(N2EY) wrote in message . com...
(Brian Kelly) wrote in message . com...
PAMNO (N2EY) wrote in message ...
switched to 10 Hz or 1 Hz. Its accuracy was dependent on how well you set
the
time base and presets. Could be used with almost any rig. Hooked it up to a
75S3
I'll bet I know where the S3 came from . . .
and got an A in the course.
Lab course at Penn?
Independent design project.
.._.
Made the circuit boards meself and all.
Lotta jollies there if yer into such things. I "burned" a number of
homebrewed circuit boards, late '60s? Something like that. Making PCBs
then was basically a drafting and photographic process which
"integrated"nicely into my darkroom "assets" so I went at it a few
times. Translate the circuit diagram in QST to a physical layout for
openers. Yeah, they can draw circuits which show conductors leaping
over other conductors without shorting them but that don't work on
single-sided boards dammit! Which all homebrewers could do then. Dunno
how you did yours but there were complete PCB "kits" available from
Kass and Radio Shack when I did mine.
They provided sheets of transfers with "donuts" for wire and component
connections and IC pinouts all of which were layed out on a
transparent film. Then ya *very carefully* connected all the dots with
thin tape to make the conductor traces. Tedious. Net result was a 1:1
photograhic negative of the circuit. From there it went into the
darkroom where the negative was positioned over a piece of sensitized
board stock and exposed, developed, neutralized and washed just like
all photos are developed even today. I did a few boards which I
sensitzed myself.
The rest was easy. Drill all the holes, trim the board to size and
stuff it with the components. Then go back and solder-patch all the
busted traces! Hee!
I guess I did ten boards all told. Three keyers, one a monster K3JH
developed which was first large-capacity memory keyer, several
stripline SWR bridges, a vacuum relay QSK TR switch, etc. I think I
showed you some of those "works of art" before I dumstered all that
old crap. I have a yen now to build a couple more widgets using
homebrewed PCBs but so far I have not been able to find the board
stock or chemicals in hobby quantities.
and you're done. Could go to 1 Hz if you were willing to have it update once
per second.
Neat! (no, I'm not willing to wait a second for the nummers to come up
. . ! )
The 74192 and other TTL family chips were hot stuff 30 years ago when
I was doing that project. You can still get pin-compatible parts
today.
I fed the aformentioned dumpster a *shoebox* full of those old 7400
series chips . . .
Wait a minnit, if there are sideband signals on the LO output the
inference seems to be that the carrier is being modulated.
That's exactly what's going on.
By something. What something?
All kinds of somethings. Here's just one:
In a PLL synthesizer, the VCO control voltage may wander a bit for a
variety of reasons. Say you have a design where a voltage swing of 5
volts causes the VCO to move 5 MHz. *Any* variation in that control
voltage, from *any* source, will cause the VCO frequency to wander a
bit. 1 millivolt variation gives a shift of 1000 Hz, 1 *microvolt* of
variation gives 1 Hz, etc. Remember that the control voltage is a DC
signal and the rest is obvious.
Not quite. I gotta chase down the links Dave supplied and keep
digging.
That's just one source of phase noise.
OK
That's why phase noise is important to hams.
Huh: I learned a bit from this post.
I hope so!
The upshot of all of it is that in real-world hamming, we often have
to deal with bands full of strong signals, yet we want to hear the
weak ones.
That leaves Sweetums and his half-vast "experience" out. Long-haul
military HF comms are channelized and if a station is weak they just
twist the Variac clockwise. 40kW with rhombics just to push RTTY from
Tokyo to the west coast . . SPARE me . . !
I've run into more than a few hams who say they "hate contests because
they make the bands so noisy". What's really going on, in at least
some cases, is that the effects of so many strong signals on the air
all at once raise the apparent noise floor of their *modern*
transceivers, in part due to phase-noisy oscillators in the
contest-haters equipment.
"If ya can't take the heat go up the band!"
One can spend two lifetimes diddling frequency synthesizers and such
but if whatever freq pops out of his gem doesn't make it to the
airwaves via an engineered radiator and it's support structure one
might as well have been a lifeguard in the Mohave desert.
And THAT'S the game!
73 de Jim, N2EY
btw - the way I'd solve the problem would be to email you for the
solution.
.. . . boink . . POINT!
It's no big deal at all. As far as the "math" goes any kid who has a
decent grip on 9th grade alegebra can hoof thru it, this is not double
integral or tensor analysis country. All one needs to pull it together
is the material physical properties and the ability to jiggle a few
simple algebraic equations which are only a half-step beyond jiggling
Ohm's Law. All of it is readily available out on the Web and it can
all be done with a pencil and a calculator.
Typical materials info source:
http://www.matweb.com/SpecificMateri...&group=General
Here's a taste of the number-crunching:
http://hsc.csu.edu.au/engineering_st...ng_stress.html
For my own part I've gotten into semi-automating the whole process in
order to design widgets like tapered aluminum yagi elememts,
fiberglass quad (squalo?) spreaders, masts and towers. I run a LISP
rountine in Autocad to come up with the cross-sectional properties
then diddle the rest in Excel or Mathcad or a slick little $50
shareware program called "DTbeam" which is a finite elememt analysis
beam analyzer. The M.E.'s version of a Java-based Smith Chart solver.
Sort of.
http://www.dtware.com/
w3rv