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tech / sci.electronics.design / Re: Large scale RF shielding

SubjectAuthor
* Large scale RF shieldingDon Y
+- Re: Large scale RF shieldingPhil Allison
+* Re: Large scale RF shieldingJohn Larkin
|+- Re: Large scale RF shieldingDecadentLinuxUserNumeroUno
|+* Re: Large scale RF shieldingPhil Hobbs
||+- Re: Large scale RF shieldingClifford Heath
||+* Re: Large scale RF shieldingjlarkin
|||`* Re: Large scale RF shieldingJeroen Belleman
||| +- Re: Large scale RF shieldingjlarkin
||| +- Re: Large scale RF shieldingPhil Hobbs
||| `- Re: Large scale RF shieldingPhil Hobbs
||`- Re: Large scale RF shieldingLasse Langwadt Christensen
|`- Re: Large scale RF shieldingPhil Allison
+- Re: Large scale RF shieldingJan Panteltje
+* Re: Large scale RF shieldingJeff Layman
|`* Re: Large scale RF shieldingDon Y
| `* Re: Large scale RF shieldingke...@kjwdesigns.com
|  `- Re: Large scale RF shieldingDon Y
+* Re: Large scale RF shieldingMartin Brown
|+* Re: Large scale RF shieldingJoe Gwinn
||+- Re: Large scale RF shieldingDon Y
||`* Re: Large scale RF shieldingMartin Brown
|| `* Re: Large scale RF shieldingrbowman
||  `* Re: Large scale RF shieldingMartin Brown
||   +* Re: Large scale RF shieldingMike Monett
||   |`* Re: Large scale RF shieldingJeroen Belleman
||   | `- Re: Large scale RF shieldingrbowman
||   +* Re: Large scale RF shieldingjlarkin
||   |`- Re: Large scale RF shieldingrbowman
||   `* Re: Large scale RF shieldingrbowman
||    `* Re: Large scale RF shieldingjlarkin
||     `* Re: Large scale RF shieldingrbowman
||      `* Re: Large scale RF shieldingjlarkin
||       +* Re: Large scale RF shieldingPhil Hobbs
||       |`* Re: Large scale RF shieldingjlarkin
||       | `- Re: Large scale RF shieldingrbowman
||       `* Re: Large scale RF shieldingrbowman
||        `* Re: Large scale RF shieldingPhil Hobbs
||         `- Re: Large scale RF shieldingrbowman
|`- Re: Large scale RF shieldingDon Y
+* Re: Large scale RF shieldingRich S
|`* Re: Large scale RF shieldingPhil Hobbs
| +- Re: Large scale RF shieldingDon Y
| +- Re: Large scale RF shieldingLasse Langwadt Christensen
| `- Re: Large scale RF shieldingMartin Brown
`* Re: Large scale RF shieldingRich S
 `- Re: Large scale RF shieldingJohn Walliker

Pages:12
Re: Large scale RF shielding

<2dd69e06-e987-4cd9-9156-665a772554c5n@googlegroups.com>

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Subject: Re: Large scale RF shielding
From: langw...@fonz.dk (Lasse Langwadt Christensen)
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 by: Lasse Langwadt Chris - Fri, 6 May 2022 21:16 UTC

fredag den 6. maj 2022 kl. 22.40.45 UTC+2 skrev Phil Hobbs:
> Rich S wrote:
> > On Thursday, May 5, 2022 at 6:46:43 PM UTC, Don Y wrote:
> >> Homes, here, tend to be reasonably opaque to RF. OTA broadcasts
> >> can only be received with a rooftop antenna (despite the fact
> >> that it's only a few unobstructed miles to the transmitters).
> >> Indoor FM reception is "iffy". GPSs can't get a fix (I've tried
> >> 2 handheld units, 2 dash-mount plus the one built into the car).
> >> Even the two "atomic" clocks that I have spend all of their
> >> time "looking for signal" (or so they claim).
> >>
> >> And *everyone* steps outside to use their cell phones. (OK,
> >> maybe the neighborhood is a deadspot due to terrain -- despite
> >> antennas being reasonably close by -- though I've no way of
> >> knowing who is "operating" each of them)
> >>
> >> I.e., the "problem" isn't confined to our home.
> >>
> >> This begs two *different* questions:
> >> 1. How to punch holes in <whatever> is attenuating the signal
> >> 2. How to identify the cause of the problem to be able to
> >> (willingly) *reproduce* it in other places
> >>
> >> Most homes are masonry - 8-12" thick walls. Interior walls on
> >> the perimeter are firred out with drywall coated with aluminum
> >> foil (moisture barrier?). All internal wiring is overhead, plumbing
> >> in the slab. Different types of roofing so I'm unsure if there
> >> is a common thread, there.
> >>
> >> Ideally, there is a *cheap* way to get this sort of attenuation
> >> that can be retrofitted to existing homes of different construction.
> >
> > uh, these homes lack windows?
> > Last I heard, glass is transparent for RF
> >
>
> IIRC some have ITO or tin oxide coatings on the inner pane for lower IR
> emissivity. That can also be a reasonable RF shield.
> Cheers

afaiu some cars have the problem because the windows have a gold film between the layers for heating

Re: Large scale RF shielding

<3d3bb046-fbe2-429c-b6c6-90d66f010ea7n@googlegroups.com>

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Subject: Re: Large scale RF shielding
From: kei...@kjwdesigns.com (ke...@kjwdesigns.com)
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 by: ke...@kjwdesigns.com - Sat, 7 May 2022 00:00 UTC

On Friday, 6 May 2022 at 10:28:07 UTC-7, Don Y wrote:
....
> Dunno. As I said elsewhere, *I* don't use cellular comms. The *cordless*
> phones work everywhere in the house so we have no problem. But, friends
> and neighbors seem to resort to "stepping outside" when they have to make
> a call of any duration.
>
> I suspect they must keep their phones located "in a sweet spot" indoors
> lest they miss calls/texts (?). Or, resort to post-processing calls
> by checking their voicemail (apparently, calls are intercepted thusly
> in relatively short order... do they have to "run" to answer the phone
> sited in that "sweet spot"? -- we have "extensions" throughout the house)
....

Most phones and carriers these days support WiFi Calling where phone calls and SMS messages are routed over the internet as an alternate to wireless. The phone will (fairly) seamlessly switch between using WiFi and cellular radio as the relative signal strengths change or wifi service is available.

The carriers still charge for time, even if they are using your own wifi.

kw

Re: Large scale RF shielding

<t551kv$43j$1@dont-email.me>

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From: blockedo...@foo.invalid (Don Y)
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Subject: Re: Large scale RF shielding
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 by: Don Y - Sat, 7 May 2022 05:55 UTC

On 5/6/2022 5:00 PM, ke...@kjwdesigns.com wrote:
> On Friday, 6 May 2022 at 10:28:07 UTC-7, Don Y wrote: ...
>> Dunno. As I said elsewhere, *I* don't use cellular comms. The *cordless*
>> phones work everywhere in the house so we have no problem. But, friends
>> and neighbors seem to resort to "stepping outside" when they have to make
>> a call of any duration.
>>
>> I suspect they must keep their phones located "in a sweet spot" indoors
>> lest they miss calls/texts (?). Or, resort to post-processing calls by
>> checking their voicemail (apparently, calls are intercepted thusly in
>> relatively short order... do they have to "run" to answer the phone sited
>> in that "sweet spot"? -- we have "extensions" throughout the house)
> ...
>
> Most phones and carriers these days support WiFi Calling where phone calls
> and SMS messages are routed over the internet as an alternate to wireless.
> The phone will (fairly) seamlessly switch between using WiFi and cellular
> radio as the relative signal strengths change or wifi service is available.
>
> The carriers still charge for time, even if they are using your own wifi.
I have to assume that they either don't use this feature, don't know *how*
to use this feature *or* that it is unreliable, as well (?)

Speaking with a colleague two days ago and the call was dropped twice
over the course of 30 minutes. I'm talking on copper wire so I doubt
it's on my end!

It seems that people now EXPECT calls to be unreliable whereas that
was far from the case with older technology (batteries dying, dead spots,
etc.)

I'll be doing a VoIP port, soon, so I'll see what quirks *that* has.

Re: Large scale RF shielding

<t559lm$1bjn$1@gioia.aioe.org>

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From: '''newsp...@nonad.co.uk (Martin Brown)
Newsgroups: sci.electronics.design
Subject: Re: Large scale RF shielding
Date: Sat, 7 May 2022 09:12:37 +0100
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 by: Martin Brown - Sat, 7 May 2022 08:12 UTC

On 06/05/2022 17:31, Joe Gwinn wrote:
> On Fri, 6 May 2022 10:46:00 +0100, Martin Brown
> <'''newspam'''@nonad.co.uk> wrote:
>

>> High end car theft gangs in Belgium did a pretty good job with lining a
>> largish HVG with supermarket grade aluminium foil and if memory serves
>> lead flashing seals on the opening joints. Good enough Faraday cage to
>> steal high end cars with notional satellite tracking on them anyway.
>
> Cute. I assume that HVG is some kind of lorry.

Its a typo!
For HGV = heavy goods vehicle 44T tractor trailer combo.
US = big rig (but yours are max 64T?)

> Where do they take the cars to? The tracking will start working once
> delivered and out in the open, unless they are able to disable all
> possibilities. So I'm assuming that it is some place without
> extradition.

They were very good at it. It was around y2k era. This isn't the right
link but gives the general idea. They were eventually caught...

https://www.expatica.com/be/uncategorized/car-theft-remains-high-in-belgium-83236/

A search with the most obvious search terms got me nowhere.

It was in the print media of the time (I was living in Belgium then).

--
Regards,
Martin Brown

Re: Large scale RF shielding

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Subject: Re: Large scale RF shielding
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 by: Martin Brown - Sat, 7 May 2022 11:21 UTC

On 06/05/2022 21:40, Phil Hobbs wrote:
> Rich S wrote:
>> On Thursday, May 5, 2022 at 6:46:43 PM UTC, Don Y wrote:
>>>
>>> Most homes are masonry - 8-12" thick walls. Interior walls on
>>> the perimeter are firred out with drywall coated with aluminum
>>> foil (moisture barrier?). All internal wiring is overhead, plumbing
>>> in the slab. Different types of roofing so I'm unsure if there
>>> is a common thread, there.
>>>
>>> Ideally, there is a *cheap* way to get this sort of attenuation
>>> that can be retrofitted to existing homes of different construction.
>>
>> uh, these homes lack windows?
>> Last I heard, glass is transparent for RF
>
> IIRC some have ITO or tin oxide coatings on the inner pane for lower IR
> emissivity.  That can also be a reasonable RF shield.

Although it does and mine are low emissivity there seems to be very
little attenuation at any of FM, DAB, Wifi or mobile phone frequencies.
I guess it is thin enough that most wavelengths are unaffected.

The stuff we had on the computer room windows for radio telescope
control had woven copper mesh inside grounded at every edge and an
airlock of two doors with all the fittings between the computer suite
and the outside world. Its attenuation was good up to 32GHz which was as
high as we could go. Door seals caused trouble from time to time.

The computer sitting in the innermost really good windowless Faraday
cage to protect IF stages and correlators from its interference. That
was a cost no object lined with 1/16" copper sheet - it looked fabulous!
(shame that the door was normally kept shut so no-one got to see it)

--
Regards,
Martin Brown

Re: Large scale RF shielding

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 by: rbowman - Sat, 7 May 2022 16:23 UTC

On 05/07/2022 02:12 AM, Martin Brown wrote:
> On 06/05/2022 17:31, Joe Gwinn wrote:
>> On Fri, 6 May 2022 10:46:00 +0100, Martin Brown
>> <'''newspam'''@nonad.co.uk> wrote:
>>
>
>>> High end car theft gangs in Belgium did a pretty good job with lining a
>>> largish HVG with supermarket grade aluminium foil and if memory serves
>>> lead flashing seals on the opening joints. Good enough Faraday cage to
>>> steal high end cars with notional satellite tracking on them anyway.
>>
>> Cute. I assume that HVG is some kind of lorry.
>
> Its a typo!
> For HGV = heavy goods vehicle 44T tractor trailer combo.
> US = big rig (but yours are max 64T?)

80,000 pounds, to avoid the ton ambiguity. Some states will license
105,000 for intrastate traffic.

Re: Large scale RF shielding

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From: '''newsp...@nonad.co.uk (Martin Brown)
Newsgroups: sci.electronics.design
Subject: Re: Large scale RF shielding
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 by: Martin Brown - Sun, 8 May 2022 08:48 UTC

On 07/05/2022 17:23, rbowman wrote:
> On 05/07/2022 02:12 AM, Martin Brown wrote:
>> On 06/05/2022 17:31, Joe Gwinn wrote:
>>> On Fri, 6 May 2022 10:46:00 +0100, Martin Brown
>>> <'''newspam'''@nonad.co.uk> wrote:
>>>
>>
>>>> High end car theft gangs in Belgium did a pretty good job with lining a
>>>> largish HVG with supermarket grade aluminium foil and if memory serves
>>>> lead flashing seals on the opening joints. Good enough Faraday cage to
>>>> steal high end cars with notional satellite tracking on them anyway.
>>>
>>> Cute.  I assume that HVG is some kind of lorry.
>>
>> Its a typo!
>> For HGV = heavy goods vehicle 44T tractor trailer combo.
>> US  = big rig (but yours are max 64T?)
>
> 80,000 pounds, to avoid the ton ambiguity. Some states will license
> 105,000 for intrastate traffic.

It is only really a problem in the US where short tons are used to
defraud the buyer of 10% of what they paid for. An Imperial or British
ton and a metric Ton are close enough for most practical purposes.

US short measure sharp practice gets you problems like the Gimli glider.

--
Regards,
Martin Brown

Re: Large scale RF shielding

<XnsAE9148305DF10idtokenpost@144.76.35.252>

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Subject: Re: Large scale RF shielding
Date: Sun, 8 May 2022 11:05:49 -0000 (UTC)
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 by: Mike Monett - Sun, 8 May 2022 11:05 UTC

Martin Brown <'''newspam'''@nonad.co.uk> wrote:

[...]

> It is only really a problem in the US where short tons are used to
> defraud the buyer of 10% of what they paid for. An Imperial or British
> ton and a metric Ton are close enough for most practical purposes.

Some background courtesy google:

What are the different types of tons?

The three types are all a measure of mass(weight) the short ton aka US ton
is 2,000/lbs. the long ton aka British ton is 2240 lbs. the third ton is
the metric ton which is, equal to 1000 kilograms, or approximately 2204
pounds.

What is a short ton vs ton?

United States. In the United States, a short ton is usually known simply as
a "ton", without distinguishing it from the tonne (1,000 kilograms or
2,204.62262 pounds), known there as the "metric ton", or the long ton also
known as the "imperial ton" (2,240 pounds or 1,016.0469088 kilograms).

Why is it called a short ton?

In the U.S. there are 100 pounds in the hundredweight, and in Britain there
are 112 pounds in the hundredweight. This causes the actual weight of the
ton to differ between countries. To distinguish between the two tons, the
smaller U.S. ton is called short, while the larger British ton is called
long.

What is the meaning of hundredweight?

A hundredweight (abbreviated as CWT) is a standard unit of weight or mass
used in certain commodities markets. It also may be used to price smaller
shipments of goods. In North America, a hundredweight is equal to 100
pounds; in the United Kingdom, a hundredweight is 112 pounds.

Why is it called a hundredweight?

In England in around 1300, different "hundreds" (centum in Medieval Latin)
were defined. The Weights and Measures Act 1835 formally established the
present imperial hundredweight of 112 lb. The United States and Canada came
to use the term "hundredweight" to refer to a unit of 100 lb.

What is the difference between a long and short ton?

ton, unit of weight in the avoirdupois system equal to 2,000 pounds (907.18
kg) in the United States (the short ton) and 2,240 pounds (1,016.05 kg) in
Britain (the long ton). The metric ton used in most other countries is
1,000 kg, equivalent to 2,204.6 pounds avoirdupois.

What is the British ton?

"The ton" was Britain's high society during the late Regency and the reign
of George IV, and later. The word means, in this context, "manners" or
"style" and is pronounced as in French.

--
MRM

Re: Large scale RF shielding

<tikf7ht0gk90elq52psqgke2s2ptopbtjd@4ax.com>

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From: jlar...@highlandsniptechnology.com
Newsgroups: sci.electronics.design
Subject: Re: Large scale RF shielding
Date: Sun, 08 May 2022 07:27:14 -0700
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 by: jlar...@highlandsniptechnology.com - Sun, 8 May 2022 14:27 UTC

On Sun, 8 May 2022 09:48:01 +0100, Martin Brown
<'''newspam'''@nonad.co.uk> wrote:

>On 07/05/2022 17:23, rbowman wrote:
>> On 05/07/2022 02:12 AM, Martin Brown wrote:
>>> On 06/05/2022 17:31, Joe Gwinn wrote:
>>>> On Fri, 6 May 2022 10:46:00 +0100, Martin Brown
>>>> <'''newspam'''@nonad.co.uk> wrote:
>>>>
>>>
>>>>> High end car theft gangs in Belgium did a pretty good job with lining a
>>>>> largish HVG with supermarket grade aluminium foil and if memory serves
>>>>> lead flashing seals on the opening joints. Good enough Faraday cage to
>>>>> steal high end cars with notional satellite tracking on them anyway.
>>>>
>>>> Cute.  I assume that HVG is some kind of lorry.
>>>
>>> Its a typo!
>>> For HGV = heavy goods vehicle 44T tractor trailer combo.
>>> US  = big rig (but yours are max 64T?)
>>
>> 80,000 pounds, to avoid the ton ambiguity. Some states will license
>> 105,000 for intrastate traffic.
>
>It is only really a problem in the US where short tons are used to
>defraud the buyer of 10% of what they paid for.

But we pay 10% less!

An Imperial or British
>ton and a metric Ton are close enough for most practical purposes.
>
>US short measure sharp practice gets you problems like the Gimli glider.

The Glider was carrying 45% of its required fuel, not 90%.

--

Anybody can count to one.

- Robert Widlar

Re: Large scale RF shielding

<t58l0h$t1u$1@gioia.aioe.org>

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https://www.novabbs.com/tech/article-flat.php?id=96553&group=sci.electronics.design#96553

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From: jer...@nospam.please (Jeroen Belleman)
Newsgroups: sci.electronics.design
Subject: Re: Large scale RF shielding
Date: Sun, 08 May 2022 16:44:33 +0200
Organization: Aioe.org NNTP Server
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 by: Jeroen Belleman - Sun, 8 May 2022 14:44 UTC

On 2022-05-08 13:05, Mike Monett wrote:
> Martin Brown <'''newspam'''@nonad.co.uk> wrote:
>
> [...]
>
>> It is only really a problem in the US where short tons are used to
>> defraud the buyer of 10% of what they paid for. An Imperial or British
>> ton and a metric Ton are close enough for most practical purposes.
>
> Some background courtesy google:
>
> What are the different types of tons?
>
> The three types are all a measure of mass(weight) the short ton aka US ton
> is 2,000/lbs. the long ton aka British ton is 2240 lbs. the third ton is
> the metric ton which is, equal to 1000 kilograms, or approximately 2204
> pounds.
>
> What is a short ton vs ton?
>
> United States. In the United States, a short ton is usually known simply as
> a "ton", without distinguishing it from the tonne (1,000 kilograms or
> 2,204.62262 pounds), known there as the "metric ton", or the long ton also
> known as the "imperial ton" (2,240 pounds or 1,016.0469088 kilograms).
>
> Why is it called a short ton?
>
> In the U.S. there are 100 pounds in the hundredweight, and in Britain there
> are 112 pounds in the hundredweight. This causes the actual weight of the
> ton to differ between countries. To distinguish between the two tons, the
> smaller U.S. ton is called short, while the larger British ton is called
> long.
>
> What is the meaning of hundredweight?
>
> A hundredweight (abbreviated as CWT) is a standard unit of weight or mass
> used in certain commodities markets. It also may be used to price smaller
> shipments of goods. In North America, a hundredweight is equal to 100
> pounds; in the United Kingdom, a hundredweight is 112 pounds.
>
> Why is it called a hundredweight?
>
> In England in around 1300, different "hundreds" (centum in Medieval Latin)
> were defined. The Weights and Measures Act 1835 formally established the
> present imperial hundredweight of 112 lb. The United States and Canada came
> to use the term "hundredweight" to refer to a unit of 100 lb.
>
> What is the difference between a long and short ton?
>
> ton, unit of weight in the avoirdupois system equal to 2,000 pounds (907.18
> kg) in the United States (the short ton) and 2,240 pounds (1,016.05 kg) in
> Britain (the long ton). The metric ton used in most other countries is
> 1,000 kg, equivalent to 2,204.6 pounds avoirdupois.
>
> What is the British ton?
>
> "The ton" was Britain's high society during the late Regency and the reign
> of George IV, and later. The word means, in this context, "manners" or
> "style" and is pronounced as in French.

That's an excellent argument in favour of metrication.

Jeroen Belleman

Re: Large scale RF shielding

<jdqctsFt391U1@mid.individual.net>

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From: bow...@montana.com (rbowman)
Newsgroups: sci.electronics.design
Subject: Re: Large scale RF shielding
Date: Sun, 8 May 2022 10:37:17 -0600
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 by: rbowman - Sun, 8 May 2022 16:37 UTC

On 05/08/2022 02:48 AM, Martin Brown wrote:
> On 07/05/2022 17:23, rbowman wrote:
>> On 05/07/2022 02:12 AM, Martin Brown wrote:
>>> On 06/05/2022 17:31, Joe Gwinn wrote:
>>>> On Fri, 6 May 2022 10:46:00 +0100, Martin Brown
>>>> <'''newspam'''@nonad.co.uk> wrote:
>>>>
>>>
>>>>> High end car theft gangs in Belgium did a pretty good job with
>>>>> lining a
>>>>> largish HVG with supermarket grade aluminium foil and if memory serves
>>>>> lead flashing seals on the opening joints. Good enough Faraday cage to
>>>>> steal high end cars with notional satellite tracking on them anyway.
>>>>
>>>> Cute. I assume that HVG is some kind of lorry.
>>>
>>> Its a typo!
>>> For HGV = heavy goods vehicle 44T tractor trailer combo.
>>> US = big rig (but yours are max 64T?)
>>
>> 80,000 pounds, to avoid the ton ambiguity. Some states will license
>> 105,000 for intrastate traffic.
>
> It is only really a problem in the US where short tons are used to
> defraud the buyer of 10% of what they paid for. An Imperial or British
> ton and a metric Ton are close enough for most practical purposes.
>
> US short measure sharp practice gets you problems like the Gimli glider.
>

A ton is defined as 20 hundredweights but a British hundredweight is 112
pounds for some obscure reason going back to stones, another strange
unit of measurement. Why there are 8 stones in a hundredweight also
escapes me. Actually Canada uses short tons.

They did use the imperial gallon so I always thought I was getting a
bargain when buying gasoline in Canada. After going to the liter and the
loonie (Canadian dollar) falling to .75 USD, I gave up trying to figure
out how badly I was getting screwed. The US uses the Queen Anne's gallon
and wasn't about to adopt the Imperial system in 1826. We also retained
the Winchester bushel. I can't find a citation but it wouldn't surprise
me if a hundredweight was 100 pounds before 1826 too.

Anyway the Gimli Glider was the end result of many more problems than a
simple conversion. It wasn't a high point for Air Canada. Boeing
certainly didn't help. I once worked for a firm that did fuel
measurement and management systems. We didn't assume the engines would
be running to keep the system powered up. Admittedly the systems
primarily went into military aircraft where a little wear and tear is
expected, but still...

Re: Large scale RF shielding

<q40g7ht2aoncbb797i08fcgnd97chrkv77@4ax.com>

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From: jlar...@highlandsniptechnology.com
Newsgroups: sci.electronics.design
Subject: Re: Large scale RF shielding
Date: Sun, 08 May 2022 10:45:27 -0700
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References: <t5162c$s9f$1@dont-email.me> <t52qoo$h2j$1@gioia.aioe.org> <u5ia7hti8eg78ufvp226qeh3clbdfo61rs@4ax.com> <t559lm$1bjn$1@gioia.aioe.org> <jdnnnrFdlfaU1@mid.individual.net> <t58041$aqp$2@gioia.aioe.org> <jdqctsFt391U1@mid.individual.net>
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 by: jlar...@highlandsniptechnology.com - Sun, 8 May 2022 17:45 UTC

On Sun, 8 May 2022 10:37:17 -0600, rbowman <bowman@montana.com> wrote:

>On 05/08/2022 02:48 AM, Martin Brown wrote:
>> On 07/05/2022 17:23, rbowman wrote:
>>> On 05/07/2022 02:12 AM, Martin Brown wrote:
>>>> On 06/05/2022 17:31, Joe Gwinn wrote:
>>>>> On Fri, 6 May 2022 10:46:00 +0100, Martin Brown
>>>>> <'''newspam'''@nonad.co.uk> wrote:
>>>>>
>>>>
>>>>>> High end car theft gangs in Belgium did a pretty good job with
>>>>>> lining a
>>>>>> largish HVG with supermarket grade aluminium foil and if memory serves
>>>>>> lead flashing seals on the opening joints. Good enough Faraday cage to
>>>>>> steal high end cars with notional satellite tracking on them anyway.
>>>>>
>>>>> Cute. I assume that HVG is some kind of lorry.
>>>>
>>>> Its a typo!
>>>> For HGV = heavy goods vehicle 44T tractor trailer combo.
>>>> US = big rig (but yours are max 64T?)
>>>
>>> 80,000 pounds, to avoid the ton ambiguity. Some states will license
>>> 105,000 for intrastate traffic.
>>
>> It is only really a problem in the US where short tons are used to
>> defraud the buyer of 10% of what they paid for. An Imperial or British
>> ton and a metric Ton are close enough for most practical purposes.
>>
>> US short measure sharp practice gets you problems like the Gimli glider.
>>
>
>A ton is defined as 20 hundredweights but a British hundredweight is 112
>pounds for some obscure reason going back to stones, another strange
>unit of measurement. Why there are 8 stones in a hundredweight also
>escapes me. Actually Canada uses short tons.
>
>They did use the imperial gallon so I always thought I was getting a
>bargain when buying gasoline in Canada. After going to the liter and the
>loonie (Canadian dollar) falling to .75 USD, I gave up trying to figure
>out how badly I was getting screwed. The US uses the Queen Anne's gallon
>and wasn't about to adopt the Imperial system in 1826. We also retained
>the Winchester bushel. I can't find a citation but it wouldn't surprise
>me if a hundredweight was 100 pounds before 1826 too.
>
>Anyway the Gimli Glider was the end result of many more problems than a
>simple conversion. It wasn't a high point for Air Canada. Boeing
>certainly didn't help. I once worked for a firm that did fuel
>measurement and management systems. We didn't assume the engines would
>be running to keep the system powered up. Admittedly the systems
>primarily went into military aircraft where a little wear and tear is
>expected, but still...
>

