button I want to be sure that
> > these are both 8 pole filters.
> >
> > John KK9A
> >
> > Sent via the Samsung Galaxy 7 edge, an AT 4G LTE smartphone.
> > __
> > Elecraft mailing list
> > Home: http://mailman.qth.net/mailman/listinfo/elecraft
> > Help: http://mailman.qth.net/mmfaq.htm
> > Post: mailto:Elecraft@mailman.qth.net
> >
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> > Please help support this email list: http://www.qsl.net/donate.html
> > Message delivered to n...@elecraft.com
>
>
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Re: [Elecraft] Roofing Filters

[Wayne Burdick]

The KFL3A is an 8-pole filter.

The KFL3C is a 6-pole filter. In a 400 Hz bandwidth, performance will be 
virtually indistinguishable from the 8-pole. 

73,
Wayne
N6KR




> On Jun 18, 2019, at 8:21 AM, j...@kk9a.com wrote:
> 
> The new Elecraft site is a little vague regarding roofing filters so I am
> going by memory.  I have two filters in my cart KFL3A-2.8K-IR  and KFL3C-400
> for my third K3S. Before I hit the purchase button I want to be sure that
> these are both 8 pole filters.
> 
> John KK9A
> 
> Sent via the Samsung Galaxy 7 edge, an AT 4G LTE smartphone.
> __
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[Elecraft] Roofing Filters

[j...@kk9a.com]

The new Elecraft site is a little vague regarding roofing filters so I am
going by memory.  I have two filters in my cart KFL3A-2.8K-IR  and KFL3C-400
for my third K3S. Before I hit the purchase button I want to be sure that
these are both 8 pole filters.

John KK9A

Sent via the Samsung Galaxy 7 edge, an AT 4G LTE smartphone.
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Re: [Elecraft] Roofing Filters

[Wayne Burdick]

Not very many, fortunately.

Wayne
N6KR


> On Jun 22, 2017, at 6:01 PM, <j...@kk9a.com> <j...@kk9a.com> wrote:
> 
> What percentage are rejected?
> 
> FWIW, I have bought filters for other brand radios direct from Inrad for
> decades however all of the filters in my K3S's were bought though Elecraft.
> I was unaware of additional screening until now.
> 
> John KK9A
> 
> Wayne Burdick n6kr at elecraft.com 
> Thu Jun 22 12:54:12 EDT 2017
> Previous message: [Elecraft] Roofing Filters
> 
> Yes. We screen every INRAD filter. Those that don't meet our dynamic range
> targets are rejected.
> 
> Wayne
> N6KR
> 
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[Elecraft] Roofing Filters

[john]

What percentage are rejected?

FWIW, I have bought filters for other brand radios direct from Inrad for
decades however all of the filters in my K3S's were bought though Elecraft.
I was unaware of additional screening until now.

John KK9A

Wayne Burdick n6kr at elecraft.com 
Thu Jun 22 12:54:12 EDT 2017
Previous message: [Elecraft] Roofing Filters

Yes. We screen every INRAD filter. Those that don't meet our dynamic range
targets are rejected.

Wayne
N6KR

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Re: [Elecraft] Roofing Filters

[Wayne Burdick]

We actually test at higher levels than this. 

The hardware AGC is *after* the crystal filter. Gain control prior to the 
filter is in discrete steps under control of the user: preamps and attenuator 
sections.

Wayne
N6KR



> On Jun 22, 2017, at 1:20 PM, Joe Subich, W4TV  wrote:
> 
> 
> >  Could you elaborate on "dynamic range" in crystal filters?
> 
> All crystals have imperfections (flaws).  Those flaws create distortion
> when the crystal is driven with a high level signal and the distortion
> (non-linear response) results in intermodulation distortion (IMD).
> 
> The K3/K3S operates the crystal filter at a higher level than many other
> receivers.  Thus, testing the filters for linearity at the maximum
> signal level (equivalent to S9 +40 dB - where the hardware AGC engages)
> is important to assure the best possible performance over the entire
> operating range of the K3/K3S.
> 
> 73,
> 
>   ... Joe, W4TV
> 
> 
> On 6/22/2017 3:12 PM, Bob wrote:
>> Hi Wayne,
>> Could you elaborate on "dynamic range" in crystal filters?  A quick 
>> search did not yield a definition.  A SWAG might be another term for 
>> ultimate rejection or it with ripple in the passband...
>> Just curious.
>> 73,
>> Bob
>> K2TK ex KN2TKR (1956) & K2TKR
>> On 6/22/2017 12:54 PM, Wayne Burdick wrote:
>>> Yes. We screen every INRAD filter. Those that don’t meet our dynamic range 
>>> targets are rejected.
>>> 
>>> Wayne
>>> N6KR
>>> 
>>> 
 On Jun 22, 2017, at 9:46 AM, Vic Rosenthal  wrote:
 
 I recall Wayne saying that Elecraft tested filters received from INRAD for 
 some specific performance characteristics. I don't remember the details.
 
 Vic 4X6GP
 
> On 22 Jun 2017, at 17:14, Clay Autery  wrote:
> 
> INRAD makes Elecraft's filters as I understand it...
> 
> I'll be getting mine from Elecraft directly.
> 
> __
> Clay Autery, KY5G
>> __
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Re: [Elecraft] Roofing Filters

[Joe Subich, W4TV]

>  Could you elaborate on "dynamic range" in crystal filters?

All crystals have imperfections (flaws).  Those flaws create distortion
when the crystal is driven with a high level signal and the distortion
(non-linear response) results in intermodulation distortion (IMD).

The K3/K3S operates the crystal filter at a higher level than many other
receivers.  Thus, testing the filters for linearity at the maximum
signal level (equivalent to S9 +40 dB - where the hardware AGC engages)
is important to assure the best possible performance over the entire
operating range of the K3/K3S.

73,

   ... Joe, W4TV


On 6/22/2017 3:12 PM, Bob wrote:

Hi Wayne,

 Could you elaborate on "dynamic range" in crystal filters?  A 
quick search did not yield a definition.  A SWAG might be another term 
for ultimate rejection or it with ripple in the passband...


 Just curious.

73,
Bob
K2TK ex KN2TKR (1956) & K2TKR


On 6/22/2017 12:54 PM, Wayne Burdick wrote:
Yes. We screen every INRAD filter. Those that don’t meet our dynamic 
range targets are rejected.


Wayne
N6KR



On Jun 22, 2017, at 9:46 AM, Vic Rosenthal  wrote:

I recall Wayne saying that Elecraft tested filters received from 
INRAD for some specific performance characteristics. I don't remember 
the details.


Vic 4X6GP


On 22 Jun 2017, at 17:14, Clay Autery  wrote:

INRAD makes Elecraft's filters as I understand it...

I'll be getting mine from Elecraft directly.

__
Clay Autery, KY5G

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Re: [Elecraft] Roofing Filters

[Bob]

Hi Wayne,

Could you elaborate on "dynamic range" in crystal filters?  A quick 
search did not yield a definition.  A SWAG might be another term for ultimate 
rejection or it with ripple in the passband...


Just curious.

73,
Bob
K2TK ex KN2TKR (1956) & K2TKR


On 6/22/2017 12:54 PM, Wayne Burdick wrote:

Yes. We screen every INRAD filter. Those that don’t meet our dynamic range 
targets are rejected.

Wayne
N6KR



On Jun 22, 2017, at 9:46 AM, Vic Rosenthal  wrote:

I recall Wayne saying that Elecraft tested filters received from INRAD for some 
specific performance characteristics. I don't remember the details.

Vic 4X6GP


On 22 Jun 2017, at 17:14, Clay Autery  wrote:

INRAD makes Elecraft's filters as I understand it...

I'll be getting mine from Elecraft directly.

__
Clay Autery, KY5G

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Re: [Elecraft] Roofing Filters

[Clay Autery]

Get what you are saying but I go by what my Dad taught me...

RE: Tools
"Son, Buy the best tool you can find for each job.  Save up if you have
to.  If you can't afford to buy the tool once, you surely can't afford
to buy it twice."

I apply that rule to tools, equipment, cabling, et al because ALL of
those things and more are merely "tools" for me to accomplish some
task.  Works for me and less expensive in the long run.

73,

__
Clay Autery, KY5G
MONTAC Enterprises
(318) 518-1389

On 6/22/2017 1:04 PM, Michael Walker wrote:
> Actually, it is just human nature to do that.  For some, every penny counts.
>
> Mike va3mw
>
> On Thu, Jun 22, 2017 at 1:56 PM, Clay Autery  wrote:
>
>> hence my earlier statement:
>>
>> "I'll be getting mine from Elecraft directly."
>>
>> Thousands of dollars in radio fear and people risk niggling problems and
>> time wasted over a few bucks...  Just simply doesn't make sense to me.
>>
>> 73,
>>
>> __
>> Clay Autery, KY5G
>>
>> On 6/22/2017 11:54 AM, Wayne Burdick wrote:
>>> Yes. We screen every INRAD filter. Those that don’t meet our dynamic
>> range targets are rejected.
>>> Wayne
>>> N6KR
>>>
>>>
 On Jun 22, 2017, at 9:46 AM, Vic Rosenthal  wrote:

 I recall Wayne saying that Elecraft tested filters received from INRAD
>> for some specific performance characteristics. I don't remember the details.
 Vic 4X6GP

> On 22 Jun 2017, at 17:14, Clay Autery  wrote:
>
> INRAD makes Elecraft's filters as I understand it...
>
> I'll be getting mine from Elecraft directly.
>
> __
> Clay Autery, KY5G
>> __
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Re: [Elecraft] Roofing Filters

[Michael Walker]

Actually, it is just human nature to do that.  For some, every penny counts.

Mike va3mw

On Thu, Jun 22, 2017 at 1:56 PM, Clay Autery  wrote:

> hence my earlier statement:
>
> "I'll be getting mine from Elecraft directly."
>
> Thousands of dollars in radio fear and people risk niggling problems and
> time wasted over a few bucks...  Just simply doesn't make sense to me.
>
> 73,
>
> __
> Clay Autery, KY5G
>
> On 6/22/2017 11:54 AM, Wayne Burdick wrote:
> > Yes. We screen every INRAD filter. Those that don’t meet our dynamic
> range targets are rejected.
> >
> > Wayne
> > N6KR
> >
> >
> >> On Jun 22, 2017, at 9:46 AM, Vic Rosenthal  wrote:
> >>
> >> I recall Wayne saying that Elecraft tested filters received from INRAD
> for some specific performance characteristics. I don't remember the details.
> >>
> >> Vic 4X6GP
> >>
> >>> On 22 Jun 2017, at 17:14, Clay Autery  wrote:
> >>>
> >>> INRAD makes Elecraft's filters as I understand it...
> >>>
> >>> I'll be getting mine from Elecraft directly.
> >>>
> >>> __
> >>> Clay Autery, KY5G
> __
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Re: [Elecraft] Roofing Filters

[Clay Autery]

hence my earlier statement:

"I'll be getting mine from Elecraft directly."

Thousands of dollars in radio fear and people risk niggling problems and
time wasted over a few bucks...  Just simply doesn't make sense to me.

73,

__
Clay Autery, KY5G

On 6/22/2017 11:54 AM, Wayne Burdick wrote:
> Yes. We screen every INRAD filter. Those that don’t meet our dynamic range 
> targets are rejected.
>
> Wayne
> N6KR
>
>
>> On Jun 22, 2017, at 9:46 AM, Vic Rosenthal  wrote:
>>
>> I recall Wayne saying that Elecraft tested filters received from INRAD for 
>> some specific performance characteristics. I don't remember the details.
>>
>> Vic 4X6GP 
>>
>>> On 22 Jun 2017, at 17:14, Clay Autery  wrote:
>>>
>>> INRAD makes Elecraft's filters as I understand it...
>>>
>>> I'll be getting mine from Elecraft directly.
>>>
>>> __
>>> Clay Autery, KY5G
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Re: [Elecraft] Roofing Filters

[Ken G Kopp]

Meaning ya get what ya pay for ... or "value added".  (:-))

73!

K0PP

On Jun 22, 2017 10:54, "Wayne Burdick"  wrote:

> Yes. We screen every INRAD filter. Those that don’t meet our dynamic range
> targets are rejected.
>
> Wayne
> N6KR
>
>
> > On Jun 22, 2017, at 9:46 AM, Vic Rosenthal  wrote:
> >
> > I recall Wayne saying that Elecraft tested filters received from INRAD
> for some specific performance characteristics. I don't remember the details.
> >
> > Vic 4X6GP
> >
> >> On 22 Jun 2017, at 17:14, Clay Autery  wrote:
> >>
> >> INRAD makes Elecraft's filters as I understand it...
> >>
> >> I'll be getting mine from Elecraft directly.
> >>
> >> __
> >> Clay Autery, KY5G
> >>
> >>> On 6/22/2017 8:10 AM, Mike Harris wrote:
> >>> Wandering the web I notice that INRAD are offering K3 Roofers somewhat
> >>> less than Elecraft prices.
> >>>
> >>> Regards,
> >>>
> >>> Mike VP8NO
> >>> __
> >>> Elecraft mailing list
> >>> Home: http://mailman.qth.net/mailman/listinfo/elecraft
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> >>>
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> >>> Message delivered to caut...@montac.com
> >>
> >> __
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Re: [Elecraft] Roofing Filters

[Wayne Burdick]

Yes. We screen every INRAD filter. Those that don’t meet our dynamic range 
targets are rejected.

Wayne
N6KR


> On Jun 22, 2017, at 9:46 AM, Vic Rosenthal  wrote:
> 
> I recall Wayne saying that Elecraft tested filters received from INRAD for 
> some specific performance characteristics. I don't remember the details.
> 
> Vic 4X6GP 
> 
>> On 22 Jun 2017, at 17:14, Clay Autery  wrote:
>> 
>> INRAD makes Elecraft's filters as I understand it...
>> 
>> I'll be getting mine from Elecraft directly.
>> 
>> __
>> Clay Autery, KY5G
>> 
>>> On 6/22/2017 8:10 AM, Mike Harris wrote:
>>> Wandering the web I notice that INRAD are offering K3 Roofers somewhat
>>> less than Elecraft prices.
>>> 
>>> Regards,
>>> 
>>> Mike VP8NO
>>> __
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>>> Message delivered to caut...@montac.com
>> 
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Re: [Elecraft] Roofing Filters

[Vic Rosenthal]

I recall Wayne saying that Elecraft tested filters received from INRAD for some 
specific performance characteristics. I don't remember the details.

Vic 4X6GP 

> On 22 Jun 2017, at 17:14, Clay Autery  wrote:
> 
> INRAD makes Elecraft's filters as I understand it...
> 
> I'll be getting mine from Elecraft directly.
> 
> __
> Clay Autery, KY5G
> 
>> On 6/22/2017 8:10 AM, Mike Harris wrote:
>> Wandering the web I notice that INRAD are offering K3 Roofers somewhat
>> less than Elecraft prices.
>> 
>> Regards,
>> 
>> Mike VP8NO
>> __
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Re: [Elecraft] Roofing Filters

[Kevin - K4VD]

An alternative thought. INRAD makes a decent product and has been around
for years. I've used their roofing filter in my FT-1000 and I think it was
in my FT-897 also(?). If I were looking to refit an existing rig, any rig,
with a roofing filter I'd give serious consideration to INRAD's offerings.

Specifications are a consideration. I'm not sure how the two products
compare in the lab. If both are very similar then I'd say thank you to
INRAD for selling at the lower price.

Don't get me wrong. I really enjoy my Elecraft. One of the best rigs I've
ever owned and definitely the best when portable. But if I want to say
thank you I'll send them a card.

