Choppy CW

N4XD
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Choppy CW

Postby N4XD » Sat Nov 27, 2021 6:12 pm

Recently I noted that the outer edge of the Thetis display would briefly flash red and the SWR would read high. I thought this meant that one of the relays was hot switching. To fix this issue (I now think its a software issue and not hot switching) I decided to change the CW delay key down setting by increasing it to 40ms or so.

This did NOT turn out well. During the CQWW CW contest, going right now, a buddy said my CW was choppy. Indeed it was. Unreadable. I reset the CW delay values back to 30ms and all is good.

My question is this:

If these values should not be changed, why do we have access to them? Are they left over from a legacy project? Or, if I've got this wrong, what am I missing?

If I have it right, perhaps, whenever someone does another update (and all that effort is appreciated) they can hide these settings or, at a minimum, if someone tries to change them a pop up note about choppy cw could be displayed.

Thanks

Ron
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Joe-W4WT
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Re: Choppy CW

Postby Joe-W4WT » Sat Nov 27, 2021 6:48 pm

Ron,

I noticed the red outline/high swr also last night (first time I've been on CW for awhile) but it only seems to occur if Semi break-in is selected. As you mention you can stop it by adjusting the cw delay but that, as you mention, can cause other undesirable problems.

I found that using QSK does not cause the red/high swr outline to occur. I don't really like QSK but with tinkering I found that if you simply set QSK mode and then adjust the delay to 200 or 300, you get back to Semi type break-in but don't have the problem with the swr warning AND you get sidetone that you don't get with Semi. The only problem I found doing this is that QSK doesn't operate if you use a separate Rx antenna and have it on Ant 2 or Ant 3. Putting it on Ext 1, however, works just fine. Using this setup, it seems to negate the need to even have the Semi break-in option.

73,

Joe W4WT
N4XD
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Red perimeter flash in Thetis

Postby N4XD » Mon Dec 13, 2021 3:24 pm

situation:
Thetis: version 12k7
Windows i7 computer
When transmitting on 160 I get, almost every time, the perimeter of Thetis flash red. Only when first character in cw is sent. I believe that means Thetis thinks its seeing a high swr.

I added a swr bridge between thetis and the antenna and no indicated swr spike.

Further experimenting showed that this only happens when a receive antenna is being used. If I switch VFO A to TX ant (vs RX Ant) NO flash. Obviously the receive antenna is not in the transmit path (I use a receive antenna on rx port 2 and also for the second receiver on RX2). And I'm not physically disconnecting the receive antennas, just de-selecting them.

For now I'm going to assume this is a software issue and not a timing issue. Timing shouldn't, I'd think, change depending on if a receive antenna is connected. And it doesn't appear the radio is being hot switched.

All that said, it sure would be nice to hear from others if, first, they have seen this and second, is there a work around? The flash is disconcerting.

Thanks

Ron
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w-u-2-o
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Re: Choppy CW

Postby w-u-2-o » Mon Dec 13, 2021 7:22 pm

Merged your new post since it was a dupe of this topic.

If you read through the CW related posts starting on 26 Nov in this topic:

viewtopic.php?f=9&t=3817&start=990

you will see that CW operation, either QSK or semi-break in, requires significant delays to be set in order to accommodate separate TX and RX antennas. This is a limitation of the hardware/firmware/software architecture overall. Switching between antennas requires more than a few tens of milliseconds. The high VSWR indication is evidence of hot switching and bad VSWR during the hot switching period.

Caution, and careful adjustment of delay settings, is required when operating CW with separate TX and RX antennas.
N4XD
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Re: Choppy CW

Postby N4XD » Mon Dec 13, 2021 9:22 pm

Scott I appreciate your information and read the posts as you suggested. However, the only number that seemed to be mentioned was, if I understand correctly, for the semi break in delay. I've already set that to 295 or so ms. But if I understand correctly that really doesn't bear on this issue. At least not at that value.

What I initially tried was to set the cw delay key down value over the 30ms which is the default in Thetis. I set it to 50ms. If I set it higher than that the cw being sent becomes choppy. At least that was the result of one of the over the air tests I did. NO idea why increasing that delay would impact in that way.

So, do you have, or has someone else come up with, the minimum value for key down delay when using an external receive antenna? If that's in the manual (either Thetis or for the radio) I have missed it.