This is one of my designs, or at least the hardware part is:

http://www.highlandtechnology.com/DSS/P330DS.shtml

Fuel volume measurement is tricky with a funny-shaped tank in a
tiltable vehicle.

Did you work for Simmonds?

--

Anybody can count to one.

- Robert Widlar

Re: Large scale RF shielding

<jdqeb1Ftb9nU1@mid.individual.net>

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From: bow...@montana.com (rbowman)
Newsgroups: sci.electronics.design
Subject: Re: Large scale RF shielding
Date: Sun, 8 May 2022 11:01:22 -0600
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In-Reply-To: <t58l0h$t1u$1@gioia.aioe.org>
 by: rbowman - Sun, 8 May 2022 17:01 UTC

On 05/08/2022 08:44 AM, Jeroen Belleman wrote:
> On 2022-05-08 13:05, Mike Monett wrote:
>> Martin Brown <'''newspam'''@nonad.co.uk> wrote:
>>
>> [...]
>>
>>> It is only really a problem in the US where short tons are used to
>>> defraud the buyer of 10% of what they paid for. An Imperial or British
>>> ton and a metric Ton are close enough for most practical purposes.
>>
>> Some background courtesy google:
>>
>> What are the different types of tons?
>>
>> The three types are all a measure of mass(weight) the short ton aka US
>> ton
>> is 2,000/lbs. the long ton aka British ton is 2240 lbs. the third ton is
>> the metric ton which is, equal to 1000 kilograms, or approximately 2204
>> pounds.
>>
>> What is a short ton vs ton?
>>
>> United States. In the United States, a short ton is usually known
>> simply as
>> a "ton", without distinguishing it from the tonne (1,000 kilograms or
>> 2,204.62262 pounds), known there as the "metric ton", or the long ton
>> also
>> known as the "imperial ton" (2,240 pounds or 1,016.0469088 kilograms).
>>
>> Why is it called a short ton?
>>
>> In the U.S. there are 100 pounds in the hundredweight, and in Britain
>> there
>> are 112 pounds in the hundredweight. This causes the actual weight of the
>> ton to differ between countries. To distinguish between the two tons, the
>> smaller U.S. ton is called short, while the larger British ton is called
>> long.
>>
>> What is the meaning of hundredweight?
>>
>> A hundredweight (abbreviated as CWT) is a standard unit of weight or mass
>> used in certain commodities markets. It also may be used to price smaller
>> shipments of goods. In North America, a hundredweight is equal to 100
>> pounds; in the United Kingdom, a hundredweight is 112 pounds.
>>
>> Why is it called a hundredweight?
>>
>> In England in around 1300, different "hundreds" (centum in Medieval
>> Latin)
>> were defined. The Weights and Measures Act 1835 formally established the
>> present imperial hundredweight of 112 lb. The United States and Canada
>> came
>> to use the term "hundredweight" to refer to a unit of 100 lb.
>>
>> What is the difference between a long and short ton?
>>
>> ton, unit of weight in the avoirdupois system equal to 2,000 pounds
>> (907.18
>> kg) in the United States (the short ton) and 2,240 pounds (1,016.05
>> kg) in
>> Britain (the long ton). The metric ton used in most other countries is
>> 1,000 kg, equivalent to 2,204.6 pounds avoirdupois.
>>
>> What is the British ton?
>>
>> "The ton" was Britain's high society during the late Regency and the
>> reign
>> of George IV, and later. The word means, in this context, "manners" or
>> "style" and is pronounced as in French.
>
> That's an excellent argument in favour of metrication.
>
> Jeroen Belleman
>

I'll drink to that... I have two US vehicles, a F150 pickup and a
Harley bike. Both are mostly SAE (inch) fasteners, except when they
aren't so I need wrenches in both sizes. I believe newer vehicles are
all metric. With the Toyota and two Suzuki bikes I know they'll be
metric. Thankfully I haven't had to deal with Whitworth in decades.

The US has been talking about metrication for decades but the
legislation has only been a suggestion not a mandate. The only
wholehearted adopters were the liquor bottlers. A 'fifth' (of a gallon)
was a customary size and was 757ml. Seems trivial to go to 750ml but
those milliliters add up.

Re: Large scale RF shielding

<jdqelhFtd7nU1@mid.individual.net>

 copy mid

https://www.novabbs.com/tech/article-flat.php?id=96557&group=sci.electronics.design#96557

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From: bow...@montana.com (rbowman)
Newsgroups: sci.electronics.design
Subject: Re: Large scale RF shielding
Date: Sun, 8 May 2022 11:06:58 -0600
Lines: 36
Message-ID: <jdqelhFtd7nU1@mid.individual.net>
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 by: rbowman - Sun, 8 May 2022 17:06 UTC

On 05/08/2022 08:27 AM, jlarkin@highlandsniptechnology.com wrote:
> On Sun, 8 May 2022 09:48:01 +0100, Martin Brown
> <'''newspam'''@nonad.co.uk> wrote:
>
>> On 07/05/2022 17:23, rbowman wrote:
>>> On 05/07/2022 02:12 AM, Martin Brown wrote:
>>>> On 06/05/2022 17:31, Joe Gwinn wrote:
>>>>> On Fri, 6 May 2022 10:46:00 +0100, Martin Brown
>>>>> <'''newspam'''@nonad.co.uk> wrote:
>>>>>
>>>>
>>>>>> High end car theft gangs in Belgium did a pretty good job with lining a
>>>>>> largish HVG with supermarket grade aluminium foil and if memory serves
>>>>>> lead flashing seals on the opening joints. Good enough Faraday cage to
>>>>>> steal high end cars with notional satellite tracking on them anyway.
>>>>>
>>>>> Cute. I assume that HVG is some kind of lorry.
>>>>
>>>> Its a typo!
>>>> For HGV = heavy goods vehicle 44T tractor trailer combo.
>>>> US = big rig (but yours are max 64T?)
>>>
>>> 80,000 pounds, to avoid the ton ambiguity. Some states will license
>>> 105,000 for intrastate traffic.
>>
>> It is only really a problem in the US where short tons are used to
>> defraud the buyer of 10% of what they paid for.
>
> But we pay 10% less!

In an era where a 5lb sack of sugar becomes 4lbs in hopes nobody
notices, I really don't think a short ton was meant to defraud. Before
Canada went metric everyone (except the completely clueless) knew what
you were getting on either side of the border when you bought a gallon
of gasoline.

