JT9 on 50 Mhz ?

[Mark Spencer]

Hi.  I've been pondering what digital modes to run this summer.  I'm curious is there any reason why JT9 would not be a good choice for 50 Mhz ?  (The added sensitivity vs FT8 would seem an advantage to me when working tropo scatter for example ?)

I'm curious is there a reason why JT9 never became popular on 50 Mhz ?

73

Mark S

VE7AFZ

[Lance Collister, W7GJ]

Hi Mark,

I think this is yet to be explored ;-)   GL and VY 73, Lance


On 4/28/2019 19:05:22, Mark Spencer wrote:
> Hi.  I've been pondering what digital modes to run this summer.  I'm curious is
> there any reason why JT9 would not be a good choice for 50 Mhz ?  (The added

> sensitivity vs FT8 would seem an advantage to me when working tropo scatter for
> example ?)
>
> I'm curious is there a reason why JT9 never became popular on 50 Mhz ?
>
> 73
> Mark S
> VE7AFZ
>
>

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--
Lance Collister, W7GJ(ex WA3GPL, WA1JXN, WA1JXN/C6A, ZF2OC/ZF8, E51SIX, 3D2LR, 5W0GJ, E6M, TX5K, KH8/W7GJ, V6M, T8GJ, VK9CGJ, VK9XGJ, C21GJ)
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URL: http://www.bigskyspaces.com/w7gj
Skype: lanceW7GJ
2m DXCC #11/6m DXCC #815

Interested in 6m EME? Ask me about subscribing to the Magic Band EME
email group, or just fill in the request box at the bottom of my web
page (above)!

[Edward R Cole]

Mark,

My manual for WSJT, which includes JT9, is on the other computer which is disconnected to install a new computer (translation: a big bother to rehook all the cables just to open the manual).  I tried to find the link but think its probably available from the WSJT program.

In there Joe Taylor discusses the various programs and their individual merits and applications.  Only a brief mention on his webpage that says JT9 is about 2 dB more sensitive than JT65 plus occupies less bandwidth.  I suspect the message structure is still the standard eme exchange which might not apply well to 6m tropo contacts.  That is where the new FT8 (and FT4) seems to shine.

But no reason not to use JT9 for tropo contacts.  You just got to get folks to run it with you (my guess FT8 has become std so you probably need to set up skeds or prior commitments.  I've not run WSJT-X so possibly it can auto-detect and switch modes??  I understand QRA64 and JT65 can do that.

GL, Ed - KL7UW

At 11:05 AM 4/28/2019, Mark Spencer wrote:

Hi.  I've been pondering what digital modes to run this summer.  I'm curious is there any reason why JT9 would not be a good choice for 50 Mhz ?  (The added sensitivity vs FT8 would seem an advantage to me when working tropo scatter for example ?

I'm curious is there a reason why JT9 never became popular on 50 Mhz ?

73
Mark S
VE7AFZ

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73, Ed - KL7UW
  http://www.kl7uw.com
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[STEVE MCDONALD]

Mark, JT9 did have a short run of extreme popularity for one summer when many of the CW-only guys were discovering and moving to digital. It was soon found that the lengthy period was too much for a fast and complete EU to NA exchange on Es before the signals dropped out which then lead to a plea for something shorter. I believe that beta versions of FT8 came out towards the end of that initial Es season and there was often a mix of the two modes. By the
next Es season, the FT8 revolution was in full swing and JT9 fell be the wayside.
I much prefer JT9 as it is more sensitive and the operator has much more control and ‘thinking time’ before responding on the next sequence. I’d love to see more JT9 on 6m but it may be too late !

Steve VE7SL

[Mark Spencer]

Thanks Steve. I must have missed out on the JT9 opportunities on 50 MHz back in the day (:

I agree it is probably not a good choice for Es, but I am thinking it might help get a bit more distance on tropo scatter if the band conditions are flat.

I recall using JT65 terrestrially on both 144 and 1296 and would expect JT9 would be even better (at least on 50 MHz.)

