Nice..Bill, you are a gracious person. Thanks for the breath of fresh air.
Gary
----- Original Message -----
From: "Billy Cox" <aa4nu@ix.netcom.com>
To: <k9yc@arrl.net>; "Discussion of Ten-Tec Equipment"
<tentec@contesting.com>
Sent: Sunday, July 27, 2014 3:26 PM
Subject: Re: [TenTec] THANK YOU AND APOLOGY
Yo Jim,
I think we all need to give each other
a bit more grace? Especially on complex
topics such as currently under review.
We all makes mistakes, you made one this
weekend with your post on the E brand
forum as to saying that someone needed
to be fired over a schematic? True?
Yet a bit later, after some time of slowing
down and studying the schematic, you found
that you have made the errors in your reading
of the data presented?
Another person helped you with your questions
and tried gently to suggest that your conclusion
was not quite 100%. You noted such a bit later.
James is on that forum, yet I don't recall
him calling you out for it as you should
have known better? Grace is good ...
Sadly, it seems too many on here, have long
forgotten what it was like when you and I
were first getting started in this hobby?
And that not everyone has or will be able to
go to school on this topic. That's not a
requirement, to be a open learner is.
Nor do I think James considers himself an
instant expert. Look at his background, it
does tend to require a high level of facts.
Some of my best students at the university
level, by the end of the term, were the ones
who struggled the most when the class started.
Should I have treated them as you guys are
doing to James? I would hope not. None of
us, including me are perfect really.
Folks learn in different ways, some have to
"get it" via a way that may not be how you
or I learn or present best. Grace is good ...
James, as well as many others, have asked me
questions too off the forum. Some I fear do
that as they don't want to be jumped on by
posts such as yours or similar recent comments
on here by a couple of others.
Let's help them learn please, but don't beat
them down in the process.
We ALL have bias about things, you do too as
an engineer, and in other topics too. Below
you are suggesting we should not value the
data from the person because he is not a contester?
One of the parties, who sadly has acted rather
ugly from the posts of yesterday, has made
repeated anti-contest postings, should we also
discount anything he says? Grace is good ...
One role of a teacher is to stay with the
student, as long as they are making an effort
to learn? James is doing his part.
Shouldn't we strive to do our part? If he has
something not quite correct, why not try and
help rather than judge him as others are doing?
By his professional training, he is trained
to secure evidence and see if it supports, or
if it does not support the statement.
No evidence presented, the conclusion can be
there is no truth. If I needed legal advice,
that is exactly the background I would expect.
How is that any different from every engineering
team that I have been part of where the unspoken
is always ... "Trust but verify"?
He asked for the evidence. Interesting, and also
very sad, to see how you and a couple others
responded in that regard. That is how we end of with
the dreaded "ham lore" of "Well, we all know that"
I really believe James has read, and re-read every
reference that others, including you have suggested.
From the questions I get back from him after suggesting
a reference, that tells me his does read and learn.
Thanks for providing him in this post with some
simple definitions of the terms that have been
tossed about. Yes, It is a very complex topic.
Even Rick made an error in his post on band pass
filters this morning, but I will let him re-read
it first and make any needed correction.
Thanks for the Q in the recent RTTY NAQP and hope to
work you again in the August CW and SSB sessions.
73 de Billy, AA4NU
-----Original Message-----
From: Jim Brown <k9yc@audiosystemsgroup.com>
Sent: Jul 27, 2014 5:53 PM
To: tentec@contesting.com
Subject: Re: [TenTec] THANK YOU AND APOLOGY
On 7/27/2014 12:54 AM, K8JHR wrote:
I was encouraged by ARRL Lab expert Bob Allison, who reviewed the
same graphs and said,
"THEY HAVE NEARLY THE SAME COMPOSITE NOISE."
Several points. Mr. Allison is probably not a contester. He is looking
as a lab tech, not as a user.
Second, they way the data are plotted with all the data at the bottom of
the graph, it IS hard to see the differences. But when you look at the
data with a reasonable scale, and plot multiple competing radios on the
same graph, the differences jump out at you.
Third, I look at this data from the perspective of someone who must
coexist with all of that noise produced by near neighbors, and others
with strong signals with crummy radios.
My plot of Bob's data clearly shows the Eagle to be, on average, 5-6 dB
cleaner than a TS590, depending on how far off frequency you are
listening. 6 dB is an S-unit, and it corresponds to 4X the transmitted
noise power. That sure matters to me if I'm trying to copy a weak signal
buried by someone else's sideband trash!
James, as part of this discussion, I and others have on several
occasions, observed that the interference between radios consists of
multiple components, most of which are the result of how the radio is
built. They are designed in characteristics, the result design decisions
made by the engineering team to build a product for a defined set of
functions and cost. That's what engineering is! Rick posted an email
from N6KR that addressed some of the design decisions he made in
designing the K3 and KX3 to make both their TX and RX as clean as
possible.
Those mechanisms include, but are not limited to, (see, I can get
lawyerly if I wanna) phase noise in the RX, distortion in the RX
(measured as intermod -- IMD), and fundamental overload (the interfering
signal drives the RX to its voltage limits); phase noise and distortion
transmitted by the other station (composite noise in the ARRL tests),
his IMD, his key clicks, and overdrive of his audio. The only one of
these not the fault of the radio's design is the last one -- overdrive
of audio.
What is phase noise? It is a byproduct of the frequency synthesizer
that determines the radio's operating frequency, how much of it is
present depends strongly on its design. Again, see N6KR's email, which
Rick has posted here at least twice. It originally ran on the Elecraft
reflector. Read the ARRL Handbook to learn more.
What is distortion? It is the non-linear behavior of a system (what you
get out of an amplifier is more than a perfect copy of what you put into
it), and the "more" consists of harmonics and sideband trash.
Overdrive of the audio also creates distortion, thus sideband trash.
Overdrive of a power amp also causes its distortion to increase.
ALL amplifiers create SOME distortion (harmonics and sidebands). Study
the ARRL Handbook to understand why. HOW MUCH distortion is produced
depends on the design and how it is driven. How much escapes as
harmonics is determined by bandpass filters, both inside the amplifier
and outside it.
In an earlier post, you made some snide, cheap lawyerly remarks about a
radio that was not clean at rated power and had to be run at lower power
to be clean. The distortion in ALL amplifiers varies with their supply
voltage (close to their design voltage, more supply voltage = cleaner)
and output power. Typical ham amplifiers are cleaner at half power than
at full power. When I use the word "amplifier" here I'm also talking
about the output stage of a ham transceiver.
And don't tell me that we have not tried to teach you. At least a month
ago, I posted a link to an excellent tutorial on the topic by K6XX. It's
still on my website. k9yc.com/publish.htm
73, Jim K9YC
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