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[K3] Filters for mixed JT65 and JT9 HF

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dberkley

[K3] Filters for mixed JT65 and JT9 HF

I am considering purchase of a K3 (I own a K2). One application is the new mixed JT65-JT9 HF mode. Possible accessories are:
-KFL3A-6K 6 kHz AM / ESSB, 8-pole filter (to allow full band mixed waterfall)
-KTCXO3-1 TCXO (0.1 ppm typ) High Stability Ref. Osc. (to provide stability especially as required by JT9)
Are these needed and reasonable choices?
73, David, K2MUN

k5oai

Re: [K3] Filters for mixed JT65 and JT9 HF

I would defiantly add the AM filter, works great for dual JT65 + JT9 wf

I do not have or need the TCXO, the stock K3 works fine for stability
the timing with a pgm like NTP is more of a key factor for QSO's

ymmv

On 9/14/2013 10:10 AM, dberkley wrote:
> I am considering purchase of a K3 (I own a K2). One application is the new
> mixed JT65-JT9 HF mode. Possible accessories are:
> -KFL3A-6K 6 kHz AM / ESSB, 8-pole filter (to allow full band mixed
> waterfall)
> -KTCXO3-1 TCXO (0.1 ppm typ) High Stability Ref. Osc. (to provide
> stability especially as required by JT9)
> Are these needed and reasonable choices?
> 73, David, K2MUN
>

--

GB & 73
K5OAI
Sam Morgan
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Tony Kennedy

Re: [K3] Filters for mixed JT65 and JT9 HF

Agree with Sam fully. I have the AM filter and currently work both modes
easily. I do not have the TXCO, however it's on my future upgrade list.

On Saturday, September 14, 2013, Sam Morgan wrote:

> I would defiantly add the AM filter, works great for dual JT65 + JT9 wf
>
> I do not have or need the TCXO, the stock K3 works fine for stability
> the timing with a pgm like NTP is more of a key factor for QSO's
>
> ymmv
>
> On 9/14/2013 10:10 AM, dberkley wrote:
>
>> I am considering purchase of a K3 (I own a K2). One application is the
>> new
>> mixed JT65-JT9 HF mode. Possible accessories are:
>> -KFL3A-6K 6 kHz AM / ESSB, 8-pole filter (to allow full band mixed
>> waterfall)
>> -KTCXO3-1 TCXO (0.1 ppm typ) High Stability Ref. Osc. (to provide
>> stability especially as required by JT9)
>> Are these needed and reasonable choices?
>> 73, David, K2MUN
>>
>>
> --
>
> GB & 73
> K5OAI
> Sam Morgan
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Joe Subich, W4TV-4

Re: [K3] Filters for mixed JT65 and JT9 HF

In reply to this post by k5oai

Sam's advice is correct ... however, the FM filter is a suitable
alternative to the AM filter if you plan to do/try FM on the top
end of 10 Meters, 6 meters or install the internal 2 m transverter
at some point. Either the FM or AM filters will provide a 4 KHz
wide waterfall (200 - 4200 Hz) with the current WSJT-X software.

The high stability TCXO is most certainly not needed - drift over
one minute at HF just isn't a factor.

73,

... Joe, W4TV

On 9/14/2013 11:20 AM, Sam Morgan wrote:

Michael Jensen

Re: [K3] Filters for mixed JT65 and JT9 HF

Hi

I am right now using this exact setup with WSJTX.
I do get the about 400Hz to 4200 on the waterfall, but TX are an issue.
As "i guess" the K3 transmit through the 2,8 Khz. filter when ever i try to work a JT9 QSO above 3,0 Khz on the waterfall i do not see any audio output. I have been looking for a way to TX through the AM filter but have not found the way.

Any hints please ?

Thanks in advance

73 De OZ1BZJ
Michael

dberkley

Re: [K3] Filters for mixed JT65 and JT9 HF

I don't have a solution for wideband transmit (since I don't own a K3) but there is a simple fix: Run split. That way, the software will keep the transmit close to 1500 Hz by offsetting the QRG automatically. You can use the full receive bandwidth and the software will take care of keeping the transmit in range.

I use this on my K2 and it is great. You just have to set it in the WSJT-X settings and make sure the K3 is set in split mode. On the K2, split is reset each time the transceiver is power cycled so I have to be sure to set it back on split mode.

73, David, K2MUN

On 10/6/13 3:41 PM, Michael Jensen [via Elecraft] wrote:

Hi

I am right now using this exact setup with WSJTX.
I do get the about 400Hz to 4200 on the waterfall, but TX are an issue.
As "i guess" the K3 transmit through the 2,8 Khz. filter when ever i try to work a JT9 QSO above 3,0 Khz on the waterfall i do not see any audio output. I have been looking for a way to TX through the AM filter but have not found the way.

Any hints please ?

Thanks in advance

73 De OZ1BZJ
Michael

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k5oai

Re: [K3] Filters for mixed JT65 and JT9 HF

In reply to this post by Michael Jensen

not sure what your TX problem is Michael?

I am running WSJTX v1.2.1, r3587
I am using the K3's AM filter for RX so I can run WSJTX in dual mode

I am running WSJTX using WSJTX's CAT through DXLabs Commander

I just tested my TX all the way from 200 up through 4400
and I can tx with the full audio out of 5 bars
and no reduction in power out

also I am running a SignaLink USB,
but that would have anything to do with it because the audio in WSJTX is
always between 1500 – 2000 Hz. when in dual mode.

to quote the help notes in WSJTX Version 1.2 Aug. 16, 2013:

Pages 11 & 12 #13.

"Note that most SSB transceivers have a fixed Tx filter that will not
pass audio frequencies higher than about 2700 Hz. WSJT-X v1.1 takes care
of this by using Split mode, receiving with VFO A and transmitting with
VFO B. The Tx dial frequency (VFO B) is offset in 500 Hz steps, and the
generated audio frequency is adjusted so that it always falls in the
range 1500 – 2000 Hz. With CAT and Split Tx enabled on the configuration
screen and your transceiver set to Split mode, frequency control will be
handled automatically."

On 10/6/2013 2:41 PM, Michael Jensen wrote:

> Hi
>
> I am right now using this exact setup with WSJTX.
> I do get the about 400Hz to 4200 on the waterfall, but TX are an issue.
> As "i guess" the K3 transmit through the 2,8 Khz. filter when ever i try to
> work a JT9 QSO above 3,0 Khz on the waterfall i do not see any audio output.
> I have been looking for a way to TX through the AM filter but have not found
> the way.
>
> Any hints please ?
>
>
> Thanks in advance
>
> 73 De OZ1BZJ
> Michael

--

GB & 73
K5OAI
Sam Morgan
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Michael Jensen

Re: [K3] Filters for mixed JT65 and JT9 HF

In reply to this post by dberkley

Hi

Thanks for the reply

Yes I can transmit using the split options. For 2 reasons I would like different approach with a wideband TX.

First of all I am interfacing through HRD. That way the split are not implemented to my understanding.
Then I really like to know exactly where i transmit. Using the split the only indication I get is that the frequency in the b VFO. But i am not able to see if i am actually doing TX on A or B VFO during a TX cycle.

73 de OZ1BZJ

Michael

Oliver Dröse

Re: [K3] Filters for mixed JT65 and JT9 HF

Hi Michael,

when in Split mode you always TX on the VFO B frequency. Besides this there
is a small arrow either above or below the TX symbol on the display pointing
to the VFO choosen for transmit. ;-)

73, Olli - DH8BQA

----- Original Message -----
From: "Michael Jensen" <[hidden email]>
To: <[hidden email]>
Sent: Monday, October 07, 2013 10:11 PM
Subject: Re: [Elecraft] [K3] Filters for mixed JT65 and JT9 HF

> Hi
>
> Thanks for the reply
>
> Yes I can transmit using the split options. For 2 reasons I would like
> different approach with a wideband TX.
>
> First of all I am interfacing through HRD. That way the split are not
> implemented to my understanding.
> Then I really like to know exactly where i transmit. Using the split the
> only indication I get is that the frequency in the b VFO. But i am not
> able
> to see if i am actually doing TX on A or B VFO during a TX cycle.
>
>
> 73 de OZ1BZJ
>
> Michael
>
>
>
> --
> View this message in context:
> http://elecraft.365791.n2.nabble.com/K3-Filters-for-mixed-JT65-and-JT9-HF-tp7578942p7579667.html
> Sent from the Elecraft mailing list archive at Nabble.com.
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Joe Subich, W4TV-4

Re: [K3] Filters for mixed JT65 and JT9 HF

In reply to this post by Michael Jensen

> Yes I can transmit using the split options. For 2 reasons I would like
> different approach with a wideband TX.

