sci.electronics.repair@googlegroups.com

Today's topics:

* Recommendation for electronics forums? - 16 messages, 8 authors
http://groups.google.com/group/sci.electronics.repair/t/a2a97ca7806d8277?hl=en
* Led Zeppelin - 1 messages, 1 author
http://groups.google.com/group/sci.electronics.repair/t/9ab1e69e1e72acb3?hl=en
* Running a PC outside of a computer case - 8 messages, 4 authors
http://groups.google.com/group/sci.electronics.repair/t/767389e3dda5bc79?hl=en

==============================================================================
TOPIC: Recommendation for electronics forums?
http://groups.google.com/group/sci.electronics.repair/t/a2a97ca7806d8277?hl=en
==============================================================================

== 1 of 16 ==
Date: Sun, Mar 20 2011 12:17 pm
From: Meat Plow

On Sun, 20 Mar 2011 13:21:16 -0400, Michael A. Terrell wrote:

> "Geoffrey S. Mendelson" wrote:
>>
>> Michael A. Terrell wrote:
>> > You've got to be kidding. I know a lot of hams who don't even own
>> > a
>> > soldering iron. They ship their radios off for factory service,
>> > unlike 40 years ago.
>>
>> Totally irrelevant. I know a lot of people who can barely figure out
>> how to put gasoline in their cars, but that does not mean there are is
>> no one who knows how they work, and repair and "upgrade" their cars.
>>
>> It's like this group. You ask a question and you get answers. Most of
>> them are not worth the paper they were never printed upon.
>>
>> You go to a web forum, you get the same results. You ask a bunch of
>> hams and you get an answer. Not from all of them, but from one or two
>> who know what they are talking about.
>
>
> Right. Sure. Maybe in your small world. I recently went to the
> local ham radio club's hamfest. 99% of the items for sale were cheap
> chinese crap that is even cheaer on Ebay. the hams that knew what they
> were doing have either quit the hobby, or are now 'Silent Keys'. I saw
> more computer related items than radio, and the couple vendors with
> components had no one at their tables.

When a few of us used to go in on a table at a hamfest we'd go dig in the
attic or basement for a bunch of junk to sell. I used to go to Dayton Oh
every year but that started being a joke. Most junk and computers. A few
vendors from Kenwood, Yaesu, Alinco, MFD etc.. Not like it was 20 years
ago.

--
Live Fast Die Young, Leave A Pretty Corpse

== 2 of 16 ==
Date: Sun, Mar 20 2011 12:39 pm
From: "Geoffrey S. Mendelson"

Michael A. Terrell wrote:
> More like 1975, not 2011 and this isn't Israel.

Actually that's the US, and not here. In Israel there are 600 or so licensed
hams, with about 250 in the IARC. With an almost 100% draft/national service,
there is no need for hams as emergency communications.

There were about 50 to 100 more two years ago, but the government sent out
bills to renew the licenses and they decided it was not worth the money.

There are plenty of radios in the government and IDF (military) and between
previous experience in the military, annual reserve duty, and volunteer
units (such as the border police, etc) there is absolutely no need for hams.

The other big privleges/service the hams did was phone patches, which have
been obsolete since 1997 when the price of international calls became
cheaper than cross country ones and cell phones became cheap.

In fact the IARC decided to do a drill this year just to do one, and they
scheduled on the sabbath, which meant that 99% of the hams in Jerusalem and
environment would not participate. It was like the ARRL scheduling a nationwide
emergency drill without Maryland, Virgina, DC and so on.

> There are plenty of commercial FM radios around, and all the county
> radios are digital. The only amateur related emergency gear is the
> club's HF station, near the county offices. They don't have a spare
> tower, or antennas that could be erected in a couple hours and there is
> no way in hell they could put up a replacement commercial digital radio
> base station or cell phone tower, even if they had months.

They don't need one. The ARRL's purpose in these drills is to do "health and
welfare" messages e.g. "your aunt Matilda's ok in a shelter, but her house
washed away". This is to offload that work from NGOs like the Red Cross
and Salvation Army, so they can provide relief services.

There also is no need to replace commercial digital radio base stations
or cell phone towers, etc. There are plenty of people in the world who can
do that, once the dust settles they will. It's the first few days that
are critical.

If things work properly, then the hams come in provide communications in
the background for the "victims" without getting in the way.

I know the hams here could not do it, and the ones that could would be
back with their reserve units anyway. but here ham radio has never been
much more than a hobby.

Going back to David's question, I pointed out ham radio because he could
use it to connect with someone who did know what he wanted and would be
willing to help him. Someone pooh-poohed the idea because they wanted one
to one instruction, which they would not of gotten from a web forum, which
was the original request.

It all comes down to expecting that someone who actually knows op-amps and
is willing to answer questions about them is going to spend their time
looking for and answering questions on a web forum.

99% of the questions asked on web forums are so basic that they are a waste
of time to answer and the self proclaimed experts are unable to answer
even those.

BTW, did Don Lancaster ever update his "OP Amp Cookbook"?

Geoff.

--
Geoffrey S. Mendelson N3OWJ/4X1GM
Those who cannot remember the past are condemned to misquote it.

