Date   

Switching between FT8 and FT4 #decode

Rory Bowers
 

In WSJT-X ver 2.5.0-rc1 I was in FT8 on 14074 and switched to FT4 on 14080.  After about 12 passes it was obvious that it was not decoding.  I have noticed this before and was able to duplicate it today.
Rory, K5CKS


Re: S/N reporting on different modes #modes #Icom

Sam Birnbaum <w2jdb@...>
 

Hi

I used my alltext.exe program to analyze the the snr of every decoded station and calculate vsriance, min, max and mean. Not only does it show that there is a large variance in the same short time period for any particular station but that the same station will have a different set of values the next day.

The program is free and available on programsbyw2jdb on groups.io

Please note it is a windows based executable.

73,

Sam W2JDB


On Tuesday, July 13, 2021, 07:18:18 AM EDT, Tom V. Segalstad <la4ln@...> wrote:


Thanks for the clarification, Bill.

 

Let’s look at repeated QSOs on 6 meters, separated some days in time, but assuming same operating techniques (at least here). The problem is that we don’t want to make duplicate contacts, so the few contacts I show here have been made by me, when using different call signs. Here are the differences in dB reporting, for a previous QSO with some of the stations listed before:

 

OD5KU    -3 dB (-18 dB in a QSO before)

HI8T       -15 dB (-11 dB in a QSO before)

KP4EIT  -13 dB (-19 dB in a QSO before)

CO7MS     -9dB (0 dB in a QSO before)

 

The tendency is still, that the other DX stations are giving a lower dB S/N report.

 

73 fromTom, LA4LN / LC1V

 

Fra: Bill Somerville
Sendt: tirsdag 13. juli 2021 kl. 12.25
Emne: Re: [WSJTX] S/N reporting on different modes #modes #ic-7600 #modes

 

Hi Tom, and Jim,

 

I believe Mike in his OP was questioning the variations in SNR numbers between two stations on different occasions. For example I might have two QSOs with you and one day my SNR for you might be 20 dB different from yours to me, yet another day the difference might be less or more. One might expect the comparison of SNR numbers between two stations using unchanging setups to be consistent unless some form of one-way propagation enhancement were taking place, or more likely the noise environment at one end of the link has changed significantly. Hence my supposition that some stations may be located in regions where local noise is highly variable, for example heavy usage of solar panels with noisy switch-mode inverters, or air-conditioning units with poor noise suppression.

 

73
Bill
G4WJS.

 

On 13/07/2021 11:15, Tom V. Segalstad wrote:

Some comparisons for FT8 reports last Thursday evening (8th of July) on 50 MHz.

Here using 1 kW output power to a 7 element Yagi antenna, and a GaAsFET LNA RX preamplifier.

Listed below are thedifferences in dB S/N reports for some DX QSOs; positive numbers meaning I received stronger S/N reports than the DX station, and negative numbers meaning I received lower S/N reports, than given by me.

OD5KU        -18 dB

HI3MRV      -12 dB

HI8T             -11 dB

HI8RD            -4 dB

4Z1TL            +4 dB

4X1TI           -11 dB

WP4G          -18 dB

WP3R            -9 dB

KP4EIT        -19 dB

CO7MS           0 dB

 I can’t say what is the reason for these fairly large differences in S/N reports for DX QSOs.

But we see that the reports from Central America are all negative.

May be due to QRM from the many stations in USA?

But we in Europe also have many stations in Europe being copied at the same time.

So we wouldn’t think that the QRM level would be much different?

Reports for contacts within Europe were in most QSOs about equal, differing +/- 1 to 2 dB, and in rare cases up to +/- 5dB.

 73 fromTom, LA4LN (and LC1V in contests)

Fra:Bill Somerville
Sendt: tirsdag 13. juli 2021 kl. 11.19
Til: main@WSJTX.groups.io
Emne: Re: [WSJTX] S/N reporting on different modes #modes #ic-7600 #modes

 

On 13/07/2021 09:00, Mike GM3PPE wrote:
> I have been very active on 6 meters this summer and have noticed great
> variability in S/N reports sent and received. For example I worked a
> YV5 station twice in the same week. On the first occasion he sent -18
> and received -05 from me, a difference of 13dB. Two days later he sent
> -15 but was +11 with me, a difference of 26dB. My setup was the same,
> and assuming his setup was unchanged, why the comparative difference?
>
> This effect has been seen on numerous occasions, and by other stations
> in a similar rural location. Are more details on exactly how the S/N
> ratio is calculated available? I want to understand how the background
> noise power is estimated, without having to read the source code!
>
> Mike GM3PPE

Hi Mike,

the noise component consists of local noise plus various other noises
via one or more propagation paths from many directions, with Sporadic E
propagation, which you are almost certainly receiving the YV5 station,
the path loss is highly variable, both over the short term of a few
seconds or minutes and from day to day. It is not reasonable to expect
the noise and signal components to remain in the same ratio during
different QSOs with the same station with such variable propagation
dynamics.