Unfortunately the K3 *can not* do "wideband TX" ... the DSP modulator
is limited to 200 - 2800 Hz when in DATA mode. There is no alternative
as ESSB modulation is not supported in DATA mode - regardless of which
filters are installed.

> First of all I am interfacing through HRD. That way the split are not
> implemented to my understanding.

Then you need to put pressure on the developers of HRD to fix the
problems with split so it operates correctly.

The alternative is to use "narrow band" with WSJT-X - disable "split"
(untick "Split TX" in Config) and leave the default frequencies as they
are for JT65A. Then click the +2 KHz box to QSY both transmit and
receive up 2 KHz for JT9. It is possible to monitor the entire 4 KHz
in "wideband" receive then simply select +2 KHz to QSY when operating
JT9.

73,

... Joe, W4TV

On 10/7/2013 4:11 PM, Michael Jensen wrote:

> Hi
>
> Thanks for the reply
>
> Yes I can transmit using the split options. For 2 reasons I would like
> different approach with a wideband TX.
>
> First of all I am interfacing through HRD. That way the split are not
> implemented to my understanding.
> Then I really like to know exactly where i transmit. Using the split the
> only indication I get is that the frequency in the b VFO. But i am not able
> to see if i am actually doing TX on A or B VFO during a TX cycle.
>
>
> 73 de OZ1BZJ
>
> Michael
>
>
>
> --
> View this message in context: http://elecraft.365791.n2.nabble.com/K3-Filters-for-mixed-JT65-and-JT9-HF-tp7578942p7579667.html
> Sent from the Elecraft mailing list archive at Nabble.com.
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
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WB4SON

Re: [K3] Filters for mixed JT65 and JT9 HF

In reply to this post by Oliver Dröse

Just be aware that current DSP firmware in the K3 limits the receive
bandwidth to something around 3400 Hz. So even if you have a wider filter,
like the 6 KHz AM filter, you will not be able to utilize the full 4 KHz
bandwidth of WSJT-X for JT65/MT9 modes.

Lyle is aware of this issue and it is on his list to work on in the future.

And even if you are in Split mode, rest assured that you know exactly where
you are transmitting -- on the exact audio offset indicated on the display.
Operating Split is the way to go. The only drawback I've seen is that
WSJT-X does nothing to make sure the K3 is in the Split mode, it just
assumes it is.

73, Bob, WB4SON
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73, Bob, WB4SON

Joe Subich, W4TV-4

Re: [K3] Filters for mixed JT65 and JT9 HF

On 10/7/2013 4:39 PM, Bob wrote:
> Just be aware that current DSP firmware in the K3 limits the receive
> bandwidth to something around 3400 Hz. So even if you have a wider
> filter, like the 6 KHz AM filter, you will not be able to utilize the
> full 4 KHz bandwidth of WSJT-X for JT65/MT9 modes.

Absolutely *not* true ... I regularly receive 200 to 2400 Hz in DATA A
with the FM (or AM) filter. It is simply a matter of adjusting the
High and Low cut frequencies to 200/4200 or shift/Width to 2200/4000.

I have been doing that ever since K1JT offered me a pre-release look
at the "wideband" decoding support in WSJT-X with no issues other than
some CAT problems with the interface to CI-V Commander from DXLab
Suite which K1JT and AA6YQ resolved quite quickly.

