Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems.

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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



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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 ...


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

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In article ,
David Nebenzahl wrote:

The subject of my current research is the ins and
outs of op amps.


A little pun, there?
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On Sat, 19 Mar 2011 17:39:54 -0800, 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 ...


One would be the combined forum for Nuts & Volts magazine and Servo
magazine at http://forums.servomagazine.com. Then there are the forums
run by Circuit Cellar at http://bbs.circuitcellar.com. Also Elektor over
at http://www.elektor.com/

--
Rich Webb Norfolk, VA
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Smitty Two wrote:

In article ,
David Nebenzahl wrote:

The subject of my current research is the ins and
outs of op amps.


A little pun, there?



A bit bipolar, if you ask me...


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


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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.

Geoff.

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

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.



** That is in the same class as needing a pint of milk and so buying a cow.




..... Phil


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David Nebenzahl wrote:

I agree, not a very good piece of advice.


It's the difference between learning to ride a bicycle by going to a riding
club versus sitting on stools and moving your feet.

(first told to me in the 1960's to describe programing classes that had
no access to a computer).

Sorry, but IMHO the level of expertise and education you will get on a web
forum is pretty low.

Why not get your education from people who actually use the things and follow
an almost 100 year tradition of educating newcomers? In my experience the
engineers who did it "for a job" were boring and uninventive, the passionate
ones were hams.

The amount of effort is nothing like it used to be, you can earn a ham
license in a weekend. You just need to answer 75% of 50 multiple choice
questions corrent about basic electronics, radio theory and law. No
morse code. No circuit drawings, etc.


Geoff.


--
Geoffrey S. Mendelson N3OWJ/4X1GM
Those who cannot remember the past are condemned to misquote it.
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On 3/19/2011 9:28 PM Phil Allison spake thus:

"Geoffrey S. Mendelson"

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.


** That is in the same class as needing a pint of milk and so buying a cow.


I agree, not a very good piece of advice.


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

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Hi David,

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.

A place that will give you "textbook" advice on how an op amp
works (or can be applied) will leave you wondering, "OK, now how
do I use that to ____________?" OTOH, a more targeted "forum"
can tell you, "Why bother with an op amp? You can use a pair of
transistors configured like ___________ to give you the results
you need... with the following advantages: " Or, "If you use
an op amp in that sort of application, you will need to add an
external output stage to give you increased ___________. You
can do that by _____________."

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 ...




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"Geoffrey S. Mendelson" 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.



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.

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



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.


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

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.



** Only the " silent majority " ever did that ..........

And none of them or the current few would have a clue about the use of
op-amps in relation to audio.

Wot a ****wit idea.

Musta come from a radio ham.



..... Phil




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"Geoffrey S. Mendelson"

Why not get your education from people who actually use the things


** Errr - since when do current radio hams use op-amps for anything ??

Most have no soldering irons or design knowledge at all.


and follow
an almost 100 year tradition of educating newcomers?


** New comers to ham radio generally get an " education " all right.


The amount of effort is nothing like it used to be, you can earn a ham
license in a weekend.


** Hmmm - that bodes well for giving new comers advice an all matters
electronic.....


You just need to answer 75% of 50 multiple choice
questions corrent about basic electronics, radio theory and law. No
morse code. No circuit drawings, etc.



** Same goes for the jokers you will find on the ham radio bands.

Like this guy:

Geoffrey S. Mendelson N3OWJ/4X1GM

BTW

The amateur bands have been damn near silent here in Australia for decades.

The hobby is all but dead.

CB radio, the internet and GSM phones have destroyed it.



..... Phil




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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.

Geoff.

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


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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.


Amateur radio has largely become a plug 'n play hobby. Hams still build
antennas, and sometimes high-power finals, but other than small projects and
accessories, they mostly buy things. Don't expect to walk into a shack and
find a home-brew receiver these days.

One of the purposes in licensing amateur radio operators was to build a base
of people with both theoretical and practical knowledge of electronics. It's
not clear that it still does this.


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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.


A place that will give you "textbook" advice on how an op
amp works (or can be applied) will leave you wondering,
"OK, now how do I use that to ______?"


Not so! If you understand The Basic Rule in op-amp circuit design, you'll
see that there is no difference among these applications. Nor will you be
wondering how to do something.

National Semiconductor had an on-line seminar "explaining" op-amp circuit
design -- hostessed by a woman, of course -- and nowhere in it is The Basic
Rule even hinted at.