It is interesting that you cite a YV station for your example, I have
noticed that stations in Venezuela on 6m, among some others, often have
some difficulty copying my signals when they are quite strong with me.
My conclusion is that either they are running very high power or they
suffer considerable levels of local QRN, my best guess is the latter.
Perhaps there are YV stations on this list that might know about any
specific issues with DX reception on 6m in their country?

73
Bill
G4WJS.

 


--
Tom (LA4LN)

 

 


--
Tom (LA4LN)




Re: Log. Adi files #WSJTX_config #adiFiles

Bill Somerville
 

On 13/07/2021 13:08, Phil Hazelton via groups.io wrote:

Hi,
I have installed a new SSD drive to replace my HDD drive in my ASUS shack win10 PC. Unfortunately, all did not go well and I lost most of my files and apps. I have managed to reload wsjtx, but all log files are missing, so my worked before colours have no log.adi files to refer to.
Can I just down load my adi file from QRZ.com straight into wsjtx log file?

thanks
Hi Phil,

yes that should work, although I have not tried it. It only requires that certain basic ADIF fields are present for each logged QSO and they are very likely to be there.

73
Bill
G4WJS.


Log. Adi files #WSJTX_config #adiFiles

Phil Hazelton
 

Hi,
I have installed a new SSD drive to replace my HDD drive in my ASUS shack win10 PC. Unfortunately, all did not go well and I lost most of my files and apps. I have managed to reload wsjtx, but all log files are missing, so my worked before colours have no log.adi files to refer to.
Can I just down load my adi file from QRZ.com straight into wsjtx log file?

thanks 


Re: WSJT-X v2.4.0, Win10 2004 Issue w/ FT4 #FT4

Ian Kahn
 

Bill,

I have not run WSJT-X since the end of the 13 Colonies event here in the US. If there are any logs I can provide for troubleshooting purposes, please let me know where to find them and how you'd like to receive them. I'll happily send them to you.

Thanks and 73,

Ian, NV4C


Re: Enable TX #error

Reino Talarmo
 

Hi Gus,

 

My mistake, my EME working is limited to admiring moon eclipses and I am not ever used JT65 on any band.

 

73, Reino OH3mA

Hi Reino,

It´s goes off only when the station i´m calling give an other station report OOO. When DX station normally listen all the time for next to work, everyone are ju calling... I´m normally calling in split abt 500 Hz up or down. Do not like this "wanted behaviour".

73 de Gus, SM5DIC

 

Den 2021-07-13 kl. 12:19, skrev Reino Talarmo:

Hi All,
Problem WSJT-X:
When calling a station and I´m in Enable TX and the station I call give the OOO to somone else, my Enable TX gos off!
Only when text include the OOO. If called station give me OOO Enable TX still go as normal.
--
SM5DIC Gus

Hi Gus,

If you are transmitting on or near the frequency the called station is using, then that is a wanted behavior to prevent unnecessary QRM. If you have Hold Tx Freq activated and your Tx frequency is not the same as Rx frequency (the frequency of the station you are calling), then Enable Tx should stay on. The behavior should not depend on the “OOO” or I have missed what “OOO” means, hi!

73, Reino OH3mA



 
 
 


--
SM5DIC Gus


Re: Enable TX #error

Reino Talarmo
 

 

On 13/07/2021 11:19, Reino Talarmo wrote:

Hi All,
Problem WSJT-X:
When calling a station and I´m in Enable TX and the station I call give the OOO to somone else, my Enable TX gos off!
Only when text include the OOO. If called station give me OOO Enable TX still go as normal.
--
SM5DIC Gus

Hi Gus,

If you are transmitting on or near the frequency the called station is using, then that is a wanted behavior to prevent unnecessary QRM. If you have Hold Tx Freq activated and your Tx frequency is not the same as Rx frequency (the frequency of the station you are calling), then Enable Tx should stay on. The behavior should not depend on the “OOO” or I have missed what “OOO” means, hi!