73,

... Joe, W4TV

On 10/7/2013 4:39 PM, Bob wrote:

> Just be aware that current DSP firmware in the K3 limits the receive
> bandwidth to something around 3400 Hz. So even if you have a wider filter,
> like the 6 KHz AM filter, you will not be able to utilize the full 4 KHz
> bandwidth of WSJT-X for JT65/MT9 modes.
>
> Lyle is aware of this issue and it is on his list to work on in the future.
>
> And even if you are in Split mode, rest assured that you know exactly where
> you are transmitting -- on the exact audio offset indicated on the display.
> Operating Split is the way to go. The only drawback I've seen is that
> WSJT-X does nothing to make sure the K3 is in the Split mode, it just
> assumes it is.
>
> 73, Bob, WB4SON
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
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Michael Jensen

Re: [K3] Filters for mixed JT65 and JT9 HF

In reply to this post by Oliver Dröse

Hi Olli

Thanks for the reply

Well yes the SW tells my radio that it should TX on the B VFO. But then
again it is SW. A piece of programming that should work on 100000 of
combinations of different PC HW and several OS. Nothing that you could
test in all combinations. 15 years of working with production and the
related automation involving a lot of SW have learned me to be
sceptical. IT mostly works yes, but sometime not. Right now i have no
indication that it works or not. My K3 do indeed display an arrow
pointing toward the A VFO, but it do dot change to B VFO during TX
despite the fact that TX are on the B VFO frequency. So the arrow on
the K3 seems not to change when a VFO B TX are initiated via CAT.

Before we get there, yes i know that there are plenty of SW (Firmware)
in the K3 as well. But the number of input possible and the number of
configurations are limited and there for possible to test and have been
very well tested by Elecraft and the K3 community.

I am sure the WSJT-X are a very well designed piece of SW and i am
indeed very happy using it. I just like to be sure where i put an signal
on the air.

73 de OZ1BZJ

Michael

.
Den 07-10-2013 22:28, Oliver Dröse skrev:

> Hi Michael,
>
> when in Split mode you always TX on the VFO B frequency. Besides this
> there is a small arrow either above or below the TX symbol on the
> display pointing to the VFO choosen for transmit. ;-)
>
> 73, Olli - DH8BQA
>
>
>
> ----- Original Message ----- From: "Michael Jensen"
> <[hidden email]>
> To: <[hidden email]>
> Sent: Monday, October 07, 2013 10:11 PM
> Subject: Re: [Elecraft] [K3] Filters for mixed JT65 and JT9 HF
>
>

Joe Subich, W4TV-4

Re: [K3] Filters for mixed JT65 and JT9 HF

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

> Absolutely *not* true ... I regularly receive 200 to 2400 Hz in DATA A
> with the FM (or AM) filter.

Correction ... 200 to 4200 Hz

73,

... Joe, W4TV

On 10/7/2013 4:51 PM, Joe Subich, W4TV wrote:

>
> On 10/7/2013 4:39 PM, Bob wrote:
>> Just be aware that current DSP firmware in the K3 limits the receive
>> bandwidth to something around 3400 Hz. So even if you have a wider
>> filter, like the 6 KHz AM filter, you will not be able to utilize the
>> full 4 KHz bandwidth of WSJT-X for JT65/MT9 modes.
>
> Absolutely *not* true ... I regularly receive 200 to 2400 Hz in DATA A
> with the FM (or AM) filter. It is simply a matter of adjusting the
> High and Low cut frequencies to 200/4200 or shift/Width to 2200/4000.
>
> I have been doing that ever since K1JT offered me a pre-release look
> at the "wideband" decoding support in WSJT-X with no issues other than
> some CAT problems with the interface to CI-V Commander from DXLab
> Suite which K1JT and AA6YQ resolved quite quickly.
>
> 73,
>
> ... Joe, W4TV
>
>
> On 10/7/2013 4:39 PM, Bob wrote:
>> Just be aware that current DSP firmware in the K3 limits the receive
>> bandwidth to something around 3400 Hz. So even if you have a wider
>> filter,
>> like the 6 KHz AM filter, you will not be able to utilize the full 4 KHz
>> bandwidth of WSJT-X for JT65/MT9 modes.
>>
>> Lyle is aware of this issue and it is on his list to work on in the
>> future.
>>
>> And even if you are in Split mode, rest assured that you know exactly
>> where
>> you are transmitting -- on the exact audio offset indicated on the
>> display.
>> Operating Split is the way to go. The only drawback I've seen is that
>> WSJT-X does nothing to make sure the K3 is in the Split mode, it just
>> assumes it is.
>>
>> 73, Bob, WB4SON
>> ______________________________________________________________
>> 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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Charlie T, K3ICH