And Bob Pease had the nerve to tell me that my editing didn't improve the
quality of his (or others') writing!


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William Sommerwerck wrote:
Amateur radio has largely become a plug 'n play hobby. Hams still build
antennas, and sometimes high-power finals, but other than small projects and
accessories, they mostly buy things. Don't expect to walk into a shack and
find a home-brew receiver these days.


That's true. But you will find home brew (or at least kit) QRP rigs,
audio and microphone amps, and similar items.

Except in the UK, where one of the requirments for getting their "foundation"
license is to have built something.


One of the purposes in licensing amateur radio operators was to build a base
of people with both theoretical and practical knowledge of electronics. It's
not clear that it still does this.


It still does. Like everyone who uses a computer, most people could never
program their way out of a paper bag, there is a large population of hams
who can't design or build anything. But there is still a small percentage,
say 10% that do. In the US, that's about 60,000 or so. Enough that David
should not have trouble finding one.

The main objective of ham radio was to have a pool of radio operators
ready in case of an emergency. In 1920 that meant being able to send and
receive Morse code. In 2011, that means knowing how to set up and operate an
FM two way radio, and how to take and pass messages correctly with little
or no instuctions and not panicing.

Geoff.


--
Geoffrey S. Mendelson N3OWJ/4X1GM
Those who cannot remember the past are condemned to misquote it.
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On 3/20/2011 5:39 AM, William Sommerwerck wrote:
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.


A place that will give you "textbook" advice on how an op
amp works (or can be applied) will leave you wondering,
"OK, now how do I use that to ______?"


Not so! If you understand The Basic Rule in op-amp circuit design, you'll
see that there is no difference among these applications. Nor will you be
wondering how to do something.


No, you only "get" to that point with experience. There
are different design issues involved in each of the above
applications. If you understand how an op amp works
"in theory", you can look at an EXISTING circuit and suss
out the functionality that the op amp is providing. But,
that doesn't mean that you would be able to come up with
the particular circuit topology that is avoiding some
particular *real* (vs theoretical) limitation of that
*particular* op amp and/or leveraging some particular
characteristic thereof.

If it could all be boiled down to a simple rule, then
EVERYONE would be able to design perfect circuits "first
time, every time" -- with/without SPICE.

I want to design a 2KW, 2KV SMPS and use an op amp to
compute the error term. Should be no different than
designing a pickup for an electric guitar, right?
Should I expect to have either/both of those designs
on my desk, this afternoon, *completed*??
error
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On 3/20/2011 5:31 AM, William Sommerwerck 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.


Amateur radio has largely become a plug 'n play hobby. Hams still build
antennas, and sometimes high-power finals, but other than small projects and
accessories, they mostly buy things. Don't expect to walk into a shack and
find a home-brew receiver these days.


I think that is a matter of simple economics. You can buy
finished, tested, "legit" product for less than you can
purchase the components needed to build same. And, often,
getting those components is tedious -- unless you have a
business account to which you can add the order (or, buy
THAT SORT OF COMPONENTS in big enough quantities that a
sales rep will sample you a few pieces). Most electronic
suppliers don't want to deal with small orders. And, the
places that *will* have hefty markups (or don't carry the
more exotic components).

One of the purposes in licensing amateur radio operators was to build a base
of people with both theoretical and practical knowledge of electronics. It's
not clear that it still does this.


I think dropping the code requirement was a clear acknowledgement
of this. Now they're just trying to hold onto their frequency
allocations. :-/

And, in practical terms, there are fewer and fewer things that
even a motivated ham can design or repair in a modern household
(contrast this with how "capable" he/she would be in a 1960's
household)


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Not so! If you understand The Basic Rule in op-amp circuit
design, you'll see that there is no difference among these
applications. Nor will you be wondering how to do something.


No, you only "get" to that point with experience. There
are different design issues involved in each of the above
applications. If you understand how an op amp works
"in theory", you can look at an EXISTING circuit and suss
out the functionality that the op amp is providing. But,
that doesn't mean that you would be able to come up with
the particular circuit topology that is avoiding some
particular *real* (vs theoretical) limitation of that
*particular* op amp and/or leveraging some particular
characteristic thereof.

If it could all be boiled down to a simple rule, then
EVERYONE would be able to design perfect circuits "first
time, every time" -- with/without SPICE.

I want to design a 2KW, 2KV SMPS and use an op amp to
compute the error term. Should be no different than
designing a pickup for an electric guitar, right?
Should I expect to have either/both of those designs
on my desk, this afternoon, *completed*??