73, Reino OH3mA

Hi Reino,

the OOO message is used in EME with modes like JT65 and is equivalent to the Tx2 message you may be more used to for answering a call. It is effectively a signal report, i.e. "I copy your call". The response would be an RRR message which in modes like JT65 when used for EME is sent as a so-called short code which is a pair of alternating tones which can be copied by the software, visually on the waterfall, or by ear. EME QSOs may use very abbreviated exchanges which allow for the many repeats necessary over the most challenging paths with possibly time limited Moon visibility at both ends of the path.

73
Bill
G4WJS.

Hi Bill,

Thanks again. Perhaps I should educate myself a bit on EME working. I see usefulness of those short messages. Well, JT65 may be outdate before I am ready to install any equipment for EME and replaced by Q65 or something else.

73, Reino OH3mA


Re: S/N reporting on different modes #modes #Icom

Tom V. Segalstad
 

Thanks for the clarification, Bill.

 

Let’s look at repeated QSOs on 6 meters, separated some days in time, but assuming same operating techniques (at least here). The problem is that we don’t want to make duplicate contacts, so the few contacts I show here have been made by me, when using different call signs. Here are the differences in dB reporting, for a previous QSO with some of the stations listed before:

 

OD5KU    -3 dB (-18 dB in a QSO before)

HI8T       -15 dB (-11 dB in a QSO before)

KP4EIT  -13 dB (-19 dB in a QSO before)

CO7MS     -9dB (0 dB in a QSO before)

 

The tendency is still, that the other DX stations are giving a lower dB S/N report.

 

73 from Tom, LA4LN / LC1V

 

Fra: Bill Somerville
Sendt: tirsdag 13. juli 2021 kl. 12.25
Emne: Re: [WSJTX] S/N reporting on different modes #modes #ic-7600 #modes

 

Hi Tom, and Jim,

 

I believe Mike in his OP was questioning the variations in SNR numbers between two stations on different occasions. For example I might have two QSOs with you and one day my SNR for you might be 20 dB different from yours to me, yet another day the difference might be less or more. One might expect the comparison of SNR numbers between two stations using unchanging setups to be consistent unless some form of one-way propagation enhancement were taking place, or more likely the noise environment at one end of the link has changed significantly. Hence my supposition that some stations may be located in regions where local noise is highly variable, for example heavy usage of solar panels with noisy switch-mode inverters, or air-conditioning units with poor noise suppression.

 

73
Bill
G4WJS.

 

On 13/07/2021 11:15, Tom V. Segalstad wrote:

Some comparisons for FT8 reports last Thursday evening (8th of July) on 50 MHz.

Here using 1 kW output power to a 7 element Yagi antenna, and a GaAsFET LNA RX preamplifier.

Listed below are the differences in dB S/N reports for some DX QSOs; positive numbers meaning I received stronger S/N reports than the DX station, and negative numbers meaning I received lower S/N reports, than given by me.

OD5KU        -18 dB

HI3MRV      -12 dB

HI8T             -11 dB

HI8RD            -4 dB

4Z1TL            +4 dB

4X1TI           -11 dB

WP4G          -18 dB

WP3R            -9 dB

KP4EIT        -19 dB

CO7MS           0 dB

 I can’t say what is the reason for these fairly large differences in S/N reports for DX QSOs.

But we see that the reports from Central America are all negative.

May be due to QRM from the many stations in USA?

But we in Europe also have many stations in Europe being copied at the same time.

So we wouldn’t think that the QRM level would be much different?

Reports for contacts within Europe were in most QSOs about equal, differing +/- 1 to 2 dB, and in rare cases up to +/- 5dB.