73

Mark Spencer
VE7AFZ
nets...@gmail.com

[Lance Collister, W7GJ]

Hi Mark,

When I worked VK in January, the only contacts I made were on JT65A. Guys were on
trying with FT8, but it just wasn't strong enough and/or the activity from down under
was on JT65A. In a marginal DX situation like that, I agree that JT9 could really be
useful on 6m. I don't know what the sensitivity would be of JT9 if it were a 15
second mode like FT8. It is my understanding that FT8 was primarily invented to be
able to take advantage of the shorter and/or marginal Es openings on 6m. That also is
why it is so popular...it really does work! And one of the HUGE assets with FT8 is
that you can see where you are being received by watching PSK REPORTER ;-)

But if the band is really wide open and signals are strong, you still can work a lot
more stations during a short opening on SSB.

However, we have not had enough Es seasons to really do much comparison, and it very
well may be that JT9 will prove itself very useful on 6m.  Time will tell!

GL and VY 73, Lance

On 4/28/2019 23:28:04, Mark Spencer wrote:
> Thanks Steve. I must have missed out on the JT9 opportunities on 50 MHz back in the day (:
>
> I agree it is probably not a good choice for Es, but I am thinking it might help get a bit more distance on tropo scatter if the band conditions are flat.
>
> I recall using JT65 terrestrially on both 144 and 1296 and would expect JT9 would be even better (at least on 50 MHz.)
>
> 73
>
> Mark Spencer
> VE7AFZ
> nets...@gmail.com
>
>
>
>> On Apr 28, 2019, at 3:43 PM, STEVE MCDONALD <ve...@shaw.ca> wrote:
>>
>> Mark, JT9 did have a short run of extreme popularity for one summer when many of the CW-only guys were discovering and moving to digital. It was soon found that the lengthy period was too much for a fast and complete EU to NA exchange on Es before the signals dropped out which then lead to a plea for something shorter. I believe that beta versions of FT8 came out towards the end of that initial Es season and there was often a mix of the two modes. By the
>> next Es season, the FT8 revolution was in full swing and JT9 fell be the wayside.

>> I much prefer JT9 as it is more sensitive and the operator has much more control and ‘thinking time’ before responding on the next sequence. I’d love to see more JT9 on 6m but it may be too late !

>>
>> Steve VE7SL
>>
>>
>> ----- Original Message -----
>> From: Mark Spencer <nets...@gmail.com>
>> To: PNWVHFS <pnw...@googlegroups.com>
>> Sent: Sun, 28 Apr 2019 13:05:22 -0600 (MDT)
>> Subject: [PNWVHFS] JT9 on 50 Mhz ?
>>
>> Hi. I've been pondering what digital modes to run this summer. I'm
>> curious is there any reason why JT9 would not be a good choice for 50 Mhz
>> ? (The added sensitivity vs FT8 would seem an advantage to me when working
>> tropo scatter for example ?)
>>
>> I'm curious is there a reason why JT9 never became popular on 50 Mhz ?
>>
>> 73
>> Mark S
>> VE7AFZ
>>
>>
>> --
>> ~The Voice of the Pacific NorthWest VHF Society~
>> You are subscribed to the Google Groups "PNWVHFS" group.
>> To post to this group, send email to PNW...@googlegroups.com
>> To read message history, visit http://groups.google.com/group/PNWVHFS
>> ---
>> You received this message because you are subscribed to the Google Groups "PNWVHFS" group.
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>> To post to this group, send email to pnw...@googlegroups.com.
>> For more options, visit https://groups.google.com/d/optout.
>>

[Steve]

>I don't know what the sensitivity would be of JT9 if it were a 15
second mode like FT8.

I suspect that it would be similar to FT8 as sensitivity seems proportional
to integration time. FT8's sensitivity is ~ -20db while when using JT9 on
630m, I regularly see decodes to -28, so its extra time definitely offers
some rewards. In practice it is well-suited for most Es work but for those
long haul multi-cloud hops to EU from out west, JT9 is probably too slow
since it would require that the selected signal hangs in for at least 3
sequences. FT8 seems perfectly suited for that mode but the lack of time to
make on the fly decisions, for me at least, is unsettling.

>And one of the HUGE assets with FT8 is
that you can see where you are being received by watching PSK REPORTER ;-)

this also happens with JT9

>But if the band is really wide open and signals are strong, you still can
>work a lot
more stations during a short opening on SSB.

YES!!! So many times last summer, FT8 signals were S9++ yet most seemed
content to stay on that mode. I really hope we see a swing back to CW and
SSB when conditions do not require FT8 or JT9. I miss hearing old friend's
voices and fists!

