"Someone transmitted a bad signal using AFSK. Therefore you shouldn't do it."
Your decision whether or not to use waveshaped AFSK today shouldn't be based on
the fact that its technically possible to do something bad. The big guns in
the RTTY world understand their stations and they know far above the average
yahoo when it comes to the "wrong thing to do" with AFSK. As of this moment,
rtty clicks are an issue to many people who understand it and know why it is an
issue for their situation. I remember (barely) when the "key click mods" were
making the rounds on a manufacturer's radios. Not all of them got changed, but
I'm willing to bet that those that continued to be used at the big contest
stations by and large did. Why? Because their users understood the issue and
were willing to do surgery on kilobuck radios to make things better for the
people around them. The people doing the modification didn't get one dB out of
it. Everything I have seen in the RTTY contesting world leads me to believe
these are the
same type of self-sacrificing people, if not in many cases the very same
people. For those who understand the size of their footprints,
one-size-fits-all answer that we should wait for manufacturers to change things
and click away in the meantime doesn't sit well.
This is probably applies to a minority of people on this list, but it is also a
very visible minority. This isn't anywhere near as big of an issue for the
occasional operatator with a 100W and a dipole as it is for the contest CQ
machine with 1000W and a stack.
Right now you many of these people do not have to wait for manufacturers to
change their FSK keying circuits (or in many cases what is more likely to be
a firmware revision). AFSK with a waveshaped input may be an alternative. Is
that ideal? Hardly. In fact it's kinda silly when you think about it from an
engineering point of view, but it is a very viable means to an end and is being
done properly by the vast majority of AFSK users in contests. The $64,000
question: it a good idea for you to do it? Alas, the corollary to the above is
also true: just because you can *possibly* transmit a click-free doesn't mean
you should do this either. Ah...economic utility rears its confounding head
again.
So, in an effort to quantify the risk-benefit tradeoff in my particular case, I
took a very popular contesting radio and set out to transmit the most rotten
signal I could.
That's right--I tried to do all the bad things AFSK abusers are supposedly
prone to doing and attempted to spread wreckage across the band with my K3. I
documented the wreckage for your entertainment and also so that other K3 owners
could take a look and have some examples for what the risk/benefits are without
having to attempt to break their own radios. I've tried to make it as
value-free as I can so that you can look at the spectra and decide for yourself
what for you, if you are a K3 owner. Even if you are not a K3 owner, you might
still find it interesting. I had fun write writing it and learned quite a bit
about my radio.
Here is where you can read my epic trail of destruction:
http://www.frontiernet.net/~aflowers/k3_afsk/
We can talk about the carnage if you find anything interesting. There are
suprises in there for those willing to take the time. Enjoy!
Keep in mind that this is an examination of the safeguards and pitfalls in one
particular model and does not represent any others, but I think it does show
that the risks of AFSK are not as universal as some would have you believe.
For the record I don't really care what you choose to do at your station so
long as you do so intelligently. If anyone wants to put together a plan to get
the manufacturers' attention to start cleaning up FSK generators I am willing
to be a part of it. It seems that is a point of agreement here and I'm willing
to work in the long term. My inbox is open for ideas (and no Bob, I'm not
calling my congressman).
Oh, and please don't shoot the messenger.
Regards,
Andy K0SM/2
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