 73 from Tom, LA4LN (and LC1V in contests)

Fra: Bill Somerville
Sendt: tirsdag 13. juli 2021 kl. 11.19
Til: main@WSJTX.groups.io
Emne: Re: [WSJTX] S/N reporting on different modes #modes #ic-7600 #modes

 

On 13/07/2021 09:00, Mike GM3PPE wrote:
> I have been very active on 6 meters this summer and have noticed great
> variability in S/N reports sent and received. For example I worked a
> YV5 station twice in the same week. On the first occasion he sent -18
> and received -05 from me, a difference of 13dB. Two days later he sent
> -15 but was +11 with me, a difference of 26dB. My setup was the same,
> and assuming his setup was unchanged, why the comparative difference?
>
> This effect has been seen on numerous occasions, and by other stations
> in a similar rural location. Are more details on exactly how the S/N
> ratio is calculated available? I want to understand how the background
> noise power is estimated, without having to read the source code!
>
> Mike GM3PPE

Hi Mike,

the noise component consists of local noise plus various other noises
via one or more propagation paths from many directions, with Sporadic E
propagation, which you are almost certainly receiving the YV5 station,
the path loss is highly variable, both over the short term of a few
seconds or minutes and from day to day. It is not reasonable to expect
the noise and signal components to remain in the same ratio during
different QSOs with the same station with such variable propagation
dynamics.

It is interesting that you cite a YV station for your example, I have
noticed that stations in Venezuela on 6m, among some others, often have
some difficulty copying my signals when they are quite strong with me.
My conclusion is that either they are running very high power or they
suffer considerable levels of local QRN, my best guess is the latter.
Perhaps there are YV stations on this list that might know about any
specific issues with DX reception on 6m in their country?

73
Bill
G4WJS.

 


--
Tom (LA4LN)

 

 


--
Tom (LA4LN)


Re: Enable TX #error

Ragge Jagero
 

Hi Reino,

It´s goes off only when the station i´m calling give an other station report OOO. When DX station normally listen all the time for next to work, everyone are ju calling... I´m normally calling in split abt 500 Hz up or down. Do not like this "wanted behaviour".

73 de Gus, SM5DIC


Den 2021-07-13 kl. 12:19, skrev Reino Talarmo:

Hi All,
Problem WSJT-X:
When calling a station and I´m in Enable TX and the station I call give the OOO to somone else, my Enable TX gos off!
Only when text include the OOO. If called station give me OOO Enable TX still go as normal.
--
SM5DIC Gus

Hi Gus,

If you are transmitting on or near the frequency the called station is using, then that is a wanted behavior to prevent unnecessary QRM. If you have Hold Tx Freq activated and your Tx frequency is not the same as Rx frequency (the frequency of the station you are calling), then Enable Tx should stay on. The behavior should not depend on the “OOO” or I have missed what “OOO” means, hi!

73, Reino OH3mA





--
SM5DIC Gus


Re: S/N reporting on different modes #modes #Icom

Andy TALBOT
 

The most effective noise estimation algorithm I've encountered uses statistics.  The power in each FFT bin is reordered by sorting into ascending power, then the bin at the lower quartile is taken.   Eg for a 4096 FFT bins the power in the 1024th bin is taken after reordering.   Add a 'fiddle factor' of about 5dB and in most scenarios including those with strong signals you end up with a close approximation of the true noise level.

This works because it doesn't take any account of the strength of a signal, just it's presence in one of the higher, resorted, bins.   SO there can be plenty of signals present, and they will all sit at the top of the list, contributing very little to teh value derived from the lower quartile. 

However it does mean you have to have a quick sorting routine for large FFT sizes.  But there are ways round that.as you're only interested in ONE value, not the contents of all the bins.   So the lower quartile sort can be found in real time rather than after a complete sort.

Andy


C media GPIO PTT support #FT8

K3EUI Barry
 

I just joined this group but I cannot find an answer to my question.

I have an Icom 746Pro  and a  MastersCommunications DRA70 sound card  (and Win 10)

When I set up the sound card for PTT via  VOX, everything works fine.
The sound card has both LEFT and RIGHT Tx channels and either can be used for VOX  PTT.
The WSJT-X  v2.3.0  works fine using VOX.

The C Media chip has the option for PTT  via  the  GPIO  pin  ( kind of a hardware PTT)
Does anyone know how to use this method for PTT  rather than  VOX?

I notice VARA  (Winlink's RMS Express) and  FLDIGI  now offer  PTT via hardware GPIO using the C Media sound chip.

I apologize in advance if this topic has already been discussed, but if so, I could not find it.