I probably overstated the case, but understanding Basic Principles can be a
major leg-up to creating a workable design.

A person who doesn't understand The Basic Rule of Op-Amp Circuit Operation
is going to have a lot of trouble.

I might add that, several years ago, I asked the English gentleman who
worked with Bob Pease at National to tell me what that Rule was -- and bang,
he said it right out, without any hints.


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On Sun, 20 Mar 2011 05:09:04 +0000 (UTC), "Geoffrey S. Mendelson"
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. While it's possible to get some
help with design and construction from ham radio, it really depends on
whom you contact.

This is the age of specialization. I can design and advise on some
aspects of RF and repair. In other areas, I'm clueless. You would do
best by finding a forum, blog, newsgroup, or mailing list that covers
the specific area that you're interested in asking questions. Don't
be fooled by the names or lack of traffic. There are often forums
where most of the answers are by email from those that just don't want
their names and advice subject to public scrutiny. For example, I've
found that the LEAST useful forum for solving Apple computer related
problems is Apple's own forums. Just post your question and see what
happens. If you get a dozen one-line useless bad guesses, move on.

As always, the quality of the answers depend heavily on the quality of
the question. Without a clue as the nature of the question, vague
answers, like this one, will be epidemic.

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


--
You can't fix stupid. You can't even put a Band-Aid™ on it, because it's
Teflon coated.
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On Sun, 20 Mar 2011 05:09:04 +0000, Geoffrey S. Mendelson 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.

Not quite a web forum, but more personal.

Geoff.


Just renewed my ticket for the 2nd time. You might find a few hams that
dabble in design but only because that's what they do for a living.

The best way to learn besides OTJ training is to read. There isn't a day
that passes that I don't read out of some old school books containing
fundamental electronics. You need to understand why electronics work,
and some mathematics involving calculating loads, current, power sine
waves etc...first. I did it ass-backwards learning on the bench first
using test equipment without knowing much about the fundamentals.



--
Live Fast Die Young, Leave A Pretty Corpse
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"Geoffrey S. Mendelson" wrote:

William Sommerwerck wrote:
Amateur radio has largely become a plug 'n play hobby. Hams still build
antennas, and sometimes high-power finals, but other than small projects and
accessories, they mostly buy things. Don't expect to walk into a shack and
find a home-brew receiver these days.


That's true. But you will find home brew (or at least kit) QRP rigs,
audio and microphone amps, and similar items.

Except in the UK, where one of the requirments for getting their "foundation"
license is to have built something.

One of the purposes in licensing amateur radio operators was to build a base
of people with both theoretical and practical knowledge of electronics. It's
not clear that it still does this.


It still does. Like everyone who uses a computer, most people could never
program their way out of a paper bag, there is a large population of hams
who can't design or build anything. But there is still a small percentage,
say 10% that do. In the US, that's about 60,000 or so. Enough that David
should not have trouble finding one.

The main objective of ham radio was to have a pool of radio operators
ready in case of an emergency. In 1920 that meant being able to send and
receive Morse code. In 2011, that means knowing how to set up and operate an
FM two way radio, and how to take and pass messages correctly with little
or no instuctions and not panicing.



More like 1975, not 2011 and this isn't Israel.

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.


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


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D Yuniskis wrote:

On 3/20/2011 5:39 AM, William Sommerwerck wrote:
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.


A place that will give you "textbook" advice on how an op
amp works (or can be applied) will leave you wondering,
"OK, now how do I use that to ______?"


Not so! If you understand The Basic Rule in op-amp circuit design, you'll
see that there is no difference among these applications. Nor will you be
wondering how to do something.


No, you only "get" to that point with experience. There
are different design issues involved in each of the above
applications. If you understand how an op amp works
"in theory", you can look at an EXISTING circuit and suss
out the functionality that the op amp is providing. But,
that doesn't mean that you would be able to come up with
the particular circuit topology that is avoiding some
particular *real* (vs theoretical) limitation of that
*particular* op amp and/or leveraging some particular
characteristic thereof.

If it could all be boiled down to a simple rule, then
EVERYONE would be able to design perfect circuits "first
time, every time" -- with/without SPICE.

I want to design a 2KW, 2KV SMPS and use an op amp to
compute the error term. Should be no different than
designing a pickup for an electric guitar, right?


Wrong. A pickup for a guitar doesn't require a stable reference
voltage to regulate it's output.