== 3 of 16 ==
Date: Sun, Mar 20 2011 1:24 pm
From: "Michael A. Terrell"

"Geoffrey S. Mendelson" wrote:
>
> Michael A. Terrell wrote:
> > More like 1975, not 2011 and this isn't Israel.
>
> Actually that's the US, and not here. In Israel there are 600 or so licensed
> hams, with about 250 in the IARC. With an almost 100% draft/national service,
> there is no need for hams as emergency communications.
>
> There were about 50 to 100 more two years ago, but the government sent out
> bills to renew the licenses and they decided it was not worth the money.
>
> There are plenty of radios in the government and IDF (military) and between
> previous experience in the military, annual reserve duty, and volunteer
> units (such as the border police, etc) there is absolutely no need for hams.
>
> The other big privleges/service the hams did was phone patches, which have
> been obsolete since 1997 when the price of international calls became
> cheaper than cross country ones and cell phones became cheap.
>
> In fact the IARC decided to do a drill this year just to do one, and they
> scheduled on the sabbath, which meant that 99% of the hams in Jerusalem and
> environment would not participate. It was like the ARRL scheduling a nationwide
> emergency drill without Maryland, Virgina, DC and so on.
>
> > There are plenty of commercial FM radios around, and all the county
> > radios are digital. The only amateur related emergency gear is the
> > club's HF station, near the county offices. They don't have a spare
> > tower, or antennas that could be erected in a couple hours and there is
> > no way in hell they could put up a replacement commercial digital radio
> > base station or cell phone tower, even if they had months.
>
> They don't need one. The ARRL's purpose in these drills is to do "health and
> welfare" messages e.g. "your aunt Matilda's ok in a shelter, but her house
> washed away". This is to offload that work from NGOs like the Red Cross
> and Salvation Army, so they can provide relief services.
>
> There also is no need to replace commercial digital radio base stations
> or cell phone towers, etc. There are plenty of people in the world who can
> do that, once the dust settles they will. It's the first few days that
> are critical.

During which no one can help. A lot of radio stations lost their
generators of STLS during the last round of hurricanes in Central
Florida. The only news was via SW, but those services are no longer
broadcasting to the US.

> If things work properly, then the hams come in provide communications in
> the background for the "victims" without getting in the way.

Few HF antennas survive a hurricane around here. Downed power lines
and little fuel availible for generators. In some places, people with a
working cable modem are the only outside communications, since the RR
backbone is buried fiber optic and it covers large areas of the US.

> I know the hams here could not do it, and the ones that could would be
> back with their reserve units anyway. but here ham radio has never been
> much more than a hobby.
>
> Going back to David's question, I pointed out ham radio because he could
> use it to connect with someone who did know what he wanted and would be
> willing to help him. Someone pooh-poohed the idea because they wanted one
> to one instruction, which they would not of gotten from a web forum, which
> was the original request.
>
> It all comes down to expecting that someone who actually knows op-amps and
> is willing to answer questions about them is going to spend their time
> looking for and answering questions on a web forum.

I posted links to the proper Usenet groups, a free spice program and
a Yahoo support group. I still don't like the idea of using an opamp in
a SMPS.

> 99% of the questions asked on web forums are so basic that they are a waste
> of time to answer and the self proclaimed experts are unable to answer
> even those.
>
> BTW, did Don Lancaster ever update his "OP Amp Cookbook"?

Ask him. He posts on sci.electronics.design once in a while. His
website is http://www.tinja.com He put a few of his books online a
while back and posted links.

--
You can't fix stupid. You can't even put a Band-Aid™ on it, because it's
Teflon coated.

== 4 of 16 ==
Date: Sun, Mar 20 2011 1:30 pm
From: "Michael A. Terrell"

Meat Plow wrote:
>
> On Sun, 20 Mar 2011 13:21:16 -0400, Michael A. Terrell wrote:
>
> > "Geoffrey S. Mendelson" wrote:
> >>
> >> Michael A. Terrell wrote:
> >> > You've got to be kidding. I know a lot of hams who don't even own
> >> > a
> >> > soldering iron. They ship their radios off for factory service,
> >> > unlike 40 years ago.
> >>
> >> Totally irrelevant. I know a lot of people who can barely figure out
> >> how to put gasoline in their cars, but that does not mean there are is
> >> no one who knows how they work, and repair and "upgrade" their cars.
> >>
> >> It's like this group. You ask a question and you get answers. Most of
> >> them are not worth the paper they were never printed upon.
> >>
> >> You go to a web forum, you get the same results. You ask a bunch of
> >> hams and you get an answer. Not from all of them, but from one or two
> >> who know what they are talking about.
> >
> >
> > Right. Sure. Maybe in your small world. I recently went to the
> > local ham radio club's hamfest. 99% of the items for sale were cheap
> > chinese crap that is even cheaer on Ebay. the hams that knew what they
> > were doing have either quit the hobby, or are now 'Silent Keys'. I saw
> > more computer related items than radio, and the couple vendors with
> > components had no one at their tables.
>
> When a few of us used to go in on a table at a hamfest we'd go dig in the
> attic or basement for a bunch of junk to sell. I used to go to Dayton Oh
> every year but that started being a joke. Most junk and computers. A few
> vendors from Kenwood, Yaesu, Alinco, MFD etc.. Not like it was 20 years
> ago.

I haven't been to the Dayton Hamvention in 25 years. Prior to that,
I went almost every year, from the late '60s. I lived closer to
Cincinnati, and hit about five hamfests each year, except while on
active duty. The only hams in that area that knew electronics both
worked for R.L. Drake in Miamisburg, and they frequently asked me for
help. I repaired a lot of older ham gear, including some homebrew with
no documentation. I also worked at Cincinnati Electronics on the PRC-77
manpack radio doing QA.

