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October 1st 04, 06:20 PM

(Avery Fineman)(so desperate to get past spam filters that he changes screen names)wrote in message ...
In article , PAMNO
(N2EY) writes:

In an ideal superheterodyne, all the oscillators would generate pure, steady
injection signals. In reality, there is always some imperfections in those
oscillator signals. In modern frequency synthesizers, particularly PLL types,
the imperfection takes the form of noise sidebands on the oscillator signal.

Technically wrong. DDS is more susceptible to spur generation and
phase noise than Fractional-N and Fractional-N is more susceptible
to that than PLLs.

Tsk. You haven't spent much time with a spectrum analyzer...

Sure have. You can nitpick over the minor points but the main thing is
correct: Frequency synthesizers do not produce perfectly clean LO
signals, and that phase noise in the LO causes performance degradation
in HF ham gear.

Trouble is, in the amateur HF environment we often want to listen to a weak
signal surrounded by many strong ones, often only a kHz or two away. Good
crystal and mechanical filters make it possible to separate such signals *if*
they can get to the filter in decent shape.

What happens when the LO signal is phase-noisy is that a close-in-frequency
unwanted signal mixes with the LO *noise*, and produces noise in the receiver
output. With a whole bunch of strong signals, the noise can be so high that
it drowns out the wanted signal. This problem is not due to IMD, blocking or
other
various nonlinearities in the front end - it's due to phase noise alone.

Tsk. Simplistic untruth.

No, it's true. You just don't understand the point.

I should have included a clarifying phrase in the above, but I thought
the average technically knoweldgeable reader would understand the
point anyway.

The clarifying phrase is:

"Even with an ideal receiver front end"

meaning that even if IMD and IP3 aren't causing problems, phase noise
*alone* can cause the apparent noise floor to rise if there are strong
adjacent-channel signals.

Note how, in lab tests, there is sometimes the annotation "noise
limited" when certain tests are made. What do you think that term
means?

Intermodulation distortion and front end noise is enough to cause that.
As part of the IMD, the 3rd Order Intercept point values figure in.

Only if the LO is clean enough to allow it. Note how, in lab tests,
there is sometimes the annotation "noise limited" when certain tests
are made. What do you think that term means?

You can get IMD in stages beyond the mixer. To "prove" that point,
you would have to measure the IMD at various gain settings (manual
or AGC).

Of course. But even in an ideal signal path, phase-noisy LOs can
degrade performance. That's the point. Note how, in lab tests, there
is sometimes the annotation "noise limited" when certain tests are
made. What do you think that term means?

The worst part of that untrue statement is that "all those other things"
were existant before the advent of frequency control by synthesizer.
In ham radios as well as the radios in every other radio service.

Nobody denies that. However, in many sets the phase noise is the
limiting factor. Particularly in real-world situations.

1 Hz is common in modern manufactured amateur equipment. But that's not
really the issue.

Tsk. Why are Jimmie and Kellie trying to make so much of that
resolution? :-)

You brought it up ;-)

R-70 is a pretty good receiver. Almost qualifies as a boatanchor now....

Only for a small liferaft. It can be easily carried in one hand. It comes
equipped with a handle on the side, apparently for that purpose. :-)

But, you will try to use my owning an R-70 as all sorts of denigrations.

Like what?

R70s were made 1982-84 (approximately), so the design is at least 23
years old (1981). You frequenctly denigrate others as "behind the
times", yet the R70 is the newest/most modern piece of HF radio
equipment you mention owning. Just another example of "do as Len says,
not as Len does".

Kellie did...and was completely wrong...but then he only "favors" those
equipments that he's owned or has handled.

Just like you, Len ;-)

Have you ever used the receiver he mentions?

How many points did Len get with it in the last CQWW? Or even the last SS or
Field Day?

Irrelevant.

No, completely relevant. One important measure of amateur equipment
quality is how it performs in actual on-air operation.

Had I an HF-privilege ham license, I wouldn't bother with
contesting. I've said that before.

So the answer is: Zero.

There are VHF/UHF contests - including Field Day.

If I wanted sports, I would go to athletics...REAL sport.

Who decides what is "real sport"? You're not the IOC. Or TAC ;-)

[if I wanted "road races," I'd get a sports car as I used to have and
do minor gymkhanas, etc., in REAL road races]

The term "road race" is not limited to motor vehicles. It's
understandable that you don't like sports.

btw, some years back I was there, at NIST in Boulder. Saw the various
standards
and how they keep WWV synchronized. Also visited the WWV/WWVB transmitter
site. Got lots of pictures, too.