Should I expect to have either/both of those designs
on my desk, this afternoon, *completed*??



Look at national Semiconductor's 'Simple Switcher' line, or Linear's
free Switchercad spice program and use ICs that are tailored to SMPS
applications. If your opamp circuit takes too long to stabilize, you'll
have an expensive failure and maybe a fire.


Switchercad III can be downloaded he
http://www.linear.com/software/

There is a Yahoo user group at:
http://groups.yahoo.com/group/LTspice/


--
You can't fix stupid. You can't even put a Band-Aid™ on it, because it's
Teflon coated.
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On 3/20/2011 10:00 AM, William Sommerwerck wrote:
Not so! If you understand The Basic Rule in op-amp circuit
design, you'll see that there is no difference among these
applications. Nor will you be wondering how to do something.


If it could all be boiled down to a simple rule, then
EVERYONE would be able to design perfect circuits "first
time, every time" -- with/without SPICE.


I probably overstated the case, but understanding Basic Principles can be a
major leg-up to creating a workable design.


But, isn't that so of everything? : I enjoy watching
folks "design by app-note" -- cutting and pasting together
circuit fragments from various publications -- and wondering
why their designs don't work.

"Um, if you UNDERSTOOD what you had /designed/, you would
understand why it WON'T work!"

This is where The Trades have a leg up (in theory) on The Sciences.
In the former, there is a hands-on learning process where you see
the practical aspects of what you are learning *before* you are
deemed "qualified" to practice that skill. In the latter, you
get an abstract exposure to things (to be fair, often a wider
range of "things" since "paper is cheap") but aren't qualified
to use *any* of them before you are "certified" (diploma-ed).

:

M Crichton's novels are typically based on this "lack of
(full) experience" -- Man having "getting" technology
before he has "earned" it (i.e., has the wisdom to know
how to *use* it).
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On 3/20/2011 10:18 AM, Jeff Liebermann wrote:
On Sun, 20 Mar 2011 05:09:04 +0000 (UTC), "Geoffrey S. Mendelson"
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... :

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

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").

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

While it's possible to get some
help with design and construction from ham radio, it really depends on
whom you contact.

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. 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).

I can design and advise on some
aspects of RF and repair. In other areas, I'm clueless. You would do
best by finding a forum, blog, newsgroup, or mailing list that covers
the specific area that you're interested in asking questions. Don't


Agreed. ------^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

be fooled by the names or lack of traffic. There are often forums
where most of the answers are by email from those that just don't want
their names and advice subject to public scrutiny. For example, I've
found that the LEAST useful forum for solving Apple computer related
problems is Apple's own forums. Just post your question and see what
happens. If you get a dozen one-line useless bad guesses, move on.

As always, the quality of the answers depend heavily on the quality of
the question. Without a clue as the nature of the question, vague
answers, like this one, will be epidemic.


Wear rubber soled shoes, remove all jewelry, keep one hand in your
pocket and *play*! It's not *chemistry* where you have to worry
about losing eyebrows or other body parts when you make a mistake :
All you have to lose is a little *money*!

(and, depending on what you are playing with, many devices nowadays
can take a LOT of abuse -- short circuit protection, etc. -- so you
don't have to worry about replacing components every two ohnoseconds!)
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Jeff Liebermann wrote:
On Sun, 20 Mar 2011 05:09:04 +0000 (UTC), "Geoffrey S. Mendelson"
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. 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.

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.

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

On any subject, it's important to ask someone who knows what he's talking
about.
Unfortunately, there are precious few of them.
Most get drowned out by the multitude.
Some of them ARE hams.
-.-



This is the age of specialization. I can design and advise on some
aspects of RF and repair. In other areas, I'm clueless. You would do
best by finding a forum, blog, newsgroup, or mailing list that covers
the specific area that you're interested in asking questions. Don't
be fooled by the names or lack of traffic. There are often forums
where most of the answers are by email from those that just don't want
their names and advice subject to public scrutiny. For example, I've
found that the LEAST useful forum for solving Apple computer related
problems is Apple's own forums. Just post your question and see what
happens. If you get a dozen one-line useless bad guesses, move on.

As always, the quality of the answers depend heavily on the quality of
the question. Without a clue as the nature of the question, vague
answers, like this one, will be epidemic.

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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


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

It's amazing there are ANY!


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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


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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
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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 ****ty 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)
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"Dave M" wrote in message
...
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.

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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!) ...


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

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Default Recommendation for electronics forums?

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 ****ty 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.


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

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