--
You can't fix stupid. You can't even put a Band-Aid™ on it, because it's
Teflon coated.

== 5 of 16 ==
Date: Sun, Mar 20 2011 1:59 pm
From: "William Sommerwerck"

> In Israel there are 600 or so licensed hams...

It's amazing there are ANY!

== 6 of 16 ==
Date: Sun, Mar 20 2011 3:47 pm
From: David Nebenzahl

On 3/20/2011 1:10 AM Michael A. Terrell spake thus:

> David Nebenzahl wrote:
>
>> I'm looking for an online electronics forum (web-based) where I can post
>> some questions.
>>
>> Don't get me wrong: I love, and usually prefer, Usenet. But I'm trying
>> to educate myself here, am working on a project, and a web forum that
>> allows one to post pictures would be better for my purposes. At least
>> I'd like to try it. (The subject of my current research is the ins and
>> outs of op amps.)
>
> news:sci.electronics.basics or news:sci.electronics.design are both
> good. You get more hand holding in the .basic group, but you see the
> same people from the .design group. They have more patience on the
> .basic group which is intended to teach electronics, while the .design
> group is to trade ideas between professional designers.

How did you miss that I specifically requested an online forum, not
other Usenet newsgroups? It's right up there in the very first sentence
I wrote, for chrissakes.

--
The phrase "jump the shark" itself jumped the shark about a decade ago.

- Usenet

== 7 of 16 ==
Date: Sun, Mar 20 2011 3:54 pm
From: David Nebenzahl

On 3/19/2011 11:51 PM D Yuniskis spake thus:

> On 3/19/2011 6:39 PM, David Nebenzahl wrote:
>
>> I'm looking for an online electronics forum (web-based) where I can post
>> some questions.
>>
>> Don't get me wrong: I love, and usually prefer, Usenet. But I'm trying
>> to educate myself here, am working on a project, and a web forum that
>> allows one to post pictures would be better for my purposes. At least
>> I'd like to try it. (The subject of my current research is the ins and
>> outs of op amps.)
>>
>> Ideally, I'd like a forum where rank amateurs like me can post questions
>> that may be answered by "respected regulars" with lotsa knowledge on the
>> subject.
>
> I think you have to refine your overall goals/interests.
> There are many places you can find out "how to use an op amp"
> (or, "how an op amp works", etc.).
>
> But, what you *want* to use that op amp for is probably where
> you will get far more pertinent information/advice if you can
> refine your needs better.
>
> E.g., using an op amp to design a battery charger is different
> than using an op amp to buffer the pickup from an electric
> guitar or to implement a feedback loop in a robotic servo
> controller.

Be that as it may, I went ahead and joined the first forum that was
suggested here (Electro-Tech Online, http://www.electro-tech-online.com)
and whaddya know, I got answers--pretty good ones--within an hour that
allowed me to get parts of my project working. Maybe it's not the
definitive, be-all and end-all of understanding op amp operation that
you seem to be suggesting, but that isn't what I asked for anyhow. I'm
just trying to muddle through at this point.

Actually, I have a pretty good textbook which probably has all the
answers I need, if I can only understand them: Albert Malvino's
/Electronic Principles/ (actually fished out of a dumpster!). It's
extremely well-written and explains all about op amp operation,
including the four feedback configurations (SP/SS/PP/PS), calculating
gain and impedance, and various op amp applications. Now if I can only
get over having to deal with the math (ugh!) ...

--
The phrase "jump the shark" itself jumped the shark about a decade ago.

- Usenet

== 8 of 16 ==
Date: Sun, Mar 20 2011 3:00 pm
From: Meat Plow

On Sun, 20 Mar 2011 14:47:36 -0800, David Nebenzahl wrote:

> On 3/20/2011 1:10 AM Michael A. Terrell spake thus:
>
>> David Nebenzahl wrote:
>>
>>> I'm looking for an online electronics forum (web-based) where I can
>>> post some questions.
>>>
>>> Don't get me wrong: I love, and usually prefer, Usenet. But I'm trying
>>> to educate myself here, am working on a project, and a web forum that
>>> allows one to post pictures would be better for my purposes. At least
>>> I'd like to try it. (The subject of my current research is the ins and
>>> outs of op amps.)
>>
>> news:sci.electronics.basics or news:sci.electronics.design are both
>> good. You get more hand holding in the .basic group, but you see the
>> same people from the .design group. They have more patience on the
>> .basic group which is intended to teach electronics, while the .design
>> group is to trade ideas between professional designers.
>
> How did you miss that I specifically requested an online forum, not
> other Usenet newsgroups? It's right up there in the very first sentence
> I wrote, for chrissakes.

Remember Dave, honey attracts more flies than vinegar :)

--
Live Fast Die Young, Leave A Pretty Corpse

== 9 of 16 ==
Date: Sun, Mar 20 2011 4:01 pm
From: David Nebenzahl

On 3/19/2011 9:09 PM Geoffrey S. Mendelson spake thus:

> David Nebenzahl wrote:
>
>> I'm looking for an online electronics forum (web-based) where I can
>> post some questions.
>
> Get a ham license. Then you can find people who actively design and build
> things, like to talk about them and would gladly help you.
>
> Not quite a web forum, but more personal.

