>Don't underestimate the importance of the words "in the sense that"!
Fair enough, Al! I've had my coffee now...
Here's a very simple way that might get at the crux of the issue. Let's say
that signal number #3 was your signal (yes, this was recorded off the air this
weekend, and no, I'm not going to identify him or her publicly):
http://www.frontiernet.net/~aflowers/rtty_examples/
Would knowing that was was being heard up and down the East (and probably West)
coast bother your conscience enough to look for ways to change something? Does
anyone want to say 'no'?
We all (well, most of the big contesters) managed to modify our early model MPs
to reduce the nasty CW key clicks without some objective standard from on
high. The problem was identified and people came up with solutions pretty
quickly. Hams have historically been able to make many changes for the better
without big brother drawing a line in the sand.
Andy K0SM/2
________________________________
From: Al Kozakiewicz <akozak@hourglass.com>
To: "aflowers@frontiernet.net" <aflowers@frontiernet.net>;
"rtty@contesting.com" <rtty@contesting.com>
Sent: Wednesday, January 9, 2013 11:08 AM
Subject: RE: [RTTY] RTTY Now trashy signals
Don't underestimate the importance of the words "in the sense that"!
While we are all ultimately responsible for operating to a set of acceptable
standards, the FSK operator has no choice to make in the matter short of
ceasing operation if their transmitter is performing poorly*. The AFSK
operator, on the other hand, makes all kinds of choices in software, soundcard,
interface, computer output levels, transmitter gain, compression, ALC, etc.
etc. All have a direct impact on signal quality.
I too would be interested in knowing both how to define and measure the quality
of FSK transmissions and how products perform with respect to those metrics.
*-Anyone can plot quality (however you'd like to define that term) of
transmitted signals along a line from bad to good. What I'd like to know is
where you draw a line distinguishing acceptable from unacceptable? If width is
king, queen and everything in between with respect to RTTY signals, how many db
down do the modulation byproducts have to be how far from the mark/space
frequency? And who gets to decide that?
Al
AB2ZY
________________________________________
From: RTTY [rtty-bounces@contesting.com] On Behalf Of aflowers@frontiernet.net
[aflowers@frontiernet.net]
Sent: Wednesday, January 09, 2013 10:28 AM
To: rtty@contesting.com
Subject: Re: [RTTY] RTTY Now trashy signals
Al,
I respectfully disagree in small detail (and please forgive me if I
misunderstood). I think everyone owns equal responsibility for his or her
signal *regardless of the process creating it*. We make the decision to either
trust that the manufacturer has implemented the feature properly and we choose
use it, or we choose to do it by other means. Contesters are always making
decisions like this. Really capable people will measure the things that matter
to them, if they can, and the magazines try to publish product reviews to help
us out. In the final analysis we make a good choice or we make a bad choice
based on available information, but either way we make the choice and we are
responsible for the signal we put out. Sometimes getting a new radio may be
the only viable option, and that is expensive, and yes, we will be upset at the
manufacturer for giving us a raw deal.
I think your main point is that "the transmitter made me do it" isn't a
justification for keeping on doing it. Spot on, in my opinion.
I think that begs a really important question though: is there any meaningful
difference among the FSK signals generated by different radios' internal FSK
generators. Forget whether it's done by switching the LO frequency, by magical
DSP fairies, or by black and white mice spinning the mark and space wheels next
to the flux capacitor: *among the internal FSK generators in the K3, IC-7800,
FT-1000MP, and IC-706, or any radio made in the last 15 years, is there any
meaningful difference when it comes to the RF coming out?*
If so, what are the differences? Anyone have pictures of radios side by side
when keyed in their "FSK" mode?
Andy K0SM/2
----------------------------------------------------------------------
Which was basically my point. Discounting analog FSK implementations from 30
years ago, there is nothing you, Joe Ham, can do should it be proved that, yes
indeed, your 2 year old DSP transceiver is splattering when modulated using
FSK. There are no user accessible adjustments and with the few DSP designs
I've looked at there are no internal hardware adjustments either so you can
probably safely attribute the problem in that case to bad design. Which has no
cure except to buy a different model radio.
A ham running AFSK owns a lot more responsibility for the cleanliness of his
signal than one running FSK in the sense that AFSK performance is more
dependent on user configuration.
Al
AB2ZY
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