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700 Hz roofing filters

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KARL MARDERIAN

700 Hz roofing filters

Why are these so popular? Please don't tell me they are being used for ssb.
Just asking.
N6XVT Karl

Sent from my iPad
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Don Wilhelm-4

Re: 700 Hz roofing filters

Karl,

I can only speak for myself, although apparently some have agreed with
me. I have ordered one, and when Gary first suggested it, I encouraged him.

I do not operate many CW contests, and do not chase DX with a fervor as
some do.
My preferred width for general CW tuning is 700 Hz. The DSP filtering
will take care of the rest for me. If there are so many undesired CW
signals on the band that the DSP cannot handle, I am likely not to be
operating there anyway.

So it gives me a good general purpose CW filter of a width I normally
use. Others are free to agree or disagree, but that is what I like.

73,
Don W3FPR

On 9/21/2010 4:18 PM, Karl Marderian wrote:
> Why are these so popular? Please don't tell me they are being used for ssb.
> Just asking.
> N6XVT Karl
>
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Joe Planisky

Re: 700 Hz roofing filters

In reply to this post by KARL MARDERIAN

They should be a pretty good choice for the wider digital modes (e.g.
Olivia 500/16).

73
--
Joe KB8AP

On Sep 21, 2010, at 1:18 PM, Karl Marderian wrote:

> Why are these so popular? Please don't tell me they are being used
> for ssb.
> Just asking.
> N6XVT Karl
>
>
> Sent from my iPad
> ______________________________________________________________
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Dunc Carter - W5DC

Re: 700 Hz roofing filters

The Inrad 500 Hz filter works for Olivia 500.

Dunc, W5DC

On 9/21/2010 2:42 PM, Joe Planisky wrote:
> They should be a pretty good choice for the wider digital modes (e.g.
> Olivia 500/16).
>
> 73
> --
> Joe KB8AP
>

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Bill W4ZV

Re: 700 Hz roofing filters

In reply to this post by KARL MARDERIAN

KARL MARDERIAN wrote

Why are these so popular?

10/4500 = 0.2% of K3s shipped. Popular?

73, Bill

Andrew Moore-3

Re: 700 Hz roofing filters

> 10/4500 = 0.2% of K3s shipped. Popular?

They were never offered with the K3s; this is a first run of this type of
filter available for the K3.

10/10 * 100 = 100% ;)
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Gary Gregory

Re: 700 Hz roofing filters

More to the point. Examine the filter shape AFTER installation and measure
the actual skirt and width installed.

I think this will tell what benefit it will be.

73's
Gary

On Wed, Sep 22, 2010 at 7:39 AM, Andrew Moore <[hidden email]> wrote:

> > 10/4500 = 0.2% of K3s shipped. Popular?
>
> They were never offered with the K3s; this is a first run of this type of
> filter available for the K3.
>
> 10/10 * 100 = 100% ;)
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--
Gary
VK4FD - Motorhome Mobile
http://www.qsl.net/vk4fd/
K3 #679
For everything else there's Mastercard!!!
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wayne burdick

Re: 700 Hz roofing filters

Administrator

In reply to this post by Bill W4ZV

700 Hz is a useful CW/DATA filter bandwidth, certainly. I'm not
surprised that some K3 owners are interested in this.

Personally, I prefer much narrow CW/DATA bandwidths, and I use all
modes. The lineup I use (and generally recommend) is:

FL1 13 kHz (FM)
FL2 6 kHz (AM/ESSB)
FL3 2.7 or 2.8 kHz (SSB and casual CW/DATA tuning)
FL4 400 or 500 Hz (normal CW/DATA)
FL5 200 Hz (CW/DATA in heavy QRM)

73,
Wayne
N6KR

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Rick Dettinger-3

Re: 700 Hz roofing filters

In reply to this post by Don Wilhelm-4

Hi Don,

I agree. That is why I bought a 1 Khz filter when I got my K3 in
2008. I just use the DSP set between 500 and 1000 Hz. My CW
operating is about the same as yours. If I need to use a sharper
filter than that, it is likely due to QRN rather than QRM, and the DSP
works fine for that. Including the NR section. I don't close the
blinds unless I need to!

73,

Rick Dettinger K7MW

>
> I do not operate many CW contests, and do not chase DX with a fervor
> as
> some do.
> My preferred width for general CW tuning is 700 Hz. The DSP filtering
> will take care of the rest for me. If there are so many undesired CW
> signals on the band that the DSP cannot handle, I am likely not to be
> operating there anyway.
>
> So it gives me a good general purpose CW filter of a width I normally
> use. Others are free to agree or disagree, but that is what I like.
>
> 73,
> Don W3FPR

Gary Gregory

Re: 700 Hz roofing filters

In reply to this post by wayne burdick

I have the same configuration as Wayne it would appear and use the same
settings I think.

YMMV

73's
Gary

On Wed, Sep 22, 2010 at 8:07 AM, Wayne Burdick <[hidden email]> wrote:

> 700 Hz is a useful CW/DATA filter bandwidth, certainly. I'm not
> surprised that some K3 owners are interested in this.
>
> Personally, I prefer much narrow CW/DATA bandwidths, and I use all
> modes. The lineup I use (and generally recommend) is:
>
> FL1 13 kHz (FM)
> FL2 6 kHz (AM/ESSB)
> FL3 2.7 or 2.8 kHz (SSB and casual CW/DATA tuning)
> FL4 400 or 500 Hz (normal CW/DATA)
> FL5 200 Hz (CW/DATA in heavy QRM)
>
> 73,
> Wayne
> N6KR
>
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
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> Please help support this email list: http://www.qsl.net/donate.html
>

Barry

Re: 700 Hz roofing filters

In reply to this post by wayne burdick

wayne burdick wrote

700 Hz is a useful CW/DATA filter bandwidth, certainly. I'm not
surprised that some K3 owners are interested in this.

Personally, I prefer much narrow CW/DATA bandwidths, and I use all
modes. The lineup I use (and generally recommend) is:

FL1 13 kHz (FM)
FL2 6 kHz (AM/ESSB)
FL3 2.7 or 2.8 kHz (SSB and casual CW/DATA tuning)
FL4 400 or 500 Hz (normal CW/DATA)
FL5 200 Hz (CW/DATA in heavy QRM)

73,
Wayne
N6KR

Joe Subich, W4TV-4

Re: 700 Hz roofing filters

In reply to this post by wayne burdick

In general I agree with Wayne although I prefer to have a more
narrow bandwidth option for SSB (1.8 or 1.5 KHz). In order to
make room for the 1.5/1.8 KHz filter, I deleted the AM filter
and use only the FM filter for the "low priority" modes wider
than 2.8 KHz. However, it continues to frustrate me that
Elecraft have *STILL* not allowed us to use the 13 KHz filter
for AM/ESSB transmit (officially).

In any case, given the measured performance of the INRAD/Elecraft
"250 Hz" filter (about 350 to 375 Hz), I can certainly see the
utility of something like:

FL1 13 kHz (FM/AM/ESSB)
FL2 2.7 or 2.8 kHz (SSB and casual CW/DATA tuning)
FL3 1.8 or 1.5 KHz (Narrow SSB and wide data modes)
FL4 700 Hz (casual/normal CW/DATA)
FL5 350 Hz (Narrow CW/RTTY in heavy QRM)

While the "350 Hz" filter would lack the absolute selectivity of
the Elecraft 200 Hz 5-pole filter, it would be nearly optimum
for 45.45 baud RTTY and still provide a useful "narrow CW" option.