Interesting suggestion, but highly impractical for me for several reasons.

First of all, it would require a whole 'nother pursuit--getting the
license AND acquiring/building/setting up a radio rig, which is
definitely *not* what I'm the least bit interested in at this point.

Then there's the problem of the medium. Web fora are perfect for my
porpoises: I can easily send text and images, and receive the same. With
radio, I'd have to exhaustively describe every little detail of what I'm
trying to do. And unless I had some kind of radio-fax setup, whereby I
could transmit images (and images of extremely shitty quality at that),
how would I exchange schematics with other hams? Email? or, ironically,
posting them on the Web?

Sorry, not a good suggestion. I will say, though, that I do have a copy
of the ARRL Handbook (1991) which has been quite useful, if a bit out of
date.

--
The phrase "jump the shark" itself jumped the shark about a decade ago.

- Usenet

== 10 of 16 ==
Date: Sun, Mar 20 2011 4:34 pm
From: David Nebenzahl

On 3/20/2011 2:00 PM Meat Plow spake thus:

> On Sun, 20 Mar 2011 14:47:36 -0800, David Nebenzahl wrote:
>
>> On 3/20/2011 1:10 AM Michael A. Terrell spake thus:
>>
>>> David Nebenzahl wrote:
>>>
>>>> I'm looking for an online electronics forum (web-based) where I can
>>>> post some questions.
>>>
>>> news:sci.electronics.basics or news:sci.electronics.design are both
>>> good. You get more hand holding in the .basic group, but you see the
>>> same people from the .design group. They have more patience on the
>>> .basic group which is intended to teach electronics, while the .design
>>> group is to trade ideas between professional designers.
>>
>> How did you miss that I specifically requested an online forum, not
>> other Usenet newsgroups? It's right up there in the very first sentence
>> I wrote, for chrissakes.
>
> Remember Dave, honey attracts more flies than vinegar :)

I'll be sure to remember that next time I want to attract a bunch of flies!

--
The phrase "jump the shark" itself jumped the shark about a decade ago.

- Usenet

== 11 of 16 ==
Date: Sun, Mar 20 2011 3:50 pm
From: D Yuniskis

Hi David,

On 3/20/2011 4:01 PM, David Nebenzahl wrote:
> On 3/19/2011 9:09 PM Geoffrey S. Mendelson spake thus:
>
>> David Nebenzahl wrote:
>>
>>> I'm looking for an online electronics forum (web-based) where I can
>>> post some questions.
>>
>> Get a ham license. Then you can find people who actively design and build
>> things, like to talk about them and would gladly help you.
>> Not quite a web forum, but more personal.
>
> Interesting suggestion, but highly impractical for me for several reasons.
>
> First of all, it would require a whole 'nother pursuit--getting the
> license AND acquiring/building/setting up a radio rig, which is
> definitely *not* what I'm the least bit interested in at this point.

Getting a "Technician" license would require about an evening
of your time -- plus travel to/from exam. And, I think, $6 (?)
exam fee. No need to set up a radio, etc. Just like getting
a driver's license doesn't require you to own -- or even
DRIVE! -- a car.

[But, I understand your point...]

> Then there's the problem of the medium. Web fora are perfect for my
> porpoises: I can easily send text and images, and receive the same. With
> radio, I'd have to exhaustively describe every little detail of what I'm
> trying to do. And unless I had some kind of radio-fax setup, whereby I
> could transmit images (and images of extremely shitty quality at that),
> how would I exchange schematics with other hams? Email? or, ironically,
> posting them on the Web?

You have access to all the same media with a ham license. The
point is, you (can) "hang with a different crowd". Hopefully
one that, at a minimum, knows that electrical power is measured
in Watts, inductance is expressed in Henries and that a current of
2 amps flowing through a resistance of 3 ohms develops a potential
of 6 volts.

I.e., questions that separate the "men" from the... um... I
forget...

[I think that about sums up the Technician Class, eh? :> ]

A good bit of the license information deals with *regulations*
and conduct/expectations/responsibility/etc.

> Sorry, not a good suggestion. I will say, though, that I do have a copy
> of the ARRL Handbook (1991) which has been quite useful, if a bit out of
> date.

I don't think the license itself will buy you anything
towards your goal (though, as an aside, you might consider
downloading the question pools for the various license
classes and wading through the "technical" questions /cold/
to get a feel for just how much you actually already *know*.
This could be encouraging -- or discouraging -- to you.)

Rather, the real value is getting you exposed to that
sort of person. Sort of like hanging around a sports bar
(instead of a LIBRARY) if you are interested in learning
about sports...

(google: technician ham questions)

== 12 of 16 ==
Date: Sun, Mar 20 2011 3:54 pm
From: "Mark Zacharias"

"Dave M" <dgminala4444@mediacombb.net> wrote in message
news:nImdnQx-34AyzBjQnZ2dnUVZ5j2dnZ2d@giganews.com...
> David Nebenzahl wrote:
>> I'm looking for an online electronics forum (web-based) where I can
>> post some questions.
>>
>> Don't get me wrong: I love, and usually prefer, Usenet. But I'm trying
>> to educate myself here, am working on a project, and a web forum that
>> allows one to post pictures would be better for my purposes. At least
>> I'd like to try it. (The subject of my current research is the ins and
>> outs of op amps.)
>>
>> Ideally, I'd like a forum where rank amateurs like me can post
>> questions that may be answered by "respected regulars" with lotsa
>> knowledge on the subject.
>>
>> Now, if the answer turns out to be "What, are you nuts? There ain't no
>> such thing!", then I guess I can live with that ...
>
>
> Give this one a try... Everything there from dummies to experts.
> http://www.electro-tech-online.com/
> --
> David
> dgminala at mediacombb dot net
>
>
>

http://www.eevblog.com/forum/

The EEVblog is headed by Dave Jones, an EE in Australia. The forum is for
beginners and experienced EE's and anyone interested in electronics design
and hardware (test equipment, etc).