73,
Kev K4VD

On Thu, Jun 22, 2017 at 11:09 AM, Raymond Sills <raysil...@verizon.net>
wrote:

> I don't have a K3, or K3S... but if I did, I'd order from Elecraft.  After
> all, if it were not for Elecraft, Inrad would not be making them.
>
>
> Paying a bit extra to Elecraft is a way to say "thank you" for their
> wonderful products, and their outstanding customer service.
>
>
>
>
> 73 de Ray
> K2ULR
> KX3 #211
>
>
>
>
> -Original Message-
> From: Clay Autery <caut...@montac.com>
> To: elecraft <elecraft@mailman.qth.net>
> Sent: Thu, Jun 22, 2017 10:26 am
> Subject: Re: [Elecraft] Roofing Filters
>
> INRAD makes Elecraft's filters as I understand it...
>
> I'll be getting mine from Elecraft directly.
>
> __
> Clay Autery, KY5G
>
> On 6/22/2017 8:10 AM, Mike Harris wrote:
> > Wandering the web I notice that INRAD are offering K3 Roofers somewhat
> > less than Elecraft prices.
> >
> > Regards,
> >
> > Mike VP8NO
> > __
> > Elecraft mailing list
> > Home: http://mailman.qth.net/mailman/listinfo/elecraft
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> >
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> > Message delivered to caut...@montac.com
>
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Re: [Elecraft] Roofing Filters

[Raymond Sills]

I don't have a K3, or K3S... but if I did, I'd order from Elecraft.  After all, 
if it were not for Elecraft, Inrad would not be making them.


Paying a bit extra to Elecraft is a way to say "thank you" for their wonderful 
products, and their outstanding customer service.




73 de Ray
K2ULR
KX3 #211




-Original Message-
From: Clay Autery <caut...@montac.com>
To: elecraft <elecraft@mailman.qth.net>
Sent: Thu, Jun 22, 2017 10:26 am
Subject: Re: [Elecraft] Roofing Filters

INRAD makes Elecraft's filters as I understand it...

I'll be getting mine from Elecraft directly.

__
Clay Autery, KY5G

On 6/22/2017 8:10 AM, Mike Harris wrote:
> Wandering the web I notice that INRAD are offering K3 Roofers somewhat
> less than Elecraft prices.
>
> Regards,
>
> Mike VP8NO
> __
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Re: [Elecraft] Roofing Filters

[Clay Autery]

INRAD makes Elecraft's filters as I understand it...

I'll be getting mine from Elecraft directly.

__
Clay Autery, KY5G

On 6/22/2017 8:10 AM, Mike Harris wrote:
> Wandering the web I notice that INRAD are offering K3 Roofers somewhat
> less than Elecraft prices.
>
> Regards,
>
> Mike VP8NO
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[Elecraft] Roofing Filters

[Mike Harris]

Wandering the web I notice that INRAD are offering K3 Roofers somewhat 
less than Elecraft prices.


Regards,

Mike VP8NO
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[Elecraft] Roofing Filters

[john]

In my opinion the 250hz filter was a good option to purchase.  I have mine
switch in at 350Hz.

John KK9A


Tom nineback wrote:
Tue Mar 14 11:47:11 EDT 2017

OOPS.  I looked a the build sheet again and see that I did get the 250
filter. I don't remember ordering it but I did.  I also took off the top
cover and the filter is properly annotated.


73,
Tom - KQ5S

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Re: [Elecraft] Roofing Filters

[Tom]

OOPS.  I looked a the build sheet again and see that I did get the 250
filter. I don't remember ordering it but I did.  I also took off the top
cover and the filter is properly annotated.


73,
Tom - KQ5S

On Tue, Mar 14, 2017 at 9:33 AM, Tom  wrote:

> Is there an easy way to tell what roofing filters are installed short of
> opening up the radio.  I ordered mine from the factory with the 2.8 and 400
> filters.  When I use XFIL I see a 250 option as well.
>
> I used the K3 util program and it shows 250 as being enabled. Unless I got
> lucky and the factory installed the 250 filter by mistake then I can only
> assume that the factory turned on the 250 filter by mistake.
>
> 73,
> Tom - KQ5S
>
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[Elecraft] Roofing Filters

[Tom]

Is there an easy way to tell what roofing filters are installed short of
opening up the radio.  I ordered mine from the factory with the 2.8 and 400
filters.  When I use XFIL I see a 250 option as well.

I used the K3 util program and it shows 250 as being enabled. Unless I got
lucky and the factory installed the 250 filter by mistake then I can only
assume that the factory turned on the 250 filter by mistake.

73,
Tom - KQ5S
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[Elecraft] Roofing filters

[William Levy]

As mentioned here a few days/weeks ago Collins is no longer making their
crystal filters.

So it seems to me there will be a time that the roofing filter idea will be
another digital filter on top of the lower digital filter.

I have played with a K3 with no roofing filters, I live in a bullet proof
area with few hams, so my preferernce on CW is to go as narrow as I can if
the other guy is stable, and SSB as narrow as need be but the K3 is so
bullet proof that unless a station is on top of the other I can certainly
remove the interference by bandwidth adjustments or passband adjustments.
If the guy is on the same frequency and lower in power then the RF gain
does away with him. If he is more powerful then I simply tell him he is
interfering and he goes away or I have to go away.

I must say that the K3 is an exceptional receiver and transmit exceptional
audio that other people report to me so I can say after 54 years a ham that
I have NEVER
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[Elecraft] Roofing Filters

[Fred Jensen]

Have never experienced AGC pumping with 500 Hz filter, even in DX 
contests.  Been playing around in FD as 1D, and strong signals are 
stacked so close that, for the first time, with the DSP at 150 Hz and 
100 Hz, strong adjacent signals are activating the HW AGC.  I can 
separate the signals with the DSP which is really surprising.  I know 
about brick wall filters, now I'm using one. :-)


20 is still wide open here on the western frontier at 0245 UTC despite 
K=4 and rising from the M.8 flare a couple days ago.


73,

Fred K6DGW
- Northern California Contest Club
- CU in the 50th Running of the Cal QSO Party 3-4 Oct 2015
- www.cqp.org
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[Elecraft] roofing filters

[Robert 'RC' Conley]

I ordered a 500hz and 200hz filters for CW on K3 #8361 The 500hz does not
seem to function. The 2.7Khz works fine as does the 200hz the 500hz seems
dead any thoughts would be helpful. Yes they were installed properly
RC KC5WA

-- 

Wiol ono

Ham Radio!
IT IS MY ADDICTION
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Re: [Elecraft] roofing filters

[Ted Bryant]

Is the 500hz filter turned ON in the CONFIG menu?  Are the filter gain and
offset set properly? 

73, Ted W4NZ

-Original Message-
From: Elecraft [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of Robert
'RC' Conley
Sent: Monday, June 23, 2014 10:46 AM
To: Elecraft@mailman.qth.net
Subject: [Elecraft] roofing filters

I ordered a 500hz and 200hz filters for CW on K3 #8361 The 500hz does not
seem to function. The 2.7Khz works fine as does the 200hz the 500hz seems
dead any thoughts would be helpful. Yes they were installed properly RC
KC5WA

-- 

Wiol ono

Ham Radio!
IT IS MY ADDICTION

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Re: [Elecraft] Roofing Filters - An Empirical Test

[Rick Tavan N6XI]

You can mitigate that problem somewhat by listening to the DX on the wide
sub and the pileup with the narrow main rx. If the split is (roughly)
larger than the filter bandwidth difference, then loud, continuous callers
in the pile don't bother the DX signal, only your ability to locate the
weak caller in the strong pile. That being said, I put a narrow filter in
both receivers.

The unconventional technique of listening to the DX on the sub and the
pileup on the main has another benefit - you don't have to use SPLIT mode
which degrades keying at high speed and disables QRQ mode. It took me a
while to get used to it after decades of doing it the other way, but I
think the benefits outweigh the change in my cage.

73,

/Rick N6XI


On Mon, May 12, 2014 at 2:49 PM, Vic Rosenthal K2VCO k2vco@gmail.comwrote:

 My K3 was originally set up this way, 400 Hz in the main and 2.8 kHz in
 the sub.

 When working DX pileups with the main on the DX and the sub on the pileup,
 I definitely noticed the 'pumping' effect on the sub only. It was sometimes
 annoying when the DX was working a weak caller and the usual loud idiots
 were continuing to call.


 On 5/12/2014 12:54 PM, Dauer, Edward wrote:

 I would be interested in knowing if anyone has done an empirical test and
 observed the difference directly.  Specifically, since the sub receiver is
 identical to the main receiver in every way, if someone has a K3 with, for
 example, a 400 Hz filter in the main but only a wider set in the sub, and
 then set the DSP bandwidth on both receivers to 200 Hz or so, what
 differences they actually noticed.  I have no doubt the theory and the
 engineering are sound - just curious what the difference sounds like in
 the field . . .

 Ted, KN1CBR


 --
 73,
 Vic, K2VCO
 Fresno CA
 http://www.qsl.net/k2vco/


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-- 
Rick Tavan N6XI
Truckee, CA
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Re: [Elecraft] Roofing Filters - An Empirical Test

[Vic Rosenthal K2VCO]

Actually, I switched to this method too, mainly because of QRQ mode. And 
I got a 400 Hz filter for the main rx.


On 5/15/2014 8:27 AM, Rick Tavan N6XI wrote:

You can mitigate that problem somewhat by listening to the DX on the
wide sub and the pileup with the narrow main rx. If the split is
(roughly) larger than the filter bandwidth difference, then loud,
continuous callers in the pile don't bother the DX signal, only your
ability to locate the weak caller in the strong pile. That being said, I
put a narrow filter in both receivers.

The unconventional technique of listening to the DX on the sub and the
pileup on the main has another benefit - you don't have to use SPLIT
mode which degrades keying at high speed and disables QRQ mode. It took
me a while to get used to it after decades of doing it the other way,
but I think the benefits outweigh the change in my cage.

73,

/Rick N6XI


On Mon, May 12, 2014 at 2:49 PM, Vic Rosenthal K2VCO
k2vco@gmail.com mailto:k2vco@gmail.com wrote:

My K3 was originally set up this way, 400 Hz in the main and 2.8 kHz
in the sub.

When working DX pileups with the main on the DX and the sub on the
pileup, I definitely noticed the 'pumping' effect on the sub only.
It was sometimes annoying when the DX was working a weak caller and
the usual loud idiots were continuing to call.


--
73,
Vic, K2VCO
Fresno CA
http://www.qsl.net/k2vco/

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[Elecraft] Roofing Filters - An Empirical Test

[Dauer, Edward]

I would be interested in knowing if anyone has done an empirical test and
observed the difference directly.  Specifically, since the sub receiver is
identical to the main receiver in every way, if someone has a K3 with, for
example, a 400 Hz filter in the main but only a wider set in the sub, and
then set the DSP bandwidth on both receivers to 200 Hz or so, what
differences they actually noticed.  I have no doubt the theory and the
engineering are sound - just curious what the difference sounds like in
the field . . . 

Ted, KN1CBR




On May 12, 2014, at 9:33 AM, Jerome Sodus jso...@comcast.net wrote:

Hello Bill,
The term roofing-filter made sense back in the 1980's when I designed
roofing-filters at 70 MHz.
Bandwidths would be in tens of KHz.
The purpose then was to protect downstream circuitry by rejecting very
strong out-of-band signals that could cause overload; selectivity was not
the purpose.
Selectivity was done further downstream.
So the term has become corrupted over the years.
73 Jerry KM3K
-Original Message-
From: Elecraft [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of
Bill
Turner
Sent: Monday, May 12, 2014 1:07 AM
To: elecraft@mailman.qth.net
Subject: Re: [Elecraft] [K3] Roofing filters are misunderstood
ORIGINAL MESSAGE:  (may be snipped)
On 5/11/2014 7:25 PM, Fred Jensen wrote:
I too think roofing filters are really not well understood.
REPLY:
A large part of the misunderstanding is due to the name. Whoever chose
the name roofing did a great disservice. A better name would simply be
it's function:  1st I.F. filter.
That's what it is and that's what it does.
I have always thought that roofing was a marketing ploy to imbue it
with some kind of magical powers.
73, Bill W6WRT




--

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Re: [Elecraft] Roofing Filters - An Empirical Test

[Scott Manthe]

The January 2009 QST has a table list the IMD numbers with various 
filters. Quite informative. There's is no easy way to cut/paste the data 
into an email, unfortunately.


73,
Scott, N9AA


On 5/12/14 3:54 PM, Dauer, Edward wrote:

I would be interested in knowing if anyone has done an empirical test and
observed the difference directly.  Specifically, since the sub receiver is
identical to the main receiver in every way, if someone has a K3 with, for
example, a 400 Hz filter in the main but only a wider set in the sub, and
then set the DSP bandwidth on both receivers to 200 Hz or so, what
differences they actually noticed.  I have no doubt the theory and the
engineering are sound - just curious what the difference sounds like in
the field . . .

Ted, KN1CBR




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Re: [Elecraft] Roofing Filters - An Empirical Test

[Wayne Burdick]

It's quite simple. If you have a very strong interfering signal that falls 
inside the SSB filter passband (2.7 or 2.8 kHz), but outside an installed 
narrow filter, the hardware AGC will not get pumped.

Lacking such a filter, a strong enough signal (typically S9+20 or higher) 
*will* activate hardware AGC, which can be annoying in mild cases and 
debilitating if it's really strong, has key clicks, etc.

This is why the K3 has slots for narrow filters. On a very busy band with lots 
of strong signals, it's the difference between a usable radio or not. 

73,
Wayne
N6KR

On May 12, 2014, at 12:54 PM, Dauer, Edward eda...@law.du.edu wrote:

 I would be interested in knowing if anyone has done an empirical test and
 observed the difference directly.  Specifically, since the sub receiver is
 identical to the main receiver in every way, if someone has a K3 with, for
 example, a 400 Hz filter in the main but only a wider set in the sub, and
 then set the DSP bandwidth on both receivers to 200 Hz or so, what
 differences they actually noticed.  I have no doubt the theory and the
 engineering are sound - just curious what the difference sounds like in
 the field . . . 
 
 Ted, KN1CBR
 

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Re: [Elecraft] Roofing Filters - An Empirical Test

[Wayne Burdick]

I should have pointed out that this effect is most noticeable with CW or narrow 
data modes, where there's a large difference in bandwidth between wide and 
narrow filters. In SSB mode, a somewhat narrower filter (say 1.8 kHz) will 
provide additional margin on an active band with strong signals, but some of 
the advantage is lost due to IMD products inherent in the received voice 
signals.

Wayne


On May 12, 2014, at 1:19 PM, Wayne Burdick n...@elecraft.com wrote:

 It's quite simple. If you have a very strong interfering signal that falls 
 inside the SSB filter passband (2.7 or 2.8 kHz), but outside an installed 
 narrow filter, the hardware AGC will not get pumped.
 
 Lacking such a filter, a strong enough signal (typically S9+20 or higher) 
 *will* activate hardware AGC, which can be annoying in mild cases and 
 debilitating if it's really strong, has key clicks, etc.
 
 This is why the K3 has slots for narrow filters. On a very busy band with 
 lots of strong signals, it's the difference between a usable radio or not. 
 
 73,
 Wayne
 N6KR
 
 On May 12, 2014, at 12:54 PM, Dauer, Edward eda...@law.du.edu wrote:
 
 I would be interested in knowing if anyone has done an empirical test and
 observed the difference directly.  Specifically, since the sub receiver is
 identical to the main receiver in every way, if someone has a K3 with, for
 example, a 400 Hz filter in the main but only a wider set in the sub, and
 then set the DSP bandwidth on both receivers to 200 Hz or so, what
 differences they actually noticed.  I have no doubt the theory and the
 engineering are sound - just curious what the difference sounds like in
 the field . . . 
 
 Ted, KN1CBR
 
 
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Re: [Elecraft] Roofing Filters - An Empirical Test

[Vic Rosenthal K2VCO]

My K3 was originally set up this way, 400 Hz in the main and 2.8 kHz in 
the sub.


When working DX pileups with the main on the DX and the sub on the 
pileup, I definitely noticed the 'pumping' effect on the sub only. It 
was sometimes annoying when the DX was working a weak caller and the 
usual loud idiots were continuing to call.


On 5/12/2014 12:54 PM, Dauer, Edward wrote:

I would be interested in knowing if anyone has done an empirical test and
observed the difference directly.  Specifically, since the sub receiver is
identical to the main receiver in every way, if someone has a K3 with, for
example, a 400 Hz filter in the main but only a wider set in the sub, and
then set the DSP bandwidth on both receivers to 200 Hz or so, what
differences they actually noticed.  I have no doubt the theory and the
engineering are sound - just curious what the difference sounds like in
the field . . .