Steve

WEB - "The VE7SL Radio Notebook": http://qsl.net/ve7sl/

VE7SL BLOG - "Homebrewing and Operating Adventures From 2200m to Nanowaves":
http://ve7sl.blogspot.ca/

[Mark Spencer]

Thanks Steve. 

 I agree with you about the likely benefits of JT9 during flat band conditions (assuming the propagation mechanism lasts long enough.)  Thinking about this issue a bit more I suppose on 50 Mhz there will of often be enough random meteors around to make MSK144 a viable alternative (particularly in the early mornings), but I suspect if the non meteor enhanced signal levels are high enough to use JT9, using JT9 is probably going to be a better plan than waiting for enough random meteors to complete a QSO.  (The use of JT9 would also depend on other stations actually listening for JT9 signals, and perhaps the radios having the required frequency stability for JT9 and probably other issues I haven`t thought of..)

Thinking out loud, I`m thinking of using MSK144 in the early mornings to hopefully work meteor scatter, then switching to the legacy analog modes and JT9 at later parts of the day.  

After reading the online manual for WSJT 2.0 I am left with the impression there may be a 6 dB signal to noise ratio improvement for JT9 vs FT8.  This would seem useful to me.  It would be fun (for me anyways) to try this mode out on 50 Mhz this summer.

I also agree with the concept of switching to the legacy analog modes when signal levels are high enough to do so.

73

Mark S
VE7AFZ

[Mark Spencer]

Thanks Lance. That is good info. Yes it will be interesting to try JT9 this summer. This may motivate me to permanently install a 50 MHz beam antenna at my home station (almost all my activity on 50 MHz currently takes place from my portable / rover station.)

73

Mark Spencer
VE7AFZ
nets...@gmail.com

[Edward R Cole]

Following this topic.  I should disclose not having used JT9 or FT8 to this point.

I have had technical issues keeping me off 6m/2m/23cm eme for almost two years.  Hope to have 6m and 2m QRV soon for both eme, ms, and long-haul tropo (incl. 6m Es).  Cable testing/upgrade in process for 2m and new az-rotator/encoder/new thrust bearing install for 6m.

Selecting the mode appropriate for existing conditions seems to be an important decision for maximum contact success.

I have found with 16-years experience using JT65 for eme that signals stronger than -18 are audible at levels good enough for CW and when near -11 probably would permit use of  SSB.  These are my personal observations so not absolute decision points for deciding best mode.

I believe I've read that FT8 decodes down to -24.  JT65 decodes to -28 or -29 depending on how good your system is (and limitations of local noise and Faraday loss).  According to Joe Taylor's website for WSJT, JT9 is about 2 dB more sensitive than FT8, which would put it somewhere between FT8 and JT65.

If meteors are dense enough MSK144 might be a better choice.  I have yet to compare that with the old FFT441 ms sw.

Should not be too hard to get adequate freq stability at 50-MHz for using WSJT modes.  My KX3 improved significantly once I performed the temp compensation procedure plus adding after-market heat sink.  My K3 uses ext.10-MHz reference which keeps 50-MHz to 3-Hz.  My observations on 2m-eme indicate needing to keep transmit drift to < 20-Hz over the 1-minute sequence.  My heated xtal LO in my DEMI transverter holds 7-Hz drift.  I use PLL on 432-MHz and above.

Another requirement for JT65/JT9/FT8 is keeping computer time within 1 second of UTC.  There are several on-line sources of time plus GPS time.  I've noted my win10pro sw "seems" to keep time accurate though I have not measured it (display is to minute level).

I am also intending to move both my 2m-1500w and 6m-1000w sspa's to their respective tower bases which will reduce coax line loss and increase effective power.  Estimate some where mid-summer for those changes.

Looking forward to trying some long distance shots on 6m and 2m.

73, Ed - KL7UW

At 07:43 PM 4/28/2019, Mark Spencer wrote:

Thanks Steve.Â

 I agree with you about the likely benefits of JT9 during flat band conditions (assuming the propagation mechanism lasts long enough.)  Thinking about this issue a bit more I suppose on 50 Mhz there will of often be enough random meteors around to make MSK144 a viable alternative (particularly in the early mornings), but I suspect if the non meteor enhanced signal levels are high enough to use JT9, using JT9 is probably going to be a better plan than waiting for enough random meteors to complete a QSO.  (The use of JT9 would also depend on other stations actually listening for JT9 signals, and perhaps the radios having the required frequency stability for JT9 and probably other issues I haven`t thought of..)

Thinking out loud, I`m thinking of using MSK144 in the early mornings to hopefully work meteor scatter, then switching to the legacy analog modes and JT9 at later parts of the day. Â

After reading the online manual for WSJT 2.0 I am left with the impression there may be a 6 dB signal to noise ratio improvement for JT9 vs FT8.  This would seem useful to me.  It would be fun (for me anyways) to try this mode out on 50 Mhz this summer.

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73, Ed - KL7UW

[Mark Spencer]

Hi Ed:

Re decode thresholds.

From the manual for WSJT-x 2.0

Mode        S/N Threshold

FT8           -21 dB

JT65A        -25 dB

JT9A          -27dB

I realize these numbers may not tell the whole story (I seem to recall that FT8 may have a more advanced decoding scheme that may help vis a vis JT9, and I realize that FT8 and MSK144 now have explicit support for VHF contests.)   

In any event I decoded a JT9 CQ on HF this morning with a -27 dB S/N which is promising.

Even if the advantage of JT9 is only 2db and not 6db, every bit helps in my view and for operations outside of contests I believe the basic none contest mode exchanges would be adequate.

I think at this point I need to get on the air and try out JT9 on 50 Mhz.

73

Mark S
VE7AFZ

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[Edward R Cole]

OK.

I was quoting JT65B which decodes better than JT65A.  Sorry for mixed comparison.

Also the manual I was citing was for WSJT10 and not for WSJT-X, although I expect descriptions to be similar for individual modes such as JT65 and JT9 in either document. 

Decoding for JT65B is -28 for a good Rx systems (and occasionally -29 dB).  I think the main difference between A, B, and C versions is bandwidth.  Narrower bw detects better. 

Difference between using 500-Hz for CW and 2500-Hz for SSB is 10Log(5) which is 7-dB.  So being able to hear tones at -18 implies a detection bw of 10^(18/10) = 63 or bw = 2500/63 = 39 Hz.  That agrees well with the implied human ability to hear down to about 50-Hz bw.

When I did CW-eme in the old days I used a 100-Hz bw to receive.  50-Hz filters had too much "ringing".  Often if signals were good I would run 200-Hz.

JT improves signal detection by more than simple bandwidth narrowing so not exactly comparable.  JT signal levels are in dB below 2500-Hz SNR = 0 dB.  So detecting at -28 dB SNR implies an effective bw of 3.9 Hz, or about 10-dB better than CW.

73, Ed - KL7UW

At 09:01 AM 4/29/2019, you wrote:

Hi Ed:

Re decode thresholds.

From the manual for WSJT-x 2.0

Mode        S/N Threshold
FT8           -21 dB
JT65A        -25 dB
JT9A          -27dB

I realize these numbers may not tell the whole story (I seem to recall that FT8 may have a more advanced decoding scheme that may help vis a vis JT9, and I realize that FT8 and MSK144 now have explicit support for VHF contests.)  Â

In any event I decoded a JT9 CQ on HF this morning with a -27 dB S/N which is promising.

Even if the advantage of JT9 is only 2db and not 6db, every bit helps in my view and for operations outside of contests I believe the basic none contest mode exchanges would be adequate.

I think at this point I need to get on the air and try out JT9 on 50 Mhz.

73
Mark S
VE7AFZ

On Monday, April 29, 2019 at 1:06:57 AM UTC-7, Edward R Cole wrote:

Following this topic.  I should disclose not having used JT9 or FT8 to this point.

I have had technical issues keeping me off 6m/2m/23cm eme for almost two years.  Hope to have 6m and 2m QRV soon for both eme, ms, and long-haul tropo (incl. 6m Es).  Cable testing/upgrade in process for 2m and new az-rotator/encoder/new thrust bearing install for 6m.

Selecting the mode appropriate for existing conditions seems to be an important decision for maximum contact success.

