Driver to drive?

On Thu, 30 Mar 2017 21:40:29 -0700 (PDT), dagmargoodboat@yahoo.com
wrote:

On Wednesday, March 29, 2017 at 6:59:53 PM UTC-4, Clifford Heath wrote:
On 29/03/17 02:12, amdx wrote:
On 3/28/2017 2:22 AM, Clifford Heath wrote:
On 28/03/17 13:18, amdx wrote:
On 3/27/2017 6:16 PM, Clifford Heath wrote:
On 27/03/17 23:25, amdx wrote:
On 3/27/2017 6:57 AM, Tauno Voipio wrote:
Joerg, you seem not understand the innermost sense of the crystal-
radio people. They are closely related to audiophools, and it is
quite impossible to use sensible technical argumentation here.

I don't get that at all, can you back that up with any facts?

~1MHz, Q=500, bandwidth ~ 2KHz. Remind me why you need Q>1500?

You haven't connected an antenna, and tried to drive a headset yet.

Umm, I think that was me in about 1971.


More voltage does not create better audio.

But if it is a very weak signal on the antenna, you don't want to
waste any signal in loss resistances.

You start to *reject* some of the received power as soon as the
Q passes 200ish, and you destroy the audio at the same time.

You can quadruple your received power by doubling your coil
diameter, or fitting a longer wire. That's *far* FAR more
effective than saving 0.2% by using higher Q.

Crystal radios do not use the coil to collect RF energy from the air,
a long wire antenna of 25ft to 150 is attached tothe coil to pickup the
RF signal.
If you want to discuss loop antennas, start a new thread.


With a crystal ear-piece, you still may have an impedance matching
problem. For that, you should use an audio transformer *after*
the detector.

Sorry to puncture your dogma.

Take a breath!
I'll start simple, Coil and tuning cap have a unloaded Q of
1000. To extract maximum power you use a load that matches the
Q times Xl of the coil. Loading the coil with it's matched
impedance lowers the Q to 500.

You're making slightly more sense than Rickman, who hasn't
responded to *any* of the numbers I suggested, but one thing
still puzzles me.

Why worry about increasing Q above 500, when you can get more
than the extra 0.2% (lost energy at Q=500) by adding 3 inches
more antenna wire?

Possible answer:

Because, if you actually need Q=500 for selectivity, an LC tank
with an unloaded Q of 500 leaves you no power to drive an earphone?
And any improvement in unloaded tank 'Q' translates directly into more
power available for audio output?

Or looking at it another way, you want the loaded Q to be high enough
to pass the signal but not the out-of-band noise. Since you're
loading the tank with a head set, you need the unloaded Q much higher.

Cheers,
James Arthur (who has *no* dog in this fight!)

Only cats here.

 

[nuny@bid.nes]

On Saturday, April 1, 2017 at 9:11:27 AM UTC-7, John Larkin wrote:

On Sat, 1 Apr 2017 11:22:41 -0400, Phil Hobbs
pcdhSpamMeSenseless@electrooptical.net> wrote:

On 04/01/2017 11:12 AM, Tom Biasi wrote:
On 4/1/2017 10:32 AM, oldschool@tubes.com wrote:
Scientists have determined that ground is no longer at ground potential.
snip a bunch of junk
Reprinted from: The Electro Scientific Journal

This is what happens from abuse of drugs.
The earth now has an 8 volt potential in reference to what?

I think one of Feynman's lectures asks about what the electrostatic
potential of the Earth is.

The answer is that it's close to zero, since the Earth is immersed in a
conducting medium (the solar wind).

Cheers

Phil Hobbs

Is the solar wind neutral? Spacecraft typically charge a bit negative.
Seems to me that the sun could be a giant thermionic cathode.

E. E. "Doc" Smith turned the whole Solar system into a gigantic weapon focusing the Sun's entire output into a single beam in _Second Stage Lensman_- he called it the Sunbeam.

The electric field near the ground is big, around 150 volts/meter,
positive going up.

http://www.feynmanlectures.caltech.edu/II_09.html

Happy AFD.


Mark L. Fergerson

 

[Lasse Langwadt Christense]

Den lørdag den 1. april 2017 kl. 23.46.42 UTC+2 skrev MJC:

In article <7ntvdc9rut5jkrg8vma0kh9jkej85c3mqj@4ax.com>,
oldschool@tubes.com says...

Considering this, is the sun AC or DC? Is it LED, Florescent or
Incandescent? Does it contain batterier or capacitors to keep it lit?
Does anyone operate a sun control panel to keep the brightness on the
same level, and color? And what is the voltage, amperage and wattage of
the sun?

I hope we can all agree, all days of the year, that the sun is
incandescent! With a daylight colour temperature...

I expect someone has worked out the wattage. It will be an astronomical
number.

astronomical

a quick google:
the sun emits about 3.86 x 10^26 watt, about 1.74 x 10^17 watts strikes the earth

 

[George Herold]

On Saturday, April 1, 2017 at 11:22:48 AM UTC-4, Phil Hobbs wrote:

On 04/01/2017 11:12 AM, Tom Biasi wrote:
On 4/1/2017 10:32 AM, oldschool@tubes.com wrote:
Scientists have determined that ground is no longer at ground potential.
snip a bunch of junk
Reprinted from: The Electro Scientific Journal

This is what happens from abuse of drugs.
The earth now has an 8 volt potential in reference to what?

I think one of Feynman's lectures asks about what the electrostatic
potential of the Earth is.

The answer is that it's close to zero, since the Earth is immersed in a
conducting medium (the solar wind).

Huh, So we're at the same potential as the sun?
Is the sun neutral? It might boil off more electrons, and be a bit
positive?