Ted, KN1CBR


--
73,
Vic, K2VCO
Fresno CA
http://www.qsl.net/k2vco/

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[Elecraft] Roofing filters

[Wayne Burdick]

David Gilbert xda...@cis-broadband.com wrote:

 Actually, a roofing filter does exactly what it says.  It protects against 
 ...  i.e.,  does not allow to pass ... out-of-passband signals from affecting 
 the ADC or hardware AGC.  It's a roof against unwanted energy and a window 
 for desired signals.  So would you prefer to call it a window?  Have at it, 
 but that doesn't alter the fact that its fundamental purpose is to protect 
 ... protect the ADC and protect the AGC so that they can perform their 
 function properly.   And it doesn't mean that anybody will recognize what 
 you're talking about, which is probably more relevant than the semantics 
 involved.


In receive I.F. applications, a crystal filter is used as a very narrow (very 
high-Q) band-pass filter. It cuts off unwanted signals above and below the 
desired passband. In a modern superhet like the K3, the crystal filter augments 
the DSP in a subsequent I.F., providing improved ultimate rejection and steeper 
skirts. 

In some implementations you can slide the I.F. associated with the crystal 
filter to the left or right of the nominal receive passband, so that the filter 
acts, in effect, like a low-pass or high-pass filter, working against the 
center frequency of later IFs. This can be useful in protecting the downstream 
I.F. on one side, but not the other. Narrow filtering takes care of both ends.

Radios that don't use hardware roofing filters of some kind typically have 
worse blocking dynamic range (BDR) than those that do. For example, the K3 has 
typical BDR of over 140 dB, 15 to 20 dB better than radios with no hardware 
filtering (i.e., pure SDRs). This is why a K3 outfitted with narrow filters 
works well for contesting, Field Day, and DXpeditions; it won't get desensed by 
either the wide- or narrow-spaced onslaught often experienced in these 
situations.

73,
Wayne
N6KR

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Re: [Elecraft] [K3] Elecraft roofing filters

[WILLIS COOKE]

I would say that you don't really need all those filters.  The DSP filter does 
all the heavy lifting except for removing the artifacts from signals that are 
inside the pass band of the roofing filter.  I have the 2.7k, 500 Hz and 250 Hz 
in my main receiver and just the 2.7K and 500 Hz in my second receiver.  I 
don't feel the need for more, but I have zero interest in FM, AM and ESSB.

Willis 'Cookie' Cooke 
K5EWJ


--- On Fri, 2/6/09, Kjeld Holm k...@kh-translation.dk wrote:

 From: Kjeld Holm k...@kh-translation.dk
 Subject: Re: [Elecraft] [K3] Elecraft roofing filters
 To: elecraft@mailman.qth.net
 Date: Friday, February 6, 2009, 12:31 AM
 Dear all,
 
 Once and again: Thanks to all for very interesting and
 informative answers.
 
 Right now my conclusion according to my planed way of
 operation is the
 following setup
 
 2 pcs KFL3A-2.8_2.7sw replacement K3 and KRX3
 2 pcs KFL3A-1.8K SSB
 2 pcs KFL3A-200 5-pole CW + matching
 2 pcs KFL3A-400 CW
 2 pcs KFL3B-FM FM
 
 For the purpose of working as many DXCC countries as
 possible including
 picking new ones during contests on crowded  bands.
 
 As I understand this configuration will not allow me to
 receive or transmit
 on AM but it will maybe allow ESSB later if the firmware
 can be modified to
 use the FM filter for ESSB. 
 
 Any further comments before my ordering will be
 appreciated.
 
 Vy 73
 OZ1CCM Kjeld
 
   
 
 -Original Message-
 From: elecraft-boun...@mailman.qth.net
 [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of
 Kjeld Holm
 Sent: 5. februar 2009 17:27
 To: elecraft@mailman.qth.net
 Subject: Re: [Elecraft] [K3] Elecraft roofing filters
 
 Dear all,
 
 Thanks for all the kind answers.
 
 Sorry for all that fuss. Somehow I mixed up everything so I
 ended up
 thinking of some nonsense like 1.0 kHz for SSB. :-o
 
 I will go for 250 Hz and 400 Hz for CW plus 2.8 kHz for
 SSB. And also
 filters for AM and FM.
 
 Vy 73
 OZ1CCM Kjeld
 
 
 
 -Original Message-
 From: W0MU Mike Fatchett [mailto:w...@w0mu.com]
 Sent: 5. februar 2009 15:28
 To: 'Kjeld Holm'
 Subject: RE: [Elecraft] [K3] Elecraft roofing filters
 
 They are available on the website.   
 
 KFL3A-1.0K  1 kHz, 8-pole roofing filter  125.95
 
 I have one in my K3 but I don't use it too much.  You
 might want to use it
 over a 250 or 500 filter to listen to a pile up so you can
 hear if the
 station is working people above or below his frequency.  I
 have listened to
 SSB a bit on the filter and while very narrow for SSB you
 can hear the
 station.
 
 The better question might be, what modes do you like to
 operate?  I am about
 to order a second K3 and I was going to go with the
 following filters.  2.8
 replacing the stock 2.7/ AM/ FM/ 400 or 500 and 250.  If
 you never play to
 transmit on AM or want to do ESSB or FM those slots would
 be available.  The
 K3 I have now has the 2.7 which is being replaced with the
 2.8/1.8/1.0/400/200 in the main rcv, 2.8/400 in the sub.
 
 Mike W0MU
 
 A slip of the foot you may soon recover, but a slip
 of the tongue you may
 never get over. Ben Franklin -Original
 Message-
 From: elecraft-boun...@mailman.qth.net
 [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of
 Kjeld Holm
 Sent: Thursday, February 05, 2009 5:44 AM
 To: 'ElecraftList'
 Subject: [Elecraft] [K3] Elecraft roofing filters
 
 Dear all,
  
 In the Roofing Filter Notes from Wayne and Eric
 link on the Order page I
 see the two sentences: Add narrower/wider filters as
 you prefer. I like to
 use the 1.0 kHz crystal filter when tuning a crowded band
 or listening to a
 pile up.
  
 Can anyone point me to a place that can tell me what
 the 1.0 kHz crystal
 filter is, where to obtain one and when it is worth
 using?
  
 Vy 73
 OZ1CCM Kjeld 
 
 
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Re: [Elecraft] [K3] Elecraft roofing filters

[Kjeld Holm]

Dear all,

Once and again: Thanks to all for very interesting and informative answers.

Right now my conclusion according to my planed way of operation is the
following setup

2 pcs KFL3A-2.8_2.7sw replacement K3 and KRX3
2 pcs KFL3A-1.8K SSB
2 pcs KFL3A-200 5-pole CW + matching
2 pcs KFL3A-400 CW
2 pcs KFL3B-FM FM

For the purpose of working as many DXCC countries as possible including
picking new ones during contests on crowded  bands.

As I understand this configuration will not allow me to receive or transmit
on AM but it will maybe allow ESSB later if the firmware can be modified to
use the FM filter for ESSB. 

Any further comments before my ordering will be appreciated.

Vy 73
OZ1CCM Kjeld

  

-Original Message-
From: elecraft-boun...@mailman.qth.net
[mailto:elecraft-boun...@mailman.qth.net] On Behalf Of Kjeld Holm
Sent: 5. februar 2009 17:27
To: elecraft@mailman.qth.net
Subject: Re: [Elecraft] [K3] Elecraft roofing filters

Dear all,

Thanks for all the kind answers.

Sorry for all that fuss. Somehow I mixed up everything so I ended up
thinking of some nonsense like 1.0 kHz for SSB. :-o

I will go for 250 Hz and 400 Hz for CW plus 2.8 kHz for SSB. And also
filters for AM and FM.

Vy 73
OZ1CCM Kjeld



-Original Message-
From: W0MU Mike Fatchett [mailto:w...@w0mu.com]
Sent: 5. februar 2009 15:28
To: 'Kjeld Holm'
Subject: RE: [Elecraft] [K3] Elecraft roofing filters

They are available on the website.   

KFL3A-1.0K  1 kHz, 8-pole roofing filter125.95

I have one in my K3 but I don't use it too much.  You might want to use it
over a 250 or 500 filter to listen to a pile up so you can hear if the
station is working people above or below his frequency.  I have listened to
SSB a bit on the filter and while very narrow for SSB you can hear the
station.

The better question might be, what modes do you like to operate?  I am about
to order a second K3 and I was going to go with the following filters.  2.8
replacing the stock 2.7/ AM/ FM/ 400 or 500 and 250.  If you never play to
transmit on AM or want to do ESSB or FM those slots would be available.  The
K3 I have now has the 2.7 which is being replaced with the
2.8/1.8/1.0/400/200 in the main rcv, 2.8/400 in the sub.

Mike W0MU

A slip of the foot you may soon recover, but a slip of the tongue you may
never get over. Ben Franklin -Original Message-
From: elecraft-boun...@mailman.qth.net
[mailto:elecraft-boun...@mailman.qth.net] On Behalf Of Kjeld Holm
Sent: Thursday, February 05, 2009 5:44 AM
To: 'ElecraftList'
Subject: [Elecraft] [K3] Elecraft roofing filters

Dear all,
 
In the Roofing Filter Notes from Wayne and Eric link on the Order page I
see the two sentences: Add narrower/wider filters as you prefer. I like to
use the 1.0 kHz crystal filter when tuning a crowded band or listening to a
pile up.
 
Can anyone point me to a place that can tell me what the 1.0 kHz crystal
filter is, where to obtain one and when it is worth using?
 
Vy 73
OZ1CCM Kjeld 


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Re: [Elecraft] [K3] Elecraft roofing filters

[Robert Naumann]

This filter mystery seems to be a common exercise for purchasers of a K3.

Having just gone through this myself, reading all of the data available, and
consulting with K3 owners for their experiences, I settled on the following
assortment of filters for my new K3:

KFL3A-6K   6.0  kHz   8 pole
KFL3A-2.7K 2.7  kHz   5 pole (standard)
KFL3A-500500 Hz   5 pole 
KFL3A-200200 Hz   5 pole

I am extremely pleased with the performance with these filters and along
with the DSP, even the bedlam that was going on in the recent CQWW 160
contest was easy to listen to and to sort out weak signals among the very
strong. I cannot say enough about how pleased I am with the performance. My
only wish is that I could be heard as well as I now hear!

If I was to add anything, it might be the 1 kHz filter to fill in the wide
gap between the 2.7k and 500 Hz filters but this is a personal suspicion
rather than a scientific determination. 

73,

Bob W5OV

-Original Message-
From: elecraft-boun...@mailman.qth.net
[mailto:elecraft-boun...@mailman.qth.net] On Behalf Of Kjeld Holm
Sent: Friday, February 06, 2009 2:32 AM
To: elecraft@mailman.qth.net
Subject: Re: [Elecraft] [K3] Elecraft roofing filters

Dear all,

Once and again: Thanks to all for very interesting and informative answers.

Right now my conclusion according to my planed way of operation is the
following setup

2 pcs KFL3A-2.8_2.7sw replacement K3 and KRX3
2 pcs KFL3A-1.8K SSB
2 pcs KFL3A-200 5-pole CW + matching
2 pcs KFL3A-400 CW
2 pcs KFL3B-FM FM

For the purpose of working as many DXCC countries as possible including
picking new ones during contests on crowded  bands.

As I understand this configuration will not allow me to receive or transmit
on AM but it will maybe allow ESSB later if the firmware can be modified to
use the FM filter for ESSB. 

Any further comments before my ordering will be appreciated.

Vy 73
OZ1CCM Kjeld

  

-Original Message-
From: elecraft-boun...@mailman.qth.net
[mailto:elecraft-boun...@mailman.qth.net] On Behalf Of Kjeld Holm
Sent: 5. februar 2009 17:27
To: elecraft@mailman.qth.net
Subject: Re: [Elecraft] [K3] Elecraft roofing filters

Dear all,

Thanks for all the kind answers.

Sorry for all that fuss. Somehow I mixed up everything so I ended up
thinking of some nonsense like 1.0 kHz for SSB. :-o

I will go for 250 Hz and 400 Hz for CW plus 2.8 kHz for SSB. And also
filters for AM and FM.

Vy 73
OZ1CCM Kjeld



-Original Message-
From: W0MU Mike Fatchett [mailto:w...@w0mu.com]
Sent: 5. februar 2009 15:28
To: 'Kjeld Holm'
Subject: RE: [Elecraft] [K3] Elecraft roofing filters

They are available on the website.   

KFL3A-1.0K  1 kHz, 8-pole roofing filter125.95

I have one in my K3 but I don't use it too much.  You might want to use it
over a 250 or 500 filter to listen to a pile up so you can hear if the
station is working people above or below his frequency.  I have listened to
SSB a bit on the filter and while very narrow for SSB you can hear the
station.

The better question might be, what modes do you like to operate?  I am about
to order a second K3 and I was going to go with the following filters.  2.8
replacing the stock 2.7/ AM/ FM/ 400 or 500 and 250.  If you never play to
transmit on AM or want to do ESSB or FM those slots would be available.  The
K3 I have now has the 2.7 which is being replaced with the
2.8/1.8/1.0/400/200 in the main rcv, 2.8/400 in the sub.

Mike W0MU

A slip of the foot you may soon recover, but a slip of the tongue you may
never get over. Ben Franklin -Original Message-
From: elecraft-boun...@mailman.qth.net
[mailto:elecraft-boun...@mailman.qth.net] On Behalf Of Kjeld Holm
Sent: Thursday, February 05, 2009 5:44 AM
To: 'ElecraftList'
Subject: [Elecraft] [K3] Elecraft roofing filters

Dear all,
 
In the Roofing Filter Notes from Wayne and Eric link on the Order page I
see the two sentences: Add narrower/wider filters as you prefer. I like to
use the 1.0 kHz crystal filter when tuning a crowded band or listening to a
pile up.
 
Can anyone point me to a place that can tell me what the 1.0 kHz crystal
filter is, where to obtain one and when it is worth using?
 
Vy 73
OZ1CCM Kjeld 


__
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Help: http://mailman.qth.net/mmfaq.htm
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Re: [Elecraft] [K3] Elecraft roofing filters

[ni0c]

Quoted discussion from K2AV and W4TV:

 
 
  Anyone who asks us what filters to buy for CW contesting, we 
  tell them 400/250 8 pole set to 450/350.  Tried and true, not 
  theory. 
  
  W4TV and I will just have to agree to disagree. 
 
 I don't think there is any disagreement ... unless you have 
 actually tried a 400/200 pair set to 450/250 and are trying 
 to say that the 250 Hz filter is tighter and suffers fewer 
 hardware AGC effects than the 200 Hz filter.  If you try to 
 make that point, there are several others including W4ZV, 
 who will disagree with you. 
 
 73, 
 
... Joe, W4TV 
  


The data I measured for the -30 dB down BW's of my 200
and 250 Hz filters supports what Joe says: 430 Hz  for the
200 Hz 5-pole versus 500 Hz for the 250 Hz 8-pole.

As a nearly 100% CW operator, I do like having three 
CW roofing filters in my rig.  Matching DSP cutoff points
to the various filters is another variable to play with, and
thanks to Guy for the suggestions there.  

I do think there is a bit of a truth in labeling issue with 
regard to narrow crystal filters that needs to be addressed
by the manufacturers.  Not everybody will remember, for
instance, that a 250 Hz filter may really have a bandwidth
of 375 Hz.  I recall a similar issue with a 125 Hz filter that
I purchased for my TS-850S some years back.  The filter
curve supplied by the manufacturer showed it was actually 
considerably wider than that (more than 200 Hz, as I recall).

I can understand the difficulty in manufacturing very high Q
multiple pole crystal filters, and that there might have been a 
design goal in mind that wasn't met.  However, once we know
that the design goal wasn't met, shouldn't we revise our labelling
to more accurately reflect real world results?   