Mark Z.

== 13 of 16 ==
Date: Sun, Mar 20 2011 4:04 pm
From: D Yuniskis

Hi David,

On 3/20/2011 3:54 PM, David Nebenzahl wrote:
> On 3/19/2011 11:51 PM D Yuniskis spake thus:
>
>> On 3/19/2011 6:39 PM, David Nebenzahl wrote:
> >
>>> I'm looking for an online electronics forum (web-based) where I can post
>>> some questions.
>>
>> I think you have to refine your overall goals/interests.
>> There are many places you can find out "how to use an op amp"
>> (or, "how an op amp works", etc.).
>>
>> But, what you *want* to use that op amp for is probably where
>> you will get far more pertinent information/advice if you can
>> refine your needs better.
>
> Be that as it may, I went ahead and joined the first forum that was
> suggested here (Electro-Tech Online, http://www.electro-tech-online.com)
> and whaddya know, I got answers--pretty good ones--within an hour that
> allowed me to get parts of my project working. Maybe it's not the

Great! Then you're set -- for now.

> definitive, be-all and end-all of understanding op amp operation that

No, quite the contrary. If you know *everything* about op amps,
then there is no difference between applications -- because you
already know all the little details that differentiate one
type of application from another.

My point was, if you find a group that is dealing with the same
types of applications that you are wanting to address, then they
will have already tweaked the "oversimplification" of what an
op amp is by appending "... except, you have to do ________ when
you use it *this* way _______" to that description. I.e., they
will have highlighted the details that are important in *that*
type of application (e.g., if you are running with a single
supply instead of balanced supplies, needing more voltage
compliance in your output than the op amp can provide, etc.)

Most of "design" is figuring out which details to *ignore* and
which to *pursue*. A group of folks working on similar
applications will have already sorted that out for you.

[I recall designing (passive) speaker crossover networks with
a friend at school. He always had "50 ..." as his expressions.
I finally asked him where the heck he kept coming up with this
"50"?? Ans: 2 * pi * 8 ohms (more or less)

D'oh!

> you seem to be suggesting, but that isn't what I asked for anyhow. I'm
> just trying to muddle through at this point.
>
> Actually, I have a pretty good textbook which probably has all the
> answers I need, if I can only understand them: Albert Malvino's
> /Electronic Principles/ (actually fished out of a dumpster!). It's
> extremely well-written and explains all about op amp operation,
> including the four feedback configurations (SP/SS/PP/PS), calculating
> gain and impedance, and various op amp applications. Now if I can only
> get over having to deal with the math (ugh!) ...

I started with Senturia & Wedlock's _Electronic Circuits and
Applications_ (and, before that, just reading data sheets). It
was one of those "good" books that predated the "sold by the
pound" trend that seems to have infected "modern" writing :<
(though it was $20+ about 35 years ago!)

There also were "Made Simple" books aeons ago (When Dinosaurs
Walked the Earth). These were the precursors of the "For Dummies"
books -- but infinitely more intense! Highly condensed but
very good to get exposed to a lot in very few pages.
(e.g., "Electronics Made Simple")

== 14 of 16 ==
Date: Sun, Mar 20 2011 4:11 pm
From: Jeff Liebermann

On Sun, 20 Mar 2011 11:03:15 -0700, D Yuniskis
<not.going.to.be@seen.com> wrote:

>On 3/20/2011 10:18 AM, Jeff Liebermann wrote:
>> On Sun, 20 Mar 2011 05:09:04 +0000 (UTC), "Geoffrey S. Mendelson"
>> <gsm@mendelson.com> wrote:
>>
>>> David Nebenzahl wrote:
>>>> I'm looking for an online electronics forum (web-based) where I can post
>>>> some questions.
>>
>>> Get a ham license. Then you can find people who actively design and build
>>> things, like to talk about them and would gladly help you.
>>
>> Locally, we have about 2800 licensed hams in the county, of which I
>> would guess about 500 are at least semi-active, 100 regularly attend
>> various club meetings, 50 bother to build things, and perhaps 4 are
>> qualified to design anything useful.
>
>Expressed in your characteristic "dry" manner... :>

I try not to get excited about such things.

>But, illustrates the point, well. Yet, doesn't say how accessible
>those "4" are nor where their interests lie.

Actually, very accessible, if they're interested. We have a local
startup, Elecraft, that makes ham radio kits and accessories. Most of
the qualified hams in the area are now working for them.
<http://www.elecraft.com>
There's not much design work being done locally, but the engineers and
techs certainly know how the radios operate.