Re: Large scale RF shielding

<jdqprmFvtjU1@mid.individual.net>

 copy mid

https://www.novabbs.com/tech/article-flat.php?id=96566&group=sci.electronics.design#96566

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From: bow...@montana.com (rbowman)
Newsgroups: sci.electronics.design
Subject: Re: Large scale RF shielding
Date: Sun, 8 May 2022 15:09:08 -0600
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<u5ia7hti8eg78ufvp226qeh3clbdfo61rs@4ax.com> <t559lm$1bjn$1@gioia.aioe.org>
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 by: rbowman - Sun, 8 May 2022 21:09 UTC

On 05/08/2022 11:45 AM, jlarkin@highlandsniptechnology.com wrote:
> On Sun, 8 May 2022 10:37:17 -0600, rbowman <bowman@montana.com> wrote:
>
>> On 05/08/2022 02:48 AM, Martin Brown wrote:
>>> On 07/05/2022 17:23, rbowman wrote:
>>>> On 05/07/2022 02:12 AM, Martin Brown wrote:
>>>>> On 06/05/2022 17:31, Joe Gwinn wrote:
>>>>>> On Fri, 6 May 2022 10:46:00 +0100, Martin Brown
>>>>>> <'''newspam'''@nonad.co.uk> wrote:
>>>>>>
>>>>>
>>>>>>> High end car theft gangs in Belgium did a pretty good job with
>>>>>>> lining a
>>>>>>> largish HVG with supermarket grade aluminium foil and if memory serves
>>>>>>> lead flashing seals on the opening joints. Good enough Faraday cage to
>>>>>>> steal high end cars with notional satellite tracking on them anyway.
>>>>>>
>>>>>> Cute. I assume that HVG is some kind of lorry.
>>>>>
>>>>> Its a typo!
>>>>> For HGV = heavy goods vehicle 44T tractor trailer combo.
>>>>> US = big rig (but yours are max 64T?)
>>>>
>>>> 80,000 pounds, to avoid the ton ambiguity. Some states will license
>>>> 105,000 for intrastate traffic.
>>>
>>> It is only really a problem in the US where short tons are used to
>>> defraud the buyer of 10% of what they paid for. An Imperial or British
>>> ton and a metric Ton are close enough for most practical purposes.
>>>
>>> US short measure sharp practice gets you problems like the Gimli glider.
>>>
>>
>> A ton is defined as 20 hundredweights but a British hundredweight is 112
>> pounds for some obscure reason going back to stones, another strange
>> unit of measurement. Why there are 8 stones in a hundredweight also
>> escapes me. Actually Canada uses short tons.
>>
>> They did use the imperial gallon so I always thought I was getting a
>> bargain when buying gasoline in Canada. After going to the liter and the
>> loonie (Canadian dollar) falling to .75 USD, I gave up trying to figure
>> out how badly I was getting screwed. The US uses the Queen Anne's gallon
>> and wasn't about to adopt the Imperial system in 1826. We also retained
>> the Winchester bushel. I can't find a citation but it wouldn't surprise
>> me if a hundredweight was 100 pounds before 1826 too.
>>
>> Anyway the Gimli Glider was the end result of many more problems than a
>> simple conversion. It wasn't a high point for Air Canada. Boeing
>> certainly didn't help. I once worked for a firm that did fuel
>> measurement and management systems. We didn't assume the engines would
>> be running to keep the system powered up. Admittedly the systems
>> primarily went into military aircraft where a little wear and tear is
>> expected, but still...
>>
>
>
> This is one of my designs, or at least the hardware part is:
>
> http://www.highlandtechnology.com/DSS/P330DS.shtml
>
> Fuel volume measurement is tricky with a funny-shaped tank in a
> tiltable vehicle.
>
> Did you work for Simmonds?
>
>
>

Yes, briefly. That was my first and last brush with DoD projects. It
didn't help that it was in the middle of the walker debacle and DISCO
put everything on hold as far as clearances went. I'd been hired to work
on the test kit software but when there's nothing to test...

The upside was I had plenty of spare time to go down to Middlebury and
learn how to fly. The FBO was run by an ag pilot whose family had
originally built the strip for their spraying operation. It was
interesting to say the least. He had a couple of elderly Larks, one of
which added pumping up the brakes to the usual final approach protocol.

I was moonlighting for another employee who had a side project going. He
contacted me almost a year later about some tax paperwork. I asked if
he'd written any code yet. The answer was no, they were still haggling
over the design document. I can fully understand why projects like the
F-35 have problems.

I'd taken a contract at GE Ft. Wayne to develop a copier power supply
testing system and it was very refreshing to actually make progress.

Re: Large scale RF shielding

<7gdg7h9nggbeddeo9o8q0hc7qb09quvi4b@4ax.com>

 copy mid

https://www.novabbs.com/tech/article-flat.php?id=96569&group=sci.electronics.design#96569

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NNTP-Posting-Date: Sun, 08 May 2022 16:35:10 -0500
From: jlar...@highlandsniptechnology.com
Newsgroups: sci.electronics.design
Subject: Re: Large scale RF shielding
Date: Sun, 08 May 2022 14:35:10 -0700
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References: <t5162c$s9f$1@dont-email.me> <t52qoo$h2j$1@gioia.aioe.org> <u5ia7hti8eg78ufvp226qeh3clbdfo61rs@4ax.com> <t559lm$1bjn$1@gioia.aioe.org> <jdnnnrFdlfaU1@mid.individual.net> <t58041$aqp$2@gioia.aioe.org> <jdqctsFt391U1@mid.individual.net> <q40g7ht2aoncbb797i08fcgnd97chrkv77@4ax.com> <jdqprmFvtjU1@mid.individual.net>
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 by: jlar...@highlandsniptechnology.com - Sun, 8 May 2022 21:35 UTC

On Sun, 8 May 2022 15:09:08 -0600, rbowman <bowman@montana.com> wrote:

>On 05/08/2022 11:45 AM, jlarkin@highlandsniptechnology.com wrote:
>> On Sun, 8 May 2022 10:37:17 -0600, rbowman <bowman@montana.com> wrote:
>>
>>> On 05/08/2022 02:48 AM, Martin Brown wrote:
>>>> On 07/05/2022 17:23, rbowman wrote:
>>>>> On 05/07/2022 02:12 AM, Martin Brown wrote:
>>>>>> On 06/05/2022 17:31, Joe Gwinn wrote:
>>>>>>> On Fri, 6 May 2022 10:46:00 +0100, Martin Brown
>>>>>>> <'''newspam'''@nonad.co.uk> wrote:
>>>>>>>
>>>>>>
>>>>>>>> High end car theft gangs in Belgium did a pretty good job with
>>>>>>>> lining a
>>>>>>>> largish HVG with supermarket grade aluminium foil and if memory serves
>>>>>>>> lead flashing seals on the opening joints. Good enough Faraday cage to
>>>>>>>> steal high end cars with notional satellite tracking on them anyway.
>>>>>>>
>>>>>>> Cute. I assume that HVG is some kind of lorry.
>>>>>>
>>>>>> Its a typo!
>>>>>> For HGV = heavy goods vehicle 44T tractor trailer combo.
>>>>>> US = big rig (but yours are max 64T?)
>>>>>
>>>>> 80,000 pounds, to avoid the ton ambiguity. Some states will license
>>>>> 105,000 for intrastate traffic.
>>>>
>>>> It is only really a problem in the US where short tons are used to
>>>> defraud the buyer of 10% of what they paid for. An Imperial or British
>>>> ton and a metric Ton are close enough for most practical purposes.
>>>>
>>>> US short measure sharp practice gets you problems like the Gimli glider.
>>>>
>>>
>>> A ton is defined as 20 hundredweights but a British hundredweight is 112
>>> pounds for some obscure reason going back to stones, another strange
>>> unit of measurement. Why there are 8 stones in a hundredweight also
>>> escapes me. Actually Canada uses short tons.
>>>
>>> They did use the imperial gallon so I always thought I was getting a
>>> bargain when buying gasoline in Canada. After going to the liter and the
>>> loonie (Canadian dollar) falling to .75 USD, I gave up trying to figure
>>> out how badly I was getting screwed. The US uses the Queen Anne's gallon
>>> and wasn't about to adopt the Imperial system in 1826. We also retained
>>> the Winchester bushel. I can't find a citation but it wouldn't surprise
>>> me if a hundredweight was 100 pounds before 1826 too.
>>>
>>> Anyway the Gimli Glider was the end result of many more problems than a
>>> simple conversion. It wasn't a high point for Air Canada. Boeing
>>> certainly didn't help. I once worked for a firm that did fuel
>>> measurement and management systems. We didn't assume the engines would
>>> be running to keep the system powered up. Admittedly the systems
>>> primarily went into military aircraft where a little wear and tear is
>>> expected, but still...
>>>
>>
>>
>> This is one of my designs, or at least the hardware part is:
>>
>> http://www.highlandtechnology.com/DSS/P330DS.shtml
>>
>> Fuel volume measurement is tricky with a funny-shaped tank in a
>> tiltable vehicle.
>>
>> Did you work for Simmonds?
>>
>>
>>
>
>Yes, briefly. That was my first and last brush with DoD projects. It
>didn't help that it was in the middle of the walker debacle and DISCO
>put everything on hold as far as clearances went. I'd been hired to work
>on the test kit software but when there's nothing to test...
>
>The upside was I had plenty of spare time to go down to Middlebury and
>learn how to fly. The FBO was run by an ag pilot whose family had
>originally built the strip for their spraying operation. It was
>interesting to say the least. He had a couple of elderly Larks, one of
>which added pumping up the brakes to the usual final approach protocol.
>
>I was moonlighting for another employee who had a side project going. He
>contacted me almost a year later about some tax paperwork. I asked if
>he'd written any code yet. The answer was no, they were still haggling
>over the design document. I can fully understand why projects like the
>F-35 have problems.
>
>I'd taken a contract at GE Ft. Wayne to develop a copier power supply
>testing system and it was very refreshing to actually make progress.

I did a tank gauging system for Simmonds, for LNG tanks on a giant
barge, when I was with someone else. I did later interview with them,
but I didn't think I'd like Vermont.

What I remembered was fabulous bbq ribs on some floating restaurant on
Lake Champlain. Ribs? In Vermont?

--

Anybody can count to one.

- Robert Widlar

Re: Large scale RF shielding

<c9a69067-c19a-f70a-be77-43b776697b67@electrooptical.net>

 copy mid

https://www.novabbs.com/tech/article-flat.php?id=96576&group=sci.electronics.design#96576

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NNTP-Posting-Date: Sun, 08 May 2022 17:49:38 -0500
Subject: Re: Large scale RF shielding
Newsgroups: sci.electronics.design
References: <t5162c$s9f$1@dont-email.me> <t52qoo$h2j$1@gioia.aioe.org>
<u5ia7hti8eg78ufvp226qeh3clbdfo61rs@4ax.com> <t559lm$1bjn$1@gioia.aioe.org>
<jdnnnrFdlfaU1@mid.individual.net> <t58041$aqp$2@gioia.aioe.org>
<jdqctsFt391U1@mid.individual.net>
<q40g7ht2aoncbb797i08fcgnd97chrkv77@4ax.com>
<jdqprmFvtjU1@mid.individual.net>
<7gdg7h9nggbeddeo9o8q0hc7qb09quvi4b@4ax.com>
From: pcdhSpam...@electrooptical.net (Phil Hobbs)
Message-ID: <c9a69067-c19a-f70a-be77-43b776697b67@electrooptical.net>
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 by: Phil Hobbs - Sun, 8 May 2022 22:49 UTC

jlarkin@highlandsniptechnology.com wrote:
> On Sun, 8 May 2022 15:09:08 -0600, rbowman <bowman@montana.com> wrote:
>
>> On 05/08/2022 11:45 AM, jlarkin@highlandsniptechnology.com wrote:
>>> On Sun, 8 May 2022 10:37:17 -0600, rbowman <bowman@montana.com> wrote:
>>>
>>>> On 05/08/2022 02:48 AM, Martin Brown wrote:
>>>>> On 07/05/2022 17:23, rbowman wrote:
>>>>>> On 05/07/2022 02:12 AM, Martin Brown wrote:
>>>>>>> On 06/05/2022 17:31, Joe Gwinn wrote:
>>>>>>>> On Fri, 6 May 2022 10:46:00 +0100, Martin Brown
>>>>>>>> <'''newspam'''@nonad.co.uk> wrote:
>>>>>>>>
>>>>>>>
>>>>>>>>> High end car theft gangs in Belgium did a pretty good job with
>>>>>>>>> lining a
>>>>>>>>> largish HVG with supermarket grade aluminium foil and if memory serves
>>>>>>>>> lead flashing seals on the opening joints. Good enough Faraday cage to
>>>>>>>>> steal high end cars with notional satellite tracking on them anyway.
>>>>>>>>
>>>>>>>> Cute. I assume that HVG is some kind of lorry.
>>>>>>>
>>>>>>> Its a typo!
>>>>>>> For HGV = heavy goods vehicle 44T tractor trailer combo.
>>>>>>> US = big rig (but yours are max 64T?)
>>>>>>
>>>>>> 80,000 pounds, to avoid the ton ambiguity. Some states will license
>>>>>> 105,000 for intrastate traffic.
>>>>>
>>>>> It is only really a problem in the US where short tons are used to
>>>>> defraud the buyer of 10% of what they paid for. An Imperial or British
>>>>> ton and a metric Ton are close enough for most practical purposes.
>>>>>
>>>>> US short measure sharp practice gets you problems like the Gimli glider.
>>>>>
>>>>
>>>> A ton is defined as 20 hundredweights but a British hundredweight is 112
>>>> pounds for some obscure reason going back to stones, another strange
>>>> unit of measurement. Why there are 8 stones in a hundredweight also
>>>> escapes me. Actually Canada uses short tons.
>>>>
>>>> They did use the imperial gallon so I always thought I was getting a
>>>> bargain when buying gasoline in Canada. After going to the liter and the
>>>> loonie (Canadian dollar) falling to .75 USD, I gave up trying to figure
>>>> out how badly I was getting screwed. The US uses the Queen Anne's gallon
>>>> and wasn't about to adopt the Imperial system in 1826. We also retained
>>>> the Winchester bushel. I can't find a citation but it wouldn't surprise
>>>> me if a hundredweight was 100 pounds before 1826 too.
>>>>
>>>> Anyway the Gimli Glider was the end result of many more problems than a
>>>> simple conversion. It wasn't a high point for Air Canada. Boeing
>>>> certainly didn't help. I once worked for a firm that did fuel
>>>> measurement and management systems. We didn't assume the engines would
>>>> be running to keep the system powered up. Admittedly the systems
>>>> primarily went into military aircraft where a little wear and tear is
>>>> expected, but still...
>>>>
>>>
>>>
>>> This is one of my designs, or at least the hardware part is:
>>>
>>> http://www.highlandtechnology.com/DSS/P330DS.shtml
>>>
>>> Fuel volume measurement is tricky with a funny-shaped tank in a
>>> tiltable vehicle.
>>>
>>> Did you work for Simmonds?
>>>
>>>
>>>
>>
>> Yes, briefly. That was my first and last brush with DoD projects. It
>> didn't help that it was in the middle of the walker debacle and DISCO
>> put everything on hold as far as clearances went. I'd been hired to work
>> on the test kit software but when there's nothing to test...
>>
>> The upside was I had plenty of spare time to go down to Middlebury and
>> learn how to fly. The FBO was run by an ag pilot whose family had
>> originally built the strip for their spraying operation. It was
>> interesting to say the least. He had a couple of elderly Larks, one of
>> which added pumping up the brakes to the usual final approach protocol.
>>
>> I was moonlighting for another employee who had a side project going. He
>> contacted me almost a year later about some tax paperwork. I asked if
>> he'd written any code yet. The answer was no, they were still haggling
>> over the design document. I can fully understand why projects like the
>> F-35 have problems.
>>
>> I'd taken a contract at GE Ft. Wayne to develop a copier power supply
>> testing system and it was very refreshing to actually make progress.
>
>
> I did a tank gauging system for Simmonds, for LNG tanks on a giant
> barge, when I was with someone else. I did later interview with them,
> but I didn't think I'd like Vermont.

My favourite technique for that sort of thing is the Helmholtz
resonance, which (to leading order) depends only on the air volume in
the tank, and not on its shape.

> What I remembered was fabulous bbq ribs on some floating restaurant on
> Lake Champlain. Ribs? In Vermont?

They have to compensate for the weather somehow. ;)

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

http://electrooptical.net
http://hobbs-eo.com

Re: Large scale RF shielding

<kjkg7htmvlcujcvlo1bham8bnohtjskhf0@4ax.com>

 copy mid

https://www.novabbs.com/tech/article-flat.php?id=96578&group=sci.electronics.design#96578

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Subject: Re: Large scale RF shielding
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References: <t5162c$s9f$1@dont-email.me> <t52qoo$h2j$1@gioia.aioe.org> <u5ia7hti8eg78ufvp226qeh3clbdfo61rs@4ax.com> <t559lm$1bjn$1@gioia.aioe.org> <jdnnnrFdlfaU1@mid.individual.net> <t58041$aqp$2@gioia.aioe.org> <jdqctsFt391U1@mid.individual.net> <q40g7ht2aoncbb797i08fcgnd97chrkv77@4ax.com> <jdqprmFvtjU1@mid.individual.net> <7gdg7h9nggbeddeo9o8q0hc7qb09quvi4b@4ax.com> <c9a69067-c19a-f70a-be77-43b776697b67@electrooptical.net>
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 by: jlar...@highlandsniptechnology.com - Sun, 8 May 2022 23:31 UTC

On Sun, 8 May 2022 18:49:36 -0400, Phil Hobbs
<pcdhSpamMeSenseless@electrooptical.net> wrote:

>jlarkin@highlandsniptechnology.com wrote:
>> On Sun, 8 May 2022 15:09:08 -0600, rbowman <bowman@montana.com> wrote:
>>
>>> On 05/08/2022 11:45 AM, jlarkin@highlandsniptechnology.com wrote:
>>>> On Sun, 8 May 2022 10:37:17 -0600, rbowman <bowman@montana.com> wrote:
>>>>
>>>>> On 05/08/2022 02:48 AM, Martin Brown wrote:
>>>>>> On 07/05/2022 17:23, rbowman wrote:
>>>>>>> On 05/07/2022 02:12 AM, Martin Brown wrote:
>>>>>>>> On 06/05/2022 17:31, Joe Gwinn wrote:
>>>>>>>>> On Fri, 6 May 2022 10:46:00 +0100, Martin Brown
>>>>>>>>> <'''newspam'''@nonad.co.uk> wrote:
>>>>>>>>>
>>>>>>>>
>>>>>>>>>> High end car theft gangs in Belgium did a pretty good job with
>>>>>>>>>> lining a
>>>>>>>>>> largish HVG with supermarket grade aluminium foil and if memory serves
>>>>>>>>>> lead flashing seals on the opening joints. Good enough Faraday cage to
>>>>>>>>>> steal high end cars with notional satellite tracking on them anyway.
>>>>>>>>>
>>>>>>>>> Cute. I assume that HVG is some kind of lorry.
>>>>>>>>
>>>>>>>> Its a typo!
>>>>>>>> For HGV = heavy goods vehicle 44T tractor trailer combo.
>>>>>>>> US = big rig (but yours are max 64T?)
>>>>>>>
>>>>>>> 80,000 pounds, to avoid the ton ambiguity. Some states will license
>>>>>>> 105,000 for intrastate traffic.
>>>>>>
>>>>>> It is only really a problem in the US where short tons are used to
>>>>>> defraud the buyer of 10% of what they paid for. An Imperial or British
>>>>>> ton and a metric Ton are close enough for most practical purposes.
>>>>>>
>>>>>> US short measure sharp practice gets you problems like the Gimli glider.
>>>>>>
>>>>>
>>>>> A ton is defined as 20 hundredweights but a British hundredweight is 112
>>>>> pounds for some obscure reason going back to stones, another strange
>>>>> unit of measurement. Why there are 8 stones in a hundredweight also
>>>>> escapes me. Actually Canada uses short tons.
>>>>>
>>>>> They did use the imperial gallon so I always thought I was getting a
>>>>> bargain when buying gasoline in Canada. After going to the liter and the
>>>>> loonie (Canadian dollar) falling to .75 USD, I gave up trying to figure
>>>>> out how badly I was getting screwed. The US uses the Queen Anne's gallon
>>>>> and wasn't about to adopt the Imperial system in 1826. We also retained
>>>>> the Winchester bushel. I can't find a citation but it wouldn't surprise
>>>>> me if a hundredweight was 100 pounds before 1826 too.
>>>>>
>>>>> Anyway the Gimli Glider was the end result of many more problems than a
>>>>> simple conversion. It wasn't a high point for Air Canada. Boeing
>>>>> certainly didn't help. I once worked for a firm that did fuel
>>>>> measurement and management systems. We didn't assume the engines would
>>>>> be running to keep the system powered up. Admittedly the systems
>>>>> primarily went into military aircraft where a little wear and tear is
>>>>> expected, but still...
>>>>>
>>>>
>>>>
>>>> This is one of my designs, or at least the hardware part is:
>>>>
>>>> http://www.highlandtechnology.com/DSS/P330DS.shtml
>>>>
>>>> Fuel volume measurement is tricky with a funny-shaped tank in a
>>>> tiltable vehicle.
>>>>
>>>> Did you work for Simmonds?
>>>>
>>>>
>>>>
>>>
>>> Yes, briefly. That was my first and last brush with DoD projects. It
>>> didn't help that it was in the middle of the walker debacle and DISCO
>>> put everything on hold as far as clearances went. I'd been hired to work
>>> on the test kit software but when there's nothing to test...
>>>
>>> The upside was I had plenty of spare time to go down to Middlebury and
>>> learn how to fly. The FBO was run by an ag pilot whose family had
>>> originally built the strip for their spraying operation. It was
>>> interesting to say the least. He had a couple of elderly Larks, one of
>>> which added pumping up the brakes to the usual final approach protocol.
>>>
>>> I was moonlighting for another employee who had a side project going. He
>>> contacted me almost a year later about some tax paperwork. I asked if
>>> he'd written any code yet. The answer was no, they were still haggling
>>> over the design document. I can fully understand why projects like the
>>> F-35 have problems.
>>>
>>> I'd taken a contract at GE Ft. Wayne to develop a copier power supply
>>> testing system and it was very refreshing to actually make progress.
>>
>>
>> I did a tank gauging system for Simmonds, for LNG tanks on a giant
>> barge, when I was with someone else. I did later interview with them,
>> but I didn't think I'd like Vermont.
>
>My favourite technique for that sort of thing is the Helmholtz
>resonance, which (to leading order) depends only on the air volume in
>the tank, and not on its shape.

We had two capacitive level probes and two inclinometers.

>
>> What I remembered was fabulous bbq ribs on some floating restaurant on
>> Lake Champlain. Ribs? In Vermont?
>
>They have to compensate for the weather somehow. ;)
>
>Cheers
>
>Phil Hobbs

--

Anybody can count to one.

- Robert Widlar

Re: Large scale RF shielding

<jdr8erF3hhmU1@mid.individual.net>

 copy mid

https://www.novabbs.com/tech/article-flat.php?id=96579&group=sci.electronics.design#96579

 copy link   Newsgroups: sci.electronics.design
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From: bow...@montana.com (rbowman)
Newsgroups: sci.electronics.design
Subject: Re: Large scale RF shielding
Date: Sun, 8 May 2022 19:18:17 -0600
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 by: rbowman - Mon, 9 May 2022 01:18 UTC

On 05/08/2022 03:35 PM, jlarkin@highlandsniptechnology.com wrote:
> On Sun, 8 May 2022 15:09:08 -0600, rbowman <bowman@montana.com> wrote:
>
>> On 05/08/2022 11:45 AM, jlarkin@highlandsniptechnology.com wrote:
>>> On Sun, 8 May 2022 10:37:17 -0600, rbowman <bowman@montana.com> wrote:
>>>
>>>> On 05/08/2022 02:48 AM, Martin Brown wrote:
>>>>> On 07/05/2022 17:23, rbowman wrote:
>>>>>> On 05/07/2022 02:12 AM, Martin Brown wrote:
>>>>>>> On 06/05/2022 17:31, Joe Gwinn wrote:
>>>>>>>> On Fri, 6 May 2022 10:46:00 +0100, Martin Brown
>>>>>>>> <'''newspam'''@nonad.co.uk> wrote:
>>>>>>>>
>>>>>>>
>>>>>>>>> High end car theft gangs in Belgium did a pretty good job with
>>>>>>>>> lining a
>>>>>>>>> largish HVG with supermarket grade aluminium foil and if memory serves
>>>>>>>>> lead flashing seals on the opening joints. Good enough Faraday cage to
>>>>>>>>> steal high end cars with notional satellite tracking on them anyway.
>>>>>>>>
>>>>>>>> Cute. I assume that HVG is some kind of lorry.
>>>>>>>
>>>>>>> Its a typo!
>>>>>>> For HGV = heavy goods vehicle 44T tractor trailer combo.
>>>>>>> US = big rig (but yours are max 64T?)
>>>>>>
>>>>>> 80,000 pounds, to avoid the ton ambiguity. Some states will license
>>>>>> 105,000 for intrastate traffic.
>>>>>
>>>>> It is only really a problem in the US where short tons are used to
>>>>> defraud the buyer of 10% of what they paid for. An Imperial or British
>>>>> ton and a metric Ton are close enough for most practical purposes.
>>>>>
>>>>> US short measure sharp practice gets you problems like the Gimli glider.
>>>>>
>>>>
>>>> A ton is defined as 20 hundredweights but a British hundredweight is 112
>>>> pounds for some obscure reason going back to stones, another strange
>>>> unit of measurement. Why there are 8 stones in a hundredweight also
>>>> escapes me. Actually Canada uses short tons.
>>>>
>>>> They did use the imperial gallon so I always thought I was getting a
>>>> bargain when buying gasoline in Canada. After going to the liter and the
>>>> loonie (Canadian dollar) falling to .75 USD, I gave up trying to figure
>>>> out how badly I was getting screwed. The US uses the Queen Anne's gallon
>>>> and wasn't about to adopt the Imperial system in 1826. We also retained
>>>> the Winchester bushel. I can't find a citation but it wouldn't surprise
>>>> me if a hundredweight was 100 pounds before 1826 too.
>>>>
>>>> Anyway the Gimli Glider was the end result of many more problems than a
>>>> simple conversion. It wasn't a high point for Air Canada. Boeing
>>>> certainly didn't help. I once worked for a firm that did fuel
>>>> measurement and management systems. We didn't assume the engines would
>>>> be running to keep the system powered up. Admittedly the systems
>>>> primarily went into military aircraft where a little wear and tear is
>>>> expected, but still...
>>>>
>>>
>>>
>>> This is one of my designs, or at least the hardware part is:
>>>
>>> http://www.highlandtechnology.com/DSS/P330DS.shtml
>>>
>>> Fuel volume measurement is tricky with a funny-shaped tank in a
>>> tiltable vehicle.
>>>
>>> Did you work for Simmonds?
>>>
>>>
>>>
>>
>> Yes, briefly. That was my first and last brush with DoD projects. It
>> didn't help that it was in the middle of the walker debacle and DISCO
>> put everything on hold as far as clearances went. I'd been hired to work
>> on the test kit software but when there's nothing to test...
>>
>> The upside was I had plenty of spare time to go down to Middlebury and
>> learn how to fly. The FBO was run by an ag pilot whose family had
>> originally built the strip for their spraying operation. It was
>> interesting to say the least. He had a couple of elderly Larks, one of
>> which added pumping up the brakes to the usual final approach protocol.
>>
>> I was moonlighting for another employee who had a side project going. He
>> contacted me almost a year later about some tax paperwork. I asked if
>> he'd written any code yet. The answer was no, they were still haggling
>> over the design document. I can fully understand why projects like the
>> F-35 have problems.
>>
>> I'd taken a contract at GE Ft. Wayne to develop a copier power supply
>> testing system and it was very refreshing to actually make progress.
>
>
> I did a tank gauging system for Simmonds, for LNG tanks on a giant
> barge, when I was with someone else. I did later interview with them,
> but I didn't think I'd like Vermont.