73,
Chuck Guenther  NI0C
K2/10  s/n 5853
K3/100 s/n 1061   
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Re: [Elecraft] [K3] Elecraft roofing filters

[Joe Subich, W4TV]

 Right now my conclusion according to my planed way of 
 operation is the following setup
 
 2 pcs KFL3A-2.8_2.7sw replacement K3 and KRX3
 2 pcs KFL3A-1.8K SSB
 2 pcs KFL3A-200 5-pole CW + matching
 2 pcs KFL3A-400 CW
 2 pcs KFL3B-FM FM

Having done the 2 x KFL3A-2.8_2.7sw replacement, I am not 
convinced that there is enough (any) performance gain to  
justify the significant cost.  As others have commented, 
you probably don't need the extra FM, 1.8K and 200 Hz 
filters in the subreceiver.  However, with the soon to be 
released independent band operation, the FM filter might be 
worthwhile to permit SWL or other general purpose listening. 

 As I understand this configuration will not allow me to 
 receive or transmit on AM but it will maybe allow ESSB later 
 if the firmware can be modified to use the FM filter for ESSB. 

The FM filter will allow you to receive AM but not transmit 
at the present time.  With the concern for transmit image 
rejection when using the FM filter in AM or ESSB, there is 
no reason that the filter could not be offset to place the 
image well down the skirt when transmitting if the skirts 
are marginal with the signal centered. 

73, 

   ... Joe, W4TV 
 


 -Original Message-
 From: elecraft-boun...@mailman.qth.net 
 [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of Kjeld Holm
 Sent: Friday, February 06, 2009 3:32 AM
 To: elecraft@mailman.qth.net
 Subject: Re: [Elecraft] [K3] Elecraft roofing filters
 
 
 Dear all,
 
 Once and again: Thanks to all for very interesting and 
 informative answers.
 
 Right now my conclusion according to my planed way of 
 operation is the following setup
 
 2 pcs KFL3A-2.8_2.7sw replacement K3 and KRX3
 2 pcs KFL3A-1.8K SSB
 2 pcs KFL3A-200 5-pole CW + matching
 2 pcs KFL3A-400 CW
 2 pcs KFL3B-FM FM
 
 For the purpose of working as many DXCC countries as possible 
 including picking new ones during contests on crowded  bands.
 
 As I understand this configuration will not allow me to 
 receive or transmit on AM but it will maybe allow ESSB later 
 if the firmware can be modified to use the FM filter for ESSB. 
 
 Any further comments before my ordering will be appreciated.
 
 Vy 73
 OZ1CCM Kjeld
 
   
 
 -Original Message-
 From: elecraft-boun...@mailman.qth.net 
 [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of Kjeld Holm
 Sent: 5. februar 2009 17:27
 To: elecraft@mailman.qth.net
 Subject: Re: [Elecraft] [K3] Elecraft roofing filters
 
 Dear all,
 
 Thanks for all the kind answers.
 
 Sorry for all that fuss. Somehow I mixed up everything so I 
 ended up thinking of some nonsense like 1.0 kHz for SSB. :-o
 
 I will go for 250 Hz and 400 Hz for CW plus 2.8 kHz for SSB. 
 And also filters for AM and FM.
 
 Vy 73
 OZ1CCM Kjeld
 
 
 
 -Original Message-
 From: W0MU Mike Fatchett [mailto:w...@w0mu.com]
 Sent: 5. februar 2009 15:28
 To: 'Kjeld Holm'
 Subject: RE: [Elecraft] [K3] Elecraft roofing filters
 
 They are available on the website.   
 
 KFL3A-1.0K  1 kHz, 8-pole roofing filter  125.95
 
 I have one in my K3 but I don't use it too much.  You might 
 want to use it over a 250 or 500 filter to listen to a pile 
 up so you can hear if the station is working people above or 
 below his frequency.  I have listened to SSB a bit on the 
 filter and while very narrow for SSB you can hear the station.
 
 The better question might be, what modes do you like to 
 operate?  I am about to order a second K3 and I was going to 
 go with the following filters.  2.8 replacing the stock 2.7/ 
 AM/ FM/ 400 or 500 and 250.  If you never play to transmit on 
 AM or want to do ESSB or FM those slots would be available.  
 The K3 I have now has the 2.7 which is being replaced with 
 the 2.8/1.8/1.0/400/200 in the main rcv, 2.8/400 in the sub.
 
 Mike W0MU
 
 A slip of the foot you may soon recover, but a slip of the 
 tongue you may never get over. Ben Franklin -Original 
 Message-
 From: elecraft-boun...@mailman.qth.net 
 [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of Kjeld Holm
 Sent: Thursday, February 05, 2009 5:44 AM
 To: 'ElecraftList'
 Subject: [Elecraft] [K3] Elecraft roofing filters
 
 Dear all,
  
 In the Roofing Filter Notes from Wayne and Eric link on the 
 Order page I see the two sentences: Add narrower/wider 
 filters as you prefer. I like to use the 1.0 kHz crystal 
 filter when tuning a crowded band or listening to a pile up.
  
 Can anyone point me to a place that can tell me what the 1.0 
 kHz crystal filter is, where to obtain one and when it is 
 worth using?
  
 Vy 73
 OZ1CCM Kjeld 
 
 
 __
 Elecraft mailing list
 Home: http://mailman.qth.net/mailman/listinfo/elecraft
 Help: http://mailman.qth.net/mmfaq.htm
 Post: mailto:Elecraft@mailman.qth.net
 
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Re: [Elecraft] [K3] Elecraft roofing filters

[W0MU Mike Fatchett]

Does he really need two FM filters?   

If you want to do diversity receive make sure you ask for matching filters.

I don't know if you really need all those filters in the sub receiver.  I
would assume most of your main operating would be off the main receiver.  

Mike W0MU

A slip of the foot you may soon recover, but a slip of the tongue you may
never get over. Ben Franklin
-Original Message-
From: elecraft-boun...@mailman.qth.net
[mailto:elecraft-boun...@mailman.qth.net] On Behalf Of Kjeld Holm
Sent: Friday, February 06, 2009 1:32 AM
To: elecraft@mailman.qth.net
Subject: Re: [Elecraft] [K3] Elecraft roofing filters

Dear all,

Once and again: Thanks to all for very interesting and informative answers.

Right now my conclusion according to my planed way of operation is the
following setup

2 pcs KFL3A-2.8_2.7sw replacement K3 and KRX3
2 pcs KFL3A-1.8K SSB
2 pcs KFL3A-200 5-pole CW + matching
2 pcs KFL3A-400 CW
2 pcs KFL3B-FM FM

For the purpose of working as many DXCC countries as possible including
picking new ones during contests on crowded  bands.

As I understand this configuration will not allow me to receive or transmit
on AM but it will maybe allow ESSB later if the firmware can be modified to
use the FM filter for ESSB. 

Any further comments before my ordering will be appreciated.

Vy 73
OZ1CCM Kjeld

  

-Original Message-
From: elecraft-boun...@mailman.qth.net
[mailto:elecraft-boun...@mailman.qth.net] On Behalf Of Kjeld Holm
Sent: 5. februar 2009 17:27
To: elecraft@mailman.qth.net
Subject: Re: [Elecraft] [K3] Elecraft roofing filters

Dear all,

Thanks for all the kind answers.

Sorry for all that fuss. Somehow I mixed up everything so I ended up
thinking of some nonsense like 1.0 kHz for SSB. :-o

I will go for 250 Hz and 400 Hz for CW plus 2.8 kHz for SSB. And also
filters for AM and FM.

Vy 73
OZ1CCM Kjeld



-Original Message-
From: W0MU Mike Fatchett [mailto:w...@w0mu.com]
Sent: 5. februar 2009 15:28
To: 'Kjeld Holm'
Subject: RE: [Elecraft] [K3] Elecraft roofing filters

They are available on the website.   

KFL3A-1.0K  1 kHz, 8-pole roofing filter125.95

I have one in my K3 but I don't use it too much.  You might want to use it
over a 250 or 500 filter to listen to a pile up so you can hear if the
station is working people above or below his frequency.  I have listened to
SSB a bit on the filter and while very narrow for SSB you can hear the
station.

The better question might be, what modes do you like to operate?  I am about
to order a second K3 and I was going to go with the following filters.  2.8
replacing the stock 2.7/ AM/ FM/ 400 or 500 and 250.  If you never play to
transmit on AM or want to do ESSB or FM those slots would be available.  The
K3 I have now has the 2.7 which is being replaced with the
2.8/1.8/1.0/400/200 in the main rcv, 2.8/400 in the sub.

Mike W0MU

A slip of the foot you may soon recover, but a slip of the tongue you may
never get over. Ben Franklin -Original Message-
From: elecraft-boun...@mailman.qth.net
[mailto:elecraft-boun...@mailman.qth.net] On Behalf Of Kjeld Holm
Sent: Thursday, February 05, 2009 5:44 AM
To: 'ElecraftList'
Subject: [Elecraft] [K3] Elecraft roofing filters

Dear all,
 
In the Roofing Filter Notes from Wayne and Eric link on the Order page I
see the two sentences: Add narrower/wider filters as you prefer. I like to
use the 1.0 kHz crystal filter when tuning a crowded band or listening to a
pile up.
 
Can anyone point me to a place that can tell me what the 1.0 kHz crystal
filter is, where to obtain one and when it is worth using?
 
Vy 73
OZ1CCM Kjeld 


__
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Re: [Elecraft] [K3] Elecraft roofing filters

[Dave G4AON]

Kleld there has been some debate over the use of FM bandwidth filtering
to transmit AM (or ESSB), I don't have an FM filter so cannot give a
measurement for the bandwidth that may result from transmitting AM or
ESSB through the filter. Using the 6 KHz AM filter gives a nice tight
transmission on AM with a bandwidth of approximately +/- 3KHz down to
many dB's below peak. ESSB through the 6 KHz filter is also nice and
tight. There are some excessively wide AM transmissions here in the UK
on AM, several have been measured at +/- 10 KHz or more, these are
usually older, or home built, transmitters rather than recent commercial
units. AM can use excessive bandwidth so I would hope K3 users would set
a good example and keep their transmissions within reasonable limits.

Bottom line, if you want to transmit AM or ESSB consider using the 6 KHz
rather than the 13 KHz filter unless you can be sure your bandwidth
isn't excessive with one.

73 Dave, G4AON
K3/100 #80


SNIP
2 pcs KFL3A-2.8_2.7sw replacement K3 and KRX3
2 pcs KFL3A-1.8K SSB
2 pcs KFL3A-200 5-pole CW + matching
2 pcs KFL3A-400 CW
2 pcs KFL3B-FM FM

For the purpose of working as many DXCC countries as possible including
picking new ones during contests on crowded bands.

As I understand this configuration will not allow me to receive or transmit
on AM but it will maybe allow ESSB later if the firmware can be modified to
use the FM filter for ESSB.

Any further comments before my ordering will be appreciated.

Vy 73
OZ1CCM Kjeld
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Re: [Elecraft] [K3] Elecraft roofing filters

[Robert Naumann]

On the K3 order page you will find:

 

KFL3A-1.0K  1 kHz, 8-pole roofing filter 

 

 

 

  _  

From: elecraft-boun...@mailman.qth.net
[mailto:elecraft-boun...@mailman.qth.net] On Behalf Of Kjeld Holm
Sent: Thursday, February 05, 2009 6:44 AM
To: 'ElecraftList'
Subject: [Elecraft] [K3] Elecraft roofing filters

 

Dear all,

 

In the Roofing Filter Notes from Wayne and Eric link on the Order page I
see the two sentences: Add narrower/wider filters as you prefer. I like to
use the 1.0 kHz crystal filter when tuning a crowded band or listening to a
pile up.

 

Can anyone point me to a place that can tell me what the 1.0 kHz crystal
filter is, where to obtain one and when it is worth using?

 

Vy 73 
OZ1CCM Kjeld 

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[Elecraft] [K3] Elecraft roofing filters

[Kjeld Holm]

Dear all,
 
In the Roofing Filter Notes from Wayne and Eric link on the Order page I
see the two sentences: Add narrower/wider filters as you prefer. I like to
use the 1.0 kHz crystal filter when tuning a crowded band or listening to a
pile up.
 
Can anyone point me to a place that can tell me what the 1.0 kHz crystal
filter is, where to obtain one and when it is worth using?
 
Vy 73 
OZ1CCM Kjeld 

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Re: [Elecraft] [K3] Elecraft roofing filters

[Kjeld Holm]

Dear all,

Thanks for all the kind answers.

Sorry for all that fuss. Somehow I mixed up everything so I ended up
thinking of some nonsense like 1.0 kHz for SSB. :-o

I will go for 250 Hz and 400 Hz for CW plus 2.8 kHz for SSB. And also
filters for AM and FM.

Vy 73
OZ1CCM Kjeld



-Original Message-
From: W0MU Mike Fatchett [mailto:w...@w0mu.com] 
Sent: 5. februar 2009 15:28
To: 'Kjeld Holm'
Subject: RE: [Elecraft] [K3] Elecraft roofing filters

They are available on the website.   

KFL3A-1.0K  1 kHz, 8-pole roofing filter125.95

I have one in my K3 but I don't use it too much.  You might want to use it
over a 250 or 500 filter to listen to a pile up so you can hear if the
station is working people above or below his frequency.  I have listened to
SSB a bit on the filter and while very narrow for SSB you can hear the
station.

The better question might be, what modes do you like to operate?  I am about
to order a second K3 and I was going to go with the following filters.  2.8
replacing the stock 2.7/ AM/ FM/ 400 or 500 and 250.  If you never play to
transmit on AM or want to do ESSB or FM those slots would be available.  The
K3 I have now has the 2.7 which is being replaced with the
2.8/1.8/1.0/400/200 in the main rcv, 2.8/400 in the sub.

Mike W0MU

A slip of the foot you may soon recover, but a slip of the tongue you may
never get over. Ben Franklin -Original Message-
From: elecraft-boun...@mailman.qth.net
[mailto:elecraft-boun...@mailman.qth.net] On Behalf Of Kjeld Holm
Sent: Thursday, February 05, 2009 5:44 AM
To: 'ElecraftList'
Subject: [Elecraft] [K3] Elecraft roofing filters

Dear all,
 
In the Roofing Filter Notes from Wayne and Eric link on the Order page I
see the two sentences: Add narrower/wider filters as you prefer. I like to
use the 1.0 kHz crystal filter when tuning a crowded band or listening to a
pile up.
 
Can anyone point me to a place that can tell me what the 1.0 kHz crystal
filter is, where to obtain one and when it is worth using?
 
Vy 73
OZ1CCM Kjeld 


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Re: [Elecraft] [K3] Elecraft roofing filters

[k4gm]

I have the 400 and don't see the need for 250
--Original Message--
From: Kjeld Holm
Sender: elecraft-boun...@mailman.qth.net
To: elecraft@mailman.qth.net
Subject: Re: [Elecraft] [K3] Elecraft roofing filters
Sent: Feb 5, 2009 11:27 AM

Dear all,

Thanks for all the kind answers.

Sorry for all that fuss. Somehow I mixed up everything so I ended up
thinking of some nonsense like 1.0 kHz for SSB. :-o

I will go for 250 Hz and 400 Hz for CW plus 2.8 kHz for SSB. And also
filters for AM and FM.

Vy 73
OZ1CCM Kjeld



-Original Message-
From: W0MU Mike Fatchett [mailto:w...@w0mu.com] 
Sent: 5. februar 2009 15:28
To: 'Kjeld Holm'
Subject: RE: [Elecraft] [K3] Elecraft roofing filters

They are available on the website.   

KFL3A-1.0K  1 kHz, 8-pole roofing filter125.95

I have one in my K3 but I don't use it too much.  You might want to use it
over a 250 or 500 filter to listen to a pile up so you can hear if the
station is working people above or below his frequency.  I have listened to
SSB a bit on the filter and while very narrow for SSB you can hear the
station.

The better question might be, what modes do you like to operate?  I am about
to order a second K3 and I was going to go with the following filters.  2.8
replacing the stock 2.7/ AM/ FM/ 400 or 500 and 250.  If you never play to
transmit on AM or want to do ESSB or FM those slots would be available.  The
K3 I have now has the 2.7 which is being replaced with the
2.8/1.8/1.0/400/200 in the main rcv, 2.8/400 in the sub.

