CW Filter width display incorrectly

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  • Problem
  • Updated 3 years ago
The default CW Filters are incorrect from 400 Hz and on.

50, 100 and 250 displayed correctly with 25, 50 and 125 on each side of the yellow line of the slice.

But 400 is actually 250 on lower side and 150 on upper side



In 800 it becomes 650 and 150





And this continues being the case all the way to 3.0k which is 2850 on lower side and 150 in upper side.

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EA4GLI - 8P9EH - Salvador

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Posted 3 years ago

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Kevin

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Salvador, under Radio Setup do you have CWU or CWL selected? I kind of thought this would be normal behavior for CWL where the wider filters lean to the lower frequencies. I have CWU set up and see the same only opposite.

Kev K4VD
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EA4GLI - 8P9EH - Salvador

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CWL

And as I am listening to 40m LSB when I select CWU it changed to USB on the phone slice! There is definitely some odd behavior!

Why is phone (LSB) changing when I select CWU which is for CW mode??
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AH0U

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Slide the filter profile over so upper and lower levels are equal
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EA4GLI - 8P9EH - Salvador

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What do you mean? These are the factory default filters, not manual adjustment.
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EA4GLI - 8P9EH - Salvador

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Even if I move it manually to center it, as soon as I click on the filter it is out of whack again.
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EA4GLI - 8P9EH - Salvador

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Kevin

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It still looks like it is doing the right thing. The filters need to be offset for wider filters because on the "low" side you can't hear below 0 Hz.

Filter at 800 Hz. Assuming your sidetone pitch is set for 400 Hz this filter includes 0 Hz to 800 Hz.

Filter at 1500 Hz.  With sidetone pitch set to 400 Hz the filter is set to -400 Hz + 1100 Hz. This is 0 Hz to 1500 Hz.

To have that symmetrical I'd have to be listening to -350 Hz audio. Not really possible.
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EA4GLI - 8P9EH - Salvador

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I still do not understand this Kevin, but thanks for making the effort to explain it.
So if this is the case, that I need a wider one sided filter when I select 1500 or 3000 so I can hear.... how is it that I can select a 50 Hz filter and hear regardless of the pitch? I do not see the correlation.
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Kevin

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If your pitch (sidetone pitch) is set to 600 for example then a 50 Hz filter would be 575 to 625 Hz. Not negative.

Note that you are only shifting if the low side tries to bring the filter to less than zero Hz. Impossible, right? So shift it so you still get the wide filter but it starts from 0 Hz.

pitch 600 hz

filter 50 Hz 575-625 Hz
filter 400 Hz 400-800 Hz
filter 800 Hz 200-1000 Hz
filter 1500 Hz 0 - 1500 Hz  <-- because you cannot go below zero.

Try this experiment. Set your Pitch to 2000 and set your filter to 3K. Symmetrical. Now start decreasing your pitch. When you get below 1500 Hz pitch the filter has to shift over so it doesn't go below 0 Hz. It happens right before your eyes.
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EA4GLI - 8P9EH - Salvador

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Great explanation.

Now, what is the relationship between pitch and frequency if any?
If i hear someone on 21.015 cw and I change the pitch the tone i hear changes but the frequency remains the same. And if I change the filter the tone doesn't vary.
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Kevin

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Analog analogies are all I can offer. In old fashioned terms, changing the pitch is accomplished by changing the beat frequency oscillator. In other words, you're not changing the carrier (as shown in your frequency readout), you are changing the signal that beats with the carrier to produce the audio tone. Carrier stays the same; frequency readout stays the same. I'm sure in a digital world there's a more Boolean way of explaining this.

You wouldn't expect the pitch to change with the filter. All you are doing with the filter is defining the range of frequencies that is passed to on to you. Again, not a very digital explanation. The filter is a window on the band.

Now I'm looking forward to someone putting me straight!
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Tim - W4TME, Customer Experience Manager

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1.) Filters on CW are asymmetric depending on if CWL or CWU is selected and the audio frequency of the sidetone.  This is the expected behavior.  

2.) There is no relationship between the sidetone frequency and the actual frequency of the CW signal.  The slice "lubber line" is the actual frequency of the CW signal.  You can change the CW pitch to whatever frequency you find most desirable.
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Tim - W4TME, Customer Experience Manager

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It has no bearing on phone modes.
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EA4GLI - 8P9EH - Salvador

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Please check the video above and look around 15 seconds into the video. Changing CWU to CWL in the Setup menu changes the passband left and right even though the mode is still LSB.
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Kevin

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Salvador:

I see what you are saying.

At 15 seconds you have set your mode to LSB. The filter is showing on the left side of the line. So far so good. Then you go to Radio Setup -> Phone/CW and you change between CWU and CWL and I see your filter area move above and below the line while LSB is still selected. I see your filter Cf move between -1.0K and 1.0K. Yes, this is weird and unexpected behavior I think. How?

Mine is not doing the same thing. I'm set for LSB. I see the shaded filter area to the left of the line. When I change Radio Setup -> Phone/CW sideband between CWU and CWL (back and forth) nothing changes in SSDR. The shaded filter area remains to the left, normal LSB. It behaves as expected. In fact, even when I'm in CW mode I don't see the filter jumping to the other side of the line.

I tried to match your settings in the video as much as possible and I can't seem to get the results you are seeing. 

I'm running SSDR v1.9.9.170 on Win10 v1607.

Curious to see how this turns out.

Kev
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EA4GLI - 8P9EH - Salvador

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Try modifying the cw pitch value to 400 or even 300. Then go to lsb and try switching between cwu and cwl, see if it happens then.
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Kevin

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When I'm at 400 Hz my filter is still symetrical (I use  a pitch of 400 Hz for CW). So I don't see the effect.

I see from your update that you've fixed the problem but the solution was pretty painful. You didn't have your profiles and memories backed up? It might have been interesting to see what happened after you reloaded the profiles.

I'm not suggesting this to anyone but I reset my radio at least once a month. It may not be necessary but I feel comfortable that any odd behavior that has built up over a month of operating and experimenting (that word gave me a headache) that a reset just kind of cleans things up. As profiles are apparently way beyond my capacity to understand I do not use them.The few times I have the did not act as I expected them to act:



Personally, I think Flex needs to rethink their whole profile architecture.

73 and glad things are working well.

Kevin K4VD
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EA4GLI - 8P9EH - Salvador

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UPDATE

Good news is that a brand new install of SmartSDR, a factory reset of the 6700 and removing all my profiles fixed the problem.

Bad news is that I have to recreate all the profiles, memories, MIC adjustments, etc... painful.

At least I am not getting the weird behavior of switching left and right on LSB when selecting CWU or CWL and it is back to behaving properly.