Re: [K3] Filters for mixed JT65 and JT9 HF

I believe that figure of 3400 Hz is the AUDIO bandwidth which is equivalent
to an AM bandwidth twice that, or 6.8 kHz. If I am correct, then you can
most certainly take advantage of your 6 kHz AM filter which will limit your
broadcast audio bandwidth to 3.0 kHz. The 15 kHz filter will get you an
extra 400 Hz.of audio, but is probably not practical due to the excessive
bandwidth. Save that one for FM.

73, Charlie k3ICH

>
>
> On 10/7/2013 4:51 PM, Joe Subich, W4TV wrote:
>>
>> On 10/7/2013 4:39 PM, Bob wrote:
>>> Just be aware that current DSP firmware in the K3 limits the receive
>>> bandwidth to something around 3400 Hz. So even if you have a wider
>>> filter, like the 6 KHz AM filter, you will not be able to utilize the
>>> full 4 KHz bandwidth of WSJT-X for JT65/MT9 modes.
>>
>>

Joe Subich, W4TV-4

Re: [K3] Filters for mixed JT65 and JT9 HF

> If I am correct, then you can most certainly take advantage of your 6
> kHz AM filter which will limit your broadcast audio bandwidth to 3.0
> kHz.

That only applies in AM transmit because of the double sideband nature
of AM. If you use the 6 KHZ filter for SSB/ESSB/DATA receive, the
entire filter passband is used for one sideband ... one edge of the
filter is placed at 50 Hz in SSB/ESSB or 200 Hz in DATA and the other
edge of the filter is 6+ KHz away from the carrier ... more than enough
for the 4200 Hz HF limit in the DSP.

73,

... Joe, W4TV

On 10/7/2013 7:31 PM, Charlie T, K3ICH wrote:

> I believe that figure of 3400 Hz is the AUDIO bandwidth which is
> equivalent to an AM bandwidth twice that, or 6.8 kHz. If I am correct,
> then you can most certainly take advantage of your 6 kHz AM filter which
> will limit your broadcast audio bandwidth to 3.0 kHz. The 15 kHz filter
> will get you an extra 400 Hz.of audio, but is probably not practical due
> to the excessive bandwidth. Save that one for FM.
>
> 73, Charlie k3ICH
>>
>>
>> On 10/7/2013 4:51 PM, Joe Subich, W4TV wrote:
>>>
>>> On 10/7/2013 4:39 PM, Bob wrote:
>>>> Just be aware that current DSP firmware in the K3 limits the receive
>>>> bandwidth to something around 3400 Hz. So even if you have a wider
>>>> filter, like the 6 KHz AM filter, you will not be able to utilize the
>>>> full 4 KHz bandwidth of WSJT-X for JT65/MT9 modes.
>>>
>>>
> ______________________________________________________________
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Don Wilhelm-4

Re: [K3] Filters for mixed JT65 and JT9 HF

In reply to this post by Charlie T, K3ICH

BUT,

The filter that must be specified for DATA mode TX is the 2.7 (or 2.8)
kHz filter. You cannot use the wider filters for DATA mode transmit -
the firmware prevents it (unless you lie to the K3 about which filter is
which width). You can use a wider filter for receive, but that does not
help transmit. The transmit audio width is fixed by the DSP, so a wider
filter will not increase that limit.

What is wrong with using the split arrangement that is provided by the
computer software - no "work-arounds" needed, it makes everything
seamless, and can automatically put the K3 into split mode.

73,
Don W3FPR

On 10/7/2013 7:31 PM, Charlie T, K3ICH wrote:
> I believe that figure of 3400 Hz is the AUDIO bandwidth which is
> equivalent to an AM bandwidth twice that, or 6.8 kHz. If I am
> correct, then you can most certainly take advantage of your 6 kHz AM
> filter which will limit your broadcast audio bandwidth to 3.0 kHz.
> The 15 kHz filter will get you an extra 400 Hz.of audio, but is
> probably not practical due to the excessive bandwidth. Save that one
> for FM.
>

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Joe Subich, W4TV-4

Re: [K3] Filters for mixed JT65 and JT9 HF

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

Bob,

On 10/8/2013 10:28 AM, Bob wrote:
> Hi Joe,
>
> I disagree with your adamant public statement as the -10 dB points
> even with the filter center shifted up to 2000 Hz are at 300 Hz and
> 3800 Hz -- That's 3500 Hz edge to edge, not 4000.

I believe your measurements are incorrect. Using an XG3 at -73 dBm
for a signal source and an audio spectrum analyzer connected to the
Line Out of K3 S/N 622 with an *unmodified* DPS board and original
transformers on the KIO3, the audio is -4 dB at 300 Hz/-15 dB at 200
Hz and -5dB at 4000 Hz/-14 dB a 4200 Hz.

Put another way, the measured -6dB points are 263 - 4016 Hz (BW[6 dB]
= 3753 Hz) and measured -10dB points are 222 - 4142 Hz (BW [10dB] =
3920 Hz). Those numbers are close enough to 4 KHz for me to be adamant
that the K3 works very well in "broadband mode" with either the FM or
AM filters in WSJT-X.

Moving the LF limit down to 50 Hz as in the case of SSB isn't going to
make a significant difference because the transformers have a good deal
of effect there. Duplicating the LF measurement in SSB with LO=0.00
moves the -10dB point down by only 50 Hz (170 Hz).

That the K3 is down less than 6dB at 4KHz is the key - could it be a
bit better, yes but at what cost? Audio frequencies below 300 Hz have
little value for WSJT-X receive (they're more than -1KHz from the old
1270 Hz "0 dF") and even with the roll off WSJT-X performs very well
at -200 Hz. Split handles any transmit bandwidth issues in any case.

73,

... Joe, W4TV

On 10/8/2013 10:28 AM, Bob wrote:

> Hi Joe,
>
> I disagree with your adamant public statement as the -10 dB points even
> with the filter center shifted up to 2000 Hz are at 300 Hz and 3800 Hz --
> That's 3500 Hz edge to edge, not 4000. This has also been confirmed by
> Lyle himself, who agrees that widening the bandwidth 400-600 HZ would be a
> good thing to do.
>
> I've also confirmed this with two other K3 owners. If your DSP response is
> wider then consider yourself lucky because others don't experience the same
> thing.
>
> 73, Bob, WB4SON
>
>
> On Mon, Oct 7, 2013 at 4:51 PM, Joe Subich, W4TV <[hidden email]> wrote:
>
>>
>> On 10/7/2013 4:39 PM, Bob wrote:
>>
>>> Just be aware that current DSP firmware in the K3 limits the receive
>>> bandwidth to something around 3400 Hz. So even if you have a wider
>>> filter, like the 6 KHz AM filter, you will not be able to utilize the
>>> full 4 KHz bandwidth of WSJT-X for JT65/MT9 modes.
>>>
>>
>> Absolutely *not* true ... I regularly receive 200 to 2400 Hz in DATA A
>> with the FM (or AM) filter. It is simply a matter of adjusting the
>> High and Low cut frequencies to 200/4200 or shift/Width to 2200/4000.
>>
>> I have been doing that ever since K1JT offered me a pre-release look
>> at the "wideband" decoding support in WSJT-X with no issues other than
>> some CAT problems with the interface to CI-V Commander from DXLab
>> Suite which K1JT and AA6YQ resolved quite quickly.
>>
>> 73,
>>
>> ... Joe, W4TV
>>
>>
>>
>> On 10/7/2013 4:39 PM, Bob wrote:
>>
>>> Just be aware that current DSP firmware in the K3 limits the receive
>>> bandwidth to something around 3400 Hz. So even if you have a wider
>>> filter,
>>> like the 6 KHz AM filter, you will not be able to utilize the full 4 KHz
>>> bandwidth of WSJT-X for JT65/MT9 modes.
>>>
>>> Lyle is aware of this issue and it is on his list to work on in the
>>> future.
>>>
>>> And even if you are in Split mode, rest assured that you know exactly
>>> where
>>> you are transmitting -- on the exact audio offset indicated on the
>>> display.
>>> Operating Split is the way to go. The only drawback I've seen is that
>>> WSJT-X does nothing to make sure the K3 is in the Split mode, it just
>>> assumes it is.
>>>
>>> 73, Bob, WB4SON
>>> ______________________________**______________________________**__
>>> Elecraft mailing list
>>> Home: http://mailman.qth.net/**mailman/listinfo/elecraft<http://mailman.qth.net/mailman/listinfo/elecraft>
>>> Help: http://mailman.qth.net/mmfaq.**htm<http://mailman.qth.net/mmfaq.htm>
>>> Post: mailto:[hidden email].**net <[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<http://mailman.qth.net/mailman/listinfo/elecraft>
>> Help: http://mailman.qth.net/mmfaq.**htm<http://mailman.qth.net/mmfaq.htm>
>> Post: mailto:[hidden email].**net <[hidden email]>
>>
>> This list hosted by: http://www.qsl.net
>> Please help support this email list: http://www.qsl.net/donate.html
>>
>

