Date   

locked WSJT-X Team wins Technical Achievement Award

Don Hill AA5AU
 

Join me in congratulating WSJT-X Development Team members Joe Taylor, K1JT, Steve Franke, K9AN, and Bill Somerville, G4WJS, for winning the 2020 Dayton Hamvention Technical Achievement Award. It's well deserved.

Great job guys!


73, Don AA5AU


locked Re: Acceptable PA Power Supply Ripple?

Steve Kavanagh
 

Carey, Jim and John are right....with typical power supplies there should be no issue with ripple.  However, for homebrew power supplies, and unregulated supplies as used in a lot of linear amps (all tube amps, some solid state), power supply ripple modulation can arise...I am just trying to quantify it.

73,
Steve VE3SMA


locked Re: Acceptable PA Power Supply Ripple?

 

I have an IC-7300 with about 1m of 20A power cord. When transmitting I see the PA voltage dropping as it draws current. I referred this to the supplier, who said no alternative cord was available, and it doesn't look readily modifiable. I'm sure there will be PA voltage variation, rather than ripple, depending on drive power.

73 Phil GM3ZZA

On 6 Mar 2020 18:52, careyfisher@... wrote:
I'd be surprised if 10% ripple on the incoming power (12VDC) would even be noticeable because the radio has internal regulators.

On Fri, Mar 6, 2020 at 1:07 PM Jim Brown <k9yc@...> wrote:
On 3/6/2020 7:45 AM, Steve Kavanagh via Groups.Io wrote:
> Has anyone any experience or opinion on what an acceptable power
> amplifier supply ripple is for WSJT-X modes?

This may be barking up the wrong tree. More likely sources of spurious
trash are

1) leakage currents on the "green wire" introducing triplen harmonics of
the mains frequency (50/60 Hz) into TX audio when equipment in the
station is not properly bonded together.

2) IMD products resulting from design shortcomings in el-cheapo JA rigs
like the Yaesu FTDX3000, FT857, FT897, and ICOM IC-7100. W4TV has
identified specific overdrive issues in the Yaesu rigs.

For bonding, study and implement http://k9yc.com/GroundingAndAudio.pdf

73, Jim K9YC



--
Carey Fisher


--
73, Carey, WB4HXE


--
73 Phil GM3ZZA


locked Re: Acceptable PA Power Supply Ripple?

careyfisher@...
 

I'd be surprised if 10% ripple on the incoming power (12VDC) would even be noticeable because the radio has internal regulators.

On Fri, Mar 6, 2020 at 1:07 PM Jim Brown <k9yc@...> wrote:
On 3/6/2020 7:45 AM, Steve Kavanagh via Groups.Io wrote:
> Has anyone any experience or opinion on what an acceptable power
> amplifier supply ripple is for WSJT-X modes?

This may be barking up the wrong tree. More likely sources of spurious
trash are

1) leakage currents on the "green wire" introducing triplen harmonics of
the mains frequency (50/60 Hz) into TX audio when equipment in the
station is not properly bonded together.

2) IMD products resulting from design shortcomings in el-cheapo JA rigs
like the Yaesu FTDX3000, FT857, FT897, and ICOM IC-7100. W4TV has
identified specific overdrive issues in the Yaesu rigs.

For bonding, study and implement http://k9yc.com/GroundingAndAudio.pdf

73, Jim K9YC



--
Carey Fisher


--
73, Carey, WB4HXE


locked Re: Acceptable PA Power Supply Ripple?

Jim Brown
 

On 3/6/2020 7:45 AM, Steve Kavanagh via Groups.Io wrote:
Has anyone any experience or opinion on what an acceptable power amplifier supply ripple is for WSJT-X modes?
This may be barking up the wrong tree. More likely sources of spurious trash are

1) leakage currents on the "green wire" introducing triplen harmonics of the mains frequency (50/60 Hz) into TX audio when equipment in the station is not properly bonded together.

2) IMD products resulting from design shortcomings in el-cheapo JA rigs like the Yaesu FTDX3000, FT857, FT897, and ICOM IC-7100. W4TV has identified specific overdrive issues in the Yaesu rigs.

For bonding, study and implement http://k9yc.com/GroundingAndAudio.pdf

73, Jim K9YC


locked Re: Acceptable PA Power Supply Ripple?

John
 

Steve,

An interesting technical investigation/exercise.

IMHO, if there was any significant influence on communications in any mode
caused by power supply ripple voltage, I would think it would have surfaced long
ago.

I just received a new switch mode power supply purchased from the USA vendor
MegaWatt, 10 to 15 VDC at 30 Amp, Ripple 0.05mVp-p and noise, Line and Load
regulation 0.5%.

John

---------- Original Message ----------
From: "Steve Kavanagh via Groups.Io" <sjkavanagh1@...>
Date: March 6, 2020 at 12:01 PM


For comparison, ARRL handbooks used to recommend better than 5% ripple for a
CW transmitter and 3% for linear amplifier plate voltages - I don't have a
recent handbooks to see if this has changed. Ripple percentage was defined as
RMS ripple voltage divided by DC voltage, times 100.

73,
Steve VE3SMA


locked Re: Acceptable PA Power Supply Ripple?

Jim Shorney
 

I don't have an answer for you but I wan to thank you very much for being concerned about it. :)

73

-Jim
NU0C

On Fri, 06 Mar 2020 09:01:45 -0800
"Steve Kavanagh via Groups.Io" <sjkavanagh1@...> wrote:

For comparison, ARRL handbooks used to recommend better than 5% ripple for a CW transmitter and 3% for linear amplifier plate voltages - I don't have a recent handbooks to see if this has changed. Ripple percentage was defined as RMS ripple voltage divided by DC voltage, times 100.

73,
Steve VE3SMA


locked Re: Acceptable PA Power Supply Ripple?

Steve Kavanagh
 

For comparison, ARRL handbooks used to recommend better than 5% ripple for a CW transmitter and 3% for linear amplifier plate voltages - I don't have a recent handbooks to see if this has changed. Ripple percentage was defined as RMS ripple voltage divided by DC voltage, times 100.

73,
Steve VE3SMA


locked Re: Acceptable PA Power Supply Ripple?

Steve Kavanagh
 

Roger

I meant that 2% number purely as an example.  But, in practice, I doubt if our regulator would really care - they try not to spend any money on the Amateur Service that isn't absolutely necessary!  There is essentially no mention of spurious signal levels in the main amateur radio technical standard in Canada (RBR-4).  Presumably, though, ITU-R-SM.1541 Annex 9 ought to apply in all countries - I have yet to work out what it means for WSJT-X modes.

73,
Steve VE3SMA


locked Re: Acceptable PA Power Supply Ripple?

Steve Kavanagh
 

oops..that should be a plus sign: 20 log (percent_ripple/100) + 3 dB


locked Re: Look Up button options

Gary - AG0N
 

On Mar 4, 2020, at 07:57, Kai-KE4PT <k.siwiak@...> wrote:

Look at the main GUI, button marked "Lookup" just above the Date and time window.
You are correct. I had forgotten that button as I rarely use it. I looked right at it and didn’t see it. However, as has been pointed out, lookup only looks internally, not externally. There’s no “QRZ” function available.

Gary - AG0N


locked Re: Acceptable PA Power Supply Ripple?

Roger
 

On 06/03/2020 15:45, Steve Kavanagh via Groups.Io wrote:
Has anyone any experience or opinion on what an acceptable power amplifier supply ripple is for WSJT-X modes?
My guess is that the suppression with respect to the main signal of the sidebands due to 120 Hz power supply ripple will be around 20 log (percent_ripple/100) - 3 dB.  Am I anywhere near the mark?
This would imply, for example that a 2% ripple will give spurious signals spaced 120 Hz (for 60 Hz AC mains & linear supply) from the main signal at 37 dB below the main signal (for slow/narrow-band modes).
What would you consider an acceptable level for these signals (for HF, VHF, EME) ?  Obviously the acceptable number depends on the transmitter power and how many people will be bothered by the extra signals.
73,
Steve VE3SMA
I'm surprised your licencing authority allows a 2% ripple. I'm sure ours would be very unhappy if it came to their attention.

Roger G4HZA


locked Acceptable PA Power Supply Ripple?

Steve Kavanagh
 

Has anyone any experience or opinion on what an acceptable power amplifier supply ripple is for WSJT-X modes?

My guess is that the suppression with respect to the main signal of the sidebands due to 120 Hz power supply ripple will be around 20 log (percent_ripple/100) - 3 dB.  Am I anywhere near the mark?

This would imply, for example that a 2% ripple will give spurious signals spaced 120 Hz (for 60 Hz AC mains & linear supply) from the main signal at 37 dB below the main signal (for slow/narrow-band modes).

What would you consider an acceptable level for these signals (for HF, VHF, EME) ?  Obviously the acceptable number depends on the transmitter power and how many people will be bothered by the extra signals.