George H.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC
Optics, Electro-optics, Photonics, Analog Electronics

160 North State Road #203
Briarcliff Manor NY 10510

hobbs at electrooptical dot net
http://electrooptical.net

 

[George Herold]

On Saturday, April 1, 2017 at 12:30:07 PM UTC-4, John Larkin wrote:

On Sat, 1 Apr 2017 12:16:35 -0400, Phil Hobbs
pcdhSpamMeSenseless@electrooptical.net> wrote:

On 04/01/2017 12:11 PM, John Larkin wrote:
On Sat, 1 Apr 2017 11:22:41 -0400, Phil Hobbs
pcdhSpamMeSenseless@electrooptical.net> wrote:

On 04/01/2017 11:12 AM, Tom Biasi wrote:
On 4/1/2017 10:32 AM, oldschool@tubes.com wrote:
Scientists have determined that ground is no longer at ground
potential.
snip a bunch of junk
Reprinted from: The Electro Scientific Journal

This is what happens from abuse of drugs. The earth now has an 8
volt potential in reference to what?

I think one of Feynman's lectures asks about what the electrostatic
potential of the Earth is.

The answer is that it's close to zero, since the Earth is immersed
in a conducting medium (the solar wind).

Cheers

Phil Hobbs

Is the solar wind neutral? Spacecraft typically charge a bit
negative. Seems to me that the sun could be a giant thermionic
cathode.

The electric field near the ground is big, around 150 volts/meter,
positive going up.

http://www.feynmanlectures.caltech.edu/II_09.html

Yup--thunderstorms pump charge in that direction, but once you get to
the top of the atmosphere the net enclosed charge is near zero.

The solar wind has to be neutral on average, because otherwise the
voltage on the Sun would increase indefinitely.



Over tens of billions of years average. Maybe all those electrons will
gradually return when the sun cools off.

It could have a slight positive charge.. till the "boil off"
rate of both charges was the same.

If earth has a net charge, it is probably not many volts. Aren't
cosmic rays almost all positive?

Lots of muons, but I think those are made in the upper atmosphere.
It all starts out as betas (electrons) and alpha's (He4 ion).

George H.

Most of the earth's surface is conductive, but dry sand might be a
good enough insulator to have local surface potentials. Sounds like a
good science project. Maybe make a drone that could scan a region and
map gradients.





--

John Larkin Highland Technology, Inc

lunatic fringe electronics

 

[George Herold]

On Saturday, April 1, 2017 at 8:50:27 PM UTC-4, George Herold wrote:

On Saturday, April 1, 2017 at 11:22:48 AM UTC-4, Phil Hobbs wrote:
On 04/01/2017 11:12 AM, Tom Biasi wrote:
On 4/1/2017 10:32 AM, oldschool@tubes.com wrote:
Scientists have determined that ground is no longer at ground potential.
snip a bunch of junk
Reprinted from: The Electro Scientific Journal

This is what happens from abuse of drugs.
The earth now has an 8 volt potential in reference to what?

I think one of Feynman's lectures asks about what the electrostatic
potential of the Earth is.

The answer is that it's close to zero, since the Earth is immersed in a
conducting medium (the solar wind).

Huh, So we're at the same potential as the sun?
Is the sun neutral? It might boil off more electrons, and be a bit
positive?

George H.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC
Optics, Electro-optics, Photonics, Analog Electronics

160 North State Road #203
Briarcliff Manor NY 10510

hobbs at electrooptical dot net
http://electrooptical.net

My first hit for charge of sun...
http://physics.stackexchange.com/questions/73763/what-is-the-electric-charge-of-the-sun-and-its-corona

77 Coulombs.
GH.

 

[Michael A. Terrell]

rickman wrote:

On 3/26/2017 2:11 AM, Michael A. Terrell wrote:
Kevin Aylward wrote:
wrote in message news:s1tcdctmds0hl22fo9hpbh5enshegc86gm@4ax.com...

On Sat, 25 Mar 2017 03:32:41 -0400, "Michael A. Terrell"
mike.terrell@earthlink.net> wrote:

Kevin Aylward wrote:
wrote in message news:mnq8dcpnbekopn07j0cu3crq12hq0905l1@4ax.com...

On Thu, 23 Mar 2017 14:58:23 -0400, "Michael A. Terrell"
mike.terrell@earthlink.net> wrote:

krw@notreal.com wrote:
On Sun, 19 Mar 2017 14:19:57 -0000 (UTC), Cursitor Doom
curd@notformail.com> wrote:

On Sat, 18 Mar 2017 20:03:50 -0400, krw wrote:

That's impossible, which is the whole "reasonable" thing.

Nothing whatsoever impossible about it!

Not at all. There is always doubt. It may be an unreasonable doubt
but there is _always_ doubt (what if the Earth was really flat?).
Hence, "beyond reasonable doubt".


What do you think of this sorry piece of work?

http://www.wftv.com/news/local/ayala-to-explain-why-she-wont-seek-death-penalty-against-murder-suspect-markeith-loyd/503151996





She should *immediately* be removed from office for violating her
oath
of office to follow the constitution and laws of the state of
Florida.
That decision isn't hers to make.

Ho hummm..

Like, what specific law says that anybody has to demand the death of
someone else? Dah....


It's her job tpoo follow the laws, not decide which ones she likes.
In that case, he murdered a police officer in front of a lot of people,

Please cite the exact law that says that a prosecutor must demand the
death penalty.

Sure, a prosecutor may well be obliged to do what is in the best
interest of society, in which case the evidence appears to show that the
"best" course of action, is to not seek the death penalty.

http://www.amnestyusa.org/our-work/issues/death-penalty/us-death-penalty-facts/death-penalty-cost




Please show the exact law that allows employees to refuse to do their
jobs, yet keep their jobs.

Show me the law that makes it a crime!!!

Show one that states otherwise.


--
Never piss off an Engineer!

They don't get mad.

They don't get even.

They go for over unity! ;-)

 

[Clifford Heath]

On 31/03/17 15:40, dagmargoodboat@yahoo.com wrote:

On Wednesday, March 29, 2017 at 6:59:53 PM UTC-4, Clifford Heath wrote:
On 29/03/17 02:12, amdx wrote:
On 3/28/2017 2:22 AM, Clifford Heath wrote:
On 28/03/17 13:18, amdx wrote:
On 3/27/2017 6:16 PM, Clifford Heath wrote:
On 27/03/17 23:25, amdx wrote:
On 3/27/2017 6:57 AM, Tauno Voipio wrote:
Joerg, you seem not understand the innermost sense of the crystal-
radio people. They are closely related to audiophools, and it is
quite impossible to use sensible technical argumentation here.