Thank you
Barry   k3eui
West Chester PA


Re: Enable TX #error

Bill Somerville
 

On 13/07/2021 11:19, Reino Talarmo wrote:

Hi All,
Problem WSJT-X:
When calling a station and I´m in Enable TX and the station I call give the OOO to somone else, my Enable TX gos off!
Only when text include the OOO. If called station give me OOO Enable TX still go as normal.
--
SM5DIC Gus

Hi Gus,

If you are transmitting on or near the frequency the called station is using, then that is a wanted behavior to prevent unnecessary QRM. If you have Hold Tx Freq activated and your Tx frequency is not the same as Rx frequency (the frequency of the station you are calling), then Enable Tx should stay on. The behavior should not depend on the “OOO” or I have missed what “OOO” means, hi!

73, Reino OH3mA

Hi Reino,

the OOO message is used in EME with modes like JT65 and is equivalent to the Tx2 message you may be more used to for answering a call. It is effectively a signal report, i.e. "I copy your call". The response would be an RRR message which in modes like JT65 when used for EME is sent as a so-called short code which is a pair of alternating tones which can be copied by the software, visually on the waterfall, or by ear. EME QSOs may use very abbreviated exchanges which allow for the many repeats necessary over the most challenging paths with possibly time limited Moon visibility at both ends of the path.

73
Bill
G4WJS.


Re: Enable TX #error

Reino Talarmo
 

Hi All,
Problem WSJT-X:
When calling a station and I´m in Enable TX and the station I call give the OOO to somone else, my Enable TX gos off!
Only when text include the OOO. If called station give me OOO Enable TX still go as normal.
--
SM5DIC Gus

Hi Gus,

If you are transmitting on or near the frequency the called station is using, then that is a wanted behavior to prevent unnecessary QRM. If you have Hold Tx Freq activated and your Tx frequency is not the same as Rx frequency (the frequency of the station you are calling), then Enable Tx should stay on. The behavior should not depend on the “OOO” or I have missed what “OOO” means, hi!

73, Reino OH3mA


Re: S/N reporting on different modes #modes #Icom

Bill Somerville
 

Hi Tom, and Jim,

I believe Mike in his OP was questioning the variations in SNR numbers between two stations on different occasions. For example I might have two QSOs with you and one day my SNR for you might be 20 dB different from yours to me, yet another day the difference might be less or more. One might expect the comparison of SNR numbers between two stations using unchanging setups to be consistent unless some form of one-way propagation enhancement were taking place, or more likely the noise environment at one end of the link has changed significantly. Hence my supposition that some stations may be located in regions where local noise is highly variable, for example heavy usage of solar panels with noisy switch-mode inverters, or air-conditioning units with poor noise suppression.

73
Bill
G4WJS.

On 13/07/2021 11:15, Tom V. Segalstad wrote:

Some comparisons for FT8 reports last Thursday evening (8th of July) on 50 MHz.

Here using 1 kW output power to a 7 element Yagi antenna, and a GaAsFET LNA RX preamplifier.

Listed below are the differences in dB S/N reports for some DX QSOs; positive numbers meaning I received stronger S/N reports than the DX station, and negative numbers meaning I received lower S/N reports, than given by me.

 

OD5KU        -18 dB

HI3MRV      -12 dB

HI8T             -11 dB

HI8RD                      -4 dB

4Z1TL                     +4 dB

4X1TI                     -11 dB

WP4G                     -18 dB

WP3R                       -9 dB

KP4EIT        -19 dB

CO7MS           0 dB

 

I can’t say what is the reason for these fairly large differences in S/N reports for DX QSOs.

But we see that the reports from Central America are all negative.

May be due to QRM from the many stations in USA?

But we in Europe also have many stations in Europe being copied at the same time.

So we wouldn’t think that the QRM level would be much different?

Reports for contacts within Europe were in most QSOs about equal, differing +/- 1 to 2 dB, and in rare cases up to +/- 5dB.

 

73 from Tom, LA4LN (and LC1V in contests)

 

 

Fra: Bill Somerville
Sendt: tirsdag 13. juli 2021 kl. 11.19
Til: main@WSJTX.groups.io
Emne: Re: [WSJTX] S/N reporting on different modes #modes #ic-7600 #modes

 

On 13/07/2021 09:00, Mike GM3PPE wrote:
> I have been very active on 6 meters this summer and have noticed great
> variability in S/N reports sent and received. For example I worked a
> YV5 station twice in the same week. On the first occasion he sent -18
> and received -05 from me, a difference of 13dB. Two days later he sent
> -15 but was +11 with me, a difference of 26dB. My setup was the same,
> and assuming his setup was unchanged, why the comparative difference?
>
> This effect has been seen on numerous occasions, and by other stations
> in a similar rural location. Are more details on exactly how the S/N
> ratio is calculated available? I want to understand how the background
> noise power is estimated, without having to read the source code!
>
> Mike GM3PPE