73,
Steve VE3SMA


locked Re: Working DX - FT8 v/s FT4

Jim Brown
 

On 3/5/2020 10:49 AM, Jim Brown wrote:
My QTH is fairly quiet in most directions most of the time, and WSJT-X almost always give signal reports than I receive by 10-15 dB! And I'm running legal limit on 160 and 6M into pretty good antennas!
Left out a word. :) I meant to say:

My QTH is fairly quiet in most directions most of the time, and WSJT-X almost always gives signal reports better than I receive by 10-15 dB!

73, Jim K9YC


locked Re: Working DX - FT8 v/s FT4

George Armstrong
 

All,

Jim, K9YC, gives the Master Class explanation below. I urge everyone to study and understand what he is saying.

Regards,
GA


From: WSJTX@groups.io <WSJTX@groups.io> on behalf of Jim Brown <k9yc@...>
Sent: Thursday, March 5, 2020 12:49 PM
To: WSJTX@groups.io <WSJTX@groups.io>
Subject: Re: [WSJTX] Working DX - FT8 v/s FT4
 
On 3/4/2020 5:52 AM, Greg Chartrand via Groups.Io wrote:
> I have chased a lot of DX on 160 m using CW and am used to waiting 20
> minutes for a 30 second QSB peak to occur to work a DX station. These
> peaks are very similar to those I have seen on 40 and 20 m and FT4 seems
> to be the mode that can take advantage of them. I'd expect the same to
> be true on 6M where sporadic E and meteor bursts provide paths of short
> duration's.

Hi Greg,

The rapid QSB you're talking about when heard on the AM broadcast band
is generally called "selective fading," and is really the result of the
same mechanism that causes "picket fencing" at VHF and UHF. The
difference between the two is frequency. That mechanism is the complex
addition at a point in space where the antenna is located of wavefronts
that have taken different paths, and thus shifted in time with respect
to each other. Because phase shift produced by this event is frequency
multiplied by time, phase is constantly changing, and at a rate directly
related by frequency. Signal peaks occur when the two arrivals are
precisely in phase, dips occur when the arrivals are equal in strength
and precisely 180 degrees out of phase.

This mechanism, which is periodic (that is, repeating at a more or less
constant rate based on the time difference) is quite different from
meteor scatter, which has no periodicity all -- it's based on ionization
produced by "rocks" entering our atmosphere. MSK144 works quite well for
this mode, but provides relatively little noise immunity.

I mostly use WSJT-X "slow modes" on 160 for long haul DX and on 6M for
multi-hop E-skip. My experience on both bands is that what's most
important is noise immunity. My QTH is fairly quiet in most directions
most of the time, and WSJT-X almost always give signal reports than I
receive by 10-15 dB! And I'm running legal limit on 160 and 6M into
pretty good antennas! (I don't use WSJT-X on other bands except to work
rare DX, and don't run much power when I do -- indeed, I'm often trying
to work them with 5W).

The other mode I'd like to see used a LOT more on 160M is JT9. It's
about 6 dB better in terms of noise immunity than FT8, and 8 dB better
than FT4. Yes, it takes longer, but can work through fades, and has long
been the dominant mode on 630m and 2200m bands.

73, Jim K9YC


locked Re: Working DX - FT8 v/s FT4

Hasan Schiers N0AN
 

It should be noted that MSK144 is VHF and above only, it cannot be run on HF in the USA
Hasan


On Thu, Mar 5, 2020 at 3:04 PM Hasan Schiers N0AN via Groups.Io <hbasri.schiers6=gmail.com@groups.io> wrote:
MSK144 on 6m is astonishing

...and it's ability to function with aggressive noise blanking is a big surprise.

I have up to 15 dB of power line noise that my TS-590sg can blank (when pointed at 60 deg). In FT8, don't copy squat (in the face of that noise), and if the signal is strong enough, I get images all over the place.

With MSK144, I get consistent decodes (and I can hear the noise mixed in with the meteor pings) ,and no artifacts or images.

It has phenomenal decoding capabilities.

....and I agree with K9YC, it is a shame that more people don't run JT9 on HF.

73, N0AN
Hasan


On Thu, Mar 5, 2020 at 2:09 PM Martin G0HDB <marting0hdb@...> wrote:
On Wed, Mar 4, 2020 at 01:52 PM, Greg Chartrand wrote:

[Snipped]

I'd expect the same to be true on 6M where sporadic E and meteor bursts provide paths of short duration's.   

Hi Greg, if you're interested in working meteor scatter, have you tried the WSJT-X mode MSK144 that is intended specifically for that purpose?  I find it works extremely well, and I can't see what advantage FT4 might offer over MSK144 - the latter has a frame duration of 72msecs which gives an effective character transmission rate of up to 250cps for standard messages, which is a darn sight faster than even FT4!