I don't get that at all, can you back that up with any facts?

~1MHz, Q=500, bandwidth ~ 2KHz. Remind me why you need Q>1500?

You haven't connected an antenna, and tried to drive a headset yet.

Umm, I think that was me in about 1971.


More voltage does not create better audio.

But if it is a very weak signal on the antenna, you don't want to
waste any signal in loss resistances.

You start to *reject* some of the received power as soon as the
Q passes 200ish, and you destroy the audio at the same time.

You can quadruple your received power by doubling your coil
diameter, or fitting a longer wire. That's *far* FAR more
effective than saving 0.2% by using higher Q.

Crystal radios do not use the coil to collect RF energy from the air,
a long wire antenna of 25ft to 150 is attached tothe coil to pickup the
RF signal.
If you want to discuss loop antennas, start a new thread.


With a crystal ear-piece, you still may have an impedance matching
problem. For that, you should use an audio transformer *after*
the detector.

Sorry to puncture your dogma.

Take a breath!
I'll start simple, Coil and tuning cap have a unloaded Q of
1000. To extract maximum power you use a load that matches the
Q times Xl of the coil. Loading the coil with it's matched
impedance lowers the Q to 500.

You're making slightly more sense than Rickman, who hasn't
responded to *any* of the numbers I suggested, but one thing
still puzzles me.

Why worry about increasing Q above 500, when you can get more
than the extra 0.2% (lost energy at Q=500) by adding 3 inches
more antenna wire?

Possible answer:

Because, if you actually need Q=500 for selectivity, an LC tank
with an unloaded Q of 500 leaves you no power to drive an earphone?
And any improvement in unloaded tank 'Q' translates directly into more
power available for audio output?

James, thanks.

That's the sanest answer yet and goes some way to explaining
what the xtal guys are after.

However, the single-diode detector is a very assymetric load.
That's going to affect things a bit, don't you think? By which
I mean that the coil will "see" the load during rising amplitude,
but not during falling amplitude. The coupling to a crystal
earpiece (generally capacitive, but highly reactive load) is
gonna make quite things weird, by pulling the resonant frequency
around a lot, dependent on the audio signal...

I should pull out my old xtal earpieces and measure the capacitance.
I suspect they'd detune a high-Q front end quite a bit, and that
really calls into question the use of Q to limit bandwidth.

Clifford Heath.

 

[Michael A. Terrell]

Kevin Aylward wrote:

"Michael A. Terrell" wrote in message
news:r-mdnXJ9t9cNxkrFnZ2dnUU7-b2dnZ2d@earthlink.com...

Kevin Aylward wrote:
wrote in message news:s1tcdctmds0hl22fo9hpbh5enshegc86gm@4ax.com...

On Sat, 25 Mar 2017 03:32:41 -0400, "Michael A. Terrell"
mike.terrell@earthlink.net> wrote:

Kevin Aylward wrote:
wrote in message news:mnq8dcpnbekopn07j0cu3crq12hq0905l1@4ax.com...

On Thu, 23 Mar 2017 14:58:23 -0400, "Michael A. Terrell"
mike.terrell@earthlink.net> wrote:

krw@notreal.com wrote:
On Sun, 19 Mar 2017 14:19:57 -0000 (UTC), Cursitor Doom
curd@notformail.com> wrote:

On Sat, 18 Mar 2017 20:03:50 -0400, krw wrote:

That's impossible, which is the whole "reasonable" thing.

Nothing whatsoever impossible about it!

Not at all. There is always doubt. It may be an unreasonable doubt
but there is _always_ doubt (what if the Earth was really flat?).
Hence, "beyond reasonable doubt".


What do you think of this sorry piece of work?

http://www.wftv.com/news/local/ayala-to-explain-why-she-wont-seek-death-penalty-against-murder-suspect-markeith-loyd/503151996




She should *immediately* be removed from office for violating her oath
of office to follow the constitution and laws of the state of Florida.
That decision isn't hers to make.

Ho hummm..

Like, what specific law says that anybody has to demand the death of
someone else? Dah....


It's her job tpoo follow the laws, not decide which ones she likes.
In that case, he murdered a police officer in front of a lot of people,

Please cite the exact law that says that a prosecutor must demand the
death penalty.

Sure, a prosecutor may well be obliged to do what is in the best
interest of society, in which case the evidence appears to show that the
"best" course of action, is to not seek the death penalty.

http://www.amnestyusa.org/our-work/issues/death-penalty/us-death-penalty-facts/death-penalty-cost



Please show the exact law that allows employees to refuse to do
their jobs, yet keep their jobs.

It is absolutely stunning that some can not understand truly simple
points. She has not refused to do her job. This is trivially obvious.

What part of "Please cite the exact law that says that a prosecutor must
demand the death penalty."

Do you not understand?

"Ayala said she plans to file a notice to withdraw the intent to seek
the death penalty in those cases that have not yet gone to trial"

In what shape or form does this imply that she is refusing to do her
job? She is simply not going to seek the death penalty. Dah...

Her job is not to kill people.

Her job is to follow the current laws. No more and no less.


--
Never piss off an Engineer!

They don't get mad.

They don't get even.

They go for over unity! ;-)

 

[Michael A. Terrell]

rickman wrote:

On 3/26/2017 2:09 AM, Michael A. Terrell wrote:
krw@notreal.com wrote:
On Sat, 25 Mar 2017 14:20:46 -0400, rickman <gnuarm@gmail.com> wrote:

On 3/25/2017 3:34 AM, Michael A. Terrell wrote:
Cursitor Doom wrote:
On Fri, 24 Mar 2017 15:31:03 +0000, Kevin Aylward wrote:

Of course, assuming the allegations are true, then the crimes are
horrendous, and would certainly warrant life in prison, with no
possibility of parole

A most costly decision. Do you have any idea how much it costs to
incarcerate a prisoner in that category for that length of time? We
have an overcrowding crisis right now because the system is clogged
up by 'bed-blockers' who could easily be removed at zero further cost
to the taxpayer.