Hi Mike,

the noise component consists of local noise plus various other noises
via one or more propagation paths from many directions, with Sporadic E
propagation, which you are almost certainly receiving the YV5 station,
the path loss is highly variable, both over the short term of a few
seconds or minutes and from day to day. It is not reasonable to expect
the noise and signal components to remain in the same ratio during
different QSOs with the same station with such variable propagation
dynamics.

It is interesting that you cite a YV station for your example, I have
noticed that stations in Venezuela on 6m, among some others, often have
some difficulty copying my signals when they are quite strong with me.
My conclusion is that either they are running very high power or they
suffer considerable levels of local QRN, my best guess is the latter.
Perhaps there are YV stations on this list that might know about any
specific issues with DX reception on 6m in their country?

73
Bill
G4WJS.

 


--
Tom (LA4LN)



Re: S/N reporting on different modes #modes #Icom

Tom V. Segalstad
 

Some comparisons for FT8 reports last Thursday evening (8th of July) on 50 MHz.

Here using 1 kW output power to a 7 element Yagi antenna, and a GaAsFET LNA RX preamplifier.

Listed below are the differences in dB S/N reports for some DX QSOs; positive numbers meaning I received stronger S/N reports than the DX station, and negative numbers meaning I received lower S/N reports, than given by me.

 

OD5KU        -18 dB

HI3MRV      -12 dB

HI8T             -11 dB

HI8RD                      -4 dB

4Z1TL                     +4 dB

4X1TI                     -11 dB

WP4G                     -18 dB

WP3R                       -9 dB

KP4EIT        -19 dB

CO7MS           0 dB

 

I can’t say what is the reason for these fairly large differences in S/N reports for DX QSOs.

But we see that the reports from Central America are all negative.

May be due to QRM from the many stations in USA?

But we in Europe also have many stations in Europe being copied at the same time.

So we wouldn’t think that the QRM level would be much different?

Reports for contacts within Europe were in most QSOs about equal, differing +/- 1 to 2 dB, and in rare cases up to +/- 5dB.

 

73 from Tom, LA4LN (and LC1V in contests)

 

 

Fra: Bill Somerville
Sendt: tirsdag 13. juli 2021 kl. 11.19
Til: main@WSJTX.groups.io
Emne: Re: [WSJTX] S/N reporting on different modes #modes #ic-7600 #modes

 

On 13/07/2021 09:00, Mike GM3PPE wrote:
> I have been very active on 6 meters this summer and have noticed great
> variability in S/N reports sent and received. For example I worked a
> YV5 station twice in the same week. On the first occasion he sent -18
> and received -05 from me, a difference of 13dB. Two days later he sent
> -15 but was +11 with me, a difference of 26dB. My setup was the same,
> and assuming his setup was unchanged, why the comparative difference?
>
> This effect has been seen on numerous occasions, and by other stations
> in a similar rural location. Are more details on exactly how the S/N
> ratio is calculated available? I want to understand how the background
> noise power is estimated, without having to read the source code!
>
> Mike GM3PPE

Hi Mike,

the noise component consists of local noise plus various other noises
via one or more propagation paths from many directions, with Sporadic E
propagation, which you are almost certainly receiving the YV5 station,
the path loss is highly variable, both over the short term of a few
seconds or minutes and from day to day. It is not reasonable to expect
the noise and signal components to remain in the same ratio during
different QSOs with the same station with such variable propagation
dynamics.

It is interesting that you cite a YV station for your example, I have
noticed that stations in Venezuela on 6m, among some others, often have
some difficulty copying my signals when they are quite strong with me.
My conclusion is that either they are running very high power or they
suffer considerable levels of local QRN, my best guess is the latter.
Perhaps there are YV stations on this list that might know about any
specific issues with DX reception on 6m in their country?