I have found with 16-years experience using JT65 for eme that signals stronger than -18 are audible at levels good enough for CW and when near -11 probably would permit use of  SSB.  These are my personal observations so not absolute decision points for deciding best mode.

I believe I've read that FT8 decodes down to -24.  JT65 decodes to -28 or -29 depending on how good your system is (and limitations of local noise and Faraday loss).  According to Joe Taylor's website for WSJT, JT9 is about 2 dB more sensitive than FT8, which would put it somewhere between FT8 and JT65.

If meteors are dense enough MSK144 might be a better choice.  I have yet to compare that with the old FFT441 ms sw.

Should not be too hard to get adequate freq stability at 50-MHz for using WSJT modes.  My KX3 improved significantly once I performed the temp compensation procedure plus adding after-market heat sink.  My K3 uses ext.10-MHz reference which keeps 50-MHz to 3-Hz.  My observations on 2m-eme indicate needing to keep transmit drift to < 20-Hz over the 1-minute sequence.  My heated xtal LO in my DEMI transverter holds 7-Hz drift.  I use PLL on 432-MHz and above.

Another requirement for JT65/JT9/FT8 is keeping computer time within 1 second of UTC.  There are several on-line sources of time plus GPS time.  I've noted my win10pro sw "seems" to keep time accurate though I have not measured it (display is to minute level).

I am also intending to move both my 2m-1500w and 6m-1000w sspa's to their respective tower bases which will reduce coax line loss and increase effective power.  Estimate some where mid-summer for those changes.

Looking forward to trying some long distance shots on 6m and 2m.

73, Ed - KL7UW

At 07:43 PM 4/28/2019, Mark Spencer wrote:

Thanks Steve.Â

 I agree with you about the likely benefits of JT9 during flat band conditions (assuming the propagation mechanism lasts long enough.)  Thinking about this issue a bit more I suppose on 50 Mhz there will of often be enough random meteors around to make MSK144 a viable alternative (particularly in the early mornings), but I suspect if the non meteor enhanced signal levels are high enough to use JT9, using JT9 is probably going to be a better plan than waiting for enough random meteors to complete a QSO.  (The use of JT9 would also depend on other stations actually listening for JT9 signals, and perhaps the radios having the required frequency stability for JT9 and probably other issues I haven`t thought of..)

Thinking out loud, I`m thinking of using MSK144 in the early mornings to hopefully work meteor scatter, then switching to the legacy analog modes and JT9 at later parts of the day. Â

After reading the online manual for WSJT 2.0 I am left with the impression there may be a 6 dB signal to noise ratio improvement for JT9 vs FT8.  This would seem useful to me.  It would be fun (for me anyways) to try this mode out on 50 Mhz this summer.

73

Mark S

VE7AFZ

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73, Ed - KL7UW

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[Lance Collister, W7GJ]

Hi Ed,

Just to correct the typo so you don't lead folks astray - JT65A is the most sensitive
mode.  That is why it is the standard for 6m EME. JT65B is about 1 dB less sensitive
but is the standard on 2m EME because most 2m stations don't have the stability
requires for JT65A.

GL and VY 73, Lance

On 4/29/2019 23:46:52, Edward R Cole wrote:
> OK.
>
> I was quoting JT65B which decodes better than JT65A.  Sorry for mixed comparison.
>
> Also the manual I was citing was for WSJT10 and not for WSJT-X, although I expect
> descriptions to be similar for individual modes such as JT65 and JT9 in either
> document.
>
> Decoding for JT65B is -28 for a good Rx systems (and occasionally -29 dB).  I think
> the main difference between A, B, and C versions is bandwidth.  Narrower bw detects
> better.
>
> Difference between using 500-Hz for CW and 2500-Hz for SSB is 10Log(5) which is
> 7-dB.  So being able to hear tones at -18 implies a detection bw of 10^(18/10) = 63
> or bw = 2500/63 = 39 Hz.  That agrees well with the implied human ability to hear
> down to about 50-Hz bw.
>
> When I did CW-eme in the old days I used a 100-Hz bw to receive. 50-Hz filters had
> too much "ringing".  Often if signals were good I would run 200-Hz.
>
> JT improves signal detection by more than simple bandwidth narrowing so not exactly
> comparable.  JT signal levels are in dB below 2500-Hz SNR = 0 dB.  So detecting at
> -28 dB SNR implies an effective bw of 3.9 Hz, or about 10-dB better than CW.
>
> 73, Ed - KL7UW
>
> At 09:01 AM 4/29/2019, you wrote:
>> Hi Ed:
>>
>> Re decode thresholds.
>>
>> From the manual for WSJT-x 2.0
>>