73,

... Joe, W4TV

On 9/21/2010 6:07 PM, Wayne Burdick wrote:

Bill W4ZV

Re: 700 Hz roofing filters

In reply to this post by Barry

Barry wrote

Personally, I follow the K3ZO school of filtering. I prefer using my neuronal network for filtering, especially when running in a contest. As my operation is mostly CW, I have the stock SSB, the 1 kHz, and 400 Hz filters. I find myself using 1 kHz most of the time and have always done it this way, going back to my Drake R4B days. I suspect Wayne got a better deal on his filter options than I did :.)
73,
Barry W2UP

I can do that on 10m but you won't get away with it on a crowded band. I once had a 1 kHz filter but quickly discovered in casual DXing on 160m that adjacent signals were pumping my AGC. I prefer a low pitch for weak signal DXing (my preference is 270 Hz but the K3's 300 Hz is acceptable). Because the K3's MCU shifts roofing filter passbands such that the low end always cuts off at 200 Hz, if you use a 1000 Hz filter with a 300 Hz pitch, the actual passband is 200-1200 Hz, so a signal 900 Hz away (1200-300) will pump your AGC. If you use 500 Hz pitch, the passband remains 200-1200 Hz, so a signal 700 kHz away will pump the AGC. In a crowded contest or large pileup, this simply doesn't cut it.

73, Bill

Jeff Cochrane - VK4XA

Re: 700 Hz roofing filters

In reply to this post by Joe Subich, W4TV-4

CONTENTS DELETED

The author has deleted this message.

Eric Swartz - WA6HHQ

Re: 700 Hz roofing filters [END of Thread]

Administrator

End of thread.

73,
Eric
Elecraft List Moderator
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Kok Chen

Re: 700 Hz roofing filters

In reply to this post by Jeff Cochrane - VK4XA

On Sep 21, 2010, at 5:19 PM, Jeff Cochrane - VK4BOF wrote:

> SSB is called mode A3J in most of the legal documents that govern our hobby.
> The reason why the mode is called A3J in all the legal stuff is that the 3 is the maximum bandwidth in khz that is permitted.)

The "3" in A3J has nothing to do with bandwidth -- the "3" stands for "a single channel containing analog information."

73
Chen, W7AY

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Gary Gregory

Re: 700 Hz roofing filters

In reply to this post by Jeff Cochrane - VK4XA

I feel compelled to state my objection to any TX capability from ALL amateur
transceiver manufacturers to NEVER allow TX bandwidth in excess of
3Khz..period.

ESSB is unwarranted and a waste of bandwidth and creates havoc wherever it
is used.

In VK we have a small minority who insist on ESSB operation and whilst we
can all find alternative frequencies not suffering from QRM it should be no
surprise to all that sure enough, on 17M were two stations running ESSB on
18.130 or right in about the centre of the SSB portion of the band.

We all love to experiment with different modes but I have to admit I must be
pretty darn slow (or worse) as I do not see why EESB is worth experimenting
with.

But then I may be just too slow..or worse..to understand.

My 2c worth...keep the change
(Flame Suit on)

73's
Gary

On Wed, Sep 22, 2010 at 10:19 AM, Jeff Cochrane - VK4BOF <
[hidden email]> wrote:

> Hi Joe et al,
> I'm going to hazzard a guess here as to why Elecraft dont allow the 13KHz
> filter for AM/ESSB TX.
>
> Because it's illegal.
> SSB is called mode A3J in most of the legal documents that govern our
> hobby.
> The reason why the mode is called A3J in all the legal stuff is that the 3
> is the maximum bandwidth in khz that is permitted.)
> Thus, anything more than the 3KHz SSB bandwidth is against the laws that
> govern us.
>
> The F.C.C. in the US of A and here in Australia, A.C.M.A. both allow a
> maximum of 3KHz for SSB TX bandwidth on any HF band.
> So it would be a fair bet then that because the K3 is a FCC type approved
> radio that part of that type approval includes that it must not transmit SSB
> bandwidths that are wider than permitted.
>
> My $0.02c worth (Plus GST/VAT/Sales Tax as applicable)
>
>
> Jeff Cochrane - VK4BOF
> Innisfail, QLD, Australia
> Elecraft K3# 4257
>
> ----- Original Message -----
> From: Joe Subich, W4TV
> To: [hidden email]
> Sent: Wednesday, September 22, 2010 9:44 AM
> Subject: Re: [Elecraft] 700 Hz roofing filters
>
>
>
> In general I agree with Wayne although I prefer to have a more
> narrow bandwidth option for SSB (1.8 or 1.5 KHz). In order to
> make room for the 1.5/1.8 KHz filter, I deleted the AM filter
> and use only the FM filter for the "low priority" modes wider
> than 2.8 KHz. However, it continues to frustrate me that
> Elecraft have *STILL* not allowed us to use the 13 KHz filter
> for AM/ESSB transmit (officially).
>
> In any case, given the measured performance of the INRAD/Elecraft
> "250 Hz" filter (about 350 to 375 Hz), I can certainly see the
> utility of something like:
>
> FL1 13 kHz (FM/AM/ESSB)
> FL2 2.7 or 2.8 kHz (SSB and casual CW/DATA tuning)
> FL3 1.8 or 1.5 KHz (Narrow SSB and wide data modes)
> FL4 700 Hz (casual/normal CW/DATA)
> FL5 350 Hz (Narrow CW/RTTY in heavy QRM)
>
> While the "350 Hz" filter would lack the absolute selectivity of
> the Elecraft 200 Hz 5-pole filter, it would be nearly optimum
> for 45.45 baud RTTY and still provide a useful "narrow CW" option.
>
> 73,
>
> ... Joe, W4TV
>
> On 9/21/2010 6:07 PM, Wayne Burdick wrote:
> > 700 Hz is a useful CW/DATA filter bandwidth, certainly. I'm not
> > surprised that some K3 owners are interested in this.
> >
> > Personally, I prefer much narrow CW/DATA bandwidths, and I use all
> > modes. The lineup I use (and generally recommend) is:
> >
> > FL1 13 kHz (FM)
> > FL2 6 kHz (AM/ESSB)
> > FL3 2.7 or 2.8 kHz (SSB and casual CW/DATA tuning)
> > FL4 400 or 500 Hz (normal CW/DATA)
> > FL5 200 Hz (CW/DATA in heavy QRM)
> >
> > 73,
> > Wayne
> > N6KR
> >
> >
> > ______________________________________________________________
> > Elecraft mailing list
> > Home: http://mailman.qth.net/mailman/listinfo/elecraft
> > Help: http://mailman.qth.net/mmfaq.htm
> > Post: mailto:[hidden email]
> >
> > This list hosted by: http://www.qsl.net
> > Please help support this email list: http://www.qsl.net/donate.html
> >
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> ______________________________________________________________
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Joe Subich, W4TV-4

Re: 700 Hz roofing filters

In reply to this post by Jeff Cochrane - VK4XA

Jeff,

> Because it's illegal.

The "roofing filter" does not set the transmitted bandwidth - that
is controlled in the DSP modulator. The only purpose for roofing
filter in transmit is to remove the image of the IF and the FM filter
has more than sufficient skirt selectivity for that job (the image
is 30 KHz away).

> > Thus, anything more than the 3KHz SSB bandwidth is against the
> laws that govern us.

Incorrect in the USA. There is no statutory maximum bandwidth though
my personal opinion is that anything more than 2.8KHz (200 Hz - 3000
Hz audio) is "bad practice." Double sideband AM will require twice
the highest modulating frequency so 6 KHz is appropriate. However,
again, it's the DSP that sets that bandwidth *not* the roofing filter.

73,

... Joe, W4TV

On 9/21/2010 8:19 PM, Jeff Cochrane - VK4BOF wrote:

> Hi Joe et al,
> I'm going to hazzard a guess here as to why Elecraft dont allow the 13KHz filter for AM/ESSB TX.
>
> Because it's illegal.
> SSB is called mode A3J in most of the legal documents that govern our hobby.
> The reason why the mode is called A3J in all the legal stuff is that the 3 is the maximum bandwidth in khz that is permitted.)
> Thus, anything more than the 3KHz SSB bandwidth is against the laws that govern us.
>
> The F.C.C. in the US of A and here in Australia, A.C.M.A. both allow a maximum of 3KHz for SSB TX bandwidth on any HF band.
> So it would be a fair bet then that because the K3 is a FCC type approved radio that part of that type approval includes that it must not transmit SSB bandwidths that are wider than permitted.
>
> My $0.02c worth (Plus GST/VAT/Sales Tax as applicable)
>
>
> Jeff Cochrane - VK4BOF
> Innisfail, QLD, Australia
> Elecraft K3# 4257
>
> ----- Original Message -----
> From: Joe Subich, W4TV
> To: [hidden email]
> Sent: Wednesday, September 22, 2010 9:44 AM
> Subject: Re: [Elecraft] 700 Hz roofing filters
>
>
>
> In general I agree with Wayne although I prefer to have a more
> narrow bandwidth option for SSB (1.8 or 1.5 KHz). In order to
> make room for the 1.5/1.8 KHz filter, I deleted the AM filter
> and use only the FM filter for the "low priority" modes wider
> than 2.8 KHz. However, it continues to frustrate me that
> Elecraft have *STILL* not allowed us to use the 13 KHz filter
> for AM/ESSB transmit (officially).
>
> In any case, given the measured performance of the INRAD/Elecraft
> "250 Hz" filter (about 350 to 375 Hz), I can certainly see the
> utility of something like:
>
> FL1 13 kHz (FM/AM/ESSB)
> FL2 2.7 or 2.8 kHz (SSB and casual CW/DATA tuning)
> FL3 1.8 or 1.5 KHz (Narrow SSB and wide data modes)
> FL4 700 Hz (casual/normal CW/DATA)
> FL5 350 Hz (Narrow CW/RTTY in heavy QRM)
>
> While the "350 Hz" filter would lack the absolute selectivity of
> the Elecraft 200 Hz 5-pole filter, it would be nearly optimum
> for 45.45 baud RTTY and still provide a useful "narrow CW" option.
>
> 73,
>
> ... Joe, W4TV
>
> On 9/21/2010 6:07 PM, Wayne Burdick wrote:
> > 700 Hz is a useful CW/DATA filter bandwidth, certainly. I'm not
> > surprised that some K3 owners are interested in this.
> >
> > Personally, I prefer much narrow CW/DATA bandwidths, and I use all
> > modes. The lineup I use (and generally recommend) is:
> >
> > FL1 13 kHz (FM)
> > FL2 6 kHz (AM/ESSB)
> > FL3 2.7 or 2.8 kHz (SSB and casual CW/DATA tuning)
> > FL4 400 or 500 Hz (normal CW/DATA)
> > FL5 200 Hz (CW/DATA in heavy QRM)
> >
> > 73,
> > Wayne
> > N6KR
> >
> >
> > ______________________________________________________________
> > Elecraft mailing list
> > Home: http://mailman.qth.net/mailman/listinfo/elecraft
> > Help: http://mailman.qth.net/mmfaq.htm
> > Post: mailto:[hidden email]
> >
> > This list hosted by: http://www.qsl.net
> > Please help support this email list: http://www.qsl.net/donate.html
> >
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>

Eric Swartz - WA6HHQ

Re: 700 Hz roofing filters [Thread REALLY closed]

Administrator

Guys - this thread has been formally closed. (both the 700 hz and ESSB sub threads).

Please take further discussion off list.

73,
Eric
Elecraft List Moderator - really!

www.elecraft.com
_..._

On Sep 21, 2010, at 6:43 PM, "Joe Subich, W4TV" <[hidden email]> wrote:

>
> Jeff,
>
>> Because it's illegal.
>
> The "roofing filter" does not set the transmitted bandwidth - that
> is controlled in the DSP modulator. The only purpose for roofing
> filter in transmit is to remove the image of the IF and the FM filter
> has more than sufficient skirt selectivity for that job (the image
> is 30 KHz away).
>
>>> Thus, anything more than the 3KHz SSB bandwidth is against the
>> laws that govern us.
>
> Incorrect in the USA. There is no statutory maximum bandwidth though
> my personal opinion is that anything more than 2.8KHz (200 Hz - 3000
> Hz audio) is "bad practice." Double sideband AM will require twice
> the highest modulating frequency so 6 KHz is appropriate. However,
> again, it's the DSP that sets that bandwidth *not* the roofing filter.
>
> 73,
>
> ... Joe, W4TV
>
>
> On 9/21/2010 8:19 PM, Jeff Cochrane - VK4BOF wrote:
>> Hi Joe et al,
>> I'm going to hazzard a guess here as to why Elecraft dont allow the 13KHz filter for AM/ESSB TX.
>>
>> Because it's illegal.
>> SSB is called mode A3J in most of the legal documents that govern our hobby.
>> The reason why the mode is called A3J in all the legal stuff is that the 3 is the maximum bandwidth in khz that is permitted.)
>> Thus, anything more than the 3KHz SSB bandwidth is against the laws that govern us.
>>
>> The F.C.C. in the US of A and here in Australia, A.C.M.A. both allow a maximum of 3KHz for SSB TX bandwidth on any HF band.
>> So it would be a fair bet then that because the K3 is a FCC type approved radio that part of that type approval includes that it must not transmit SSB bandwidths that are wider than permitted.
>>
>> My $0.02c worth (Plus GST/VAT/Sales Tax as applicable)
>>
>>
>> Jeff Cochrane - VK4BOF
>> Innisfail, QLD, Australia
>> Elecraft K3# 4257
>>
>> ----- Original Message -----
>> From: Joe Subich, W4TV
>> To: [hidden email]
>> Sent: Wednesday, September 22, 2010 9:44 AM
>> Subject: Re: [Elecraft] 700 Hz roofing filters
>>
>>
>>
>> In general I agree with Wayne although I prefer to have a more
>> narrow bandwidth option for SSB (1.8 or 1.5 KHz). In order to
>> make room for the 1.5/1.8 KHz filter, I deleted the AM filter
>> and use only the FM filter for the "low priority" modes wider
>> than 2.8 KHz. However, it continues to frustrate me that
>> Elecraft have *STILL* not allowed us to use the 13 KHz filter
>> for AM/ESSB transmit (officially).
>>
>> In any case, given the measured performance of the INRAD/Elecraft
>> "250 Hz" filter (about 350 to 375 Hz), I can certainly see the
>> utility of something like:
>>
>> FL1 13 kHz (FM/AM/ESSB)
>> FL2 2.7 or 2.8 kHz (SSB and casual CW/DATA tuning)
>> FL3 1.8 or 1.5 KHz (Narrow SSB and wide data modes)
>> FL4 700 Hz (casual/normal CW/DATA)
>> FL5 350 Hz (Narrow CW/RTTY in heavy QRM)
>>
>> While the "350 Hz" filter would lack the absolute selectivity of
>> the Elecraft 200 Hz 5-pole filter, it would be nearly optimum
>> for 45.45 baud RTTY and still provide a useful "narrow CW" option.
>>
>> 73,
>>
>> ... Joe, W4TV
>>
>> On 9/21/2010 6:07 PM, Wayne Burdick wrote:
>>> 700 Hz is a useful CW/DATA filter bandwidth, certainly. I'm not
>>> surprised that some K3 owners are interested in this.
>>>
>>> Personally, I prefer much narrow CW/DATA bandwidths, and I use all
>>> modes. The lineup I use (and generally recommend) is:
>>>
>>> FL1 13 kHz (FM)
>>> FL2 6 kHz (AM/ESSB)
>>> FL3 2.7 or 2.8 kHz (SSB and casual CW/DATA tuning)
>>> FL4 400 or 500 Hz (normal CW/DATA)
>>> FL5 200 Hz (CW/DATA in heavy QRM)
>>>
>>> 73,
>>> Wayne
>>> N6KR
>>>
>>>
>>> ______________________________________________________________
>>> Elecraft mailing list
>>> Home: http://mailman.qth.net/mailman/listinfo/elecraft
>>> Help: http://mailman.qth.net/mmfaq.htm
>>> Post: mailto:[hidden email]
>>>
>>> This list hosted by: http://www.qsl.net
>>> Please help support this email list: http://www.qsl.net/donate.html
>>>
>> ______________________________________________________________
>> Elecraft mailing list
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>>
>> This list hosted by: http://www.qsl.net
>> Please help support this email list: http://www.qsl.net/donate.html
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>> Post: mailto:[hidden email]
>>
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>>
> ______________________________________________________________
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>
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Nr4c