73
Bill
G4WJS.

 


--
Tom (LA4LN)


Re: S/N reporting on different modes #modes #Icom

Jim Brown
 

On 7/13/2021 1:00 AM, Mike GM3PPE wrote:
This effect has been seen on numerous occasions, and by other stations in a similar rural location. Are more details on exactly how the S/N ratio is calculated available?
It is common for 6M propagation to be wildly variable over rather short periods of time. Last evening, I worked an HL2 station who I could decode for about 5 minutes, with the report (S/N) beginning around -22, peaking around -6, fading a minute or two later. On the next pass after our QSO completed, he was around -20, and on his next TX, he was gone.

73, Jim K9YC (CM87, S of San Francisco)


Re: S/N reporting on different modes #modes #Icom

Bill Somerville
 

On 13/07/2021 09:00, Mike GM3PPE wrote:
I have been very active on 6 meters this summer and have noticed great variability in S/N reports sent and received. For example I worked a YV5 station twice in the same week. On the first occasion he sent -18 and received -05 from me, a difference of 13dB. Two days later he sent -15 but was +11 with me, a difference of 26dB. My setup was the same, and assuming his setup was unchanged, why the comparative difference?

This effect has been seen on numerous occasions, and by other stations in a similar rural location. Are more details on exactly how the S/N ratio is calculated available? I want to understand how the background noise power is estimated, without having to read the source code!

Mike GM3PPE
Hi Mike,

the noise component consists of local noise plus various other noises via one or more propagation paths from many directions, with Sporadic E propagation, which you are almost certainly receiving the YV5 station, the path loss is highly variable, both over the short term of a few seconds or minutes and from day to day. It is not reasonable to expect the noise and signal components to remain in the same ratio during different QSOs with the same station with such variable propagation dynamics.

It is interesting that you cite a YV station for your example, I have noticed that stations in Venezuela on 6m, among some others, often have some difficulty copying my signals when they are quite strong with me. My conclusion is that either they are running very high power or they suffer considerable levels of local QRN, my best guess is the latter. Perhaps there are YV stations on this list that might know about any specific issues with DX reception on 6m in their country?

73
Bill
G4WJS.


Re: S/N reporting on different modes #modes #Icom

Bill Somerville
 

On 13/07/2021 01:59, Bruce KX4AZ wrote:
On Mon, Jul 12, 2021 at 05:37 AM, Bill Somerville wrote:

.. The noise estimation algorithms in WSJT-X reflect
both the expected band occupancy and the evolution of noise estimatiin the software. ...

This is something I have always wondered about - does the noise estimation algorithm attempt to use an area of the audio spectrum where no signals were decoded?  But I guess a crowded band would make that nearly impossible.  In any event, it would be fascinating to hear more details about how the noise power is estimated to arrive at the S/N ratios.

Hi Bruce,

I believe we use variations on two basic strategies:-

  1. measure the noise power in unused symbol tone bins and interpolate to a 2500 Hz bandwidth noise power,
  2. measure the noise power in a 2500 Hz bandwidth by using a baseline fitting algorithm.

(1) is relatively straightforward as we are already measuring signal power in all symbol tone bins as part of decoding, but is liable to inaccuracies when there are overlapping signals or other QRM.

(2) is a little more computationally complex but will perform well on a busy sub-band with many signals that may overlap, but requires that the receiver pass band is at least 2500 Hz wide.

You can do a simple experiment to determine which type is being used by reducing your receiver pass band while decoding a signal. Mode decoders that use (1) will give reasonably consistent SNR numbers so long as the wanted signal is within the restricted pass band, modes that use (2) will give greatly exaggerated SNR numbers as the receiver pass band is reduced below 2500 Hz.

73
Bill
G4WJS.


Re: S/N reporting on different modes #modes #Icom

Mike GM3PPE
 

I have been very active on 6 meters this summer and have noticed great variability in S/N reports sent and received. For example I worked a YV5 station twice in the same week. On the first occasion he sent -18 and received -05 from me, a difference of 13dB. Two days later he sent -15 but was +11 with me, a difference of 26dB. My setup was the same, and assuming his setup was unchanged, why the comparative difference?

This effect has been seen on numerous occasions, and by other stations in a similar rural location. Are more details on exactly how the S/N ratio is calculated available? I want to understand how the background noise power is estimated, without having to read the source code!

Mike GM3PPE


Enable TX #error

Ragge Jagero
 

Hi All,
Problem WSJT-X:
When calling a station and I´m in Enable TX and the station I call give the OOO to somone else, my Enable TX gos off!
Only when text include the OOO. If called station give me OOO Enable TX still go as normal.
--
SM5DIC Gus

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