73
--
Martin G0HDB


locked Re: Working DX - FT8 v/s FT4

Hasan Schiers N0AN
 

MSK144 on 6m is astonishing

...and it's ability to function with aggressive noise blanking is a big surprise.

I have up to 15 dB of power line noise that my TS-590sg can blank (when pointed at 60 deg). In FT8, don't copy squat (in the face of that noise), and if the signal is strong enough, I get images all over the place.

With MSK144, I get consistent decodes (and I can hear the noise mixed in with the meteor pings) ,and no artifacts or images.

It has phenomenal decoding capabilities.

....and I agree with K9YC, it is a shame that more people don't run JT9 on HF.

73, N0AN
Hasan


On Thu, Mar 5, 2020 at 2:09 PM Martin G0HDB <marting0hdb@...> wrote:
On Wed, Mar 4, 2020 at 01:52 PM, Greg Chartrand wrote:

[Snipped]

I'd expect the same to be true on 6M where sporadic E and meteor bursts provide paths of short duration's.   

Hi Greg, if you're interested in working meteor scatter, have you tried the WSJT-X mode MSK144 that is intended specifically for that purpose?  I find it works extremely well, and I can't see what advantage FT4 might offer over MSK144 - the latter has a frame duration of 72msecs which gives an effective character transmission rate of up to 250cps for standard messages, which is a darn sight faster than even FT4!

73
--
Martin G0HDB


locked Re: Working DX - FT8 v/s FT4

Martin G0HDB
 

On Wed, Mar 4, 2020 at 01:52 PM, Greg Chartrand wrote:

[Snipped]

I'd expect the same to be true on 6M where sporadic E and meteor bursts provide paths of short duration's.   

Hi Greg, if you're interested in working meteor scatter, have you tried the WSJT-X mode MSK144 that is intended specifically for that purpose?  I find it works extremely well, and I can't see what advantage FT4 might offer over MSK144 - the latter has a frame duration of 72msecs which gives an effective character transmission rate of up to 250cps for standard messages, which is a darn sight faster than even FT4!

73
--
Martin G0HDB


locked Re: Working DX - FT8 v/s FT4

Jim Brown
 

On 3/4/2020 5:52 AM, Greg Chartrand via Groups.Io wrote:
I have chased a lot of DX on 160 m using CW and am used to waiting 20 minutes for a 30 second QSB peak to occur to work a DX station. These peaks are very similar to those I have seen on 40 and 20 m and FT4 seems to be the mode that can take advantage of them. I'd expect the same to be true on 6M where sporadic E and meteor bursts provide paths of short duration's.
Hi Greg,

The rapid QSB you're talking about when heard on the AM broadcast band is generally called "selective fading," and is really the result of the same mechanism that causes "picket fencing" at VHF and UHF. The difference between the two is frequency. That mechanism is the complex addition at a point in space where the antenna is located of wavefronts that have taken different paths, and thus shifted in time with respect to each other. Because phase shift produced by this event is frequency multiplied by time, phase is constantly changing, and at a rate directly related by frequency. Signal peaks occur when the two arrivals are precisely in phase, dips occur when the arrivals are equal in strength and precisely 180 degrees out of phase.

This mechanism, which is periodic (that is, repeating at a more or less constant rate based on the time difference) is quite different from meteor scatter, which has no periodicity all -- it's based on ionization produced by "rocks" entering our atmosphere. MSK144 works quite well for this mode, but provides relatively little noise immunity.

I mostly use WSJT-X "slow modes" on 160 for long haul DX and on 6M for multi-hop E-skip. My experience on both bands is that what's most important is noise immunity. My QTH is fairly quiet in most directions most of the time, and WSJT-X almost always give signal reports than I receive by 10-15 dB! And I'm running legal limit on 160 and 6M into pretty good antennas! (I don't use WSJT-X on other bands except to work rare DX, and don't run much power when I do -- indeed, I'm often trying to work them with 5W).

The other mode I'd like to see used a LOT more on 160M is JT9. It's about 6 dB better in terms of noise immunity than FT8, and 8 dB better than FT4. Yes, it takes longer, but can work through fades, and has long been the dominant mode on 630m and 2200m bands.

73, Jim K9YC


locked Re: Added Feature?

Barry Green
 

Thanks, all! I wasn't aware of JTAlert  but I am now. I appreciate the prompt help, and 73.

Barry
W1JFK