Mike W0MU

A slip of the foot you may soon recover, but a slip of the tongue you may
never get over. Ben Franklin -Original Message-
From: elecraft-boun...@mailman.qth.net
[mailto:elecraft-boun...@mailman.qth.net] On Behalf Of Kjeld Holm
Sent: Thursday, February 05, 2009 5:44 AM
To: 'ElecraftList'
Subject: [Elecraft] [K3] Elecraft roofing filters

Dear all,
 
In the Roofing Filter Notes from Wayne and Eric link on the Order page I
see the two sentences: Add narrower/wider filters as you prefer. I like to
use the 1.0 kHz crystal filter when tuning a crowded band or listening to a
pile up.
 
Can anyone point me to a place that can tell me what the 1.0 kHz crystal
filter is, where to obtain one and when it is worth using?
 
Vy 73
OZ1CCM Kjeld 


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Sent from my Verizon Wireless BlackBerry
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Re: [Elecraft] [K3] Elecraft roofing filters

[David Ferrington, M0XDF]

I agree with that, but the 1.8kHz sure helps in SSB Contests
73 de M0XDF, K3 #174
-- 
Mathematics is the language with which God has written the universe.
-Galileo Galilei, physicist and astronomer (1564-1642)

On 5 Feb 2009, at 16:53, k...@verizon.net wrote:

 I have the 400 and don't see the need for 250
 --Original Message--
 From: Kjeld Holm
 Sender: elecraft-boun...@mailman.qth.net
 To: elecraft@mailman.qth.net
 Subject: Re: [Elecraft] [K3] Elecraft roofing filters
 Sent: Feb 5, 2009 11:27 AM

 Dear all,

 Thanks for all the kind answers.

 Sorry for all that fuss. Somehow I mixed up everything so I ended up
 thinking of some nonsense like 1.0 kHz for SSB. :-o

 I will go for 250 Hz and 400 Hz for CW plus 2.8 kHz for SSB. And also
 filters for AM and FM.

 Vy 73
 OZ1CCM Kjeld

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Re: [Elecraft] [K3] Elecraft roofing filters

[Doug Faunt N6TQS +1-510-655-8604]

The 250Hz and 400Hz filters are very similar, in reality.  Having both
is redundant.  But having a 1.8kHz or 2.1kHz for SSB RX is a good
thing for contesting.  Note that some people have used a custom 1.5kHz
roofing filter with good success for SSB contesting.

This is all from a little experience, and listening to people with
LOTS of experince and knowledge.
73, doug

   From: David Ferrington, M0XDF m0...@alphadene.co.uk
   Date: Thu, 5 Feb 2009 17:46:52 +

   I agree with that, but the 1.8kHz sure helps in SSB Contests
   73 de M0XDF, K3 #174
   -- 
   Mathematics is the language with which God has written the universe.
   -Galileo Galilei, physicist and astronomer (1564-1642)

   On 5 Feb 2009, at 16:53, k...@verizon.net wrote:

I have the 400 and don't see the need for 250
--Original Message--
From: Kjeld Holm
Sender: elecraft-boun...@mailman.qth.net
To: elecraft@mailman.qth.net
Subject: Re: [Elecraft] [K3] Elecraft roofing filters
Sent: Feb 5, 2009 11:27 AM
   
Dear all,
   
Thanks for all the kind answers.
   
Sorry for all that fuss. Somehow I mixed up everything so I ended up
thinking of some nonsense like 1.0 kHz for SSB. :-o
   
I will go for 250 Hz and 400 Hz for CW plus 2.8 kHz for SSB. And also
filters for AM and FM.
   
Vy 73
OZ1CCM Kjeld

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Re: [Elecraft] [K3] Elecraft roofing filters

[Joe Subich, W4TV]

 I will go for 250 Hz and 400 Hz for CW plus 2.8 kHz for SSB. 
 And also filters for AM and FM.

The difference between the 250 and 400 Hz filters is not 
enough to be worthwhile (approximately 375 Hz vs. 430 Hz). 
If you want a narrow filter get the Elecraft 200 Hz 5-pole 
unit. 

In addition, you should not need both the FM and AM filters 
if the firmware was fixed to allow the use of the FM filter 
for ESSB and AM transmit.  If you plan to use the AM filter
only for receiving, that is even more reason to bypass the 
AM roofer and leave a space for the 1.5 or 1.8 KHz SSB filter. 

73, 

   ... Joe, W4TV 
  


 --Original Message--
 From: Kjeld Holm
 Sender: elecraft-boun...@mailman.qth.net
 To: elecraft@mailman.qth.net
 Subject: Re: [Elecraft] [K3] Elecraft roofing filters
 Sent: Feb 5, 2009 11:27 AM
 
 Dear all,
 
 Thanks for all the kind answers.
 
 Sorry for all that fuss. Somehow I mixed up everything so I 
 ended up thinking of some nonsense like 1.0 kHz for SSB. :-o
 
 I will go for 250 Hz and 400 Hz for CW plus 2.8 kHz for SSB. 
 And also filters for AM and FM.
 
 Vy 73
 OZ1CCM Kjeld
 



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Re: [Elecraft] [K3] Elecraft roofing filters

[Andreas Junge]

 The 250Hz and 400Hz filters are very similar, in reality.  Having both
 is redundant.  But having a 1.8kHz or 2.1kHz for SSB RX is a good
 thing for contesting.  Note that some people have used a custom 1.5kHz
 roofing filter with good success for SSB contesting.
 

I have to agree with Doug on this, get either one, but not both. I have both
the 400Hz and 250Hz and I saw little difference between them. When I
installed my KRX3 I took the 400hz filter out of the main receiver and moved
it over to the 2nd receiver. I am happy the way it works now. So, that's
2.7Khz and 250Hz for the main receiver and 2.7Khz and 400Hz for the sub.
Diversity receive still works fine. YMMV.

Andreas, N6NU


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[Elecraft] [K3] Elecraft roofing filters

[ni0c]

W4TV wrote:
The difference between the 250 and 400 Hz filters is not 
enough to be worthwhile (approximately 375 Hz vs. 430 Hz). 

Joe, what is your source for these numbers?  I've seen numbers 
like this mentioned previously on the reflector.

I recently tested my K3 CW roofing filters using the XG-2 generator 
at 7040 KHz (50 microvolts input) and KS7D's nice software package, 
K3 Filter Tools.  

Here's what I came up with, with AGC off and with the DSP 
bandwidth set at least as wide as 900 Hz for all tests (to isolate 
the effects of just the crystal roofing filter):

200 Hz, 5-pole: -6 dB BW = 210 Hz; -30 dB BW = 430 Hz

250 Hz, 8-pole: -6 dB BW = 260 Hz; -30 dB BW = 500 Hz

400 Hz, 8-pole: -6 dB BW = 380 Hz; -30 dB BW = 580 Hz

Note the uncertainty in each of the bandwidths above is 
plus or minus 20 Hz, because I ran these sweeps in 10 Hz 
increments to save time. (I'll repeat these tests using a 
1 or 2 Hz increment, when I have some spare time.) 

These tests on my filters (as well as my experience by ear) 
indicate there is an appreciable difference in the 250 and 
400 Hz 8-pole filters.  I've always wondered, too, about 
manufacturing tolerances on narrow crystal filters.  

73, 
Chuck Guenther  NI0C


   

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Re: [Elecraft] [K3] Elecraft roofing filters

[Joe Subich, W4TV]

 The difference between the 250 and 400 Hz filters is not 
 enough to be worthwhile (approximately 375 Hz vs. 430 Hz). 
 
 Joe, what is your source for these numbers?  I've seen numbers 
 like this mentioned previously on the reflector.

My source is Elecraft: www.elecraft.com/K3/K3_8_pole_plots.htm

Look specifically at the last two plots which show: 

   KFL3A-400  KFL3A-250 
  -6 dB  435 Hz 370 Hz 
 -60 dB  935 Hz 785 Hz 
   SF2.15:1 2.12:1  

INRAD do not publish the curves for the Elecraft (or Yaesu 
8215 KHz) 250 Hz filter.  However, they do show the curve 
for the 8830 KHz (Kenwood) version of the same filter and 
it shows a similar percentage bandwidth (367.5/845 Hz at 
-6/60dB). 

 Here's what I came up with, with AGC off and with the DSP 
 bandwidth set at least as wide as 900 Hz for all tests (to 
 isolate the effects of just the crystal roofing filter):
 
 200 Hz, 5-pole: -6 dB BW = 210 Hz; -30 dB BW = 430 Hz
 
 250 Hz, 8-pole: -6 dB BW = 260 Hz; -30 dB BW = 500 Hz
 
 400 Hz, 8-pole: -6 dB BW = 380 Hz; -30 dB BW = 580 Hz

Did you run those tests in a Data mode or with the CW pitch 
set to 800 Hz?  If not, the low frequency skirts will be 
sharpened significantly and the measured bandwidth will 
less than the roofing filter.  With a CW pitch of 560 Hz 
I measure 10% less bandwidth than in DATA (CF = 1500 Hz or 
2210 Hz).  If I reduce the pitch to 300 Hz, the measured 
bandwidth is further reduced (due to the DSP filter's low 
frequency cut-off). 

73, 

   ... Joe, W4TV 
 


 -Original Message-
 From: elecraft-boun...@mailman.qth.net 
 [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of ni0c
 Sent: Thursday, February 05, 2009 3:47 PM
 To: elecraft@mailman.qth.net
 Subject: [Elecraft] [K3] Elecraft roofing filters
 
 
 W4TV wrote:
 The difference between the 250 and 400 Hz filters is not 
 enough to be worthwhile (approximately 375 Hz vs. 430 Hz). 
 
 Joe, what is your source for these numbers?  I've seen numbers 
 like this mentioned previously on the reflector.
 
 I recently tested my K3 CW roofing filters using the XG-2 generator 
 at 7040 KHz (50 microvolts input) and KS7D's nice software package, 
 K3 Filter Tools.  
 
 Here's what I came up with, with AGC off and with the DSP 
 bandwidth set at least as wide as 900 Hz for all tests (to isolate 
 the effects of just the crystal roofing filter):
 
 200 Hz, 5-pole: -6 dB BW = 210 Hz; -30 dB BW = 430 Hz
 
 250 Hz, 8-pole: -6 dB BW = 260 Hz; -30 dB BW = 500 Hz
 
 400 Hz, 8-pole: -6 dB BW = 380 Hz; -30 dB BW = 580 Hz
 
 Note the uncertainty in each of the bandwidths above is 
 plus or minus 20 Hz, because I ran these sweeps in 10 Hz 
 increments to save time. (I'll repeat these tests using a 
 1 or 2 Hz increment, when I have some spare time.) 
 
 These tests on my filters (as well as my experience by ear) 
 indicate there is an appreciable difference in the 250 and 
 400 Hz 8-pole filters.  I've always wondered, too, about 
 manufacturing tolerances on narrow crystal filters.  
 
 73, 
 Chuck Guenther  NI0C
 
 

 

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Re: [Elecraft] [K3] Elecraft roofing filters

[ni0c]

W4TV wrote: 


 My source is Elecraft: www.elecraft.com/K3/K3_8_pole_plots.htm
 
 Look specifically at the last two plots which show: 
 
KFL3A-400  KFL3A-250 
   -6 dB  435 Hz 370 Hz 
  -60 dB  935 Hz 785 Hz 
SF2.15:1 2.12:1  
 
 INRAD do not publish the curves for the Elecraft (or Yaesu 
 8215 KHz) 250 Hz filter.  However, they do show the curve 
 for the 8830 KHz (Kenwood) version of the same filter and 
 it shows a similar percentage bandwidth (367.5/845 Hz at 
 -6/60dB). 
 

NI0C responds:

I'm still wondering what the tolerance is on such published curves.  

 
 Did you run those tests in a Data mode or with the CW pitch 
 set to 800 Hz?  If not, the low frequency skirts will be 
 sharpened significantly and the measured bandwidth will 
 less than the roofing filter.  With a CW pitch of 560 Hz 
 I measure 10% less bandwidth than in DATA (CF = 1500 Hz or 
 2210 Hz).  If I reduce the pitch to 300 Hz, the measured 
 bandwidth is further reduced (due to the DSP filter's low 
 frequency cut-off). 
 
 73, 
 
... Joe, W4TV 

NI0C responds:

My testing was done in CW mode with the pitch in the 
low 300's (320 Hz, as I recall).  So, when I repeat the tests,
I'll vary the pitch and see what happens, say 300 Hz, 600 hz, 
and 800 Hz.  

73  Thanks, Joe,  for your info!

Chuck Guenther NI0C



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Re: [Elecraft] [K3] Elecraft roofing filters

[Bill W4ZV]

ni0c wrote:
 
 My testing was done in CW mode with the pitch in the 
 low 300's (320 Hz, as I recall).  So, when I repeat the tests,
 I'll vary the pitch and see what happens, say 300 Hz, 600 hz, 
 and 800 Hz.
 

Another person who likes a low pitch!  This really affects what you will
hear because the MCU firmware shifts the bandpass so that the low end always
truncates at ~200 Hz.  If you use a nominal 500 Hz filter, this means it
will be positioned from 200-700 Hz, so you'll hear signals 400 Hz above your
zero beat frequency of 300.  This would be equivalent to an 800 Hz filter if
centered.  The K3 operates differently from Orion which I know you had
before.  This is exactly why I sold my 1000 Hz filter.  With a nominal
bandwidth of 1100 Hz and 300 Hz PITCH, I was hearing signals 1 kHz above my
zero beat QRG (i.e. my actual bandpass was 200-1300 Hz).  1 kHz above my QRG
is not practical on any sort of crowded band.  If the band is not crowded
with strong signals then the stock 2.7k filter is about as effective.

73,  Bill

-- 
View this message in context: 
http://n2.nabble.com/Elecraft-roofing-filters-tp2277174p2278065.html
Sent from the [K3] mailing list archive at Nabble.com.

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Re: [Elecraft] [K3] Elecraft roofing filters

[Joe Subich, W4TV]

 I'm still wondering what the tolerance is on such published 
 curves. 

I would not be so much concerned about tolerance as sampling 
error on the curves.  Still, the Elecraft curves are generally 
similar to those given by INRAD for the same filter or those 
with a similar (e.g., 8215 or 8830 KHz) center frequency and 
bandwidth.  For example, Inrad's curves for the KFL3A-2.1K  
KFL3A-1.0 are identical to those from Elecraft ... Inrad's 
curves are wider for the KFL3A-6K  KFL3A-400 and Elecraft's 
cure is wider for the KFL3A-1.8K.  (Inrad does not publish 
curves for the KFL3A-2.8K or KFL3A-250 ... nor do they have 
any information on the 1500 and 500 Hz custom filters) 

 My testing was done in CW mode with the pitch in the 
 low 300's (320 Hz, as I recall). 

The DSP begins to roll off at 200 Hz even if LO = 0.00.  Any 
measurement where FC (Pitch) is less than [BW60/2 + 200] will 
be inaccurate on the skirts and any measurement where FC is 
less than BW6/2 + 200 will have essentially identical lower 
frequency responses.

73, 

   ... Joe, W4TV 
   



 -Original Message-
 From: ni0c [mailto:n...@earthlink.net] 
 Sent: Thursday, February 05, 2009 5:42 PM
 To: li...@subich.com; elecraft@mailman.qth.net
 Subject: Re: [Elecraft] [K3] Elecraft roofing filters
 
 
 W4TV wrote: 
 
 
  My source is Elecraft: www.elecraft.com/K3/K3_8_pole_plots.htm
  
  Look specifically at the last two plots which show:
  
 KFL3A-400  KFL3A-250 
-6 dB  435 Hz 370 Hz 
   -60 dB  935 Hz 785 Hz 
 SF2.15:1 2.12:1  
  
  INRAD do not publish the curves for the Elecraft (or Yaesu
  8215 KHz) 250 Hz filter.  However, they do show the curve 
  for the 8830 KHz (Kenwood) version of the same filter and 
  it shows a similar percentage bandwidth (367.5/845 Hz at 
  -6/60dB). 
  
