[RTTY] Getting rid of clicks--what's the risk?

[aflowers at frontiernet.net]

Joe,
 
I said:
 > ... I think it does show that the risks of AFSK are not as universal
> as some would have you believe.

Reading that back makes it look like it might have been directed at you, personally.  I didn't mean it that way, please forgive me if that is how it came across.   I want to make it clear that I'm not trying to steer people away from good quality FSK keying schemes (yours or anyone else's), especially when there are good reasons for those people to use them.  You have good arguements with which I am in agreement and I don't think you are trying to mislead anyone. 
 
What started this discussion was complaints about wide signals and some on this list made claims that this was an FSK/AFSK issue.  I and others have demonstrated that this is a waveshaping/filtering issue at the transmitter and makes no difference how that modulation is done.  It was a new realization for many people that their FSK generators "click" and have very real consequences that generate complaints.   Now we know that we can look in the mirror and stop blaming mythical AFSK operators for that portion of our woes.
 
 (For the record, MMTTY filters its output by default so I suspect a large number of AFSK users are waveshaping without knowing it.)
 
VE3KI's observation that not all radios have the "idiot-resistant" nature that the K3 has is what made me undertake that little exercise.  I imagine it is a rather extreme example in the grand scheme of things.  Even so, I was rather taken back by just how hard it was to mess things up even without the added protection of the AFSK TX filter in the DSP chain.  It's too bad that FSK generator is significantly worse from the QRM point of view, at least for the moment.  That may be a notable exception that is worth something to people who own K3s.  There are probably quite a few connected to amplifiers, so if there is a easy, low-risk way for them to declick we all benefit.
 
To take your other extreme, I actually have an FT-840 as luck would have it.  It now serves as a signal generator for various experiments rather than a communication device.  As I'm sure you know, AFSK through the (dynamic) mic jack is the only option on this radio.  Without any kind of feedback that seems to me to be like tightrope walking blindfolded without a net--it can be done, but that doesn't make it a good idea.   It would be an interesting exercise to see just how, eh... clean.... it can be under ideal circumstances.  If there is enough sincere (morbid?) interest in that I'd be happy to abuse it and take pictures, but it doesn't matter for the current issue since those aren't the radio largely hooked up to kilowatts on the contest weekend.  At least the MP has a "Packet" port in the back, but I will take it on faith that it is not forgiving with gain levels if one decides to wander off script.  Joe, you would certainly know more about
 that than I.
 
I emailed about 20 people who had noticeably narrow signals during the roundup to figure out what they were doing right (many are on this list).  I had to choose CQing stations (its a software thing) that were >50dB SNR to be able to get a good picture of what the signals looked like.  All but two of them were K3's running AFSK with MMTTY, an only a few were using the TX filter that does all the magic (there was a Flex 5K and there was an Omni VII in there, also MMTTY/AFSK).  I also found one AFSK signal with some low-level buzz and a spur at -40dBc, and it was probably a little worse than the clicks would have been in FSK mode--it was a common contesting radio, modulated through the mic jack.  I'm quite certain that problem has already been rectified.
 
I think that little sample says more about how lazy people are in hooking up their radios for RTTY than it says about Elecraft's "contest market share", so don't too excited about the numbers.  (It does make me wonder about the unintended consequences of burying the line-in port in a 50-pin connector that only elves can solder, but I'll let that be.)
 
I am quite sure that same attitude when applied to some other radios speaks straight to your points, Joe.  
 
Regards,
 
Andy K0SM/2