PRC as a amplifier in GPS question.

[Michael A. Terrell]

Mark Harriss wrote:

You try to help some of these people such as GB and
all they can do is get personal with the insults.
Good thing they are not diplomats.

Its their problem, not ours. ;-)


--
HELP! My sig file has escaped! ;-)

 

[GB]

"Michael A. Terrell" <mike.terrell@earthlink.net> wrote in
news:445127C3.4589331@earthlink.net:

GB wrote:
Ahhh, I get it. You're *American*. That explains pretty much
everything.
Really? In what way?\

You're American, you wouldn't understand. I'm not going to
waste my breath trying to understand. The bits where you *think*
you have 'freedom' (a term bandied about in America so much
that it has lost its meaning), you *think* you're a christian,
and you *think* that "serving your country" (ie: tromping around
the planet fucking up other people's countries) somehow makes
you a better person.

"the supreme and most insidious exercise of power [is] to
prevent people, to whatever degree, from having grievances
by shaping their perceptions, cognitions and preferences in
such a way that they accept their role in the existing order
of things, either because they see or imagine no alternative
to it, or because they see it as natural and unchangeable,
or because they value it because it is divinely ordained
and beneficial." (Lukes 1974)


You and your countrymen have been hoodwinked boy. You're a
blind as bats and yet you *think* you see. You're more tightly
controlled and restricted than any other people on this planet,
and the people who control you have you liking it, so much so
that you *think* it's real.


My proof is that you've just read this, and you think that
I'm quite mad!


See, I told you that you wouldn't understand.

GB
--
"Men will never be free until the last king is strangled with the
entrails of the last priest." (Diderot, paraphrasing Meslier)

 

[Michael A. Terrell]

GB wrote:

"Michael A. Terrell" <mike.terrell@earthlink.net> wrote in
news:445127C3.4589331@earthlink.net:
GB wrote:
Ahhh, I get it. You're *American*. That explains pretty much
everything.
Really? In what way?\

You're American, you wouldn't understand. I'm not going to
waste my breath trying to understand. The bits where you *think*
you have 'freedom' (a term bandied about in America so much
that it has lost its meaning), you *think* you're a christian,
and you *think* that "serving your country" (ie: tromping around
the planet fucking up other people's countries) somehow makes
you a better person.

My God, you are as blind as Skippy. A lot of the US military never
leave US soil while serving their country

to
prevent people, to whatever degree, from having grievances
by shaping their perceptions, cognitions and preferences in
such a way that they accept their role in the existing order
of things, either because they see or imagine no alternative
to it, or because they see it as natural and unchangeable,
or because they value it because it is divinely ordained
and beneficial." (Lukes 1974)

You and your countrymen have been hoodwinked boy. You're a
blind as bats and yet you *think* you see. You're more tightly
controlled and restricted than any other people on this planet,
and the people who control you have you liking it, so much so
that you *think* it's real.

Sure, your government kills people for owning guns, but mine doesn't
care. Right. Are you related to Phil and the frog? Maybe their
illegitement spawn?

My proof is that you've just read this, and you think that
I'm quite mad!

See, I told you that you wouldn't understand.

GB
--
"Men will never be free until the last king is strangled with the
entrails of the last priest." (Diderot, paraphrasing Meslier)

What a truly sad and pathetic rant. I pity your good countrymen that
you are so full of hate and ignorance. There is no hope for you, so its
plonk you go. You are now "free" to swim in my bit bucket forever. ;-)


--
Subject: Re: Try ``this``
Date: Tue, 05 Jul 2005 14:04:00 GMT
From: "Steven Dinius" <sameas@always.com.invalid>
Organization: Ispeed Wireless Inc. (srvinet.com)
Newsgroups: rec.antiques.radio+phono
References: 1 , 2 , 3 , 4 , 5 , 6

I complained to this church of yours that you haven't been very
"Christian"
in response to a genuine want to help your case. You should feel
ashamed. I
feel disgusted.

Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida

 

[G.B.]

"Michael A. Terrell" <mike.terrell@earthlink.net> wrote in
news:44516918.82D90FE0@earthlink.net:

My God, you are as blind as Skippy. A lot of the US military never
leave US soil while serving their country

I was right. You're American, and you didn't understand. Enjoy
your 'freedom', moron.

GB
--
"Men will never be free until the last king is strangled with the
entrails of the last priest." (Diderot, paraphrasing Meslier)

 

[Gryph]

That's a self fulfilling prophecy right there. Whilst twits
like you respond to the guy and give him encouragement by
acknowledging his presence, he keeps responding. You have
only yourself to blame.

Seriously, he's been posting to newsgroups since time immemorial and he'll
keep posting whether he gets a response or not.

 

[Michael A. Terrell]

"G.B." wrote:

"Michael A. Terrell" <mike.terrell@earthlink.net> wrote in
news:44516918.82D90FE0@earthlink.net:
My God, you are as blind as Skippy. A lot of the US military never
leave US soil while serving their country

I was right. You're American, and you didn't understand. Enjoy
your 'freedom', moron.

GB
--
"Men will never be free until the last king is strangled with the
entrails of the last priest." (Diderot, paraphrasing Meslier)

Moron? At least I'm smarter than you. Otherwise I would live near
enough to you for your drivvel to mean something. Whine, Whine, Whine.
What does the G B dstand for? Gross Bastard?


--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida

 

[Andrew McMeikan]

The Real Andy wrote:

What about an lm2576 with a pass transistor for extra amps?


Hot and inefficent. If you cant do it with the reg alone these days
then you should be instantly thinking smps.

13.5 - 15.0 is a fairly broad spec. Do you meant you want 14.25
+/-0.75? or do you want the o/p adjustable between 13.5 and 15.0?

lm2576 is a switcher, using a pass alows higher switching I have
achieved 80% conversion, and easy to adjust.

cya, Andrew...

 

[Andrew M]

How many do you need, per batch and per year?

This will affect the packaging, type and surrounding parts, and also
the design economics.

BTW, 'cost' is important for everyone, but if you only need 1kpcs,
'cost' is a complex thing. Do you value your time?

-Andrew M



On 24 Feb 2006 23:25:07 -0800, "Andy" <agw@woodtech.net.au> wrote:

Hello,

I am trying to track down some DC to DC converters with the following
specs:
Input: 10-30V
Output: 13.5 - 15.0V @ 3-4A

No need for a complete packaged item as it will be part of a larger
project. I have had a bit of a snoop around however I haven't found
anything suitable so far. Cost is a major factor with this one.

Thanks in advance for any info.

Regards,

Andy (Change "agw" to "andy" to reply by email)

 

[Terry Given]

Mr.T wrote:

"Trevor Wilson" <trevor@SPAMBLOCKrageaudio.com.au> wrote in message
news:443a33a1$0$87574$c30e37c6@ken-reader.news.telstra.net...

Just how much signal loss do you usually measure at 20kHz due to skin
effect Trevor?

**That would depend on the constrution of the wire and the impedance of

the

load.


Why not give us some typical examples then! Not hand selected exceptions.
Or in your case, NOTHING at all.


That, again, is not what you stated. You stated:

"True, but pretty hard to measure at audio frequencies though!"

I suggest you study up on electrical theory.


I suggest you pull your head in or give us some REAL figures to prove what a
pedantic prick you are being.


Sadly, the equations surrounding skin effect are not trivial ones.

Measuring skin effect,

however, is pretty straightforward.

yes they are pretty trivial.

delta = 1/sqrt(pi*f*mu*sigma)

mu = permeability of material = 4*pi*10^-7 * mu_r,

mu_r = relative permeability of material = 1 for copper

sigma = conductivity of Copper


bung in the numbers, and for copper at room temp you get:

delta = 66mm/sqrt(f) where f is in Hz. which aint that hard. at 100C it
changes to 75mm/sqrt(f).

at 20kHz, delta = 0.467mm in Cu at 20C, and 0.53mm at 100C.

Yep, sure is if you have the right equipment, and the results at 20kHz are
pretty trivial.

easy. a signal generator and an audio amplifier, along with a length of
non-inductively wound cable (eg a single tightly twisted loop), say
4mm^2. Use a CT (or a small resistor) to measure the current, and slowly
wind up the frequency. watch the current drop, proportional to 1/sqrt(f).

4mm^2 = 5mm OD. At 20kHz, it looks like a 5mm OD hollow pipe 0.5mm
thick. the AC/DC resistance ratio at 20kHz will be about

Fr = R20kHz/Rdc = 5mm^2/(5mm^2 - 4mm^2) = 2.8x

At 100kHz, it will be 6.5x the DC value


in a choke, 4 layers (one atop the other) of 4mm^2 Cu winding will have
Fr = 90 at 20kHz. proximity effect makes things get a lot worse, a lot
faster

Trivial would apply there as well!

**Not necessarily. Unless you know all the factors, you can't say.


We do know typical figures for Hi-Fi equipment. Obviously you want to prove
you are right by using outrageous examples.

If you were making, say, a 2kW tweeter, you had BETTER pay attention to
skin and proximity effect. normally there aint that much energy at the
higher frequencies....


I'd expect to see proximity effect in mid-range and tweeter crossovers.
Again, the severity is reduced by the lower power levels at higher
frequencies.

True, and I admitted that, but if you weren't being simply pedantic, you
would have clarified what you actually meant for the benefit of others.

**I don't need. I am merely stating fact.


And adding NOTHING usefull at all, simply grandstanding it would seem.
I hope you are feeling suitably smug.

MrT.

HTH

Cheers
Terry

 

[Terry Given]

Phil Allison wrote:

"Andrew M

If the calculations on this website can be trusted, the effective skin
depth in copper at 20kHz is 0.5mm. So with very large diameter cables
(high powered systems) this could easily influence HF response with low
impedance loads.

http://www.microwaves101.com/encyclopedia/calsdepth.cfm



** Nope.

Simple, linear inductance has a *much* greater effect on cable impedance
than copper resistance at high audio frequencies.

that I'd believe.

I did a pair of 15m cable runs in the loung of my last hous (it was a
BIG lounge), 4mm^2 twin cable. I worked out the inductance (I forget the
cable dimensions), and at 10kHz it was a sizeable chunk of my 4Ohm
speaker impedance - about 10% IIRC, so perhaps 6uH. compare that with
the 0.165Ohm DC resistance....

So I ignored it, and was still happy. I could have twisted the speaker
cables, but that required effort, and climbing up a scaffold.

A 1 inch long copper wire of 1 sq mm cross section has as much inductive
reactance as resistance at 3kHz.


....... Phil

OK, assume resistivity of copper = 22nano-Ohm-meters (pure Cu is 18nOm).

R = rho*l/a = 22e-9 * 25.4e-3/1e-6 = 0.558 mOhms

0.558mOhms/(2*pi*3e3Hz) = 29nH

yep, thats about right, 1nH/mm


1mm^2 = 1.13mm diameter.

skin depth at 3kHz = 1.2mm, so the effect is negligible. bit of a straw
man, really.


but if you were trying to build a 29nH inductor, it would be very lossy
at 3kHz.

and if you were trying to build an 0.558mOhm resistor, it would be
horribly inductive - the magnitude of its impedance is 41% higher than
expected, and its step response would be evil


lets make it a real test, at 20kHz. skin depth = 0.47mm, so Fr = 2.5 and
Rac = 1.35mOhms

Xl = 3.6mOhms

now that is a seriously piss-poor 0.558mOhm resistor, but only a
moderately shitty 29nH inductor.

Xl starts to overcome Rac, because it increases linearly with f, whereas
Rac increases as sqrt(f), so a lot slower.

Cheers
Terry

 

[Terry Given]

Phil Allison wrote:

"Jasen Betts"
Phil Allison

"Andrew M

If the calculations on this website can be trusted, the effective skin
depth in copper at 20kHz is 0.5mm. So with very large diameter cables
(high powered systems) this could easily influence HF response with low
impedance loads.

http://www.microwaves101.com/encyclopedia/calsdepth.cfm


** Nope.

Simple, linear inductance has a *much* greater effect on cable impedance
than copper resistance at high audio frequencies.

A 1 inch long copper wire of 1 sq mm cross section has as much inductive
reactance as resistance at 3kHz.

I guess that's why they use paired conductors...

more likely because 2 wires is a pain....

** Only works when constructed as a transmission line and terminated with
the load equal to the characteristic impedance.

rubbish. That wont help reduce the inductance or skin effect at all!

What it will do is prevent ringing due to reflections (electrically
"long" cable runs = distributed circuits) or L-C resonance (electrically
"short" cable runs = lumped circuits). and a simple RC damper would do that.

twisting the wires will reduce the inductance, it should be easy to get
a tenfold reduction in inductance. It will increase the DC resistance
(more cable), but make *NO* difference whatsoever to the skin effect.

no reason why you cant RC terminate a long speaker cable. not that you'd
ever hear cable resonance....for my long cables, C = 2nF or so, and L =
6uH, so Fo ~ 2MHz.

A twin or twisted pair cable does not match a 4 or 8 ohm speaker load not is
a speaker a defined impedance.

conjugate matching is a bad idea for power delivery, as the source
dissipates as much energy as the load gets. RF power amps dont do it,
why would audio?


I presume you meant "NOR is a speaker a defined impedance"

thats an understatement.

........ Phil

do you have a schematic of a really, really good crossover? AIUI its
quite tricky designing a good crossover, theres all the pseaker
resonances, as well as those of the crossover itself.

Cheers
Terry

 

[Phil Allison]

"Terry Given"

** A 1 inch long copper wire of 1 sq mm cross section has as much
inductive
reactance as resistance at 3kHz.

I guess that's why they use paired conductors...


** Only works when constructed as a transmission line and terminated
with the load equal to the characteristic impedance.

rubbish.

** Piss off, Terry - you have no idea what I even said.

That wont help reduce the inductance or skin effect at all!

** Of course a matched transmission line eliminates the effect of linear
inductance.

What second rate NZ anti-ADHD drugs are you on now ?

A twin or twisted pair cable does not match a 4 or 8 ohm speaker load not
is a speaker a defined impedance.


conjugate matching is a bad idea for power delivery, as the source
dissipates as much energy as the load gets.

** Not even faintly related to my remark.

Given is an extreme ADHD victim.




.......... Phil

 

[Terry Given]

Phil Allison wrote:

"Terry Given"


** A 1 inch long copper wire of 1 sq mm cross section has as much
inductive
reactance as resistance at 3kHz.

I guess that's why they use paired conductors...


** Only works when constructed as a transmission line and terminated
with the load equal to the characteristic impedance.

rubbish.



** Piss off, Terry - you have no idea what I even said.




That wont help reduce the inductance or skin effect at all!



** Of course a matched transmission line eliminates the effect of linear
inductance.

but it wont reduce the inductance. and the inductance governs the
overall velocity of the cable.

the context was the reduction of inductance.

What second rate NZ anti-ADHD drugs are you on now ?




A twin or twisted pair cable does not match a 4 or 8 ohm speaker load not
is a speaker a defined impedance.


conjugate matching is a bad idea for power delivery, as the source
dissipates as much energy as the load gets.



** Not even faintly related to my remark.

Given is an extreme ADHD victim.




......... Phil

 

[Phil Allison]

"Terry Given"

( snip asinine tripe)


** Go away - you insane, Kiwi, ASD fucked freak.






......... Phil

 

Hi,
Not sure if it is ok to post here or not,

www.australianhotspots.com.au and www.wifisearch.com.au is an on-line
list of wifi hot spot locations.


At this point in time there are over 2000 locations listed, some are
free access and some are paid access hot spots.


There is also a forum to discuss wi-fi related topics. It would be
great if we could get a few people to sign up here and start chating.
As this site is completely free we rely on people joining and hopefully

clicking on advertising links.


If your any good at writing you can get paid $15 for submitting
original wi-fi related articles.


Thanks

 

[Pete]

info@australianhotspots.com.au wrote:

If your any good at writing you can get paid $15 for submitting
original wi-fi related articles.

It's "you're" as in "you are", not "your" as in "belonging to you".

I normally just sigh and shake my head over things like this, but when
you're talking about running a publishing venture, you really need to
try harder to get the language right.

Peter

 

[Terry Collins]

info@australianhotspots.com.au wrote:

Hi,
Not sure if it is ok to post here or not,

www.australianhotspots.com.au and www.wifisearch.com.au is an on-line
list of wifi hot spot locations.


At this point in time there are over 2000 locations listed, some are
free access and some are paid access hot spots.

you might find more if you cruise www.whereis.com.au as they have a
hotspots tag.

Also, maybe Bigpond will give you a free list of all their paid access
points.

 

Sorry,
That was a simple typing mistake.
Often I find mistakes in top 20 publications, Hence a minor "typo" in
an informal posting on a news group can be excused.

Thanks for your concern,

 

[two bob]

Sorry,
That was a simple typing mistake.
Often I find mistakes in top 20 publications, Hence a minor "typo" in
an informal posting on a news group can be excused.

No it can't! In the context of you trying to encourage writers, you need to
show you are after a response from literate people.

 

[T.T.]

"two bob" <tb@department9.com.au> wrote in message
news:4462d4bb_1@news.iprimus.com.au...

Sorry,
That was a simple typing mistake.
Often I find mistakes in top 20 publications, Hence a minor "typo" in
an informal posting on a news group can be excused.

No it can't! In the context of you trying to encourage writers, you need
to show you are after a response from literate people.
In the context of your trying..........