alsopb

Re: [K3] Filters for mixed JT65 and JT9 HF

I wonder if someone who has significant WSJT-X experience would like to
pontificate of the real benefit of squeezing out another KHz of
bandwidth out?

It seems to me on HF one is simply inviting in more signals which can
potentially de-sense the RX. That wipes out the benefit of the weak
signal mode. I really doubt these band segment is devoid of users of
different high power modes.

Maybe WSJT-X is magic....

73 de Brian/K3KO

On 10/8/2013 15:34, Joe Subich, W4TV wrote:

>
> Bob,
>
> On 10/8/2013 10:28 AM, Bob wrote:
> > Hi Joe,
> >
>> I disagree with your adamant public statement as the -10 dB points
>> even with the filter center shifted up to 2000 Hz are at 300 Hz and
>> 3800 Hz -- That's 3500 Hz edge to edge, not 4000.
>
> I believe your measurements are incorrect. Using an XG3 at -73 dBm
> for a signal source and an audio spectrum analyzer connected to the
> Line Out of K3 S/N 622 with an *unmodified* DPS board and original
> transformers on the KIO3, the audio is -4 dB at 300 Hz/-15 dB at 200
> Hz and -5dB at 4000 Hz/-14 dB a 4200 Hz.
>
> Put another way, the measured -6dB points are 263 - 4016 Hz (BW[6 dB]
> = 3753 Hz) and measured -10dB points are 222 - 4142 Hz (BW [10dB] =
> 3920 Hz). Those numbers are close enough to 4 KHz for me to be adamant
> that the K3 works very well in "broadband mode" with either the FM or
> AM filters in WSJT-X.
>
> Moving the LF limit down to 50 Hz as in the case of SSB isn't going to
> make a significant difference because the transformers have a good deal
> of effect there. Duplicating the LF measurement in SSB with LO=0.00
> moves the -10dB point down by only 50 Hz (170 Hz).
>
> That the K3 is down less than 6dB at 4KHz is the key - could it be a
> bit better, yes but at what cost? Audio frequencies below 300 Hz have
> little value for WSJT-X receive (they're more than -1KHz from the old
> 1270 Hz "0 dF") and even with the roll off WSJT-X performs very well
> at -200 Hz. Split handles any transmit bandwidth issues in any case.
>
> 73,
>
> ... Joe, W4TV
>
>
> On 10/8/2013 10:28 AM, Bob wrote:
>> Hi Joe,
>>
>> I disagree with your adamant public statement as the -10 dB points even
>> with the filter center shifted up to 2000 Hz are at 300 Hz and 3800 Hz --
>> That's 3500 Hz edge to edge, not 4000. This has also been confirmed by
>> Lyle himself, who agrees that widening the bandwidth 400-600 HZ would
>> be a
>> good thing to do.
>>
>> I've also confirmed this with two other K3 owners. If your DSP
>> response is
>> wider then consider yourself lucky because others don't experience the
>> same
>> thing.
>>
>> 73, Bob, WB4SON
>>
>>
>> On Mon, Oct 7, 2013 at 4:51 PM, Joe Subich, W4TV <[hidden email]>
>> wrote:
>>
>>>
>>> On 10/7/2013 4:39 PM, Bob wrote:
>>>
>>>> Just be aware that current DSP firmware in the K3 limits the receive
>>>> bandwidth to something around 3400 Hz. So even if you have a wider
>>>> filter, like the 6 KHz AM filter, you will not be able to utilize the
>>>> full 4 KHz bandwidth of WSJT-X for JT65/MT9 modes.
>>>>
>>>
>>> Absolutely *not* true ... I regularly receive 200 to 2400 Hz in DATA A
>>> with the FM (or AM) filter. It is simply a matter of adjusting the
>>> High and Low cut frequencies to 200/4200 or shift/Width to 2200/4000.
>>>
>>> I have been doing that ever since K1JT offered me a pre-release look