>E.g., you would be
>hard-pressed to get me to help you design an audio amp out of
>discretes -- but, could probably keep me obsessed with trying to
>cut power consumption by half a milliwatt on a battery powered
>device! (and I'm a *helpful* soul ;-)

I have a similar problem. When I was still designing electronics, the
major obsession was reducing the cost. At that time, it meant
reducing the component count. If you get my attention, I can waste
enormous amounts of time, on futile exercises in component count
reduction. Same with unusual ways to implement simple things.

>A lot also depends on how dense that population of "experts" is,
>as well. E.g., our county is 9,200 sq mi with a population of just
>over 1,000,000. So, 90 people / sq mile. *If* we have those 2800
>hams, here (no idea), that would be one ham for every 4 sq mi. That
>can make accessing that "expert" a bit problematic (I find learning
>is usually faster "in person").

You can get a fair idea of the number of hams by diving into the FCC
ULS database and searching for counts by your local zip codes.
<http://wireless2.fcc.gov/UlsApp/UlsSearch/searchAmateur.jsp>
For 95005 (Ben Lomond, CA), it shows 61 licenses. Unfortunately, the
FCC updates the data perhaps every 10 years, so some hams that have
moved out or died are still listed.

>And, if the hams (and population, in general) are not evenly
>distributed throughout the county, it only gets worse (potentially).

Worse, most hams seem to live in post office boxes.

>E.g., there are *no* electronic suppliers, here, within driving
>distance. The closest possible (overpriced) retailer is clear across
>town (and would never have the types of components that I am
>interested in).

We have one local supplier (other than Radio Shock). They're
expensive, but not outrageous.
<http://www.santacruzelectronics.com>

>> This is the age of specialization.
>
>Exactly! The days of being able to keep a drawer full of transistors,
>diodes, resistors, etc. and hack together an amplifier -- or a logic
>gate (!) -- are long behind us.

Yep. Just finding the part in my mess is difficult. However, I do
have a fairly good collection of 1980's vintage discrete parts, which
are useful for raising the dead and repairing the antiques.

One problem with specialization is that it tends to create some rather
bizarre implementations. I once reverse engineered a microprocessor
design that could have been replaced by a quad op amp.

>Sure, you can still do it, but there
>is no point. I can recall building 8 digit counters out of discretes
>with nixie displays... would I bother wasting my time on that *now*??
>(though I *have* been sorely tempted to build a Difference Engine).

Hint: I never build or design anything that I can't sell or turn into
a sellable product. When I do build something for myself, I usually
build 3 to 5 extras, to sell to friends and recover my expenses.
Expertise in PCB layout is a must.

Note that it's still possible to have fun with electronics:
"How to blow up a microwave"
<http://www.youtube.com/watch?v=V9Gn0auLFUA>

--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

== 15 of 16 ==
Date: Sun, Mar 20 2011 4:41 pm
From: Jeff Liebermann

On Sun, 20 Mar 2011 11:42:01 -0700, mike <spamme9@gmail.com> wrote:

>> Locally, we have about 2800 licensed hams in the county, of which I
>> would guess about 500 are at least semi-active, 100 regularly attend
>> various club meetings, 50 bother to build things, and perhaps 4 are
>> qualified to design anything useful. While it's possible to get some
>> help with design and construction from ham radio, it really depends on
>> whom you contact.
>
>Valid point, although I think you exaggerate a bit.

I'm fairly sure about the 2800 hams in Santa Cruz County. The other
numbers are from many years of experience dealing with exactly the
issues that were mentioned. For example, the local electronics dealer
(Santa Cruz Electronics) often sends me customers who need some
expertise beyond what could be provided by the counter sales person,
but not so much that it would require a consulting contract. Much of
the stuff people want designed already exists. Other time, I end up
building some abomination for yet another get rich quick scheme.
Sometimes, I have to ask for help (i.e. I'm a lousy programmer), so I
have a clue as to how many locals are available and able to help. Of
course, since I'm a member of both SCZ County radio clubs, I know how
many of those are hams. My numbers might be off perhaps +/- 25%, but
not much more.

>Now, give those same numbers for the denizens of sci.electronics.repair.
>Maybe two numbers, with and without the profuse few who insist
>on pushing the SNR toward zero.

Well, if you mean topic drift, you're discussing the problem with the
chief culprit. If the original question is boring or of little
interest, I simply change the topic. If the OP wants his question
answered, he can simply rephrase it so that it's more interesting and
less boring.

>I'd also like to hear your estimate of the percentage that even
>attempt to add USEFUL new information that helps answer the
>original question.

That's easy. Just grep through the answers and see how many answers
supply calculations, numbers, references, and specifics. It won't be
many, but if you look hard, you may find some specific answers. URL's
don't count because most people don't explain why the URL should be
read.

In my case, I always try to add something useful to my answers. It
may not answer the original question, but it should be at least
interesting.

>Percentages by post will be different than percentage
>by author.

True. Quantity is a bad substitute for quality. Just ignore the
quantity of my words and postings.

>And the percentage that just want to argue for the sake of arguing,
>name calling, backstabbing, "hey look how smart I think I am", etc.

That would be 100%. I doubt that everyone is interested in helping
the OP as much as grandstanding, ego inflation, or some kind of power
trip. It's a futile effort, but it's still commonly practiced. My
motivation varies radically by the day. For example, todays endless
drivel is justified by my procrastinating on working on my income
taxes. Other days, I'm don't have a clue about the original question,
but am sufficiently interested in the topic to do the necessary
research on the topic, and present a passable summary of what I've
found. In rare cases, I may have some experience or knowledge about
the topic, and deign to pontificate about it. Whatever works.