Okay, so your resume got rejected.

Nope. Didn't bring one; wasn't looking for a job.

Sorry to hear about it. Glad you
got nice pictures.

Anyone can see nice pictures at the NIST website.

Not the same as being there. It seems you enjoy only second-hand
experiences.

Still living in the past...

Tsk. You are repeating yourself...as you've done many times in the
past.

Not nearly so many times as you, Len. ;-)

Time for a radio story...

Back in high school I knew a local ham down Collingdale way who was always
working on a pet project. Same age as me, saw him in school every day. Had
all
kinds of grand ideas of how he was going to build the next generation
state-of-the-art ham rig. All solid-state, full features, all bands, all
modes,
etc.

Now this kid was no dummy and his ideas were basically very sound. But he
didn't have anywhere near the resources or practical experience to actually
finish anything. He'd draw all kinds of schematics, spin all kinds of yarns
and
sometimes even gather some parts. But build a working rig? Never happened.
Not
once. When he *did* get on the air, it was with borrowed equipment that he
conned some local ham into lending him "temporarily". Until said local ham
had
to come over and take it back. I made the mistake of loaning the kid a QST,
which I never saw again. I learned fast.

Meanwhile, those of us willing to make do with less than "SOTA" were on the
air
and having fun and QSOs while he pontificated.

That was about 35 years ago but the lesson is still valid: All this bafflegab
doesn't make one QSO.

For some reason I was reminded of him. He sounded just like Len...

Poor baby. Still with the insults sugar-coated with hypocritical
"civility?"

Are you insulted? Why?

The above story is true. The ham involved (actually an ex-ham; he no
longer shows up in the database) behaved exactly as described. He
probably went on to a career in electronics in some capacity or other.
And as I said, most of his ideas were pretty good - he just never
carried them to completion or even to partial implementation. At least
he held a ham license for a while - you haven't even done that.

You *do* sound just like him, Len. Lots of words and lots of put-downs
and lots of theory. But in terms of actual radios built on your own
time, with your own resources, from your own design....nada. Zip.
Zilch. Zero. Nothing. Not that anyone here knows about in all your
years and petabytes of posting.

I even looked through the online database of ham radio magazine
articles. You had 24 "bylines" in ham radio from 1977 to 1982 (even
though ham radio magazine was in operation a lot longer than that).
Most of them were in the 1977-79 time frame (20 bylines). Not one
"build this radio!" article - lots of commentary, some theory, lots of
basic stuff on digital logic theory.

Last mention was over 22 years ago...

You talk about "independent thought". Designing and building a ham
station with only one's available personal resources requires a lot of
independent thought - and action. It also explodes the myth of
amateurs as simple consumers of manufactured products.

Tsk. I lost interest in DXing in "radio sports" and the wallpaper
collection of QSLs after working at station ADA long ago.

To each his own. Why do you denigrate what others find as fun? What is
wrong with live and let live?

Became a professional in the radio-electronics industry, got regular
money for not only designing, but building and testing, following
through in the field, etc., etc., on many projects.

Completely different game. You sound like someone saying the Tour de
France is no big deal because you did the same route in a car in less
time. Or that a marathon is no big deal because you can do 26.22 miles
in less than half the time on a motorcycle.

Point is, for your own personal use, you just go out and buy a radio.
Yet you put down the salesfolk of 20+ years ago for not knowing some
arcane bit of info about the innards of the set.

Does it work any better because you know it has a 3 loop PLL?

Do you find that without honor?

Nope.

Without any worth?

Nope. You got paid, I presume?

Why do you?

Why do you presuppose my answer?

And why do you make fun of others' work and accomplishments, yet
expect honor for your own?

"Do as Len says, not as Len does".

The main point is simple: Hams did not need synthesizers to stay in their
bands and subbands. Nor do they need 1 Hz or even 10 Hz accuracy on HF.

In Jimmie's world, yes. :-)

Why is such accuracy needed by hams, Len?

It must be right across the border from nursieworld. :-)

Tsk. Some "runner." Takes up one phrase and runs and runs and
runs trying to prove another is unworthy in his presence. :-)

Tsk. Those runs could be cured with some kaopectate...

Well, now we know where *your* mind is at, Len...

So there's only one logical thing for me to do: