Driver to drive?

[Martin Riddle]

On Thu, 1 Mar 2018 16:04:00 -0500, Phil Hobbs
<pcdhSpamMeSenseless@electrooptical.net> wrote:

On 08/09/2017 04:24 PM, Joerg wrote:
While I know that our US phone system is beginning to unravel this is
new: A fuel supplier (Suburban Propane) sent me two emails to accounts
at two different providers. No bounce message on their side, nothing has
arrived, nothing in the spam folder either. So I called and sent one to
them. No bounce message back to me yet it did not arrive either. All
those emails quietly went phut.

Does anyone know what could cause that?


Lots of outfits don't send bounce messages.

Cheers

Phil Hobbs

Sometimes I see a 'Cannot find recipient' bounce message 72 hours
after sending an email.
But I never experience a black hole like that.

Cheers

 

[Robert Baer]

boB wrote:

On Thu, 22 Feb 2018 13:44:54 -0800, Robert Baer
robertbaer@localnet.com> wrote:

..since at least Eagle ver 5 if not earlier.
Did you know that the produced Gerbers in cases DO NOT reflect what
you see on the screen?

Now, someone pointed out that Gerbers are vector.
True,but that has noting to do with fonts or anything else except the
Gerber strokes as a collection, are supposed to represent the original:
a PCB pad, a logo scribble, Cyrilic font, Arabic font, or any other font
AS CREATED AND SEEN ON THE SCREEN.

MOST irritating is that any text in proportional font on the screen
is rendered as their vector font.



All of the Gerbers I have created from Eagle (or Pads) appear to be
changed to sweeps/swipes of the gerber aperature. I started at Eagle
4 and went up only to eagle 4.5.

* If i understand you correctly, that is exactly like "pen up" and "pen
down" movements.
Still the same in version 7.

Next, that the (vector font) characters look stunted; most especially
the "R" looks as if its legs were sawed off.
The screen version is elegant; you will NOT get what you see.

Also, some of the vector font symbols are totally trashed, for
example the Registered Trademark symbol Ž looks like a rotated "L" and
there is no replacement unless one wishes to construct one using a
circle and (at least on the screen) a "R"; result has the inelegant and
trashy looking vector font "R".

Such junk is not seen unless one uses an independent Gerber viewer.
**

Now, on occasion, a layer may "inherit" AND/OR "ghost" something from
another layer, and move the position as well.
In one particular case, (so to speak) without asking, a text got
solder-masked (the "ghost" because i never saw it since i do not bother
turning that layer on). And that solder mask was (o be polite)
mis-positioned.
At the same time, a placed circle (layer 1 Top, made for no hole in
center) got duplicated in layer 30 Bstop and position was changed (here
is the "ghosting").
Furthermore, that layer 1 circle got duplicated in layer 290 Tstop
and the position was ALSO changed.
The result was a total mess
**
SO, VERY carefully review ALL layers on the screen at minimum and fix
as needed.
Use a Gerber viewer to double-check the results, especially fonts.

Naturally, because a rich owner of Eagle has decided to also be
greedy, expect these problems WILL NEVER be fixed.

 

[Robert Baer]

Steve Wilson wrote:

John Larkin <jjlarkin@highland_snip_technology.com> wrote:

On Thu, 22 Feb 2018 13:44:54 -0800, Robert Baer
robertbaer@localnet.com> wrote:

..since at least Eagle ver 5 if not earlier.
Did you know that the produced Gerbers in cases DO NOT reflect what
you see on the screen?

Now, someone pointed out that Gerbers are vector.
True,but that has noting to do with fonts or anything else except the
Gerber strokes as a collection, are supposed to represent the original:
a PCB pad, a logo scribble, Cyrilic font, Arabic font, or any other font
AS CREATED AND SEEN ON THE SCREEN.

MOST irritating is that any text in proportional font on the screen
is rendered as their vector font.

Gerbers ARE vectors. Maybe the aperature list could be tweaked to
improve character resolution.

There is an option in Cadsoft V7.7.0 that might help:

Options->User Interface->Misc->Always Vector Font

* Interesting. Checked that out and found the "Always Vector Font" box
was UNCHECKED, so maybe they got that F*ked up and ignore the implied
NOT "always".

The help file states:

always displays texts in drawings with the builtin vector font, regardless
of which font is actually set for a particular text
* They might as well as HAVE NO FONT OPTIONS rather than, in effect, LIE.

I don't know if this option exists in the Autocad version.

 

[Robert Baer]

Johann Klammer wrote:

On 02/28/2018 03:15 AM, Robert Baer wrote:
So you were able to find undocumented fonts (line type 22?) that one cannot use?
What i complained about is seen by various Gerber viewers and thus from Eagle.
Hell, there is inconsistency *IN* Eagle, most especially with characters/symbols/glyphs in Eagle fonts.
Try the registered trademark symbol as i previously noted.
Even the "work-around" using a circle and an "R" gets munged because their "proportional font" gets transformed to their "vector font" which gets transformed from "see" mode to Gerber mode; ALSO different that using their print option to a PDF printer.

No that was just one way to draw a line (macro primitive) that isn't in the Specification.
https://www.ucamco.com/en/file-formats/gerber/downloads
(the first entry)
Sec 4.5.4.1

Gerber does not know any fonts at all.
Everything is composed of circular arcs and lines. (contours and strokes)
You should always be using the stroked font. It's likely internal to eagle anyway.
Also not surprising they don't have your TM. probably no linear b glyps either.

Yes, yes, yes.
What does that have to do with the price of rice in China?

If one gives the CORRECT set of instructions, one can render any
shape,squiggle, etc.

My complaint is that Eagle DOES NOT do that; the result is NOT WHAT
ONE SEES in Eagles screen.

 

[Martin Brown]

On 02/03/2018 00:04, Martin Riddle wrote:

On Thu, 1 Mar 2018 16:04:00 -0500, Phil Hobbs
pcdhSpamMeSenseless@electrooptical.net> wrote:

On 08/09/2017 04:24 PM, Joerg wrote:
While I know that our US phone system is beginning to unravel this is
new: A fuel supplier (Suburban Propane) sent me two emails to accounts
at two different providers. No bounce message on their side, nothing has
arrived, nothing in the spam folder either. So I called and sent one to
them. No bounce message back to me yet it did not arrive either. All
those emails quietly went phut.

Does anyone know what could cause that?

Lots of outfits don't send bounce messages.

Rather their mailservers do this now by default.
I doubt if most of them even know how to alter the settings

Sometimes I see a 'Cannot find recipient' bounce message 72 hours
after sending an email.
But I never experience a black hole like that.

Badly set up SPF records at either end are capable of doing this.

Several of my corporate contacts are behind firewalls that interpret
certain ISPs email systems as sending forged emails because parts of the
SPF give a soft fail mismatch and bin them with no bounce.

They do this to avoid backscatter of spam bounce messages onto innocent
forged email addresses. The bulk of what gets bounced is spam. In the
bad old days you would sometimes find your email used this way and get
half a million bounce messages in the inbox spread over a couple of
days. Now they don't bounce to envelope sender if they think its spam.

It is a real problem because plenty of ISPs and email providers have not
set their systems up right so SPF is now worse than useless. It causes
too much collateral damage of lost emails for the benefits it provides.

--
Regards,
Martin Brown

 

[Jeff Layman]

On 01/03/18 21:04, Phil Hobbs wrote:

On 08/09/2017 04:24 PM, Joerg wrote:
While I know that our US phone system is beginning to unravel this is
new: A fuel supplier (Suburban Propane) sent me two emails to accounts
at two different providers. No bounce message on their side, nothing has
arrived, nothing in the spam folder either. So I called and sent one to
them. No bounce message back to me yet it did not arrive either. All
those emails quietly went phut.

Does anyone know what could cause that?


Lots of outfits don't send bounce messages.

Cheers

Phil Hobbs

I wonder if it has appeared in the intervening 6 months? ;-)

In cases such as these where an email client is being used, it is useful
to see if you can check the inbox via webmail if that is possible. I
recently had problems with my ISP-provided mail account (which I use
rarely as a secondary account). Nothing appeared in Thunderbird's inbox
for the mail account, but all the messages were in that inbox when
viewed by webmail.

Changing the IMAP mailserver name and port number in TB solved the problem.

--

Jeff

 

[rangerssuck]

On Tuesday, February 20, 2018 at 9:28:13 AM UTC-5, olds...@tubes.com wrote:

On Tue, 20 Feb 2018 08:57:14 -0500, bitrex
bitrex@de.lete.earthlink.net> wrote:

On 02/20/2018 05:05 AM, oldschool@tubes.com wrote:
On Mon, 19 Feb 2018 22:37:04 -0800, Robert Baer
robertbaer@localnet.com> wrote:

oldschool@tubes.com wrote:
Kind of off topic, but I have a prepaid flipphone cell phone. Almost
every day I get messages showing a text message that is listed as n/a on
my screen. None of them are valid phone numbers. Most are 5 digits. What
the heck are these? I assume it's some sort of advertising (spam), but
they are always blank, so whats the point?

I can be on a call, or preparing a text message and I hear a beep. Then
it shows those n/a things.....

Quite annoying!

Also annoying are calls that either have no phone number, a
non-existent number, or unlisted number.
First two types are most common.

Well, these calls have no real number. I tried to call one just to see
what would happen. A cellphone needs the area code, (even for local
calls) so that means all calls are 10 digits. These 5 digit numbers dont
work.

I looked at my missed calls or I guess it's missed texts, but no number
is the same. I did not have this on my older phone. Same provider, just
an older phone, which quit working properly. I told this to a friend and
he said he never gets them, but he has a different company. He laughed
and said God is calling me. I said that at my old age, that might be
true.



It's "short code" "sonar spam"; the spammers don't know which cell phone
carriers number are in active service so they buy say 100,000 text
messages from a "shared short code provider" and blast out a bunch of
empty texts to a large block of numbers looking for responses e.g.
someone who has their phone set up to auto-reply with an away message to
all SMS messages.

If a reply comes back the cell number it came from gets added to a "live
one" list which once you accumulate say 10k "live ones" you sell that
list on the internet black market for a tidy sum

What a bunch of crap!!! I thought having a prepaid phone meant it was
pretty private. I guess not!!!

Isn't there a DNC (Do not call) list for cellphones, or is that only for
landlines?

The Do Not Call list doesn't apply to cell phones because it is already illegal to spam a cell phone. These days with the total deregulation of the phone system, it's virtually a given that the spammers will spoof their caller ID, and you haven't got a hope of stopping them. It truly sucks.

I use nomorobo (google it) on all my numbers and it does a pretty good job of intercepting spam calls. There still are many, though, that make it through with fake caller ID. The bad guys have fucked the world up for the rest of us.

 

[Albert van der Horst]

In article <VCLBB.121804$WI2.89201@fx38.iad>,
bitrex <bitrex@de.lete.earthlink.net> wrote:

On 10/05/2017 10:02 PM, Bill Bowden wrote:
I suppose it has something to do with basic units of mass, length and time
The coulomb would be a more standard unit of charge if it was say 10 times
10 to the 18th instead if some weird number of 6.25 times 10 to the 18th..
One volt is defined as one joule of work per coulomb of charge. So, what is
the charge of one electron and how do we measure that? Why are the numbers
so screwed up?

The actual values are completely arbitrary and historical, the only
thing that matters is the relationships between the fundamental constants.

No they are not. The actual definitions are updated to reflect the
most accurate method to measure the physicial entity.
E.g. now that we can count individual atoms Avogrado's constant
is defined as a simple integer number.