>> Mode        S/N Threshold
>> FT8           -21 dB
>> JT65A        -25 dB
>> JT9A          -27dB

>>
>> I realize these numbers may not tell the whole story (I seem to recall that FT8
>> may have a more advanced decoding scheme that may help vis a vis JT9, and I

>> realize that FT8 and MSK144 now have explicit support for VHF contests.)  Â

>>
>> In any event I decoded a JT9 CQ on HF this morning with a -27 dB S/N which is
>> promising.
>>
>> Even if the advantage of JT9 is only 2db and not 6db, every bit helps in my view
>> and for operations outside of contests I believe the basic none contest mode
>> exchanges would be adequate.
>>
>> I think at this point I need to get on the air and try out JT9 on 50 Mhz.
>>
>> 73
>> Mark S
>> VE7AFZ
>>
>>
>> On Monday, April 29, 2019 at 1:06:57 AM UTC-7, Edward R Cole wrote:
>>

>> Following this topic.  I should disclose not having used JT9 or FT8 to this

>> point.
>>
>> I have had technical issues keeping me off 6m/2m/23cm eme for almost two

>> years.  Hope to have 6m and 2m QRV soon for both eme, ms, and long-haul
>> tropo (incl. 6m Es).  Cable testing/upgrade in process for 2m and new

>> az-rotator/encoder/new thrust bearing install for 6m.
>>
>> Selecting the mode appropriate for existing conditions seems to be an
>> important decision for maximum contact success.
>>
>> I have found with 16-years experience using JT65 for eme that signals stronger
>> than -18 are audible at levels good enough for CW and when near -11 probably

>> would permit use of  SSB.  These are my personal observations so not

>> absolute decision points for deciding best mode.
>>

>> I believe I've read that FT8 decodes down to -24.  JT65 decodes to -28 or

>> -29 depending on how good your system is (and limitations of local noise and

>> Faraday loss).  According to Joe Taylor's website for WSJT, JT9 is about 2

>> dB more sensitive than FT8, which would put it somewhere between FT8 and JT65.
>>

>> If meteors are dense enough MSK144 might be a better choice.  I have yet to

>> compare that with the old FFT441 ms sw.
>>
>> Should not be too hard to get adequate freq stability at 50-MHz for using WSJT

>> modes.  My KX3 improved significantly once I performed the temp compensation
>> procedure plus adding after-market heat sink.  My K3 uses ext.10-MHz
>> reference which keeps 50-MHz to 3-Hz.  My observations on 2m-eme indicate
>> needing to keep transmit drift to < 20-Hz over the 1-minute sequence.  My
>> heated xtal LO in my DEMI transverter holds 7-Hz drift.  I use PLL on

>> 432-MHz and above.
>>
>> Another requirement for JT65/JT9/FT8 is keeping computer time within 1 second

>> of UTC.  There are several on-line sources of time plus GPS time.  I've

>> noted my win10pro sw "seems" to keep time accurate though I have not measured
>> it (display is to minute level).
>>
>> I am also intending to move both my 2m-1500w and 6m-1000w sspa's to their
>> respective tower bases which will reduce coax line loss and increase effective

>> power.  Estimate some where mid-summer for those changes.

>>
>> Looking forward to trying some long distance shots on 6m and 2m.
>>
>> 73, Ed - KL7UW
>>
>> At 07:43 PM 4/28/2019, Mark Spencer wrote:

>>> Thanks Steve.Â
>>>
>>> Â I agree with you about the likely benefits of JT9 during flat band

>>> conditions (assuming the propagation mechanism lasts long

>>> enough.)  Thinking about this issue a bit more I suppose on 50 Mhz

>>> there will of often be enough random meteors around to make MSK144 a
>>> viable alternative (particularly in the early mornings), but I suspect if
>>> the non meteor enhanced signal levels are high enough to use JT9, using
>>> JT9 is probably going to be a better plan than waiting for enough random