 
 NI0C responds:
 
 I'm still wondering what the tolerance is on such published curves.  
 
  
  Did you run those tests in a Data mode or with the CW pitch 
  set to 800 Hz?  If not, the low frequency skirts will be 
  sharpened significantly and the measured bandwidth will 
  less than the roofing filter.  With a CW pitch of 560 Hz 
  I measure 10% less bandwidth than in DATA (CF = 1500 Hz or 
  2210 Hz).  If I reduce the pitch to 300 Hz, the measured 
  bandwidth is further reduced (due to the DSP filter's low 
  frequency cut-off). 
  
  73, 
  
 ... Joe, W4TV 
 
 NI0C responds:
 
 My testing was done in CW mode with the pitch in the 
 low 300's (320 Hz, as I recall).  So, when I repeat the tests,
 I'll vary the pitch and see what happens, say 300 Hz, 600 hz, 
 and 800 Hz.  
 
 73  Thanks, Joe,  for your info!
 
 Chuck Guenther NI0C
 
 
 

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Re: [Elecraft] [K3] Elecraft roofing filters

[Guy Olinger, K2AV]

Having used three different K3's equipped with 4 different sets of 250  400 hz 
8 poles in overload city major contests, the usefulness of these filters is 
belied by the apparent closeness of numbers.

In practice we have found that associating the 400 with a DSP width of 450, and 
the 250 with a DSP width of 350 has been extremely useful, however too close 
by the numbers that may look on paper. 

We use 450 for running for as long as it may last, and when the inevitable 30 
over 9 crowder squeezes down on us, I reduce to 350 and if that isn't enough, 
*ADDITIONALLY* shift the center away 50 hz more. This combination plus the 
noise blanker for key clicks has worked extremely well. (Having 50 Hz 
granularity on the CW shift/widths would be *SO* useful here...) 

I have measured the combined (roofing+DSP) drop on the steepest part of the 
skirts at ~12 db per 10 Hz with these two 8 pole filters. So bringing in the 
skirt only 30 or 40 Hz is enough to push down the crowder quite a bit, 
usually well out of hardware AGC, without narrowing the listening window to the 
point of missing QSO points and multipliers from all the inevitable 
off-frequency callers. 

Anyone who asks us what filters to buy for CW contesting, we tell them 400/250 
8 pole set to 450/350.  Tried and true, not theory. 

W4TV and I will just have to agree to disagree. 

73, Guy.
  - Original Message - 
  From: ni0c 
  To: elecraft@mailman.qth.net 
  Sent: Thursday, February 05, 2009 4:47 PM
  Subject: [Elecraft] [K3] Elecraft roofing filters


  W4TV wrote:
  The difference between the 250 and 400 Hz filters is not 
  enough to be worthwhile (approximately 375 Hz vs. 430 Hz). 

  Joe, what is your source for these numbers?  I've seen numbers 
  like this mentioned previously on the reflector.

  I recently tested my K3 CW roofing filters using the XG-2 generator 
  at 7040 KHz (50 microvolts input) and KS7D's nice software package, 
  K3 Filter Tools.  

  Here's what I came up with, with AGC off and with the DSP 
  bandwidth set at least as wide as 900 Hz for all tests (to isolate 
  the effects of just the crystal roofing filter):

  200 Hz, 5-pole: -6 dB BW = 210 Hz; -30 dB BW = 430 Hz

  250 Hz, 8-pole: -6 dB BW = 260 Hz; -30 dB BW = 500 Hz

  400 Hz, 8-pole: -6 dB BW = 380 Hz; -30 dB BW = 580 Hz

  Note the uncertainty in each of the bandwidths above is 
  plus or minus 20 Hz, because I ran these sweeps in 10 Hz 
  increments to save time. (I'll repeat these tests using a 
  1 or 2 Hz increment, when I have some spare time.) 

  These tests on my filters (as well as my experience by ear) 
  indicate there is an appreciable difference in the 250 and 
  400 Hz 8-pole filters.  I've always wondered, too, about 
  manufacturing tolerances on narrow crystal filters.  

  73, 
  Chuck Guenther  NI0C


 




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Re: [Elecraft] [K3] Elecraft roofing filters

[Guy Olinger, K2AV]

That's a wish for 10 Hz shift/width below, not 50 :)
  - Original Message - 
  From: Guy Olinger, K2AV 
  To: ni0c ; elecraft@mailman.qth.net 
  Sent: Tuesday, August 04, 2009 10:14 PM
  Subject: Re: [Elecraft] [K3] Elecraft roofing filters


  Having used three different K3's equipped with 4 different sets of 250  400 
hz 8 poles in overload city major contests, the usefulness of these filters is 
belied by the apparent closeness of numbers.

  In practice we have found that associating the 400 with a DSP width of 450, 
and the 250 with a DSP width of 350 has been extremely useful, however too 
close by the numbers that may look on paper. 

  We use 450 for running for as long as it may last, and when the inevitable 30 
over 9 crowder squeezes down on us, I reduce to 350 and if that isn't enough, 
*ADDITIONALLY* shift the center away 50 hz more. This combination plus the 
noise blanker for key clicks has worked extremely well. (Having 50 Hz 
granularity on the CW shift/widths would be *SO* useful here...) 

  I have measured the combined (roofing+DSP) drop on the steepest part of the 
skirts at ~12 db per 10 Hz with these two 8 pole filters. So bringing in the 
skirt only 30 or 40 Hz is enough to push down the crowder quite a bit, 
usually well out of hardware AGC, without narrowing the listening window to the 
point of missing QSO points and multipliers from all the inevitable 
off-frequency callers. 

  Anyone who asks us what filters to buy for CW contesting, we tell them 
400/250 8 pole set to 450/350.  Tried and true, not theory. 

  W4TV and I will just have to agree to disagree. 

  73, Guy.
- Original Message - 
From: ni0c 
To: elecraft@mailman.qth.net 
Sent: Thursday, February 05, 2009 4:47 PM
Subject: [Elecraft] [K3] Elecraft roofing filters


W4TV wrote:
The difference between the 250 and 400 Hz filters is not 
enough to be worthwhile (approximately 375 Hz vs. 430 Hz). 

Joe, what is your source for these numbers?  I've seen numbers 
like this mentioned previously on the reflector.

I recently tested my K3 CW roofing filters using the XG-2 generator 
at 7040 KHz (50 microvolts input) and KS7D's nice software package, 
K3 Filter Tools.  

Here's what I came up with, with AGC off and with the DSP 
bandwidth set at least as wide as 900 Hz for all tests (to isolate 
the effects of just the crystal roofing filter):

200 Hz, 5-pole: -6 dB BW = 210 Hz; -30 dB BW = 430 Hz

250 Hz, 8-pole: -6 dB BW = 260 Hz; -30 dB BW = 500 Hz

400 Hz, 8-pole: -6 dB BW = 380 Hz; -30 dB BW = 580 Hz

Note the uncertainty in each of the bandwidths above is 
plus or minus 20 Hz, because I ran these sweeps in 10 Hz 
increments to save time. (I'll repeat these tests using a 
1 or 2 Hz increment, when I have some spare time.) 

These tests on my filters (as well as my experience by ear) 
indicate there is an appreciable difference in the 250 and 
400 Hz 8-pole filters.  I've always wondered, too, about 
manufacturing tolerances on narrow crystal filters.  

73, 
Chuck Guenther  NI0C


   







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Re: [Elecraft] [K3] Elecraft roofing filters

[Joe Subich, W4TV]

 Having used three different K3's equipped with 4 different 
 sets of 250  400 hz 8 poles in overload city major contests, 
 the usefulness of these filters is belied by the apparent 
 closeness of numbers.

I'm happy that you are finding success with the 400/250 filter 
pair but given the published specifications I suspect your 
results have more to do with the DSP performance than the 
actual width of the 250 Hz filter. 

There is so little difference in the published curves for the 
two filters (150 Hz at -60 dB) that roofing filter performance 
alone can not be responsible for the differences performance 
you describe.  If one is looking for improved narrow CW 
performance, the 400/200 combination is a more effective and 
cost efficient pairing. 

 Anyone who asks us what filters to buy for CW contesting, we 
 tell them 400/250 8 pole set to 450/350.  Tried and true, not 
 theory. 
 
 W4TV and I will just have to agree to disagree. 

I don't think there is any disagreement ... unless you have 
actually tried a 400/200 pair set to 450/250 and are trying 
to say that the 250 Hz filter is tighter and suffers fewer 
hardware AGC effects than the 200 Hz filter.  If you try to 
make that point, there are several others including W4ZV, 
who will disagree with you. 

73, 

   ... Joe, W4TV 
 


 -Original Message-
 From: elecraft-boun...@mailman.qth.net 
 [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of Guy 
 Olinger, K2AV
 Sent: Tuesday, August 04, 2009 10:14 PM
 To: ni0c; elecraft@mailman.qth.net
 Subject: Re: [Elecraft] [K3] Elecraft roofing filters
 
 
 Having used three different K3's equipped with 4 different 
 sets of 250  400 hz 8 poles in overload city major contests, 
 the usefulness of these filters is belied by the apparent 
 closeness of numbers.
 
 In practice we have found that associating the 400 with a DSP 
 width of 450, and the 250 with a DSP width of 350 has been 
 extremely useful, however too close by the numbers that may 
 look on paper. 
 
 We use 450 for running for as long as it may last, and when 
 the inevitable 30 over 9 crowder squeezes down on us, I 
 reduce to 350 and if that isn't enough, *ADDITIONALLY* shift 
 the center away 50 hz more. This combination plus the noise 
 blanker for key clicks has worked extremely well. (Having 50 
 Hz granularity on the CW shift/widths would be *SO* useful here...) 
 
 I have measured the combined (roofing+DSP) drop on the 
 steepest part of the skirts at ~12 db per 10 Hz with these 
 two 8 pole filters. So bringing in the skirt only 30 or 40 
 Hz is enough to push down the crowder quite a bit, usually 
 well out of hardware AGC, without narrowing the listening 
 window to the point of missing QSO points and multipliers 
 from all the inevitable off-frequency callers. 
 
 Anyone who asks us what filters to buy for CW contesting, we 
 tell them 400/250 8 pole set to 450/350.  Tried and true, not theory. 
 
 W4TV and I will just have to agree to disagree. 
 
 73, Guy.
 - Original Message - 
 From: ni0c 
 To: elecraft@mailman.qth.net 
 Sent: Thursday, February 05, 2009 4:47 PM
 Subject: [Elecraft] [K3] Elecraft roofing filters
 
 
 W4TV wrote:
 The difference between the 250 and 400 Hz filters is not 
 enough to be worthwhile (approximately 375 Hz vs. 430 Hz). 
 
 Joe, what is your source for these numbers?  I've seen numbers 
 like this mentioned previously on the reflector.
 
 I recently tested my K3 CW roofing filters using the XG-2 generator 
 at 7040 KHz (50 microvolts input) and KS7D's nice software package, 
 K3 Filter Tools.  
 
 Here's what I came up with, with AGC off and with the DSP 
 bandwidth set at least as wide as 900 Hz for all tests (to isolate 
 the effects of just the crystal roofing filter):
 
 200 Hz, 5-pole: -6 dB BW = 210 Hz; -30 dB BW = 430 Hz
 
 250 Hz, 8-pole: -6 dB BW = 260 Hz; -30 dB BW = 500 Hz
 
 400 Hz, 8-pole: -6 dB BW = 380 Hz; -30 dB BW = 580 Hz
 
 Note the uncertainty in each of the bandwidths above is 
 plus or minus 20 Hz, because I ran these sweeps in 10 Hz 
 increments to save time. (I'll repeat these tests using a 
 1 or 2 Hz increment, when I have some spare time.) 
 
 These tests on my filters (as well as my experience by ear) 
 indicate there is an appreciable difference in the 250 and 
 400 Hz 8-pole filters.  I've always wondered, too, about 
 manufacturing tolerances on narrow crystal filters.  
 
 73, 
 Chuck Guenther  NI0C
 
 

 
 
 
 
 
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RE: RES: RES: [Elecraft] ROOFING FILTERS CW PY5EG

[py5eg]

Hi Don

I deactivated the KXV3, power of, and then re-activate and still ERR XVR.
Can you help me on that?
Thanks in advance
Oms 

-Original Message-
From: Don Wilhelm [mailto:[EMAIL PROTECTED] 
Sent: Sunday, September 21, 2008 10:37 PM
To: py5eg
Subject: Re: RES: RES: [Elecraft] ROOFING FILTERS CW PY5EG

Oms,

ERR XV3 is associated with the KXV3 option, and is not related to the filters.
The manual indicates that one should de-install the KXV3 option.
You could try deactivating it in the menu, power off, and then re-activate it 
before you actually remove the option.

73,
Don W3FPR

py5eg wrote:
 Hi Don
 Thanks again
 It is showing an ERR XV3
 I done the set up via the K3 utility
 I still don´t know what I done wrong
 Sorry to keep you working
 73
 Oms PY5EG


 -Mensagem original-
 De: Don Wilhelm [mailto:[EMAIL PROTECTED] Enviada em: Sunday, 
 September 21, 2008 9:55 PM
 Para: py5eg
 Cc: [EMAIL PROTECTED]; elecraft@mailman.qth.net
 Assunto: Re: RES: [Elecraft] ROOFING FILTERS CW PY5EG

 Oms,

 You may either use the K3 Utility program to set up your transmit 
 filter or you may use the K3 Config: Menu.  The FLTX menu entry must 
 be set for each mode.

 73,
 Don W3FPR

 py5eg wrote:
   
 Hi Don
 Thanks for being so fast.
 Where can I pre-set the CW filter?
 I have the 2,7 Khz, 1,8 , 1,0 and 0,4
 73
 Oms

 -Mensagem original-
 De: Don Wilhelm [mailto:[EMAIL PROTECTED] Enviada em: Sunday, 
 September 21, 2008 9:14 PM
 Para: py5eg
 Cc: elecraft@mailman.qth.net
 Assunto: Re: [Elecraft] ROOFING FILTERS CW PY5EG

 What is the filter that you have configured for CW transmit?  It must 
 be

 the 2.7 or 2.8 kHz filter.

 73,
 Don W3FPR

 py5eg wrote:
   
 
 Hi Folks:

 I installed, 2,1  1,8  1.0  and 0,4 roofing filters on my K3.

 It is working perfectly on SSB, but it is no working in the other
 
   
 modes
   
 
 i.e CW.

 Did I make something wrong?

 Oms PY5EG

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 Checked by AVG - http://www.avg.com
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 9/21/2008 10:10 AM
   
 
   
 
 


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 Checked by AVG - http://www.avg.com
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Re: [Elecraft] ROOFING FILTERS CW PY5EG

[dj7mgq]

Hi Oms,

filter set up is described on page 45 and pages 53  54 of the owners  
manual, e.g. K3 Owners Manual D1.pdf:  FLx BW, FLx FRQ, FLx GN, FLx  
ON and FLTX{md}.


If you have done this correctly, then everything should be ok. If not,  
you may need to contact Elecraft.


vy 73 de toby





Hi Folks:

I installed, 2,1  1,8  1.0  and 0,4 roofing filters on my K3.

It is working perfectly on SSB, but it is no working in the other modes
i.e CW.

Did I make something wrong?

Oms PY5EG

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[Elecraft] ROOFING FILTERS CW PY5EG

[py5eg]

Hi Folks:

I installed, 2,1  1,8  1.0  and 0,4 roofing filters on my K3.

It is working perfectly on SSB, but it is no working in the other modes
i.e CW.

Did I make something wrong?

Oms PY5EG

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Re: [Elecraft] ROOFING FILTERS CW PY5EG

[Don Wilhelm]

What is the filter that you have configured for CW transmit?  It must be 
the 2.7 or 2.8 kHz filter.


73,
Don W3FPR

py5eg wrote:

Hi Folks:

I installed, 2,1  1,8  1.0  and 0,4 roofing filters on my K3.

It is working perfectly on SSB, but it is no working in the other modes
i.e CW.

Did I make something wrong?

