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Author Topic: Morse code with FSK??  (Read 21752 times)

Posts: 154

« on: January 18, 2015, 10:57:05 AM »

I heard something strange on 20m just now.  I happened to be tuning through the digital bit of the 20m band, and heard some fsk signal that sounded a bit odd...   I stopped and listened a bit, and it turns out that the guy was sending Morse code on 14.074MHz with FSK.  So I punched in a narrow filter and tuned out the higher pitched tone.   He was banging away at about 20wpm, just rag chewing away.   I listened for about 15 minutes.  I couldn't hear the other station to see if he was doing the same thing.

I don't suppose it's against the rules.   It just seems strange.   I'm guessing that it was keyboard code, because it was keyboard perfect.   It makes me wonder if someone just got their settings wrong with a soundcard setup...   But, the other guys seemed to be responding, so who knows...

If nothing else, I would think it would be unnecessarily hard on your finals.   No sense running them at 100% duty cycle just to send Morse.

I do a lot of CW, a little sideband, and have dabbled in FSK RTTY.  But, I'm really not a digital guy.

Has anyone else noticed this?  Is it a thing nowadays?

Just curious

73, mike

Posts: 631


« Reply #1 on: January 18, 2015, 03:06:47 PM »

Allot of the guys running digital modes use FSK tones to generate CW ID. I've also heard guys making CW contacts using it. To me it just doesn't sound right as CW, the space tone is distracting for me.
Just my opinion.

Posts: 418

« Reply #2 on: January 19, 2015, 07:44:17 AM »

Yes, when you have a Japanese final because you are an appliance operator, it is a lot of power loss.

 But I expect it is a guy with a VFO and a final of 5 to 50 watts after the VFO. In that case on-off tuning as in A1A (CW)  is just making a severe bunch of clicks when you switch the VFO on and off. BUT when you just detune the spaces (FSK), that effect is gone. No band wide clicks.

Afterall we  radioamateurs are expected to develop our technical skills by investigating. Of course that will be investigating the already invented wheel, but the purpose of the ITU of developing your OWN skills by experimenting is fullfilled.

Not so when you buy a Japanese appliance an prepacked see-through packed antenna, and start 5nn contesting, in that case  you are spending your time instead of watching talking heads on television, to listening  to guys with far  less education, complaining about their neighbors due to TVI and BCI, and their gallstones.   



Posts: 58

« Reply #3 on: January 20, 2015, 04:12:05 AM »

One possibility is that you heard a coherent continuous wave (CCW) signal.

I read an article that appeared in QST in the mid-1970s which described synchronized CW stations
communicating with improved copy as each station had receiving and decoding locked to the timing of the transmitting station's signal. That is a simplified description best as I can recall. I don't think the technology existed then to allow most hams to experiment with it.

However, MultiPSK software has among it's many modes, Coherent CW. This software is freely available, although the CCW mode isn't often heard.

There are two options in this software for transmitting and receiving CCW: ON/OFF keying  and  FSK CW.
Both sound like CW (they are CW) with synchronizing characters sent at idle moments to maintain sync with the receiving station, but FSK CCW is much like what you described in your post, to wit, a frequency shifted  continuous carrier which transmits CW characters.

Posts: 1501


« Reply #4 on: January 20, 2015, 06:11:35 AM »

I thought that any type of MCW was illegal except in a few places in the VHF and higher bands.     Huh


Posts: 521

« Reply #5 on: January 20, 2015, 08:40:50 AM »

was illegal

Guess that depends on how your licence is drafted. There are certainly some jurisdictions where the licence is drafted in a mode-indifferent manner, so if the signal's within band, within power limits, and it's not encrypted...

Posts: 268

« Reply #6 on: January 20, 2015, 08:56:52 AM »

From AE2EU: "I thought that any type of MCW was illegal except in a few places in the VHF and higher bands."

Jim in theory, single tone SSB and carrier CW are identical so it is a legal way of generating CW with an SSB transmitter.  In practice it rarely produces clean results.  Opposite sideband suppression is not absolute, etc...

73 - Luke

Posts: 32

« Reply #7 on: January 21, 2015, 08:09:53 PM »

Could it have been the distorted second harmonic from a close-by station on 7.037MHz ?

Posts: 8

« Reply #8 on: March 01, 2015, 05:42:59 AM »

MCW - Modulated CW - is illegal in the US on HF (except maybe 10 meters?). MCW transmits a carrier and one or more sidebands. It can be emission type A2 or F2, depending on whether you modulate the carrier in amplitude or frequency. FSK transmits just a single carrier, which is shifted in frequency to "key" the Morse characters; hence it is classified as emission type F1. "Normal" cw turns the carrier on and off - varies the amplitude between zero and peak, and hence is A1 emission.
MCW was common in pre-SSB days in non-amateur services because you did not need a BFO to receive it. Tune below the AM broadcast band and you may still find some "Non-Directional Beacons" for marine/aviation navigation. They use A2 MCW.

Posts: 575

« Reply #9 on: March 01, 2015, 06:26:49 AM »

Thank you, W1KRT for your comment.  That's something I was, also, wondering about? 

I've decided to go with the A1-emission for CW; using a keyer.

Ken KC8Y

Posts: 15066

« Reply #10 on: March 01, 2015, 06:49:57 AM »

I'd suggest that the mode is still FSK even though it is using Morse encoding rather than Baudot. I wouldn't consider it MCW.

Bob  AA4PB
Garrisonville, VA

Posts: 5593

« Reply #11 on: March 01, 2015, 01:39:04 PM »

Some "true FSK rigs" use a keying line to shift between mark and space. If he was confused and rig was in RTTY mode but computer or paddle was sending CW through that keying line, that would do what you described. If it was 170Hz shift, someone listening with a super narrow filter (e.g. 50Hz or 100Hz) might not hear the other tone at all.

Is it possible that there was a constant carrier circa 170 Hz away from him, he was sending plain old CW, and your rig's AGC made the result sound like FSK?

Posts: 8

« Reply #12 on: March 03, 2015, 07:09:18 AM »

Silly me. I forgot to mention an application of MCW almost all of us are very familiar with. Ever hear a repeater identify in cw?
That was using MCW, mode F2. If it were FSK (F1) it would sound like a dead carrier. No 'tone' to it. Listening to FSK RTTY with an AM receiver is the same, except if the signal is strong you might hear some clicks or thumps.
FSK CW? I've heard stories of Navy radar ops doing it in a pinch, switching the radar freq. Don't know whether it is true or not.
On the ham bands, my *guess* is that it is legal in the band segments where RTTY and other data modes are OK. It would be the same as Baudot RTTY or ASCII teleprinter, just using Morse code instead. We are authorized to use any code which is publicly known. International Morse has certainly been public knowledge for a while now! Why would anyone want to? I've got no idea about that. I see no advantages and several disadvantages. Perhaps it was a case of "I'll do it because I can." Whatever...
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