Re: 700 Hz roofing filters

In reply to this post by Jeff Cochrane - VK4XA

Are you sure that's not "J3E" for AM, Single sideBand, surpressed carrier,
one analoge channel with telephony?

...bc

-----Original Message-----
From: Jeff Cochrane - VK4BOF [mailto:[hidden email]]
Sent: Tuesday, September 21, 2010 8:19 PM
To: [hidden email]
Subject: Re: [Elecraft] 700 Hz roofing filters

Hi Joe et al,
I'm going to hazzard a guess here as to why Elecraft dont allow the 13KHz
filter for AM/ESSB TX.

Because it's illegal.
SSB is called mode A3J in most of the legal documents that govern our hobby.
The reason why the mode is called A3J in all the legal stuff is that the 3
is the maximum bandwidth in khz that is permitted.)
Thus, anything more than the 3KHz SSB bandwidth is against the laws that
govern us.

The F.C.C. in the US of A and here in Australia, A.C.M.A. both allow a
maximum of 3KHz for SSB TX bandwidth on any HF band.
So it would be a fair bet then that because the K3 is a FCC type approved
radio that part of that type approval includes that it must not transmit SSB
bandwidths that are wider than permitted.

My $0.02c worth (Plus GST/VAT/Sales Tax as applicable)

Jeff Cochrane - VK4BOF
Innisfail, QLD, Australia
Elecraft K3# 4257

----- Original Message -----
From: Joe Subich, W4TV
To: [hidden email]
Sent: Wednesday, September 22, 2010 9:44 AM
Subject: Re: [Elecraft] 700 Hz roofing filters

In general I agree with Wayne although I prefer to have a more
narrow bandwidth option for SSB (1.8 or 1.5 KHz). In order to
make room for the 1.5/1.8 KHz filter, I deleted the AM filter
and use only the FM filter for the "low priority" modes wider
than 2.8 KHz. However, it continues to frustrate me that
Elecraft have *STILL* not allowed us to use the 13 KHz filter
for AM/ESSB transmit (officially).

In any case, given the measured performance of the INRAD/Elecraft
"250 Hz" filter (about 350 to 375 Hz), I can certainly see the
utility of something like:

FL1 13 kHz (FM/AM/ESSB)
FL2 2.7 or 2.8 kHz (SSB and casual CW/DATA tuning)
FL3 1.8 or 1.5 KHz (Narrow SSB and wide data modes)
FL4 700 Hz (casual/normal CW/DATA)
FL5 350 Hz (Narrow CW/RTTY in heavy QRM)

While the "350 Hz" filter would lack the absolute selectivity of
the Elecraft 200 Hz 5-pole filter, it would be nearly optimum
for 45.45 baud RTTY and still provide a useful "narrow CW" option.

73,

... Joe, W4TV

On 9/21/2010 6:07 PM, Wayne Burdick wrote:
> 700 Hz is a useful CW/DATA filter bandwidth, certainly. I'm not
> surprised that some K3 owners are interested in this.
>
> Personally, I prefer much narrow CW/DATA bandwidths, and I use all
> modes. The lineup I use (and generally recommend) is:
>
> FL1 13 kHz (FM)
> FL2 6 kHz (AM/ESSB)
> FL3 2.7 or 2.8 kHz (SSB and casual CW/DATA tuning)
> FL4 400 or 500 Hz (normal CW/DATA)
> FL5 200 Hz (CW/DATA in heavy QRM)
>
> 73,
> Wayne
> N6KR
>
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>
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Post: mailto:[hidden email]

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