Suppose the meter was still *defined* as one 1/10000 of the distance
between the equator and the northpole. How would you do accurate measurements
based on that?
The situation with the ever shrinking platinum standard meter in Paris
is not better, in principle.
>

<SNIP>

Groetjes Albert
--
Albert van der Horst, UTRECHT,THE NETHERLANDS
Economic growth -- being exponential -- ultimately falters.
albert@spe&ar&c.xs4all.nl &=n http://home.hccnet.nl/a.w.m.van.der.horst

 

[dcaster@krl.org]

On Saturday, February 24, 2018 at 2:48:56 PM UTC-5, George Herold wrote:

twisted up a harbor freight 'security' torx bit in
a relatively new product. I blamed it on the hole down
the center. I've got some old sears craftsman and vermont
american bits that are good. I don't know about newer ones.

George H.

I buy screw driver bits from AliExpress. They seem to be as good as the expensive ones. Must admit I do not care if they last forever. They are cheap enough to throw away bits that get worn out. The latest ones I ordered were a three lobed set needed to open an electric kettle. The cost was $2 for four bits each one a different size.

Dan

 

[Pomegranate Bastard]

On Mon, 19 Feb 2018 01:23:48 +0000 (UTC), Long Hair
<DecadentLinuxUserNumeroUno@decadentlinuxuser.org> wrote:

mpm wrote:

On Sunday, February 18, 2018 at 5:27:55 PM UTC-5, Long Hair wrote:

I think Walgreens is open late if you need to re-up your meds.

And then jackasses like you throughout history get all pissed when a
club ends up impacting the side of your face.
You are an imbecile.

---
This email has been checked for viruses by Avast antivirus software.
https://www.avast.com/antivirus

 

[pedro]

On Sat, 3 Feb 2018 15:27:59 -0800 (PST), bill.sloman@ieee.org wrote:

On Sunday, February 4, 2018 at 3:10:19 AM UTC+11, pedro wrote:
On Wed, 31 Jan 2018 18:27:53 -0800 (PST), Phil Allison
pallison49@gmail.com> wrote:

pedro wrote:

--------------


SA has loads of natural gas available ( split between electricity
generation and domestic use) but little coal


What a load of codswallop.

** Fraid it is absolute fact.


Leigh Creek had more than 30 years worth
when it was closed by a state govt decision that was all about vote
catching.

** https://en.wikipedia.org/wiki/Leigh_Creek

There was more to it.

There's nothing in that Wikipedia article that states, infers or
implies that there was any shortage of available coal there, but that
was the line the SA govco fed to the public. The reality of supply is
as I stated. You need to get out of your Sydney flat a bit more if
you want to find out what really happened.

Who cares how the government spun the decision.

Any thinking person.

>There's no point in keeping old coal-fired generators running, no matter how much sentimental right-wingers like the link to the past.

There was plenty of point when they lost the feeder and SA went black.
But left-wing-greenie-thinking struck. If you lot lived by the
philosophies you espouse, you'd be living in caves without fires.

 

[Pomegranate Bastard]

On Tue, 20 Feb 2018 15:58:41 -0500, krw@notreal.com wrote:

On Mon, 19 Feb 2018 15:03:58 +0000, Pomegranate Bastard
pommyB@dsl.pipex.com> wrote:

On Wed, 31 Jan 2018 22:47:03 -0500, krw@notreal.com wrote:

On Thu, 1 Feb 2018 02:36:10 +0000 (UTC), Long Hair
DecadentLinuxUserNumeroUno@decadentlinuxuser.org> wrote:

krw@notreal.com wrote:

On Tue, 30 Jan 2018 17:10:57 +0000, Pomegranate Bastard
pommyB@dsl.pipex.com> wrote:

On Sat, 27 Jan 2018 01:00:18 +0000 (UTC), Long Hair
DecadentLinuxUserNumeroUno@decadentlinuxuser.org> wrote:

Phil Allison wrote:


** Yet you come hear, posting like a egomaniac having a mental meltdown.


Show me where, and I will show you someone else doing it first and
insulting me. They get it right back in their face.

"Egomaniac"? Yeah, right.... sure bub.

You are an imbecile.

You know better. The term for AlwaysWrong is "Nymbecile".

You two should go diddle each other clits somewhere else.

It's surprising that you would even know what one is, AlwaysWrong.

She owns one.

FGM, undoubtedly.

FGM? Would that stand for Foul-mouthed Gruesome Minger?

---
This email has been checked for viruses by Avast antivirus software.
https://www.avast.com/antivirus

 

On Sunday, March 11, 2018 at 8:13:06 PM UTC+11, pedro wrote:

On Sat, 3 Feb 2018 15:27:59 -0800 (PST), bill.sloman@ieee.org wrote:

On Sunday, February 4, 2018 at 3:10:19 AM UTC+11, pedro wrote:
On Wed, 31 Jan 2018 18:27:53 -0800 (PST), Phil Allison
pallison49@gmail.com> wrote:

pedro wrote:

--------------


SA has loads of natural gas available ( split between electricity
generation and domestic use) but little coal


What a load of codswallop.

** Fraid it is absolute fact.


Leigh Creek had more than 30 years worth
when it was closed by a state govt decision that was all about vote
catching.

** https://en.wikipedia.org/wiki/Leigh_Creek

There was more to it.

There's nothing in that Wikipedia article that states, infers or
implies that there was any shortage of available coal there, but that
was the line the SA govco fed to the public. The reality of supply is
as I stated. You need to get out of your Sydney flat a bit more if
you want to find out what really happened.

Who cares how the government spun the decision.

Any thinking person.

There's no point in keeping old coal-fired generators running, no matter how much sentimental right-wingers like the link to the past.

There was plenty of point when they lost the feeder and SA went black.

https://en.wikipedia.org/wiki/2016_South_Australian_blackout

What blacked out South Australian was "storm damage to electricity transmission infrastructure on 28 September 2016". There has been a suggestion that was gas-fired generator that should have been brought on line, but wasn't.

But left-wing-greenie-thinking struck. If you lot lived by the
philosophies you espouse, you'd be living in caves without fires.

Somehow I doubt that left-wing-greenie-thinking had much to do with the storm damage that took down the electricity generation network, nor with the absence of generators that might have used the working bits of the transmission network to keep more of the state on-line.

The Liberal Party did spin the events as excuse to be rude about the relatively high renewable component in the South Australian generator mix, but storm damage has a way of confounding carefully laid plans. There was a big gas-fired generator that should have been able to kick in rapidly, and didn't, and nobody has explained why.

Since then, the Federal Government has made a fuss about planning to spend a lot of money on the Snowy Mountains hydroelectric scheme to modify it to offer a lot of pumped storage. It seems they could get as much pumped storage at about half-the price per stored kilowatt hour in Tasmania, but it would be in lots of smaller chunks, so doesn't make the same dramatic impact or link to the iconic Snowy Mountains scheme.

Nothing in the story suggests that investing in lots of new coal-fired base-load generators would be a good idea. Fast-starting gas-fired stations do make more sense, but they'd spend most of their time doing nothing - wind and photovoltaic power is now cheaper, and it's probably still cheaper after you've stored it in some kind of pumped storage scheme, which is presumably why the government is going the Snowy scheme upgrade.

--
Bill Sloman, Sydney

 

[Pomegranate Bastard]

On Sat, 17 Feb 2018 15:43:17 -0000 (UTC), Cursitor Doom
<curd@notformail.com> wrote:

On Fri, 16 Feb 2018 17:28:59 -0800, robertjong wrote:

You're one of those that rails against the "liberal media" because
according to people like you they publish nothing but lies.

Well I'm sorry, but that's precisely what they do. For example, within
hours of the Florida school shooting, the Liberal media were claiming
that the shooter was a white nationalist - despite none of the victims
being black! Only later do we find out the truth - that he was not
aligned with *any* right wing movement: https://tinyurl.com/yaqwyv9a

Yet, here you are, again, posting purely opinion trash. The excerpt you
posted appears to have little or no objectivity. What a hypocrite you
are.

Well I for one at least find Jim's postings both informing and
entertaining and if you don't like what he has to say I suggest you
simply don't read his posts. Don't deprive the rest of us of valuable
insight in your all-consuming quest to crush any dissenting opinion.


So I suppose this is what happens when a person primarily reads extreme
right or left wing opinion pieces.

Nonsense.

Dear Mr Doom
Thank you for your application to become a member of Britain First.
Following Donald J Chump's ringing endorsement of our organisation you
will appreciate our need to maintain the high standard of our
applicants. May I refer to Rule 94 of our constitution. "Members must
at all times propagate the far-right views of Britiain First."
Your posts on USENET display both mental deficiency and a staggering
level of ignorance. This, along with your stated admiration of Mr
Thompson, a reknowned far-right lunatic, makes you an ideal candidate
for membership. Welcome aboard and Heil Mosley!

---
This email has been checked for viruses by Avast antivirus software.
https://www.avast.com/antivirus

 

On Sun, 11 Mar 2018 10:02:41 +0000, Pomegranate Bastard
<PommyB@aol.com> wrote:

On Tue, 20 Feb 2018 15:58:41 -0500, krw@notreal.com wrote:

On Mon, 19 Feb 2018 15:03:58 +0000, Pomegranate Bastard
pommyB@dsl.pipex.com> wrote:

On Wed, 31 Jan 2018 22:47:03 -0500, krw@notreal.com wrote:

On Thu, 1 Feb 2018 02:36:10 +0000 (UTC), Long Hair
DecadentLinuxUserNumeroUno@decadentlinuxuser.org> wrote:

krw@notreal.com wrote:

On Tue, 30 Jan 2018 17:10:57 +0000, Pomegranate Bastard
pommyB@dsl.pipex.com> wrote:

On Sat, 27 Jan 2018 01:00:18 +0000 (UTC), Long Hair
DecadentLinuxUserNumeroUno@decadentlinuxuser.org> wrote:

Phil Allison wrote:


** Yet you come hear, posting like a egomaniac having a mental meltdown.


Show me where, and I will show you someone else doing it first and
insulting me. They get it right back in their face.

"Egomaniac"? Yeah, right.... sure bub.

You are an imbecile.

You know better. The term for AlwaysWrong is "Nymbecile".

You two should go diddle each other clits somewhere else.

It's surprising that you would even know what one is, AlwaysWrong.

She owns one.

FGM, undoubtedly.

FGM? Would that stand for Foul-mouthed Gruesome Minger?

Et Tu?

<https://en.wikipedia.org/wiki/Female_genital_mutilation>

 

[JM]

On 24/02/2018 23:32, Phil Hobbs wrote:

On 02/24/2018 06:29 PM, Phil Hobbs wrote:
On 02/24/2018 06:23 PM, JM wrote:
On 23/02/2018 17:11, Phil Hobbs wrote:
On 02/23/2018 11:15 AM, JM wrote:
On 21/02/2018 01:29, pcdhobbs@gmail.com wrote:
I have written a program that controls that thing over the network
and measures spectra from 0.1 Hz to 1MHz, one FFT per decade, reads
the results, combines them and plots them with gnuplot.

One needs a converter box from coax ethernet to contemporary
network,
then one just opens port 5000-something on 192.168.178.111 and
simply
reads and writes GPIB-strings. And the coax needs 2 terminations,
even
when the "cable" is only 5 inch long.

No need for GPIB cards and semi-supported drivers.

These measurements of voltage regulator noise have been done with
it:

https://www.flickr.com/photos/137684711@N07/24070698809/in/album-72157662535945536/





Just in case you win it and are interested.

Hi, Gerhard,

I did, and I am. I'll have to gin up a nice low-1/f-noise preamp for
it, but that'll be fun.

Thanks

Phil Hobbs


Note that the software options can easily be unlocked on these
(although
they would be of little use for your intended application).

The cell-phone stuff won't help much, but I'm hoping that I can turn on
the AYB (spectrogram and waterfall) option without scrooching it.

You'll be able to do that.

(Option AY8, the internal source, would be useful too, but it's
probably
a HW option.)


Oh, you got an 89431A as well as a 89410A? You'll soon be welding a
couple of 42H racks on top of each other to save on floor space.

The software one should be no big issue as long as the floppy drive
works reliably.

Cheers

Phil Hobbs


I got the complete 89441A 2.65 GHz gizmo. I'll move my spare
Tek11801C out of the rack to make space.

You can fit a lot in a 7-foot EIA rack.


Speaking of which, I could use a shorter four-post instrument rack with
adjustable rails, but they never seem to come up on eBay--just the
flimsy audio and gigundo server racks.

Any sourcing suggestions? I bought my present HP one from long-lost SED
regular ecnerwal in about 2009.

Cheers

Phil Hobbs

I like the Zpas SRX open racks, but they not be available in the US.
Having said that, I also thought it would be nice to have a couple of
smaller (24U) racks, but in practice I thought they were just too bulky.
I ended up replacing them with a couple of carts, which seem to be
happy enough with upto three boat anchors, two on the table and one on
the bottom shelf.

https://imgur.com/D6hhXi9.jpg
https://imgur.com/s78dEM8.jpg

 

[JM]

On 25/02/2018 16:14, Winfield Hill wrote:

JM wrote...

On 23/02/2018 20:17, Gerhard Hoffmann wrote:
Am 21.02.2018 um 02:29 schrieb pcdhobbs@gmail.com:


I did, and I am. I'll have to gin up a nice low-1/f-noise preamp for
it, but that'll be fun.


I'm working on a chopper preamp that should be flat down to at least
100mHz, but it seems that I cannot verify that with the 89441A.

It works with parallel ADG819 analog switches, step up transformers,
more low noise gain with ADA4898s on 500 KHz, synchronous demodulator
back to baseband and some more gain.

A Xilinx Coolrunner II generates the timing from a 100 MHz osc.
It looks like I get 120 pV/rtHz.

I designed a CSEM receiver 20 or so years ago with sub 100pV noise
(0.01-15Hz BW and 120dB overall gain) with a similar architecture.
These worked with Ag-AgCl field sensors with a source resistance of
about 5 ohms.

Just as a reminder, Paul and I made a simple 65 pV/rt-Hz preamp,
all the how-to details reported in AoE III, pages 505 to 508.

I think Gerhard is interested in measurements in the 0.1Hz region and
below, where your preamp would be about 26dB noisier than the one he's
working on.

 

[Castorp]

I've used a number of 89410A devices, and they have exhibited some spread in the noise floor. Usually the flat part is around 8-9 nV/sqrtHz, and the 1/f corner could be in the kHz or tens of kHz. One device had popcorn-like noise in one channel.

With a preamp built of 4 paralleled ADA4522s and LT5400 resistor arrays, I managed to get noise floor of about 5 nV/sqrtHz flat down to a few mHz. If there's interest, I can dig up those measurements. I used it to measure excess 1/f noise in resistors hooked up in a biased Wheatstone bridge, like this:
https://dcc.ligo.org/public/0002/T0900200/001/current_noise.pdf

Another nice trick with the 2-channel FFT is cross-spectrum measurement. With two good preamps and some patience it buys you another 10-20 dB downwards:

https://www.researchgate.net/publication/3622215_Measurement_of_voltage_noise_in_chemical_batteries

Cheers,
Nikolai