>On any subject, it's important to ask someone who knows what he's talking
>about.

Not really. I ask very few questions. My last attempt resulted in
demonstrating how I can ignore the obvious by installing several
polarized capacitors backwards.
<http://802.11junk.com/jeffl/crud/GX520-bad-caps.jpg>
Even so, there were plenty of wrong answers supplied by various people
trying to be helpful. In most cases, I can eliminate the clueless by
simply looking at the writing style. No numbers means no clue. One
line answers means no thinking was involved in crafting the answer.
Pontifications without substantiation means that they're not really
certain about their answer or their abilities. I don't even bother
with RTFM type answers. However, I'm perfectly willing to grovel
through the garbage for an answer and NEVER pass judgment on the
author. The reason dates back to my introduction to usenet, where I
managed to accidentally insult a well known expert, who didn't have
the time or interest to offer more than a general clue.

Incidentally, I've seen more wrong answers by established experts, who
are either too much in a hurry to supply a complete answer, or make
assumptions that the reader may not be able to catch.

>Unfortunately, there are precious few of them.

On the contrary. Everyone is an expert on something. Where the
problems start are when they go out of their area of expertise. The
recent discussions on nuclear reactors in various forums is a great
example. Most of those posting are perfectly competent in their areas
of expertise, but rather marginal when discussing nuclear power.
Similarly, the amazing number of climate experts in the global warming
discussion should make one wonder how there can possibly be so many
climate experts in a field that didn't really exist more than perhaps
10 years ago.

Incidentally, ever notice that the more insignificant the question,
the more answers are supplied. Really well written and important
questions, rarely get any attention.

>Most get drowned out by the multitude.

At the bottom of every dumpster is a diamond. It's yours if you're
willing to dig through the muck.

>Some of them ARE hams.

Sure. However, the typical 10 minute monologue on 80 meters doesn't
offer much of an endorsement.

--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

== 16 of 16 ==
Date: Sun, Mar 20 2011 4:55 pm
From: Jeff Liebermann

On Sun, 20 Mar 2011 19:39:12 +0000 (UTC), "Geoffrey S. Mendelson"
<gsm@mendelson.com> wrote:

>BTW, did Don Lancaster ever update his "OP Amp Cookbook"?
>Geoff.

As far as I can determine from Googling, the 3rd and last edition was
published in 1986.

Hmmm... that's odd. It's not listed:
<http://www.tinaja.com/books/bkdons.asp>

--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

==============================================================================
TOPIC: Led Zeppelin
http://groups.google.com/group/sci.electronics.repair/t/9ab1e69e1e72acb3?hl=en
==============================================================================

== 1 of 1 ==
Date: Sun, Mar 20 2011 1:31 pm
From: titia

If you like Classic Rock and Led Zeppelin this is a good
place
http://titia-ledzeppelin.blogspot.com/

You are also invited to join Led Zeppelin Music group
http://groups.yahoo.com/group/Ledzeppelinmusic/join,a place where you
will find everything about this legendary band

Enjoy!

==============================================================================
TOPIC: Running a PC outside of a computer case
http://groups.google.com/group/sci.electronics.repair/t/767389e3dda5bc79?hl=en
==============================================================================

== 1 of 8 ==
Date: Sun, Mar 20 2011 2:54 pm
From: D

I've built one computer, and will soon be building another. I would
like to initially set up & test this new machine on the bench, outside
of a computer case (simply connecting the PSU, etc., w/o all the bits
being in a case). Seems straightforward, but I have a couple questions.
First, am I correct that the front panel on/off switch generally used
to start the PC is simply a momentary contact switch that briefly
connects the "PW+" and "PW-" terminals on the MOBO? Same with the
reset/reboot switch function, using "res+" and "RES-"? Also, is it
necessary to run a ground wire between the PSU case, and one of the MOBO
pads where the screws go to attach the MOBO to the case when installed?
Since the metal case would "ground" these 2 together, I was wondering.
If this is required, should all metal cases (HDD, DVD drive, etc) be
so "grounded together"?

Any other helpful points about running a PC on the bench this way would
be greatly appreciated.

TIA

Dan

== 2 of 8 ==
Date: Sun, Mar 20 2011 3:18 pm
From: Meat Plow

On Sun, 20 Mar 2011 14:54:26 -0700, D wrote:

> I've built one computer, and will soon be building another. I would
> like to initially set up & test this new machine on the bench, outside
> of a computer case (simply connecting the PSU, etc., w/o all the bits
> being in a case). Seems straightforward, but I have a couple questions.
> First, am I correct that the front panel on/off switch generally used
> to start the PC is simply a momentary contact switch that briefly
> connects the "PW+" and "PW-" terminals on the MOBO? Same with the
> reset/reboot switch function, using "res+" and "RES-"? Also, is it
> necessary to run a ground wire between the PSU case, and one of the MOBO
> pads where the screws go to attach the MOBO to the case when installed?
> Since the metal case would "ground" these 2 together, I was wondering.
> If this is required, should all metal cases (HDD, DVD drive, etc) be
> so "grounded together"?
>
> Any other helpful points about running a PC on the bench this way would
> be greatly appreciated.
>
> TIA
>
> Dan

It will run just fine without a case except that most cases add
additional airflow to cool the CPU and other components.

