RadioBanter - View Single Post

September 29th 04, 06:17 PM

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...

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.

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

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).

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.

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? :-)

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

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

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

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

[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]

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

Anyone can see nice pictures at the NIST website.

Still living in the past...

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

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?"

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

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.

Do you find that without honor? Without any worth?

Why do you?

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. :-)

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...