Oms PY5EG

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No virus found in this incoming message.
Checked by AVG - http://www.avg.com 
Version: 8.0.169 / Virus Database: 270.7.0/1683 - Release Date: 9/21/2008 10:10 AM


  

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RES: [Elecraft] ROOFING FILTERS CW PY5EG

[py5eg]

Hi Don
Thanks for being so fast.
Where can I pre-set the CW filter?
I have the 2,7 Khz, 1,8 , 1,0 and 0,4
73
Oms

-Mensagem original-
De: Don Wilhelm [mailto:[EMAIL PROTECTED] 
Enviada em: Sunday, September 21, 2008 9:14 PM
Para: py5eg
Cc: elecraft@mailman.qth.net
Assunto: Re: [Elecraft] ROOFING FILTERS CW PY5EG

What is the filter that you have configured for CW transmit?  It must be

the 2.7 or 2.8 kHz filter.

73,
Don W3FPR

py5eg wrote:
 Hi Folks:

 I installed, 2,1  1,8  1.0  and 0,4 roofing filters on my K3.

 It is working perfectly on SSB, but it is no working in the other
modes
 i.e CW.

 Did I make something wrong?

 Oms PY5EG

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 Elecraft web page: http://www.elecraft.com




 No virus found in this incoming message.
 Checked by AVG - http://www.avg.com 
 Version: 8.0.169 / Virus Database: 270.7.0/1683 - Release Date:
9/21/2008 10:10 AM

   
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Re: RES: [Elecraft] ROOFING FILTERS CW PY5EG

[Don Wilhelm]

Oms,

You may either use the K3 Utility program to set up your transmit filter 
or you may use the K3 Config: Menu.  The FLTX menu entry must be set for 
each mode.


73,
Don W3FPR

py5eg wrote:

Hi Don
Thanks for being so fast.
Where can I pre-set the CW filter?
I have the 2,7 Khz, 1,8 , 1,0 and 0,4
73
Oms

-Mensagem original-
De: Don Wilhelm [mailto:[EMAIL PROTECTED] 
Enviada em: Sunday, September 21, 2008 9:14 PM

Para: py5eg
Cc: elecraft@mailman.qth.net
Assunto: Re: [Elecraft] ROOFING FILTERS CW PY5EG

What is the filter that you have configured for CW transmit?  It must be

the 2.7 or 2.8 kHz filter.

73,
Don W3FPR

py5eg wrote:
  

Hi Folks:

I installed, 2,1  1,8  1.0  and 0,4 roofing filters on my K3.

It is working perfectly on SSB, but it is no working in the other


modes
  

i.e CW.

Did I make something wrong?

Oms PY5EG

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No virus found in this incoming message.
Checked by AVG - http://www.avg.com 
Version: 8.0.169 / Virus Database: 270.7.0/1683 - Release Date:


9/21/2008 10:10 AM
  
  




No virus found in this incoming message.
Checked by AVG - http://www.avg.com 
Version: 8.0.169 / Virus Database: 270.7.0/1683 - Release Date: 9/21/2008 10:10 AM




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[Elecraft] roofing filters

[Ken]

My experience with roofing filters is from using Orion and Orion ii.

On my first transceiver, Orion, I ordered the narrow filters, and found 
anything less than about 600 cycles not to be useful.

From a practical point of view, a roof of even 1 kc was more than adequate for 
CW, RTTY, and PSK operation

On my second transceiver, Orion II, I did not waste my money on these 200 cycle 
filters.  If you are a purist, maybe once
a month you will be in qso with a IK3 station on PSK (31 cycles wide) and find 
a W2 cranking up 50 cycles away at high power, and
your AGC will be affected by it.  Then it might be helpbul to use a very narrow 
filter, but in my opinion, this seldom to none experience  it is not worth the 
bucks.
DSP bandwidth adjustments will handle most situations just fine.

I suggest nothing smaller than 400 cycles as a roofing filter.

Ken K5WK
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RE: [Elecraft] Roofing Filters

[Brett Howard]

So in reading the inrad description of roofing filters at:

http://www.qth.com/inrad/roofing-filters.pdf

It seems that they all but tell you to buy the elecraft 5-pole filters when
talking about 500Hz and narrower bandwidths.  Does this hold true in the
case of the K3 in that the higer pole count results in a lower roof I
guess you could call it and then end up needing more gain in the next stage
therefore ending up with less dynamic range?  

-Original Message-
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] On Behalf Of Bill W4ZV
Sent: Wednesday, February 20, 2008 12:30 PM
To: elecraft@mailman.qth.net
Subject: Re: [Elecraft] Roofing Filters




AnnLatz wrote:
 
 Can someone explain the meaning of roofing filters. I have searched
 everywhere and can't find a good explanation. Lisa recommended the FAQ
 section of Elecraft and there they just mention them. Maybe I should order
 an updated Ham bible from ARRL.
 
 Thanks, Alan KA9UCP
 
 

See below, written by W2VJN of Inrad:

http://www.qth.com/inrad/roofing-filters.pdf

73,  Bill  W4ZV



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[Elecraft] Roofing Filters

[AnnLatz]

Can someone explain the meaning of roofing filters. I have searched 
everywhere and can't find a good explaination. Lisa recommended the FAQ 
secftion of Elecraft and there they just mention them. Maybe I should order an 
updated Ham bible from ARRL.

Thanks, Alan KA9UCP
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[Elecraft] Roofing Filters

[Don Rasmussen]

Can someone explain the meaning of roofing filters.
I have searched everywhere and can't find a good
explaination. Lisa recommended the FAQ secftion of
Elecraft and there they just mention them. Maybe I
should order an updated Ham bible from ARRL.

Thanks, Alan KA9UCP

http://www.zerobeat.net/mediawiki/index.php/K3_Roofing_Filters

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Re: [Elecraft] Roofing Filters

[Ken K3IU]

You can check here...

   http://www.elecraft.com/K3/Roofing_Filters.htm

73, Ken K3IU

AnnLatz wrote:

Can someone explain the meaning of roofing filters. I have searched 
everywhere and can't find a good explaination. Lisa recommended the FAQ secftion of 
Elecraft and there they just mention them. Maybe I should order an updated Ham bible from 
ARRL.

Thanks, Alan KA9UCP
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RE: [Elecraft] Roofing Filters

[Gary Hvizdak]

At 14:38:02 EST on Wed 20 Feb 2008  Alan Latz (KA9UCP) wrote .

Can someone explain the meaning of roofing filters. I have searched
everywhere and can't find a good explanation.  Lisa recommended the FAQ
section of Elecraft and there they just mention them.  Maybe I should order
an updated Ham bible from ARRL.

--

Alan,

At the top of the K3 FAQ page under the heading ...
Options and Accessories
... there's a link ...
Elecraft and Roofing Filters (detailed explanation)
... the direct URL is ...
http://elecraft.com/K3/Roofing_Filters.htm 

73,
Gary  KI4GGX 

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Re: [Elecraft] Roofing Filters

[Bill W4ZV]

AnnLatz wrote:
 
 Can someone explain the meaning of roofing filters. I have searched
 everywhere and can't find a good explanation. Lisa recommended the FAQ
 section of Elecraft and there they just mention them. Maybe I should order
 an updated Ham bible from ARRL.
 
 Thanks, Alan KA9UCP
 
 

See below, written by W2VJN of Inrad:

http://www.qth.com/inrad/roofing-filters.pdf

73,  Bill  W4ZV



-- 
View this message in context: 
http://www.nabble.com/Roofing-Filters-tp15597160p15597952.html
Sent from the Elecraft mailing list archive at Nabble.com.

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RE: [Elecraft] Roofing Filters

[Ron D'Eau Claire]

Can someone explain the meaning of roofing filters. I have searched
everywhere and can't find a good explaination. Lisa recommended the FAQ
secftion of Elecraft and there they just mention them. Maybe I should order
an updated Ham bible from ARRL.



The K3 receiver, like many current superhetrodyne receivers, has more than
one high-performance filter in the system. 

I don't know how long you've been tinkering with superhets, but a few
decades we ago we just called the roofing filter the first I.F. filter. 

You probably know  that a superheterodyne receiver takes the selected
incoming signal, no matter where it is in the tuning range of the receiver,
and converts it to one fixed frequency before it is demodulated. That fixed
frequency is called the intermediate frequency (I.F.). 

From a design standpoint, it's a good idea to put all the selectivity as
early in the receiver chain as possible so the first I.F. filter has been
the most important in the system. Indeed, we normally tried to do all  the
significant filtering there. That's who the K2 is designed. 

Nowadays higher performance amplifiers and mixers allow more signal
processing before it's necessary to use a filter to strip off all but the
exact signal we want to hear. 

We use the first I.F. filter to reject signals that are completely outside
the range of interest, then use a second filter further along in the signal
path to finish the filtering to set the final bandwidth to just what we
want. 

The first I.F. filter, therefore, defines how far off each side of the
center frequency we can hear. That is, it sets the limit or roof on the
bandpass. (I think of it as the upper and lower sides to the bandpass, but
no one checked with me before choosing the name roofing filter.) 

The K3's second filter is provided by digital signal processing (DSP) and
allows controlling the bandpass and center frequency to set it anywhere
within the range of the first I.F. (roofing) filter bandpass. 

Even though mixers and amplifiers are much better today than a few years
ago, it's still a good idea to reject all unwanted signals as early in the
signal path as possible. That's why the K3 offers up to five roofing
filters of various bandwidths to fit the sort of signal you're receiving
from very wide FM signals down to a very narrow CW/PSK signal. Within the
bandpass of the roofing filter, the DSP filter provides additional
flexibility to set the exact upper and lower frequency limits, provide a
notch filter to remove a specific heterodyne, etc.

Ron AC7AC



-Original Message-
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] On Behalf Of AnnLatz
Sent: Wednesday, February 20, 2008 11:38 AM
To: elecraft@mailman.qth.net
Subject: [Elecraft] Roofing Filters


Can someone explain the meaning of roofing filters. I have searched
everywhere and can't find a good explaination. Lisa recommended the FAQ
secftion of Elecraft and there they just mention them. Maybe I should order
an updated Ham bible from ARRL.

Thanks, Alan KA9UCP ___
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RE: [Elecraft] Roofing Filters

[Dave Van Wallaghen]

First, thank you Ron for putting that in a very comprehensive manner that
even I could understand ;-) As usual, you've turned on the light bulb.

Now, when I purchased my K3 and debated on my purchase of the roofing
filters, I spoke with a few hams who said that the roofing filters were
primarily for blocking out close in and powerful signals and that if I
didn't have that problem where I live, that the standard DSP filter with the
standard 2.7khz filter would probably suffice. And that is what I did.

But I wonder (always dangerous), if operating on some of the noisier bands,
would there be a benefit to using a narrower filter to cut down on the
amount of energy hitting the DSP in order to help with digging out weak
signals? Or is that not a consideration with this particular implementation
of DSP in the K3?

As is, it has been fun playing around with digging out weak signals and
enhancing them. I need to get a better antenna to rig switching setup so I
can make a/b comparisons with my K2.

Thanks in advance,
Dave W8FGU

 
 Can someone explain the meaning of roofing filters. I have searched
 everywhere and can't find a good explaination. Lisa recommended the FAQ
 secftion of Elecraft and there they just mention them. Maybe I should
 order
 an updated Ham bible from ARRL.
 
 
 
 The K3 receiver, like many current superhetrodyne receivers, has more than
 one high-performance filter in the system.
 
 I don't know how long you've been tinkering with superhets, but a few
 decades we ago we just called the roofing filter the first I.F. filter.
 
 You probably know  that a superheterodyne receiver takes the selected
 incoming signal, no matter where it is in the tuning range of the
 receiver,
 and converts it to one fixed frequency before it is demodulated. That
 fixed
 frequency is called the intermediate frequency (I.F.).
 
 From a design standpoint, it's a good idea to put all the selectivity as
 early in the receiver chain as possible so the first I.F. filter has been
 the most important in the system. Indeed, we normally tried to do all  the
 significant filtering there. That's who the K2 is designed.
 
 Nowadays higher performance amplifiers and mixers allow more signal
 processing before it's necessary to use a filter to strip off all but the
 exact signal we want to hear.
 
 We use the first I.F. filter to reject signals that are completely outside
 the range of interest, then use a second filter further along in the
 signal
 path to finish the filtering to set the final bandwidth to just what we
 want.
 
 The first I.F. filter, therefore, defines how far off each side of the
 center frequency we can hear. That is, it sets the limit or roof on
 the
 bandpass. (I think of it as the upper and lower sides to the bandpass,
 but
 no one checked with me before choosing the name roofing filter.)
 
 The K3's second filter is provided by digital signal processing (DSP) and
 allows controlling the bandpass and center frequency to set it anywhere
 within the range of the first I.F. (roofing) filter bandpass.
 
 Even though mixers and amplifiers are much better today than a few years
 ago, it's still a good idea to reject all unwanted signals as early in the
 signal path as possible. That's why the K3 offers up to five roofing
 filters of various bandwidths to fit the sort of signal you're receiving
 from very wide FM signals down to a very narrow CW/PSK signal. Within the
 bandpass of the roofing filter, the DSP filter provides additional
 flexibility to set the exact upper and lower frequency limits, provide a
 notch filter to remove a specific heterodyne, etc.
 
 Ron AC7AC

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Re: [Elecraft] Roofing Filters

[Lyle Johnson]

But I wonder (always dangerous), if operating on some of the noisier bands,
would there be a benefit to using a narrower filter to cut down on the
amount of energy hitting the DSP in order to help with digging out weak
signals? Or is that not a consideration with this particular implementation
of DSP in the K3?


In general, the DSP can handle signals and noise below about S9+40 or so 
without undesired effects.  Signals between about S9+40 and S9+60 will 
start to activate the hardware AGC (to protect the analog to digital 
converter from overload), so if there are strong signals inside the 
roofing filter passband but outside the DSP IF filter passband, they can 
make their presence known by activating (or pumping) the AGC.


So, it isn't the weak signals or noise that are of concern, but the 
presence of adjacent signals that are (a) stronger than the one you are 
trying to copy and (b) above the hardware AGC threshold.


Contests -- and therefore weekends -- come to mind :-)

73,

Lyle KK7P

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RE: [Elecraft] Roofing Filters

[Dave Van Wallaghen]

Hey Lyle,

Thanks for the reply. Man, if anyone knows about how the K? DSP works...

So if I read this right (bear with me, I'm learning), in keeping strong
signals out of its passband, it will keep the hardware AGC from activating
to eliminate pumping. And that makes perfect sense. Keeping the high
energy out from interfering with the signal you want.

But, in the same scenario, if I had a 2.7khz filter and a 200hz filter with
no strong signals, just band noise (or maybe static crash type QRN), the DSP
filter would act the same and my desired signal would come through the same
way regardless of which roofing filter I used. In other words, if I had a
weak signal just above the noise floor in the above scenario, it would not
make a difference which roofing filter I chose, the signal would sound the
same. 

Obviously, I would narrow the DSP filter to chop off some of the noise. And
that is where, in my above scenario, the elimination of extra energy from
noise would be eliminated. Reduction in bandwidth in the roofing filter
would have no redeeming effect.

And if you would permit me one more scenario. In the case of strong static
crash type QRN, in my case, either the noise blanker or noise reduction
would be able to handle the really heavy stuff. I know the hardware noise
blanker is set in front of the roofing filters and well ahead of the DSP,
therefore protecting it. I guess that statement is more of a question than a
statement.

Am I getting this clear?

73,
Dave W8FGU

 
  But I wonder (always dangerous), if operating on some of the noisier
 bands,
  would there be a benefit to using a narrower filter to cut down on the
  amount of energy hitting the DSP in order to help with digging out weak
  signals? Or is that not a consideration with this particular
 implementation
  of DSP in the K3?
 
 In general, the DSP can handle signals and noise below about S9+40 or so
 without undesired effects.  Signals between about S9+40 and S9+60 will
 start to activate the hardware AGC (to protect the analog to digital
 converter from overload), so if there are strong signals inside the
 roofing filter passband but outside the DSP IF filter passband, they can
 make their presence known by activating (or pumping) the AGC.
 