Indeed. Give him life, and he'll file appeal after appeal, until
he's
dead. It can run into millions of dollars.

I believe the cost of executing someone is even higher.

Utter nonsense. It's the appeal after appeal, until he's dead that's
the expensive part. There is absolutely *no* reason it should take 20
years.

All appeals should have to be completed within two years. Also,
someone other than the public should have to pay the costs for any new
trials.

"Someone"? So if you can't afford it you don't get justice?

Why are you so worried? What can they pin on you?


--
Never piss off an Engineer!

They don't get mad.

They don't get even.

They go for over unity! ;-)

 

[rickman]

On 4/2/2017 12:36 AM, Clifford Heath wrote:

On 02/04/17 13:55, rickman wrote:
On 4/1/2017 10:59 PM, Clifford Heath wrote:
On 31/03/17 15:40, dagmargoodboat@yahoo.com wrote:
On Wednesday, March 29, 2017 at 6:59:53 PM UTC-4, Clifford Heath wrote:
On 29/03/17 02:12, amdx wrote:
On 3/28/2017 2:22 AM, Clifford Heath wrote:
On 28/03/17 13:18, amdx wrote:
On 3/27/2017 6:16 PM, Clifford Heath wrote:
On 27/03/17 23:25, amdx wrote:
On 3/27/2017 6:57 AM, Tauno Voipio wrote:
Joerg, you seem not understand the innermost sense of the
crystal-
radio people. They are closely related to audiophools, and it is
quite impossible to use sensible technical argumentation here.

I don't get that at all, can you back that up with any facts?

~1MHz, Q=500, bandwidth ~ 2KHz. Remind me why you need Q>1500?

You haven't connected an antenna, and tried to drive a headset
yet.

Umm, I think that was me in about 1971.


More voltage does not create better audio.

But if it is a very weak signal on the antenna, you don't want to
waste any signal in loss resistances.

You start to *reject* some of the received power as soon as the
Q passes 200ish, and you destroy the audio at the same time.

You can quadruple your received power by doubling your coil
diameter, or fitting a longer wire. That's *far* FAR more
effective than saving 0.2% by using higher Q.

Crystal radios do not use the coil to collect RF energy from the
air,
a long wire antenna of 25ft to 150 is attached tothe coil to pickup
the
RF signal.
If you want to discuss loop antennas, start a new thread.


With a crystal ear-piece, you still may have an impedance matching
problem. For that, you should use an audio transformer *after*
the detector.

Sorry to puncture your dogma.

Take a breath!
I'll start simple, Coil and tuning cap have a unloaded Q of
1000. To extract maximum power you use a load that matches the
Q times Xl of the coil. Loading the coil with it's matched
impedance lowers the Q to 500.

You're making slightly more sense than Rickman, who hasn't
responded to *any* of the numbers I suggested, but one thing
still puzzles me.

Why worry about increasing Q above 500, when you can get more
than the extra 0.2% (lost energy at Q=500) by adding 3 inches
more antenna wire?

Possible answer:

Because, if you actually need Q=500 for selectivity, an LC tank
with an unloaded Q of 500 leaves you no power to drive an earphone?
And any improvement in unloaded tank 'Q' translates directly into more
power available for audio output?

James, thanks.

That's the sanest answer yet and goes some way to explaining
what the xtal guys are after.

However, the single-diode detector is a very assymetric load.
That's going to affect things a bit, don't you think? By which
I mean that the coil will "see" the load during rising amplitude,
but not during falling amplitude. The coupling to a crystal
earpiece (generally capacitive, but highly reactive load) is
gonna make quite things weird, by pulling the resonant frequency
around a lot, dependent on the audio signal...

I should pull out my old xtal earpieces and measure the capacitance.
I suspect they'd detune a high-Q front end quite a bit, and that
really calls into question the use of Q to limit bandwidth.

I'm unclear what you are describing. When you say "detune" you are not
describing an effect on the Q, but rather an effect on the tuned
frequency.

Both. When the diode conducts (as it must to transmit power)
it connects the filter capacitance and the capacitance of the
earpiece to the tuned circuit. This will happen whenever the
diode is forward biassed, i.e. when the audio signal is rising.

The extra capacitance on rising audio signals will pull the tuned
circuit to a much lower frequency. As soon as the diode turns off
(when the audio signal starts to fall), the tuned circuit will
jump to a higher frequency, perhaps receiving a different station,
and hence affecting the audio signal once again.

I would expect a double-hump response in the overall receiver,
and the gap between the humps will depend on the filter and
earpiece capacitance.

Maybe you could build one and test that?

If the capacitance of the earpiece impacts the tuning of the
receiver, the adjustment of the tuning capacitor would make up for that
when operated.

Or do you mean detune as a way of describing the reduced Q from the
loading of the circuit by the earpiece? How exactly would the
capacitance of a crystal earpiece affect the loading?

When you measure the capacitance of the earpiece, also measure the
resistance at audio frequencies. The capacitance is only significant in
that context.

Fair enough. I think I've given some answers above.

I believe a serious crystal set operator will use high end headphones
however. I believe various military headsets are valued for this use
due to their high sensitivity. So the functioning of an inexpensive
peizo earpiece may not be so relevant, but interesting anyway. When I
read about the detail explored to characterize the detecting diode I was
very impressed. So I can see every part of such a simple radio being
optimized to the nth degree.

Perhaps. The earpiece still has to present some load, or it will
receive no energy. For optimum power transfer, you want its audio
impedance to roughly approximate the equivalent parallel resistance
across the tank - which is why Q gets halved. Or not... perhaps
that only happens on audio half-cycles.

"Presenting a load" is a description of the power transfer. Of course
that has to happen or you don't hear a signal. But how much of that
power gets converted to sound depends on the earpiece used.

