On 2013-09-18, Larry Jaques wrote:
rOn 17 Sep 2013 23:20:03 GMT, "DoN. Nichols"
wrote:
On 2013-09-17, Larry Jaques wrote:
On 17 Sep 2013 04:57:44 GMT, "DoN. Nichols"
wrote:
[ ... ]
My favorites were made by Power Designs, and I got them for good
prices at hamfests, because I knew them from having worked with them at
work. Two styles.
2005 0-20V 0-0.5 A adjustable in steps of 1 mV. Just dial
in the desired voltage from 0-10V, and a switch adds
another 10V if you need it. It has a nice current
limit. They even have the zener reference in a crystal
oven, so the voltage does not drift with room
temperature variations. Plug them in and the ovens
starts working, and once the front panel light for
the oven starts cycling, it will be stable.
3650 0-36V, 0-5A, with a variac built in so the difference
between the voltage out of the transformer and the
voltage desired out of the front panel terminals is not
too different, so you don't have to drop too much
voltage (and thus heat in the regulator.
I'll keep eyeballs peeled for those, Don. Thanks. Speaking of crystal
ovens, I have one from the '50s which I use as a fire safe. It's made
with that horrid OHMIGODWEREALLGONNADIE asbestos stuff.
BTW -- I was meaning to ask how big a crystal oven you *have*.
A fire safe for *what*? The crystal ovens I have plug into an octal
tube socket, and have just enough room inside for the heating element,
the thermal switch, and a quartz crystal (say about 1" x 3/4" by 3/8"
depending on the age and the style). The Power Designs 2005s have a
zener diode in there instead -- same principle -- keep the temperature
steady to keep the value (frequency or voltage) steady. I do have a
larger one which could hold a medium size prescription pill bottle. It
has a glass enclosed (and likely in vacuum) crystal. Overall size is
about that of a beer can.
Here is what my 2005s look like -- eBay auction #261287963296
including a back view showing the terminal strip where the
jumpers are -- or should be. :-) This is not the least expensive
in the auctions -- but the first with a good clear photo.
And *here*: (ebay auction #370875530364) is a newer version.
Ouch! They aren't giving those away, are they?
Nope -- but they were around $500-$900 in the late 1960s. which
would be several K these days. Hamfests are better than eBay -- but you
have to wait longer to find what you want. :-)
Yeah, I keep forgetting that I stopped wrenching before most of the
cars went to digital systems. I haven't had to troubleshoot any of
the newer ones since I've owned only brand new trucks (2) since then.
Most of my work on cars was back when, too. Except for a few
things on the Mazda Navajo (really a Ford SUV with a badge change. :-)
The worst was changing the radius rods, which either required tools to
compress and take apart the front suspension (which I did not have), or
removing two big heavy rivets on each side on the rails below the front
seats. A combination of drilling and an air chisel to get those off.
:-) Replaced with bolts, of course. :-)
Um, rivets aren't supposed to be removed, sir. g That means you
usually have to support the engine/trans, then remove the xmember and
about 400 other things to get at the item you need to replace. Lots
of fun, that.
Well ... I went through several web pages about how to change
them (actually the bushings on the radius rods), and given the tools I
had, the remove the rivets and put in the bolts fit better. Just
getting a big enough socket inside the front coil spring was a nasty
job, and I did not want to put that much torque on it without having a
hydraulic lift. Jack stands are just not that steady, even with several
extras.
And some of the web pages said that they *may* have bolts
already, suggesting that either the factory used them some of the time,
and rivets the rest -- or that it was a common repair approach. :-)
It worked, which is what matters. :-)
Cool! Was your "dainty" above facetious?
A mere 16 lbs -- by the step on the bathroom scale holding it,
vs not holding it approach. :-) It is the larges which I have not built
into something, though the one in the Best Power Systems UPS is bigger.
And perhaps in a couple of smaller UPS as well.
Thot so.