 So, it isn't the weak signals or noise that are of concern, but the
 presence of adjacent signals that are (a) stronger than the one you are
 trying to copy and (b) above the hardware AGC threshold.
 
 Contests -- and therefore weekends -- come to mind :-)
 
 73,
 
 Lyle KK7P

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RE: [Elecraft] Roofing Filters

[Ron D'Eau Claire]

I see that Lyle (Mr. DSP) stepped in with the answer I couldn't have given
you anyway G. That's the beauty of this reflector: lots of expertise and
resources. I seldom answer a question without learning something myself! 

Someone else dropped me a note reminding me that Wayne discusses roofing
filters on the Elecraft web site and, in particular how he addressed the
design issues of employing them in the K3. That FB write up is here:

http://elecraft.com/K3/Roofing_Filters.htm

Ron AC7AC



-Original Message-
From: Dave Van Wallaghen [mailto:[EMAIL PROTECTED] 
Sent: Wednesday, February 20, 2008 2:21 PM
To: 'Ron D'Eau Claire'; elecraft@mailman.qth.net
Subject: RE: [Elecraft] Roofing Filters


First, thank you Ron for putting that in a very comprehensive manner that
even I could understand ;-) As usual, you've turned on the light bulb.

Now, when I purchased my K3 and debated on my purchase of the roofing
filters, I spoke with a few hams who said that the roofing filters were
primarily for blocking out close in and powerful signals and that if I
didn't have that problem where I live, that the standard DSP filter with the
standard 2.7khz filter would probably suffice. And that is what I did.

But I wonder (always dangerous), if operating on some of the noisier bands,
would there be a benefit to using a narrower filter to cut down on the
amount of energy hitting the DSP in order to help with digging out weak
signals? Or is that not a consideration with this particular implementation
of DSP in the K3?

As is, it has been fun playing around with digging out weak signals and
enhancing them. I need to get a better antenna to rig switching setup so I
can make a/b comparisons with my K2.

Thanks in advance,
Dave W8FGU



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Re: [Elecraft] Roofing Filters

[Lyle Johnson]

Hello Dave!


So if I read this right (bear with me, I'm learning), in keeping strong
signals out of its passband, it will keep the hardware AGC from activating
to eliminate pumping...


Correct.


But, in the same scenario, if I had a 2.7khz filter and a 200hz filter with
no strong signals, just band noise (or maybe static crash type QRN), the DSP
filter would act the same and my desired signal would come through the same
way regardless of which roofing filter I used...


Also correct.  The key is if signals stronger than the desired signal 
are in the roofing filter passband, and are also strong enough to 
activate the hardware AGC.



And if you would permit me one more scenario. In the case of strong static
crash type QRN, in my case, either the noise blanker or noise reduction
would be able to handle the really heavy stuff. I know the hardware noise
blanker is set in front of the roofing filters and well ahead of the DSP,
therefore protecting it. I guess that statement is more of a question than a
statement.


We have pulse-suppressing AGC in addition to DSP and IF blankers.  Won't 
kill all the noise types, but makes a very effective arsenal against 
noise.  Narrow roofing filters can help in some cases here, too.


In the end, you may not often need narrow roofing filters in your 
particular station's interference environment, but when you need 'em, 
you need 'em :-)


73,

Lyle KK7P

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RE: [Elecraft] Roofing Filters

[Dave Van Wallaghen]

Thanks again Lyle, I believe I now have the proper prospective (looking at
the block diagram of the K3 helped out too). So far in my limited operation
of K3 #338, anytime I've tried to dig out a weaker CW signal next to a
stronger one, the DSP filter has worked just fine. And I found when it was a
little too close I was able to shift the filter away from the offending
signal enough to hear the desired one very comfortably. Of course, these
were in non contest and non-aggressive situations.

I saw a post the other day about the notch filter. I have used it a couple
of times in the old novice portion of 40m (where I hang out with the QRS
crowd). When some of the BC stations start up, I was able to notch out that
carrier just fine and turn an irritating listening situation into something
very comfortable.

Very nice work. Thanks again Lyle (hope I didn't bore too many on the list).

73,
Dave 
W8FGU


 
 Hello Dave!
 
  So if I read this right (bear with me, I'm learning), in keeping strong
  signals out of its passband, it will keep the hardware AGC from
 activating
  to eliminate pumping...
 
 Correct.
 
  But, in the same scenario, if I had a 2.7khz filter and a 200hz filter
 with
  no strong signals, just band noise (or maybe static crash type QRN), the
 DSP
  filter would act the same and my desired signal would come through the
 same
  way regardless of which roofing filter I used...
 
 Also correct.  The key is if signals stronger than the desired signal
 are in the roofing filter passband, and are also strong enough to
 activate the hardware AGC.
 
  And if you would permit me one more scenario. In the case of strong
 static
  crash type QRN, in my case, either the noise blanker or noise reduction
  would be able to handle the really heavy stuff. I know the hardware
 noise
  blanker is set in front of the roofing filters and well ahead of the
 DSP,
  therefore protecting it. I guess that statement is more of a question
 than a
  statement.
 
 We have pulse-suppressing AGC in addition to DSP and IF blankers.  Won't
 kill all the noise types, but makes a very effective arsenal against
 noise.  Narrow roofing filters can help in some cases here, too.
 
 In the end, you may not often need narrow roofing filters in your
 particular station's interference environment, but when you need 'em,
 you need 'em :-)
 
 73,
 
 Lyle KK7P

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RE: [Elecraft] Roofing Filters

[Dave Van Wallaghen]

Thanks Ron, that was a good read and reiterated what you and Lyle stated
here. I read that before, but I think now that I've been playing around with
#338, it is just sinking in now.

Thanks again for the help.

73,
Dave W8FGU

 -Original Message-
 From: [EMAIL PROTECTED] [mailto:elecraft-
 [EMAIL PROTECTED] On Behalf Of Ron D'Eau Claire
 Sent: Wednesday, February 20, 2008 7:35 PM
 To: elecraft@mailman.qth.net
 Subject: RE: [Elecraft] Roofing Filters
 
 I see that Lyle (Mr. DSP) stepped in with the answer I couldn't have given
 you anyway G. That's the beauty of this reflector: lots of expertise and
 resources. I seldom answer a question without learning something myself!
 
 Someone else dropped me a note reminding me that Wayne discusses roofing
 filters on the Elecraft web site and, in particular how he addressed the
 design issues of employing them in the K3. That FB write up is here:
 
 http://elecraft.com/K3/Roofing_Filters.htm
 
 Ron AC7AC
 
 
 
 -Original Message-
 From: Dave Van Wallaghen [mailto:[EMAIL PROTECTED]
 Sent: Wednesday, February 20, 2008 2:21 PM
 To: 'Ron D'Eau Claire'; elecraft@mailman.qth.net
 Subject: RE: [Elecraft] Roofing Filters
 
 
 First, thank you Ron for putting that in a very comprehensive manner that
 even I could understand ;-) As usual, you've turned on the light bulb.
 
 Now, when I purchased my K3 and debated on my purchase of the roofing
 filters, I spoke with a few hams who said that the roofing filters were
 primarily for blocking out close in and powerful signals and that if I
 didn't have that problem where I live, that the standard DSP filter with
 the
 standard 2.7khz filter would probably suffice. And that is what I did.
 
 But I wonder (always dangerous), if operating on some of the noisier
 bands,
 would there be a benefit to using a narrower filter to cut down on the
 amount of energy hitting the DSP in order to help with digging out weak
 signals? Or is that not a consideration with this particular
 implementation
 of DSP in the K3?
 
 As is, it has been fun playing around with digging out weak signals and
 enhancing them. I need to get a better antenna to rig switching setup so I
 can make a/b comparisons with my K2.
 
 Thanks in advance,
 Dave W8FGU
 
 
 
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Re: [Elecraft] Roofing Filters

[Lyle Johnson]

...Thanks again Lyle (hope I didn't bore too many on the list).


Thank you for your interest in all this.  Self-education is one of the 
pillars of our avocation, and it is always a pleasure to try to help in 
this process when I am able.


73,

Lyle KK7P

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[Elecraft] Roofing Filters

[Barry Simpson]

I am about to take the plunge and order a K3. Does it accommodate five
roofing filters in addition to that supplied or is it limited to five in
total ?

 

Merry Christmas to all.

 

73

 

Barry Simpson  VK2BJ

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Re: [Elecraft] Roofing Filters

[Ian J Maude]

Barry Simpson wrote:

I am about to take the plunge and order a K3. Does it accommodate five
roofing filters in addition to that supplied or is it limited to five in
total ?
  
5 in total Barry.  However the general coverage board is a separate 
board so does not take a slot.  You can order up to 4 additional filters 
as well as the one that comes with it.


Merry Christmas

Ian

--

Ian J Maude, G0VGS
SysOp GB7MBC DX Cluster
Member RSGB, GQRP
K2 #4044 |K3 #?

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[Elecraft] Roofing Filters

[Dave G4AON]

Barry

The K3 takes up to a maximum of 5 roofing filters, if you opt for the 
2.8 KHz instead of the 2.7 KHz there is a price reduction of $30 off the 
2.8 KHz filter (ask Lisa at time of ordering).
The second receiver (if you order that option) also takes up to 5 
filters and would be supplied with a 2.7 KHz 5 pole filter by default.


I'm currently using 2.8 KHz 8 pole and 400 Hz 8 pole filters. The latest 
DSP firmware gives good clean receive on CW down to an indicated 50 Hz 
bandwidth without any signs of ringing.


73 and Merry Christmas

Dave, G4AON
K3/100 #80
++
I am about to take the plunge and order a K3. Does it accommodate five
roofing filters in addition to that supplied or is it limited to five in
total ?

Barry Simpson VK2BJ
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[Elecraft] Roofing filters - on the other end

[Val]

While the discussion on the roofing filters was flowing here, there was a
huge talk over BS7H expedition on the cluster and DX reflectors, and a lot
of dissatisfaction and criticism. The operators were blamed for the slow
traffic and the RX bandwidth, sometimes taking a good part of the band. The
skill of the members was put in a doubt until UR0MC, a member of N8S
expedition explained:
My opinion is that a wide split is not through operators fault. I don't
know what kind of transceivers they used on BS7H, most probably the same as
we used on N8S - PROIII. Please imagine how in the 15 KHz first filter input
clutters up thousands stations with level 599+20db. All that nuisance going
to DSP. Finally you can hear in the phones some modulated 'hunk'. And you
can get some signal only at the end of this 'hunk'. After 2-3 QSO on this
frequency grows a new 'hunk'  and so on, and so on
With K2 with 200 Hz filter pileups were processed much easier. The stations
stood as pins, you have only to turn the knob and pick them up.
The conclusion is: The expedition equipments sponsors must be changed :-) 

Translated by
Val LZ1VB
K2 2745, K3 ?


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Re: [Elecraft] Roofing filters - on the other end

[johnny]

Hi Val,

Purely from your description, operators' skills could be another factor.

73

Johnny Siu VR2XMC

- Original Message - 
From: Val [EMAIL PROTECTED]

To: Elecraft@mailman.qth.net
Sent: Wednesday, May 09, 2007 9:37 PM
Subject: [Elecraft] Roofing filters - on the other end



While the discussion on the roofing filters was flowing here, there was a
huge talk over BS7H expedition on the cluster and DX reflectors, and a lot
of dissatisfaction and criticism. The operators were blamed for the slow
traffic and the RX bandwidth, sometimes taking a good part of the band. 
The

skill of the members was put in a doubt until UR0MC, a member of N8S
expedition explained:
My opinion is that a wide split is not through operators fault. I don't
know what kind of transceivers they used on BS7H, most probably the same 
as
we used on N8S - PROIII. Please imagine how in the 15 KHz first filter 
input
clutters up thousands stations with level 599+20db. All that nuisance 
going

to DSP. Finally you can hear in the phones some modulated 'hunk'. And you
can get some signal only at the end of this 'hunk'. After 2-3 QSO on this
frequency grows a new 'hunk'  and so on, and so on
With K2 with 200 Hz filter pileups were processed much easier. The 
stations

stood as pins, you have only to turn the knob and pick them up.
The conclusion is: The expedition equipments sponsors must be changed :-) 



Translated by
Val LZ1VB
K2 2745, K3 ?



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Re: [Elecraft] Roofing filters - on the other end

[Brendan Minish]

Surely the best way to deal with this is to use the attenuator to
improve the strong signal IMD performance, this applies to all radios,
Analog and DSP based

The BS7H CW Pileups were just dreadful.

73
Brendan EI6IZ  


On Wed, 2007-05-09 at 16:37 +0300, Val wrote:
 While the discussion on the roofing filters was flowing here, there was a
 huge talk over BS7H expedition on the cluster and DX reflectors, and a lot
 of dissatisfaction and criticism. The operators were blamed for the slow
 traffic and the RX bandwidth, sometimes taking a good part of the band. The
 skill of the members was put in a doubt until UR0MC, a member of N8S
 expedition explained:
 My opinion is that a wide split is not through operators fault. I don't
 know what kind of transceivers they used on BS7H, most probably the same as
 we used on N8S - PROIII. Please imagine how in the 15 KHz first filter input
 clutters up thousands stations with level 599+20db. All that nuisance going
 to DSP. Finally you can hear in the phones some modulated 'hunk'. And you
 can get some signal only at the end of this 'hunk'. After 2-3 QSO on this
 frequency grows a new 'hunk'  and so on, and so on
 With K2 with 200 Hz filter pileups were processed much easier. The stations
 stood as pins, you have only to turn the knob and pick them up.
 The conclusion is: The expedition equipments sponsors must be changed :-) 
 
 Translated by
 Val LZ1VB
 K2 2745, K3 ?
 
 
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Re: [Elecraft] Roofing Filters

[dj7mgq]

Zitat von Bill Tippett [EMAIL PROTECTED]:

  Filling K3 with filters as Toby suggested is
 both unnecessary and expensive IMHO.  I think he is
 forgetting that there is very good DSP filtering in

 many lines removed 

 Even a perfect receiver cannot prevent an adjacent TX
 signal's defects!

From my layman's view, I am not sure that I fully agree with you. Here in the 
EU the CW segment of the 40m band is (still) only 40kHz wide, in other words, 
assuming that in a major contest there are 200 european stations on 40m, then 
you have an average spacing of 200Hz. In SSB the bandwidth is 60kHz giving an 
average spacing of 600Hz - assuming 100 stations. (To be honest the number of 
stations calling CQ is an educated guess.)

As you may be able to imagine, the 40m band can be a real zoo, and every bit of 
(clean) selection, as early as possible, helps. Some of the major contest 
stations go so far as to use a bank of switchable crystal filters in front of 
the mixer http://www.yt6a.com/en/front-end-filters/index.php.

As I see it the main job for the roofing filter in the K3 is to help protect 
the ADC and prevent AGC pumping. If I am listening to a weakish signal (S5) 
between two strong (9+40) stations with a 200Hz bandwidth DSP and a roofing 
filter of say 500Hz on 40m then either the AGC will densense the RX (AGC 
pumping) or the strong stations will overpower the ADC.

I contest mostly in SSB, so I need good early selection in SSB. At out contest 
QTH, where my K3, may end up living, there are many avid CW operators and they 
will need good selection in CW. Not to mention the RTTY contests. Also, when 
the K3 is not at our contest QTH, e.g. if I take it with me on vacation, then I 
do want to be able to listen to broadcast stations or when using a transverter 
work over relais (FM).

This why my personal dream(!) filter setup is so rich. It might be expensive 
but I doubt that it is totally unnecessary. 

As to the side effects of poor signals (TX phase noise etc.), I agree with you 
fully. It DOES make things much more difficult.

But the again, what do I know... ;-)

vy 73 de toby
-- 
DD5FZ, 4N6FZ
K2 #885, K2/100 #3248, K3 #200


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[Elecraft] Roofing Filters

[Lee Buller]

 
   
  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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Re: [Elecraft] Roofing Filters

[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   [EMAIL PROTECTED]
Twisted Oak Winery  http://www.twistedoak.com/
Winery Blog http://www.elbloggotorcido.com/

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Re: [Elecraft] Roofing Filters

[Toby Deinhardt]

 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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