>>> meteors to complete a QSO.  (The use of JT9 would also depend on

>>> other stations actually listening for JT9 signals, and perhaps the radios
>>> having the required frequency stability for JT9 and probably other issues
>>> I haven`t thought of..)
>>>
>>> Thinking out loud, I`m thinking of using MSK144 in the early mornings to
>>> hopefully work meteor scatter, then switching to the legacy analog modes

>>> and JT9 at later parts of the day. Â

>>>
>>> After reading the online manual for WSJT 2.0 I am left with the
>>> impression there may be a 6 dB signal to noise ratio improvement for JT9

>>> vs FT8.  This would seem useful to me.  It would be fun

>>> <https://groups.google.com/d/optout>.
>>
>> 73, Ed - KL7UW
>> Â http://www.kl7uw.com
>> <http://www.kl7uw.com/>
>> Dubus-NA Business mail:
>>   dubu...@gmail.com

>>
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>
> 73, Ed - KL7UW
> http://www.kl7uw.com

> <http://www.kl7uw.com/>Dubus-NA Business mail:

>   dubu...@gmail.com
>
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[Edward R Cole]

Lance,'

Thanks for the correction and that makes sense as
JY65C is used at 1296 and is wider in bw to not
be so restrictive in freq. stability.
I've not studied closely what the differenced in
sensitivity were (only read on current WSJT
website that JT9 was 2 dB more sensitive than FT8).

73, Ed - KL7UW

Dubus-NA Business mail:
dubu...@gmail.com

[Edward R Cole]

JY65C should be JT65C (of course). Typing with
nine fingers doesn't help with typo's. Sorry!

73, Ed - KL7UW

>>>>Mode    S/N Threshold
>shold
>>>>FT8Â Â Â Â Â Â -21 dB
>€š -21 dB
>>>>JT65AÂ Â Â Â -25 dB
>25 dB
>>>>JT9AÂ Â Â Â Â -27dB

> -27dB
>>>>
>>>>I realize these numbers may not tell the
>>>>whole story (I seem to recall that FT8 may
>>>>have a more advanced decoding scheme that may
>>>>help vis a vis JT9, and I realize that FT8

>>>>and MSK144 now have explicit support for VHF contests.)Â Â
>š

>>>>
>>>>In any event I decoded a JT9 CQ on HF this
>>>>morning with a -27 dB S/N which is promising.
>>>>
>>>>Even if the advantage of JT9 is only 2db and
>>>>not 6db, every bit helps in my view and for
>>>>operations outside of contests I believe the
>>>>basic none contest mode exchanges would be adequate.
>>>>
>>>>I think at this point I need to get on the air and try out JT9 on 50 Mhz.
>>>>
>>>>73
>>>>Mark S
>>>>VE7AFZ
>>>>
>>>>
>>>>On Monday, April 29, 2019 at 1:06:57 AM UTC-7, Edward R Cole wrote:
>>>>

>>>> Following this topic. I should

> >>> disclose not having used JT9 or FT8 to this
>>>> point.
>>>>
>>>> I have had technical issues keeping me
>>>> off 6m/2m/23cm eme for almost two

>>>> years. Hope to have 6m and 2m QRV soon

> >>> for both eme, ms, and long-haul

>>>> tropo (incl. 6m Es). Cable

>>>> testing/upgrade in process for 2m and new
> >>> az-rotator/encoder/new thrust bearing install for 6m.
>>>>
>>>> Selecting the mode appropriate for existing conditions seems to be an
>>>> important decision for maximum contact success.
>>>>
>>>> I have found with 16-years experience
>>>> using JT65 for eme that signals stronger
>>>> than -18 are audible at levels good
>>>> enough for CW and when near -11 probably

>>>> would permit use of SSB. These are

>
>>>>my personal observations so not
>>>> absolute decision points for deciding best mode.
>>>>
>>>> I believe I've read that FT8 decodes

>>>> down to -24. JT65 decodes to -28 or

> >>> -29 depending on how good your system is
>>>>(and limitations of local noise and

>>>> Faraday loss). According to Joe

> >>> Taylor's website for WSJT, JT9 is about 2
>>>> dB more sensitive than FT8, which would
>>>> put it somewhere between FT8 and JT65.
>>>>
>>>> If meteors are dense enough MSK144 might

>>>> be a better choice. I have yet to

> >>> compare that with the old FFT441 ms sw.
>>>>
>>>> Should not be too hard to get adequate
>>>> freq stability at 50-MHz for using WSJT

>>>> modes. My KX3 improved significantly

> >>> once I performed the temp compensation
>>>> procedure plus adding after-market heat

>>>> sink. My K3 uses ext.10-MHz

> >>> reference which keeps 50-MHz to

>>>>3-Hz. My observations on 2m-eme indicate

> >>> needing to keep transmit drift to < 20-Hz

>>>>over the 1-minute sequence. My

> >>> heated xtal LO in my DEMI transverter

> holds 7-Hz drift. I use PLL on

> >>> 432-MHz and above.
>>>>
>>>> Another requirement for JT65/JT9/FT8 is
>>>> keeping computer time within 1 second

>>>> of UTC. There are several on-line
> >>> sources of time plus GPS time. I've

> >>> noted my win10pro sw "seems" to keep time
>>>>accurate though I have not measured
>>>> it (display is to minute level).
>>>>
>>>> I am also intending to move both my
>>>> 2m-1500w and 6m-1000w sspa's to their
>>>> respective tower bases which will reduce
>>>> coax line loss and increase effective

>>>> power. Estimate some where mid-summer for those changes.

> >>>
>>>> Looking forward to trying some long distance shots on 6m and 2m.
>>>>
>>>> 73, Ed - KL7UW
>>>>
>>>> At 07:43 PM 4/28/2019, Mark Spencer wrote:

>>>>> Thanks Steve.Â
>
>>>>>
>>>>> Â I agree with you about the

>
>>>>>likely benefits of JT9 during flat band
>>>>> conditions (assuming the propagation mechanism lasts long

>>>>> enough.)ÂÂ Thinking about this

>s
>>>>>issue a bit more I suppose on 50 Mhz
>>>>> there will of often be enough
>>>>> random meteors around to make MSK144 a
>>>>> viable alternative (particularly in
>>>>> the early mornings), but I suspect if
>>>>> the non meteor enhanced signal
>>>>> levels are high enough to use JT9, using
>>>>> JT9 is probably going to be a
>>>>> better plan than waiting for enough random
>>>>> meteors to complete a

>>>>> QSO.ÂÂ (The use of JT9 would also depend on

>on
>>>>> other stations actually listening
>>>>> for JT9 signals, and perhaps the radios
>>>>> having the required frequency
>>>>> stability for JT9 and probably other issues
>>>>> I haven`t thought of..)
>>>>>
>>>>> Thinking out loud, I`m thinking of
>>>>> using MSK144 in the early mornings to
>>>>> hopefully work meteor scatter, then
>>>>> switching to the legacy analog modes

>>>>> and JT9 at later parts of the day. Â
>¬Å¡

>>>>>
>>>>> After reading the online manual for WSJT 2.0 I am left with the
>>>>> impression there may be a 6 dB
>>>>> signal to noise ratio improvement for JT9

>>>>> vs FT8.ÂÂ This would seem
>m
>>>>>useful to me.ÂÂ It would be fun

>>>> Â http://www.kl7uw.com

> >>> <http://www.kl7uw.com/> Dubus-NA Business mail:

>>>> Â dubu...@gmail.com

>pnwvhfs+u...@googlegroups.com.
>To post to this group, send email to pnw...@googlegroups.com.

>For more options, visit https://groups.google.com/d/optout.

[Mark Spencer]

Sorry to reply to my own thread..

First, thanks for the off list and on list interest in this topic.

Second, after a certain amount of experimentation on my part and some input from a member of the WSJT-x dev team I have concluded that JT9 on 50 Mhz is not a good fit for my roving / portable operations.   Essentially I doubt that my radio has the necessary frequency stability for to fully exploit the advantages of JT9 on 50 Mhz in "field conditions" (especially as I also need to assume that the radio at the other end of the link will also have less than perfect frequency stability, so ideally I would want my radio to have a significant degree of "margin" in this regards.)

All that being said I am still interested in experimenting with this and other modes going forwards but at this point I don't intend to run it during the June contest with my current equipment.  

Perhaps one day I will have a GPS frequency locked 50 Mhz radio for my portable outings (:

I'l announce any further on the air tests.

73

Mark S

VE7AFZ