The bridge rectifier is one of the metal housing ones, and I've
got it held in a small drill press vise as a temporary heat sink, and it
does get rather warm. :-)
Har!
I don't want to know how hot it would get without the drill
press vise. I really ought to put it on a proper heat sink -- if I want
to make this a permanent assembly.
I also ought to measure just how much current I'm drawing from
the thing. :-)
20A usually isn't schmall.
Now that I own a ham radio (Baofeng UV-5R portable) I need to get my
tickee and go to those ham fests so I can find your treasures here.
Well ... you need the ticket to use the transmit function of the
radio, but you don't need it to go to the hamfests. I've been going to
them for over 30 years (they've gotten smaller and fewer over that
period) and up until this year, I didn't have a license.
I knew that. I was just saying that I need to go to learn stuff and
to find those treasures you found.
Learning what you need to pass the exam(s) won't tell you what
these good things in the hamfests are. The hams who bought the lot at
the surplus sale have already pulled out the directly ham-related stuff
for their own use. :-)
I recognized these because I used to work for an Army R&D lab
(Night Vision Labs at the time), and we had *good* test and lab
equipment.
About three hamfests back, I won a door prize for the first time
-- a little handheld Yeasu FT250 2-meter transceiver, and decided that
the time had come.
Congrats for the old win!
Thanks. Just the motivation I needed to try for my license. :-)
So I dove into a couple of sites giving the practice
exams to see how much I needed to learn, and after a little while at the
Technician (entry) level, I decided to try the General, and found that I
felt pretty good about that, too. I then tried the one for the Extra
class, and actually passed that (barely) the first try, so I kept diving
into that too. By the time the next local exams came up, I decided to
try for all three -- and passed all three. The Extra class was the one
which really needed my calculator quite a bit. (But, interestingly
enough, the actual exam I took did not need it -- it was pretty easy.)
In the practice, I had to refresh my memory on things like calculating
reactance at frequencies in capacitors and inductors, and calculating
resonant frequencies. Also a lot of summing resistance, inductance, and
capacitance at a given frequency (or just with the reactances given, and
figure out which of a number of labeled points on a graph it is.
You went whole hog into it, dincha?
Well ... as I was learning about the questions in the earlier
exams, I was learning that there were things which I could not do as a
Technician which I could as a General, and things which I could not do
as a General which I could do only as an Extra, so I figured that I
should go for the highest so I would not wind up accidentally doing
something which I could only do as a higher class.
*And* -- since I retired, I normally sleep until 1:00 PM, and
stay up really late working on various things, and I had to be at the
exam site at 0900. I figured that if I could do that only *once* I
would be happier. :-)
[ ... ]
My approach worked for me, since I had been an electronic
technician for a long time, and could easily spot the ridiculous answers
given (multiple-guess) and narrow things down fairly quickly, and make
pretty good guesses at some of the others, including what happens when
you combine more than one antenna in a particular way (I didn't know, but
I was able to guess a number of them.)
I only spent 3 years as a tech and didn't really learn as much as I
would have wished. I have regrets about that, but I wasn't prepared
to drive 2-3 hours in rush hour traffic to the outskirts of Sandy Eggo
to get it.
Understood. I was driving about 45 minutes each way (going the
opposite direction of the majority of rush-hour traffic), so that was
not too bad -- until the government would pull the wintertime game of
"There's a blizzard out there, but you can't go home yet." "Still not
too bad -- stick around" (repeat several time), and then finally "No
sane man should be on the roads -- go home!" at the exact same time that
all the other government employees are sent home throughout the
Washington DC area. (DC, Southern MD, and Northern VA). This makes for
a five or six hour drive home. :-)
Except for the complete lack of money while self-employed, I haven't
regretted going solo. ;-/
Understood.
[ ... ]
Here is one of the practice sites: http://aa9pw.com/radio/
and the other: http://www.eham.net/exams/
Both are built from the real questions used in the exams, and
each time you take one, you get a different collection of questions.
Both tell you what you got right and wrong, and what was right
if you got a question wrong. The first one tells you in order, while
the other one tells you in some sort of scrambled order.
I have a Ham CD a friend gave to me with all the exam questions and
answers, programs, and information on it, and I bought the Dummies
Guide to Ham Radio (pdf) the other day. It's just a matter of
studying them and takee tickee.
How long ago did he give it to you? The exams are updated about
once every three years, with the Extra class one updated in 2011 IIRC.
So it is about time for the Technician class to be updated next year, I
think.
[ ... ]
Good Luck with your exam(s) (however many you choose to take.)
Just the Tech, at least for now.
O.K. You're more used to getting up early than I am these days. :-)
[ ... ]
FWIW -- I'm now KV4PH.
When did you get that? I think they're up to 6 digits nowadays.
I got it about mid-September this year. The "Extra Class" gets
the more desirable shorter call signs by default. (If you have a longer
one from Technician class, and later pass the General and Extra class
exams, you have the option of keeping the call you got earlier (you're
used to using it), or to go to a shorter call as you prefer. You can
also put in requests for the even shorter ones as they come available
(two years after the holder gives up his license, or dies). There is a
big scramble for those, of course. :-) So, this is one other benefit of
going for all three exams at once. I don't have to decide whether to
change calls later. :-)
And so far, nothing with greater range than the little handheld
2-meter, which reaches from Vienna out to the Bluemont repeater (perhaps
45 miles -- but Bluemont has a *big* antenna tower on a mountain, so
that is a lot better than from handheld at ground level to another
handheld at ground level.
I haven't been terribly intrigued by Ham, so I'd likely just use it as
a local emergency radio when (not if) the SHTF.
O.K. Of course, when it hits, the license will probably not be
worth the paper it is printed on. :-) But being used to using the radio,
and knowing the other people in the area will probably be a benefit.
AFAIK, I've never lived where lighting struck wires or antennas. It
has never affected me personally during my 60 years so far. (Me glad,
BTW)
BTW -- Part of the exams -- even the Technician class ones -- is
how to properly ground an antenna tower. One of the questions is about
how to run the ground wires, with one of the choices being that you make
neat right-angle bends in the wires. (That is a no-no. Same for
lightning rods -- they take a gentle curve out from the edge of the roof
and curve back to the vertical part. A sharp bend increases the
inductance, and thus a lot more voltage appears across that bend.
Smooth curves and as short as possible to each of multiple grounding rods
driven into the earth.
Interesting. I grew up in South Texas, and the old house had
lightning rods. And I remember them "thummm"ing when struck. And we
also had a few trees (not many in South Texas) hit and large chunks
split off. There was not much rain, but when there was, it was often a
serious thunderstorm, and I remember sitting on the porch watching it
approach -- and loved to watch it.
I'll bet that was fantastic, though loud as hell.
As a little kid, I loved the noise and the sight of the bolts.
I know some adults who can't stand the lighting and thunder.
[ ... ]
Oh yes -- and occasionally in the winter we get thunder-snow. :-)
That's weird. Nevahoiduvit.
Tends to happen only in certain weather conditions, usually a
blizzard in this area. It is uncommon enough so the TV weather men make
a big thing about it each time it happens. Probably about once every
three years, here.
I find thunder and lightning
fascinating, too. AFAIK, I've never been scared of it.
Earthquakes are kinda cool, too. (Well, up to 4.5 is all I've felt.)
I've only *noticed* one -- a couple of years ago towards central
Virginia. It shook a few things off shelves up here, but no damage to
the house. However, it brought the triangular brick part under the end
of a roof toppling down on a bunch of cars in the parking lot a few
miles way -- sort of variable how hard it hit.
The other I've been in, but did not notice directly, was in
Guyaquil Ecuador. I woke up and heard voices out in the street
(vendors) crying "terramoto" (earthquake), but the springing on the bed
kept me from feeling it -- though it might have helped me wake up then. :-)
Enjoy,
DoN.
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