filtering question / challenge (morse code )

[mstram]

For all you Audacity "gurus" :

I'd like to remove as much as the "mechanical /metal clacking" as possible from this video's audio track, leaving only the "morse tone", which is ~780hz

I tried messing with the "noise reduction" effect, and had some limited success, but as an Audacity newbie, I'm thinking there might be better techniques ?

MIke

https://www.youtube.com/watch?v=RYhrSEERvbI

[Trebor]

... I'd like to remove as much as the "mechanical /metal clacking" as possible from this video's audio track, leaving only the "morse tone"...

Could try "Ultra narrow" plugin, see ... http://forum.audacityteam.org/viewtopic ... 073#p78073

The settings used on Ultra Narrow.png (6.71 KiB) Viewed 1320 times

Ultra Narrow 700Hz (2) audio from YouTube v=RYhrSEERvbI.flac

"Ultra Narrow" plug-in on 700Hz , 2 iterations. [ Suggestion : try higher setting on iterations ].

(1.06 MiB) Downloaded 55 times

[kozikowski]

You understand there are two different messages going on there, right? The beeps are being received even though she's not keying them, so that's the incoming message, different from what she's doing.

I found the tone annoying. I can do much of it from just her clicks—classic Morse.

CQ CQ CQ BE....and then I lose it. She's going too fast for me, although she's using a sidewinder key and is a little easier to understand than a regular up and down key.

CQ is an all-call for any response from anyone. "Seek You."

Amaze your friends.

Koz

[mstram]

You understand there are two different messages going on there, right? The beeps are being received even though she's not keying them, so that's the incoming message, different from what she's doing.

The ~700 hz tone is HER sending.

There is a faint higher frequency, sounds about ~1200 that is incoming

Y
I found the tone annoying. I can do much of it from just her clicks—classic Morse.

CQ CQ CQ BE....and then I lose it. She's going too fast for me, although she's using a sidewinder key and is a little easier to understand than a regular up and down key.

CQ is an all-call for any response from anyone. "Seek You."

Koz

Actually it's CQ CQ CQ DE (DE - this is)

Then it sounds like TAPHN.

Her "stylized" sending, while admired by all the old timers, is hard for a newb like me to decipher

[mstram]

... I'd like to remove as much as the "mechanical /metal clacking" as possible from this video's audio track, leaving only the "morse tone"...

Could try "Ultra narrow" plugin, see ... http://forum.audacityteam.org/viewtopic ... 073#p78073

The settings used on Ultra Narrow.png

Ultra Narrow 700Hz (2) audio from YouTube v=RYhrSEERvbI.flac

Thanks that works but .....

Since the "clacks" were in the upper frequencies (~1000+), when the filter is applied it necessarily "muffles" the sound of the ~700hz tone ( the harmonics I guess), as well as removing the clacks.

I'm guessing the "clacks" are a fairly complex signal, and might be tough to eliminate while leaving the bright harmonics of the morse "tone" ?

[kozikowski]

Actually it's CQ CQ CQ DE (DE - this is)

Yes. That is what I was expecting, but I swear she sent a B rather than D. _... Don't send anything important through me.

Then it sounds like TAPHN.

I believe you. I didn't get that far. Given how hard it is to strip out the clicks without destroying the quality of the tone, I would still strip out the tone instead.

Have you tried the vinyl click and pop filters and techniques?

http://manual.audacityteam.org/man/tuto ... iques.html

Koz

[flynwill]

If the goal is to decode the message she is sending, why not just slow the recording down a factor of two.

[mstram]

I tried the "click and pop", but just used the default settings, didn't do anything. Looks like a bit of a complicated plugin to use.

>If the goal is to decode the message she is sending, why not just slow the recording down a factor of two.

Well the initial goal was to get rid of the clacking as I found it very annoying.

But after playing with the filter stuff, I think I prefer the clacking + high freq clarity to the "muffled" filtered tone.

Even though I'm a novice, I don't find her speed all that fast .. as long as I'm only listening to ~5 seconds at a time ... over and over
I did slow down one section but only about 10%

The problem I find is with her "stylized" sending method, combined of course with my very limited (literally weeks) of "non-experienced" listening / morse skills.

The morse software I've been using all send "perfect" morse, which is why I find the transition to trying to listen to "swing" morse a challenge.

It turns out what I thought was "TAPH/TST" at the beginning is actually "KPH/KSES/KSM" , at least that's the answer I got on a ham forum.
(Which makes sense, given the recording is taken from this event : http://www.kparc.org/bars/nights.htm

[Trebor]

I tried the "click and pop", but just used the default settings, didn't do anything. Looks like a bit of a complicated plugin to use.

After trying the "Pop Mute" filter on that morse I deleted the post where I suggested it :
that plugin can insert gaps in the morse which weren't in the original message, corrupting its meaning.