Thanks

Ron
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w-u-2-o
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Re: Choppy CW

Postby w-u-2-o » Mon Dec 13, 2021 9:35 pm

Unfortunately I don't know what the right value would be. I've never seen a manual. I understand there is an unofficial one, but I've never read it.
N4XD
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Re: Choppy CW

Postby N4XD » Mon Dec 13, 2021 10:13 pm

Thanks Scott.

Experimenting some it seems 49ms for key down delay works. I.E no more swr red perimeter flash warning. Any larger delay and the cw starts to sound choppy. I've no idea why key down delay would affect cw this way. Makes no sense.
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Re: Choppy CW

Postby K1LSB » Mon Dec 13, 2021 11:29 pm

On the contrary, it makes perfect sense. As Scott succinctly stated, CW operation requires significant delays to be set in order to accommodate separate TX and RX antennas. If the antenna swapping sequence is not yet complete by the time your transmission begins, then your transmit antenna is not yet connected so you should expect your SWR will be high and the perimeter will flash red, not to mention the myriad other potential problems cause by hot switching (which is exactly what's happening).

That's exactly why the Key-Down delay feature exists.

Here's what the Thetis 1.1 User Manual says:

The key-down delay (Menu > Setup > General > Options) is now limited to permit a setting
no shorter than 7ms to ensure a clean CW signal. Setting it lower than this would cause key
clicks to be transmitted due to keying the CW signal before the relays have fully engaged.
This is not healthy for the relays, and other operators on the band will not appreciate the
resulting key clicks that are produced, which may extend up and down the band for 10s of
KHz. Some external amplifiers may also need a longer delay, although this setting should
work with most. Check your amplifier’s manual and timing requirements before using its
QSK capability. In the other direction, increasing key-down delay longer than about 10ms
reduces the time available to hear signals between CW elements, defeating the purpose of
QSK.


Regards,
Mark
N4XD
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Re: Choppy CW

Postby N4XD » Mon Dec 13, 2021 11:41 pm

Mark, I appreciate your post but I am not confused about the delay required. I completely understand that. And, if using external receive antennas the delay has to be longer than if you're not using them.

What doesn't make any sense to me is why, if I increase the key down delay beyond 49 msec the cw being sent becomes so choppy its unreadable. All the relays have switched over, everything is settled down. Absolutely no hardware reason why key down setting being longer than, in my case 49 msec (because I am using eternal receive antennas) cw quality should be affected.

CW quality should not be affected, AT ALL, by the key down delay. Perhaps if that delay is too short the first character might be truncated but that's not the issue I'm hearing.

I hope 49 msec is going to be long enough since it can't be longer.

Ron
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Re: Choppy CW

Postby K1LSB » Tue Dec 14, 2021 1:12 am

Ron,

Thanks for clarifying.

Mark
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w-u-2-o
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Re: Choppy CW

Postby w-u-2-o » Tue Dec 14, 2021 5:43 pm

This issue has also been discussed in this topic:

viewtopic.php?f=17&t=3974&p=17210&hilit=paris#p17210

From the other topic:

At 30ms it is very possible to miss a first dit, send or receive, at higher send rates. Using the "PARIS" standard, a dit length is approximately 60/(50*words-per-minute), so at 20 WPM a dit is only 60ms.

This would appear to be an unavoidable consequence of the delays inherent in the software/firmware commanding the relays to switch between antennas, and the physical relay switching speed. When Chris coded up and improved the break-in performance, it was predicated on no T/R switching, i.e. the radio operates in full duplex mode when break-in is set to "semi".


I don't know exactly what the code is doing in semi-break-in, however I'm going to guess that the main TX-RX antenna switching occurs on the first key down after the break-in delay expires. That means that the Key Down delay setting needs to be larger than the time necessary to switch from the RX to the TX antenna. Clearly this time is right around 49ms.

Taking this assumption further, the Key Down delay is processed on every key down event and not just the "first key down" as described above. And, probably now making a really big assumption, the key-down delay is not implemented as a delay line, but merely truncates the leading portion of any dot or dash.

Thus, looking again to the PARIS standard, with a Key Down delay set to 50ms this is really going to hurt dot and dash lengths even at a mere 10WPM.

What is needed is a separate delay associated with the use of separate TX and RX antennas for CW that is only applied on "first key down" events.
N4XD
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Re: Choppy CW

Postby N4XD » Tue Dec 14, 2021 6:28 pm

Scott I understand the need to put in a higher delay value when using the receive antennas.

But, still left unanswered is why, after a key down delay beyond 49ms, the resulting cw is choppy. Not the first dit or dah (actually those sound fine) but ALL the cw that follows. It sounds like its lost the timing between and of characters. Why on earth would key down delay settings affect this??

I've tested this over and over and even at 49ms you can tell the cw is not what it should be. Already being chopped up some.

In my thinking this is a serious flaw: if you want to take advantage of external receive antennas you have to increase the key down delay. Yet, if you increase it too much (perhaps needed to completely eliminate the hi sswr warning) , you're cw sounds terrible. So bad that NO reverse beacons will decode it.
N4XD
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Re: Choppy CW

Postby N4XD » Tue Dec 14, 2021 7:21 pm

I should have noted that if you want to hear what I'm talking about, turn the key down delay up to 50 and listen on a separate receiver. From 40 to 49 it sounds a bit choppy. After that it sounds what I'd call mushy. Characters run together.

Ron
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w-u-2-o
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Re: Choppy CW

Postby w-u-2-o » Tue Dec 14, 2021 7:25 pm

N4XD wrote:Scott I understand the need to put in a higher delay value when using the receive antennas.

But, still left unanswered is why, after a key down delay beyond 49ms, the resulting cw is choppy. Not the first dit or dah (actually those sound fine) but ALL the cw that follows. It sounds like its lost the timing between and of characters. Why on earth would key down delay settings affect this??

Re-read my last post above. Asked and answered (well, theoretically, since I don't know for sure that the code does what I have assumed it does).
N4XD
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Re: Choppy CW

Postby N4XD » Tue Dec 14, 2021 7:38 pm

Scott, sorry. I discounted the assumed part of your answer. Probably shouldn't have. guess I really don't care why its happening other than that understanding would provide a path, hopefully, to fixing this.

I am trying to find other ways to solve this problem (I use a winkeyer and hope I can massage the settings to provide the delay needed). If this can't be solved it kills the rig for low band dxing and contesting.

I do agree, the fix would be a separate delay setting that has no affect on the sent cw.

Ron
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Re: Choppy CW

Postby N4XD » Wed Dec 15, 2021 3:28 am

Just thought of this. Does Powersdr work this same way (re key down delay)? I've never tried that operating interface.

Thanks
Ron
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w-u-2-o
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Re: Choppy CW

Postby w-u-2-o » Wed Dec 15, 2021 12:16 pm

It works the same way.
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w9ac
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Re: Choppy CW

Postby w9ac » Wed Dec 15, 2021 12:40 pm

Ron, I heard you on 160m the other morning and definitely heard what sounds like a key weighting issue. Up until then, your CW keying has always been perfect.

I can't offer any suggestions through; I operate everything with absolute minimum delays with QSK and apart from correct amp timing, I'm not protecting anything else in the system like a Rx preamp or separate Rx antenna.

Paul, W9AC
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Re: Choppy CW

Postby N4XD » Wed Dec 15, 2021 12:53 pm

Paul thanks for the note. I have increased the key down delay and that does cause, if the delay is set between 40 and 49, a shortening of the cw characters.

Do you use any receive antennas? That is where Thetis flashes the red hi swr warning. I now understand its likely because the Anan internal relay has not completed switching the receive antennas out of the "circuit".

I think I now have a set up that minimizes the shortening of characters and (mostly) eliminates the swr warning. I say mostly as occasionally, with no changes in set up, I get the flash. I'm now thinking it might be due to cpu loading in the computer. Anything over about 20% seems to cause the random warnings.

So much to figure out!

Thanks again for the note.

Ron
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w9ac
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Re: Choppy CW

Postby w9ac » Wed Dec 15, 2021 1:34 pm

N4XD wrote:Paul thanks for the note. I have increased the key down delay and that does cause, if the delay is set between 40 and 49, a shortening of the cw characters. Do you use any receive antennas?

Not at my home QTH where I use an ANAN 7000DLE. Here, an 80m dipole is up in the pine trees at 60 ft. and fed with balanced, open transmission line.

At my remote site, a K3S is used with many more antennas, including a 200 ft. diam. Hi-Z 8-circle for 160m.

Paul, W9AC
N4XD
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Re: Choppy CW

Postby N4XD » Wed Dec 15, 2021 1:56 pm

RR. If not using receive antennas then timing isn't an issue. Its only with receive antennas that the key down issue becomes, well, an issue.
N4XD
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Re: Choppy CW update

Postby N4XD » Thu Dec 16, 2021 2:15 pm

After a lot of experimenting it appears that the way to solve this problem is with ptt delay. The pop up box (when you hover over it) says "sets the hang time in ms". It appears this is not correct.

What it appears to do, which is EXACTLY what I am looking for, is set the delay from ptt application to rf out. So its really key down delay. I've no idea what (useful) thing key down delay does.

Will keep experimenting and monitoring but for now, setting ptt delay to 140ms has eliminated the swr flash when using external receive only antennas. Seems extremely long but I can live with it. May try shortening this time to see what minimum might be.


Thanks for all the input on this.

Ron
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Re: Choppy CW

Postby K9RX » Thu Dec 16, 2021 2:24 pm

Ron,

I resorted to always using the foot switch to send CW when operating 80/160 w/ a RX antenna. I have the same issue re SWR and it would also occasionally trip out the amp - it would trip on "out of band".

I'll give your fix a try - see what I find as a 2nd data point.

Gary
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w-u-2-o
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Re: Choppy CW

Postby w-u-2-o » Thu Dec 16, 2021 3:21 pm

Great find, Ron!

Were you able to/did you go back and reduce the key up and down times? If so, what did you reduce them to?

This all actually makes some sense, i.e. it seems logical that there should be separate settings for overall PTT (TX vs. RX) transition states, and purely RF transition states (key down, key up). The multiple delay settings, while somewhat obscure and possibly hard to understand, clearly do provide a high level of flexibility and fine grain control over what the radio is doing.
N4XD
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Re: Choppy CW

Postby N4XD » Thu Dec 16, 2021 3:34 pm

Scott i reduced key down delay to 38ms. Might now be able to go back down to 30ms.

I'm still experimenting with ptt delay. Have to get it working well with N1MM for contests. N1MM also has a settable delay setting. Between the two (thetis and n1mm) I think I'm set.

One other variable is cpu usage which seems to affect the Anan relay switch time....or at least timing of when its started. Next big goal is a computer with 8 vs 4 cpu's. Right now I use a 4th gen I7. You'd think that would be enough......

Ron
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Re: Choppy CW

Postby N4XD » Sun Jan 09, 2022 2:09 pm

Hopefully final update. To clarify, this is a 7000dle not the mk2 so no qsk.

Using a K1EL winkeyer I have now connected its PTT line in parallel with a foot switch. Should have started with this!

- In Thetis, turn cw break in "off".

Using this combination I've virtually eliminated the timing issue causing the red SWR flash in Thetis.

I've also upgraded the PC to a I7 11th gen. Very significant speed increases across the board and no longer any issues with processor loading (computer loafs along at around 5% with DX labs open including spot collector and several web pages open using both Opera and Chrome).

A side benefit I've heard with the new pc is NR2 in Thetis sounds "cleaner". Fewer what I'll call dsp artifacts which tended to confuse my ears. Not quite ringing but noise sounded like random cw .

Thanks to all for their input.

Ron
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Re: Choppy CW

Postby w-u-2-o » Sun Jan 09, 2022 3:55 pm

N4XD wrote:Hopefully final update. To clarify, this is a 7000dle not the mk2 so no qsk.

That is not correct. All Orion and Orion Mk 2 platforms are QSK capable with P2 firmware. That includes the 200D, all variants of the 7000, and the 8000.

All 7000 variants and the 8000 use the Orion Mk 2 board. They are effectively identical at the board level.
N4XD
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Re: Choppy CW

Postby N4XD » Tue Jan 11, 2022 12:07 pm

Scott, at first your post confused me. When I cycled through the CW break in options on Thetis, QSK never came up. But "semi" would come up twice. Then "OFF".

Recalling something you wrote, found that this only happened on bands where I had assigned one of the hardware antenna ports to be for a receive antenna. Makes sense now.

Thanks

Ron

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