Anyhow, those are the reasons for my skepticism about the whole
project. If the detector and earpiece presented a purely resistive
load, or even a fixed capacitive+R load, regardless of audio
polarity, then you wouldn't get a double hump. But I think that's
unlikely.

Theory is nice, but it is easy to miss important aspects. That's why
people build crystal radios, to learn what is important and what is not.

--

Rick C

 

[Michael A. Terrell]

Cursitor Doom wrote:

On Sun, 26 Mar 2017 02:18:31 -0400, Michael A. Terrell wrote:


You would be surprised how smart some Rednecks are, if you weren't
so stupid. The original 'rednecks' were farmers, who worked out in the
hot sun from dawn till dark.

Yes, they worked hard and there was nothing they couldn't fix-up for
themselves when they had to. Resourceful, productive people - unlike all
those scheming cunts in Washington.

Wouldn't you like to see them dumped into a falling down old cabin,
miles from anywhere with little food, tools, and no money. Most would be
dead inside of a week. Yet the ones they make fun of would have little
or no trouble surviving. A new version of 'Survivor', with drone cameras
so they can't steal food from the production crews.



--
Never piss off an Engineer!

They don't get mad.

They don't get even.

They go for over unity! ;-)

 

[Michael A. Terrell]

John Robertson wrote:

On 2017/03/25 11:12 PM, Michael A. Terrell wrote:
rickman wrote:
On 3/25/2017 3:32 AM, Michael A. Terrell wrote:
Kevin Aylward wrote:
wrote in message news:mnq8dcpnbekopn07j0cu3crq12hq0905l1@4ax.com...

On Thu, 23 Mar 2017 14:58:23 -0400, "Michael A. Terrell"
mike.terrell@earthlink.net> wrote:

krw@notreal.com wrote:
On Sun, 19 Mar 2017 14:19:57 -0000 (UTC), Cursitor Doom
curd@notformail.com> wrote:

On Sat, 18 Mar 2017 20:03:50 -0400, krw wrote:

That's impossible, which is the whole "reasonable" thing.

Nothing whatsoever impossible about it!

Not at all. There is always doubt. It may be an unreasonable doubt
but there is _always_ doubt (what if the Earth was really flat?).
Hence, "beyond reasonable doubt".


What do you think of this sorry piece of work?

http://www.wftv.com/news/local/ayala-to-explain-why-she-wont-seek-death-penalty-against-murder-suspect-markeith-loyd/503151996






She should *immediately* be removed from office for violating her
oath
of office to follow the constitution and laws of the state of
Florida.
That decision isn't hers to make.

Ho hummm..

Like, what specific law says that anybody has to demand the death of
someone else? Dah....


It's her job tpoo follow the laws, not decide which ones she likes.
In that case, he murdered a police officer in front of a lot of people,
and he has a long history of violence, If she can't or won't do her
job,
she needs to be fired.

What law did she violate?


What laws do you obey?



You didn't answer the question. Which was - What law did she disobey by
refusing to ask for the death penalty?

She is a Florida state attorney and can recommend that the death
sentence to be chosen by the jury. Or not. She simply expressed her
decision to not ask for the death penalty as she had come to the
conclusion, after much study, that it served no useful purpose.

Here is the Florida statute:

- 921.141 Sentence of death or life imprisonment for capital felonies;
further proceedings to determine sentence.—

http://www.leg.state.fl.us/Statutes/index.cfm?App_mode=Display_Statute&Search_String=&URL=0900-0999/0921/Sections/0921.141.html

Where does it state that she can refuse to seek the death penalty in
every case?


--
Never piss off an Engineer!

They don't get mad.

They don't get even.

They go for over unity! ;-)

 

[Michael A. Terrell]

rickman wrote:

Lol! I know which one I think is garbage. I can only guess you think
both shows are garbage.

I have no desire to watch a lying, pissed off moron, or the former
Mayor of Cincinnati.



--
Never piss off an Engineer!

They don't get mad.

They don't get even.

They go for over unity! ;-)

 

[Michael A. Terrell]

Cursitor Doom wrote:

On Sun, 26 Mar 2017 02:03:24 -0400, Michael A. Terrell wrote:

Do you watch that garbage? It's intended for the low intelligence
liberals. Oh! Sorry, I forgot who I was asking that.

He probably hasn't moved on from Sesame Street yet.

Is that crap still on TV?



--
Never piss off an Engineer!

They don't get mad.

They don't get even.

They go for over unity! ;-)

 

[rickman]

On 4/1/2017 10:59 PM, Clifford Heath wrote:

On 31/03/17 15:40, dagmargoodboat@yahoo.com wrote:
On Wednesday, March 29, 2017 at 6:59:53 PM UTC-4, Clifford Heath wrote:
On 29/03/17 02:12, amdx wrote:
On 3/28/2017 2:22 AM, Clifford Heath wrote:
On 28/03/17 13:18, amdx wrote:
On 3/27/2017 6:16 PM, Clifford Heath wrote:
On 27/03/17 23:25, amdx wrote:
On 3/27/2017 6:57 AM, Tauno Voipio wrote:
Joerg, you seem not understand the innermost sense of the crystal-
radio people. They are closely related to audiophools, and it is
quite impossible to use sensible technical argumentation here.

I don't get that at all, can you back that up with any facts?

~1MHz, Q=500, bandwidth ~ 2KHz. Remind me why you need Q>1500?

You haven't connected an antenna, and tried to drive a headset yet.

Umm, I think that was me in about 1971.


More voltage does not create better audio.

But if it is a very weak signal on the antenna, you don't want to
waste any signal in loss resistances.

You start to *reject* some of the received power as soon as the
Q passes 200ish, and you destroy the audio at the same time.

You can quadruple your received power by doubling your coil
diameter, or fitting a longer wire. That's *far* FAR more
effective than saving 0.2% by using higher Q.

Crystal radios do not use the coil to collect RF energy from the air,
a long wire antenna of 25ft to 150 is attached tothe coil to pickup the
RF signal.
If you want to discuss loop antennas, start a new thread.


With a crystal ear-piece, you still may have an impedance matching
problem. For that, you should use an audio transformer *after*
the detector.

Sorry to puncture your dogma.

Take a breath!
I'll start simple, Coil and tuning cap have a unloaded Q of
1000. To extract maximum power you use a load that matches the
Q times Xl of the coil. Loading the coil with it's matched
impedance lowers the Q to 500.

You're making slightly more sense than Rickman, who hasn't
responded to *any* of the numbers I suggested, but one thing
still puzzles me.

Why worry about increasing Q above 500, when you can get more
than the extra 0.2% (lost energy at Q=500) by adding 3 inches
more antenna wire?

Possible answer:

Because, if you actually need Q=500 for selectivity, an LC tank
with an unloaded Q of 500 leaves you no power to drive an earphone?
And any improvement in unloaded tank 'Q' translates directly into more
power available for audio output?

James, thanks.

That's the sanest answer yet and goes some way to explaining
what the xtal guys are after.

However, the single-diode detector is a very assymetric load.
That's going to affect things a bit, don't you think? By which
I mean that the coil will "see" the load during rising amplitude,
but not during falling amplitude. The coupling to a crystal
earpiece (generally capacitive, but highly reactive load) is
gonna make quite things weird, by pulling the resonant frequency
around a lot, dependent on the audio signal...

I should pull out my old xtal earpieces and measure the capacitance.
I suspect they'd detune a high-Q front end quite a bit, and that
really calls into question the use of Q to limit bandwidth.

I'm unclear what you are describing. When you say "detune" you are not
describing an effect on the Q, but rather an effect on the tuned
frequency. If the capacitance of the earpiece impacts the tuning of the
receiver, the adjustment of the tuning capacitor would make up for that
when operated.

Or do you mean detune as a way of describing the reduced Q from the
loading of the circuit by the earpiece? How exactly would the
capacitance of a crystal earpiece affect the loading?

When you measure the capacitance of the earpiece, also measure the
resistance at audio frequencies. The capacitance is only significant in
that context.

I believe a serious crystal set operator will use high end headphones
however. I believe various military headsets are valued for this use
due to their high sensitivity. So the functioning of an inexpensive
peizo earpiece may not be so relevant, but interesting anyway. When I
read about the detail explored to characterize the detecting diode I was
very impressed. So I can see every part of such a simple radio being
optimized to the nth degree.

--

Rick C

 

[Clifford Heath]

On 02/04/17 13:55, rickman wrote:

On 4/1/2017 10:59 PM, Clifford Heath wrote:
On 31/03/17 15:40, dagmargoodboat@yahoo.com wrote:
On Wednesday, March 29, 2017 at 6:59:53 PM UTC-4, Clifford Heath wrote:
On 29/03/17 02:12, amdx wrote:
On 3/28/2017 2:22 AM, Clifford Heath wrote:
On 28/03/17 13:18, amdx wrote:
On 3/27/2017 6:16 PM, Clifford Heath wrote:
On 27/03/17 23:25, amdx wrote:
On 3/27/2017 6:57 AM, Tauno Voipio wrote:
Joerg, you seem not understand the innermost sense of the
crystal-
radio people. They are closely related to audiophools, and it is
quite impossible to use sensible technical argumentation here.

I don't get that at all, can you back that up with any facts?

~1MHz, Q=500, bandwidth ~ 2KHz. Remind me why you need Q>1500?

You haven't connected an antenna, and tried to drive a headset yet.

Umm, I think that was me in about 1971.


More voltage does not create better audio.

But if it is a very weak signal on the antenna, you don't want to
waste any signal in loss resistances.

You start to *reject* some of the received power as soon as the
Q passes 200ish, and you destroy the audio at the same time.

You can quadruple your received power by doubling your coil
diameter, or fitting a longer wire. That's *far* FAR more
effective than saving 0.2% by using higher Q.

Crystal radios do not use the coil to collect RF energy from the air,
a long wire antenna of 25ft to 150 is attached tothe coil to pickup
the
RF signal.
If you want to discuss loop antennas, start a new thread.


With a crystal ear-piece, you still may have an impedance matching
problem. For that, you should use an audio transformer *after*
the detector.

Sorry to puncture your dogma.

Take a breath!
I'll start simple, Coil and tuning cap have a unloaded Q of
1000. To extract maximum power you use a load that matches the
Q times Xl of the coil. Loading the coil with it's matched
impedance lowers the Q to 500.

You're making slightly more sense than Rickman, who hasn't
responded to *any* of the numbers I suggested, but one thing
still puzzles me.

Why worry about increasing Q above 500, when you can get more
than the extra 0.2% (lost energy at Q=500) by adding 3 inches
more antenna wire?

Possible answer:

Because, if you actually need Q=500 for selectivity, an LC tank
with an unloaded Q of 500 leaves you no power to drive an earphone?
And any improvement in unloaded tank 'Q' translates directly into more
power available for audio output?

James, thanks.

That's the sanest answer yet and goes some way to explaining
what the xtal guys are after.

However, the single-diode detector is a very assymetric load.
That's going to affect things a bit, don't you think? By which
I mean that the coil will "see" the load during rising amplitude,
but not during falling amplitude. The coupling to a crystal
earpiece (generally capacitive, but highly reactive load) is
gonna make quite things weird, by pulling the resonant frequency
around a lot, dependent on the audio signal...

I should pull out my old xtal earpieces and measure the capacitance.
I suspect they'd detune a high-Q front end quite a bit, and that
really calls into question the use of Q to limit bandwidth.

I'm unclear what you are describing. When you say "detune" you are not
describing an effect on the Q, but rather an effect on the tuned
frequency.

Both. When the diode conducts (as it must to transmit power)
it connects the filter capacitance and the capacitance of the
earpiece to the tuned circuit. This will happen whenever the
diode is forward biassed, i.e. when the audio signal is rising.

The extra capacitance on rising audio signals will pull the tuned
circuit to a much lower frequency. As soon as the diode turns off
(when the audio signal starts to fall), the tuned circuit will
jump to a higher frequency, perhaps receiving a different station,
and hence affecting the audio signal once again.

I would expect a double-hump response in the overall receiver,
and the gap between the humps will depend on the filter and
earpiece capacitance.

If the capacitance of the earpiece impacts the tuning of the
receiver, the adjustment of the tuning capacitor would make up for that
when operated.

Or do you mean detune as a way of describing the reduced Q from the
loading of the circuit by the earpiece? How exactly would the
capacitance of a crystal earpiece affect the loading?

When you measure the capacitance of the earpiece, also measure the
resistance at audio frequencies. The capacitance is only significant in
that context.

Fair enough. I think I've given some answers above.

I believe a serious crystal set operator will use high end headphones
however. I believe various military headsets are valued for this use
due to their high sensitivity. So the functioning of an inexpensive
peizo earpiece may not be so relevant, but interesting anyway. When I
read about the detail explored to characterize the detecting diode I was
very impressed. So I can see every part of such a simple radio being
optimized to the nth degree.

Perhaps. The earpiece still has to present some load, or it will
receive no energy. For optimum power transfer, you want its audio
impedance to roughly approximate the equivalent parallel resistance
across the tank - which is why Q gets halved. Or not... perhaps
that only happens on audio half-cycles.

Anyhow, those are the reasons for my skepticism about the whole
project. If the detector and earpiece presented a purely resistive
load, or even a fixed capacitive+R load, regardless of audio
polarity, then you wouldn't get a double hump. But I think that's
unlikely.

Clifford Heath.

 

[Michael A. Terrell]

krw@notreal.com wrote:

On Sun, 26 Mar 2017 03:11:20 -0400, rickman <gnuarm@gmail.com> wrote:

On 3/26/2017 2:07 AM, Michael A. Terrell wrote:
rickman wrote:
On 3/24/2017 9:03 AM, Michael A. Terrell wrote:
krw@notreal.com wrote:
On Thu, 23 Mar 2017 14:58:23 -0400, "Michael A. Terrell"
mike.terrell@earthlink.net> wrote:

krw@notreal.com wrote:
On Sun, 19 Mar 2017 14:19:57 -0000 (UTC), Cursitor Doom
curd@notformail.com> wrote:

On Sat, 18 Mar 2017 20:03:50 -0400, krw wrote:

That's impossible, which is the whole "reasonable" thing.

Nothing whatsoever impossible about it!

Not at all. There is always doubt. It may be an unreasonable doubt
but there is _always_ doubt (what if the Earth was really flat?).
Hence, "beyond reasonable doubt".


What do you think of this sorry piece of work?

http://www.wftv.com/news/local/ayala-to-explain-why-she-wont-seek-death-penalty-against-murder-suspect-markeith-loyd/503151996




She should *immediately* be removed from office for violating her
oath of office to follow the constitution and laws of the state of
Florida.
That decision isn't hers to make.


The Governor has removed her from the case, but she want to sue
over it.

Disbar the jackass.

What did she do wrong? It is in the prosecutor's domain to decide how
to prosecute a case. I haven't looked up the law, but I seriously
doubt it says the death penalty is mandatory in all cases.


You are truly a Sloman. She refuses to do it for any case brought
before her. If you would actually look at links instead of firing from
the lip, you wouldn't look like someone with the IQ if ice water.

What did she do that was illegal? What rule did she break that should
get her fired?

Prosecutors don't make law, Ricky. Legislatures do. The executive's
job is to carry out the laws as the legislature writes them. If they
can't, or won't do it, they have no business in that job. I know
you're too stupid to see.

We need a few of the old 'Hanging Judges' that helped to clean up
the 'Old West'.


--
Never piss off an Engineer!

They don't get mad.

They don't get even.

They go for over unity! ;-)

 

On Sunday, April 2, 2017 at 4:07:07 PM UTC+10, Michael Terrell wrote:

rickman wrote:
On 3/26/2017 2:11 AM, Michael A. Terrell wrote:
Kevin Aylward wrote:
wrote in message news:s1tcdctmds0hl22fo9hpbh5enshegc86gm@4ax.com...

On Sat, 25 Mar 2017 03:32:41 -0400, "Michael A. Terrell"
mike.terrell@earthlink.net> wrote:

Kevin Aylward wrote:
wrote in message news:mnq8dcpnbekopn07j0cu3crq12hq0905l1@4ax.com...

On Thu, 23 Mar 2017 14:58:23 -0400, "Michael A. Terrell"
mike.terrell@earthlink.net> wrote:

krw@notreal.com wrote:
On Sun, 19 Mar 2017 14:19:57 -0000 (UTC), Cursitor Doom
curd@notformail.com> wrote:

On Sat, 18 Mar 2017 20:03:50 -0400, krw wrote:

<snip>

Like, what specific law says that anybody has to demand the death of
someone else? Dah....

It's her job to follow the laws, not decide which ones she likes.
In that case, he murdered a police officer in front of a lot of people,

Please cite the exact law that says that a prosecutor must demand the
death penalty.

Sure, a prosecutor may well be obliged to do what is in the best
interest of society, in which case the evidence appears to show that the
"best" course of action, is to not seek the death penalty.

http://www.amnestyusa.org/our-work/issues/death-penalty/us-death-penalty-facts/death-penalty-cost

Please show the exact law that allows employees to refuse to do their
jobs, yet keep their jobs.

Show me the law that makes it a crime!!!

Show one that states otherwise.

You can't prove a negative. If you don't do your job to the satisfaction of your employer, that can constitute grounds for dismissal. Doing it badly enough can constitute negligence, and you can get sued for the consequences.

Neither is criminal. There is a crime of criminal negligence

https://en.wikipedia.org/wiki/Criminal_negligence

but a prosecutor failing to ask for the death penalty isn't going to qualify. Asking for the death penalty in a situation where this made the jury less likely to convict might qualify, but no prosecutor is going to get charged with that - simply because it would be too hard to get a conviction.

--
Bill Sloman, Sydney

 

[Clifford Heath]

On 02/04/17 15:56, rickman wrote:

On 4/2/2017 12:36 AM, Clifford Heath wrote:
On 02/04/17 13:55, rickman wrote:
On 4/1/2017 10:59 PM, Clifford Heath wrote:
On 31/03/17 15:40, dagmargoodboat@yahoo.com wrote:
On Wednesday, March 29, 2017 at 6:59:53 PM UTC-4, Clifford Heath
wrote:
On 29/03/17 02:12, amdx wrote:
On 3/28/2017 2:22 AM, Clifford Heath wrote:
On 28/03/17 13:18, amdx wrote:
On 3/27/2017 6:16 PM, Clifford Heath wrote:
On 27/03/17 23:25, amdx wrote:
On 3/27/2017 6:57 AM, Tauno Voipio wrote:
Joerg, you seem not understand the innermost sense of the
crystal-
radio people. They are closely related to audiophools, and
it is
quite impossible to use sensible technical argumentation here.

I don't get that at all, can you back that up with any facts?

~1MHz, Q=500, bandwidth ~ 2KHz. Remind me why you need Q>1500?

You haven't connected an antenna, and tried to drive a headset
yet.

Umm, I think that was me in about 1971.


More voltage does not create better audio.

But if it is a very weak signal on the antenna, you don't
want to
waste any signal in loss resistances.

You start to *reject* some of the received power as soon as the
Q passes 200ish, and you destroy the audio at the same time.

You can quadruple your received power by doubling your coil
diameter, or fitting a longer wire. That's *far* FAR more
effective than saving 0.2% by using higher Q.

Crystal radios do not use the coil to collect RF energy from the
air,
a long wire antenna of 25ft to 150 is attached tothe coil to pickup
the
RF signal.
If you want to discuss loop antennas, start a new thread.


With a crystal ear-piece, you still may have an impedance matching
problem. For that, you should use an audio transformer *after*
the detector.

Sorry to puncture your dogma.

Take a breath!
I'll start simple, Coil and tuning cap have a unloaded Q of
1000. To extract maximum power you use a load that matches the
Q times Xl of the coil. Loading the coil with it's matched
impedance lowers the Q to 500.

You're making slightly more sense than Rickman, who hasn't
responded to *any* of the numbers I suggested, but one thing
still puzzles me.

Why worry about increasing Q above 500, when you can get more
than the extra 0.2% (lost energy at Q=500) by adding 3 inches
more antenna wire?

Possible answer:

Because, if you actually need Q=500 for selectivity, an LC tank
with an unloaded Q of 500 leaves you no power to drive an earphone?
And any improvement in unloaded tank 'Q' translates directly into more
power available for audio output?

James, thanks.

That's the sanest answer yet and goes some way to explaining
what the xtal guys are after.

However, the single-diode detector is a very assymetric load.
That's going to affect things a bit, don't you think? By which
I mean that the coil will "see" the load during rising amplitude,
but not during falling amplitude. The coupling to a crystal
earpiece (generally capacitive, but highly reactive load) is
gonna make quite things weird, by pulling the resonant frequency
around a lot, dependent on the audio signal...

I should pull out my old xtal earpieces and measure the capacitance.
I suspect they'd detune a high-Q front end quite a bit, and that
really calls into question the use of Q to limit bandwidth.

I'm unclear what you are describing. When you say "detune" you are not
describing an effect on the Q, but rather an effect on the tuned
frequency.

Both. When the diode conducts (as it must to transmit power)
it connects the filter capacitance and the capacitance of the
earpiece to the tuned circuit. This will happen whenever the
diode is forward biassed, i.e. when the audio signal is rising.

The extra capacitance on rising audio signals will pull the tuned
circuit to a much lower frequency. As soon as the diode turns off
(when the audio signal starts to fall), the tuned circuit will
jump to a higher frequency, perhaps receiving a different station,
and hence affecting the audio signal once again.

I would expect a double-hump response in the overall receiver,
and the gap between the humps will depend on the filter and
earpiece capacitance.

Maybe you could build one and test that?


If the capacitance of the earpiece impacts the tuning of the
receiver, the adjustment of the tuning capacitor would make up for that
when operated.

Or do you mean detune as a way of describing the reduced Q from the
loading of the circuit by the earpiece? How exactly would the
capacitance of a crystal earpiece affect the loading?

When you measure the capacitance of the earpiece, also measure the
resistance at audio frequencies. The capacitance is only significant in
that context.

Fair enough. I think I've given some answers above.

I believe a serious crystal set operator will use high end headphones
however. I believe various military headsets are valued for this use
due to their high sensitivity. So the functioning of an inexpensive
peizo earpiece may not be so relevant, but interesting anyway. When I
read about the detail explored to characterize the detecting diode I was
very impressed. So I can see every part of such a simple radio being
optimized to the nth degree.

Perhaps. The earpiece still has to present some load, or it will
receive no energy. For optimum power transfer, you want its audio
impedance to roughly approximate the equivalent parallel resistance
across the tank - which is why Q gets halved. Or not... perhaps
that only happens on audio half-cycles.

"Presenting a load" is a description of the power transfer. Of course
that has to happen or you don't hear a signal. But how much of that
power gets converted to sound depends on the earpiece used.


Anyhow, those are the reasons for my skepticism about the whole
project. If the detector and earpiece presented a purely resistive
load, or even a fixed capacitive+R load, regardless of audio
polarity, then you wouldn't get a double hump. But I think that's
unlikely.

Theory is nice, but it is easy to miss important aspects. That's why
people build crystal radios, to learn what is important and what is not.

It would need a fairly ornate test setup compared to what I have
available; specifically two different signals, one fixed, one swept,
to see at what frequencies the swept one gets in. Possible, but I
can't easily do it at present.

It seems easier to just ask: with your high-Q receiver, do you ever
hear two stations at the same time that are on different frequencies?
What do the community report?

The crystal set I built as a kid seemed often to get multiple stations,
but it probably didn't have enough pixie dust.

Clifford Heath