>>> at the "wideband" decoding support in WSJT-X with no issues other than
>>> some CAT problems with the interface to CI-V Commander from DXLab
>>> Suite which K1JT and AA6YQ resolved quite quickly.
>>>
>>> 73,
>>>
>>> ... Joe, W4TV
>>>
>>>
>>>
>>> On 10/7/2013 4:39 PM, Bob wrote:
>>>
>>>> Just be aware that current DSP firmware in the K3 limits the receive
>>>> bandwidth to something around 3400 Hz. So even if you have a wider
>>>> filter,
>>>> like the 6 KHz AM filter, you will not be able to utilize the full 4
>>>> KHz
>>>> bandwidth of WSJT-X for JT65/MT9 modes.
>>>>
>>>> Lyle is aware of this issue and it is on his list to work on in the
>>>> future.
>>>>
>>>> And even if you are in Split mode, rest assured that you know exactly
>>>> where
>>>> you are transmitting -- on the exact audio offset indicated on the
>>>> display.
>>>> Operating Split is the way to go. The only drawback I've seen is
>>>> that
>>>> WSJT-X does nothing to make sure the K3 is in the Split mode, it just
>>>> assumes it is.
>>>>
>>>> 73, Bob, WB4SON
>>>> ______________________________**______________________________**__
>>>> Elecraft mailing list
>>>> Home:
>>>> http://mailman.qth.net/**mailman/listinfo/elecraft<http://mailman.qth.net/mailman/listinfo/elecraft>
>>>>
>>>> Help:
>>>> http://mailman.qth.net/mmfaq.**htm<http://mailman.qth.net/mmfaq.htm>
>>>> Post: mailto:[hidden email].**net <[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<http://mailman.qth.net/mailman/listinfo/elecraft>
>>>
>>> Help:
>>> http://mailman.qth.net/mmfaq.**htm<http://mailman.qth.net/mmfaq.htm>
>>> Post: mailto:[hidden email].**net <[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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>
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>
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WB4SON

Re: [K3] Filters for mixed JT65 and JT9 HF

"I wonder if someone who has significant WSJT-X experience would like to
pontificate of the real benefit of squeezing out another KHz of bandwidth
out?"

Certainly no expert here, but the slightly wider bandwidth does allow a
WSJT-X user to copy the full suggested sub-bands for both JT65 and JT9 at
the same time. While, to your point, that might not be the wisest thing to
do on 20 meters during a contest when folks tend to ignore the "suggested"
band plans, many times on the WARC bands there are no strong signals to
worry about.

So the bottom line is when it is appropriate, you can use it, and when it
isn't you can always shift to a more narrow roofing filter and focus on one
mode vs the other. It's simply an option.

The ability of JT65 and JT9 to decode signals below the noise level is the
closest thing to magic that I've come across in my ham experience, allowing
extremely low power communication to be accomplished with sub-optimal
antennas. I can work Australia, half way around the world, regularly with
0.5 watts of output But it isn't magic, just applied mathematics. And
there is no denying there is something almost magical about decoding a
signal that you can't even hear.

73, Bob, WB4SON
______________________________________________________________
Elecraft mailing list
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Post: mailto:[hidden email]

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73, Bob, WB4SON