--
Live Fast Die Young, Leave A Pretty Corpse

== 3 of 8 ==
Date: Sun, Mar 20 2011 3:43 pm
From: "William Sommerwerck"

"Obviously" (???) you're trying to avoid mounting the MOBO. But I suspect
that the additional work needed to place the MOBO on a clean, non-conductive
surface, and hold it there safely -- along with all the other components --
will be greater than the work needed to mount it safely in the case.

You might want to reconsider.

== 4 of 8 ==
Date: Sun, Mar 20 2011 4:51 pm
From: David Nebenzahl

On 3/20/2011 2:43 PM William Sommerwerck spake thus:

> "Obviously" (???) you're trying to avoid mounting the MOBO. But I suspect
> that the additional work needed to place the MOBO on a clean, non-conductive
> surface, and hold it there safely -- along with all the other components --
> will be greater than the work needed to mount it safely in the case.

Hell, most work table tops, or a piece of cardboard, would do the trick.

The company I used to work for did this all the time when they built
systems; lay everything out on the bench with a monitor and keyboard and
power it up. Simple, so long as you use common sense and watch what
you're doing.

--
The phrase "jump the shark" itself jumped the shark about a decade ago.

- Usenet

== 5 of 8 ==
Date: Sun, Mar 20 2011 4:15 pm
From: D

On 3/20/2011 4:51 PM, David Nebenzahl wrote:
> On 3/20/2011 2:43 PM William Sommerwerck spake thus:
>
>> "Obviously" (???) you're trying to avoid mounting the MOBO. But I suspect
>> that the additional work needed to place the MOBO on a clean,
>> non-conductive
>> surface, and hold it there safely -- along with all the other
>> components -- will be greater than the work needed to mount it safely
>> in the case.
>
> Hell, most work table tops, or a piece of cardboard, would do the trick.
>
> The company I used to work for did this all the time when they built
> systems; lay everything out on the bench with a monitor and keyboard and
> power it up. Simple, so long as you use common sense and watch what
> you're doing.
>
>

Thanks for the replies. I only have one ATX case, which currently
contains my working computer, which I want to have available until I get
the new bits checked out, OS loaded, up and running, etc. I have a
momentary contact switch from an older machine which should do nicely
for powering up, although I've heard of people simply using a small
screwdriver for this. I'd rather not run the risk of accidentally
shorting to the wrong terminals, though. Agreed care is in order,
probably don't want to have my pitcher of Koolaid on the same table as
the spread-out bits, but I think it should be OK.

I gather then that there's no need to ground the PSU case & other bits
together with clip leads?

Dan

== 6 of 8 ==
Date: Sun, Mar 20 2011 4:28 pm
From: "William Sommerwerck"

> I gather then that there's no need to ground the PSU case
> & other bits together with clip leads?

Probably not, as the cables have the necessary ground wires.

== 7 of 8 ==
Date: Sun, Mar 20 2011 5:30 pm
From: David Nebenzahl

On 3/20/2011 3:15 PM D spake thus:

> Thanks for the replies. I only have one ATX case, which currently
> contains my working computer, which I want to have available until I get
> the new bits checked out, OS loaded, up and running, etc. I have a
> momentary contact switch from an older machine which should do nicely
> for powering up, although I've heard of people simply using a small
> screwdriver for this. I'd rather not run the risk of accidentally
> shorting to the wrong terminals, though. Agreed care is in order,
> probably don't want to have my pitcher of Koolaid on the same table as
> the spread-out bits, but I think it should be OK.
>
> I gather then that there's no need to ground the PSU case & other bits
> together with clip leads?

No, the case isn't required as a ground. All needed grounds are already
in the connection betwixt PSU and motherboard.

Of course, you won't have an FCC-compliant setup without the case, RF
emission-wise, but no need to sweat that so long as you don't plan on
running the "naked" setup more than a short time.

--
The current state of literacy in our advanced civilization:

yo
wassup
nuttin
wan2 hang
ok
where
here
ok
l8tr
by

- from Usenet (what's *that*?)

== 8 of 8 ==
Date: Sun, Mar 20 2011 7:23 pm
From: D

On 3/20/2011 5:30 PM, David Nebenzahl wrote:
> On 3/20/2011 3:15 PM D spake thus:
>
>> Thanks for the replies. I only have one ATX case, which currently
>> contains my working computer, which I want to have available until I
>> get the new bits checked out, OS loaded, up and running, etc. I have a
>> momentary contact switch from an older machine which should do nicely
>> for powering up, although I've heard of people simply using a small
>> screwdriver for this. I'd rather not run the risk of accidentally
>> shorting to the wrong terminals, though. Agreed care is in order,
>> probably don't want to have my pitcher of Koolaid on the same table as
>> the spread-out bits, but I think it should be OK.
>>
>> I gather then that there's no need to ground the PSU case & other bits
>> together with clip leads?
>
> No, the case isn't required as a ground. All needed grounds are already
> in the connection betwixt PSU and motherboard.
>
> Of course, you won't have an FCC-compliant setup without the case, RF
> emission-wise, but no need to sweat that so long as you don't plan on
> running the "naked" setup more than a short time.
>
>

Hadn't considered the RF emissions. If that pitcher of Koolaid I
mentioned starts to boil (or my garage door keeps going up and down),
I'll now something's up! ;-)

Thanks again everyone for the helpful replies.

Dan

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