Excellent decision! That was the longest winter of my life and since I
grew up down around Troy NY, that's saying something.
>
> What I remembered was fabulous bbq ribs on some floating restaurant on
> Lake Champlain. Ribs? In Vermont?
>

Burlington is, um, different. Part of it is NYC escapees like Bernie
Sanders. UVM leavens the mixture, and IBM had a chip plant at Essex
Junction that they sold to GlobalFoundries when they went out of the fab
business.

I have to say UVM has a hell of a winter carnival. They should; they
have enough raw material to build a full size snow sculpture of the
World Trade Center.

I really can't judge how it is to work there under normal conditions.
The DISCO thing brought clearances to a screeching halt. They weren't
letting people go but there was little to do. It would have been
interesting since the test kits were to be programmed in FORTH for
extensibility. I did get to go to the FORTH conference in Rochester NY.

Re: Large scale RF shielding

<jdracgF3smkU1@mid.individual.net>

 copy mid

https://www.novabbs.com/tech/article-flat.php?id=96580&group=sci.electronics.design#96580

 copy link   Newsgroups: sci.electronics.design
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From: bow...@montana.com (rbowman)
Newsgroups: sci.electronics.design
Subject: Re: Large scale RF shielding
Date: Sun, 8 May 2022 19:51:09 -0600
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 by: rbowman - Mon, 9 May 2022 01:51 UTC

On 05/08/2022 05:31 PM, jlarkin@highlandsniptechnology.com wrote:
> On Sun, 8 May 2022 18:49:36 -0400, Phil Hobbs
> <pcdhSpamMeSenseless@electrooptical.net> wrote:
>
>> jlarkin@highlandsniptechnology.com wrote:
>>> On Sun, 8 May 2022 15:09:08 -0600, rbowman <bowman@montana.com> wrote:
>>>
>>>> On 05/08/2022 11:45 AM, jlarkin@highlandsniptechnology.com wrote:
>>>>> On Sun, 8 May 2022 10:37:17 -0600, rbowman <bowman@montana.com> wrote:
>>>>>
>>>>>> On 05/08/2022 02:48 AM, Martin Brown wrote:
>>>>>>> On 07/05/2022 17:23, rbowman wrote:
>>>>>>>> On 05/07/2022 02:12 AM, Martin Brown wrote:
>>>>>>>>> On 06/05/2022 17:31, Joe Gwinn wrote:
>>>>>>>>>> On Fri, 6 May 2022 10:46:00 +0100, Martin Brown
>>>>>>>>>> <'''newspam'''@nonad.co.uk> wrote:
>>>>>>>>>>
>>>>>>>>>
>>>>>>>>>>> High end car theft gangs in Belgium did a pretty good job with
>>>>>>>>>>> lining a
>>>>>>>>>>> largish HVG with supermarket grade aluminium foil and if memory serves
>>>>>>>>>>> lead flashing seals on the opening joints. Good enough Faraday cage to
>>>>>>>>>>> steal high end cars with notional satellite tracking on them anyway.
>>>>>>>>>>
>>>>>>>>>> Cute. I assume that HVG is some kind of lorry.
>>>>>>>>>
>>>>>>>>> Its a typo!
>>>>>>>>> For HGV = heavy goods vehicle 44T tractor trailer combo.
>>>>>>>>> US = big rig (but yours are max 64T?)
>>>>>>>>
>>>>>>>> 80,000 pounds, to avoid the ton ambiguity. Some states will license
>>>>>>>> 105,000 for intrastate traffic.
>>>>>>>
>>>>>>> It is only really a problem in the US where short tons are used to
>>>>>>> defraud the buyer of 10% of what they paid for. An Imperial or British
>>>>>>> ton and a metric Ton are close enough for most practical purposes.
>>>>>>>
>>>>>>> US short measure sharp practice gets you problems like the Gimli glider.
>>>>>>>
>>>>>>
>>>>>> A ton is defined as 20 hundredweights but a British hundredweight is 112
>>>>>> pounds for some obscure reason going back to stones, another strange
>>>>>> unit of measurement. Why there are 8 stones in a hundredweight also
>>>>>> escapes me. Actually Canada uses short tons.
>>>>>>
>>>>>> They did use the imperial gallon so I always thought I was getting a
>>>>>> bargain when buying gasoline in Canada. After going to the liter and the
>>>>>> loonie (Canadian dollar) falling to .75 USD, I gave up trying to figure
>>>>>> out how badly I was getting screwed. The US uses the Queen Anne's gallon
>>>>>> and wasn't about to adopt the Imperial system in 1826. We also retained
>>>>>> the Winchester bushel. I can't find a citation but it wouldn't surprise
>>>>>> me if a hundredweight was 100 pounds before 1826 too.
>>>>>>
>>>>>> Anyway the Gimli Glider was the end result of many more problems than a
>>>>>> simple conversion. It wasn't a high point for Air Canada. Boeing
>>>>>> certainly didn't help. I once worked for a firm that did fuel
>>>>>> measurement and management systems. We didn't assume the engines would
>>>>>> be running to keep the system powered up. Admittedly the systems
>>>>>> primarily went into military aircraft where a little wear and tear is
>>>>>> expected, but still...
>>>>>>
>>>>>
>>>>>
>>>>> This is one of my designs, or at least the hardware part is:
>>>>>
>>>>> http://www.highlandtechnology.com/DSS/P330DS.shtml
>>>>>
>>>>> Fuel volume measurement is tricky with a funny-shaped tank in a
>>>>> tiltable vehicle.
>>>>>
>>>>> Did you work for Simmonds?
>>>>>
>>>>>
>>>>>
>>>>
>>>> Yes, briefly. That was my first and last brush with DoD projects. It
>>>> didn't help that it was in the middle of the walker debacle and DISCO
>>>> put everything on hold as far as clearances went. I'd been hired to work
>>>> on the test kit software but when there's nothing to test...
>>>>
>>>> The upside was I had plenty of spare time to go down to Middlebury and
>>>> learn how to fly. The FBO was run by an ag pilot whose family had
>>>> originally built the strip for their spraying operation. It was
>>>> interesting to say the least. He had a couple of elderly Larks, one of
>>>> which added pumping up the brakes to the usual final approach protocol.
>>>>
>>>> I was moonlighting for another employee who had a side project going. He
>>>> contacted me almost a year later about some tax paperwork. I asked if
>>>> he'd written any code yet. The answer was no, they were still haggling
>>>> over the design document. I can fully understand why projects like the
>>>> F-35 have problems.
>>>>
>>>> I'd taken a contract at GE Ft. Wayne to develop a copier power supply
>>>> testing system and it was very refreshing to actually make progress.
>>>
>>>
>>> I did a tank gauging system for Simmonds, for LNG tanks on a giant
>>> barge, when I was with someone else. I did later interview with them,
>>> but I didn't think I'd like Vermont.
>>
>> My favourite technique for that sort of thing is the Helmholtz
>> resonance, which (to leading order) depends only on the air volume in
>> the tank, and not on its shape.
>
> We had two capacitive level probes and two inclinometers.

Measuring the fuel is only half the fun. Moving fuel to maintain the CG
within the envelope is the other half. One person at Simmonds was either
a hero or a pariah depending. Rather late in the project she pointed out
that in some configurations of the B-1 you couldn't pump enough fuel to
maintain the CG.

Then you have something like the AH-64. There are a number of auxiliary
tank configurations both internal and external to worry about and the
configuration determines how many Hellfire and/or 70 mm rockets you can
carry as well as how much 30mm ammo. Missiles, rockets, and ammo may be
expended at odd intervals. It gets more complex than bad math on the
Gimli glider.

As an aside, many military aircraft can't be flown by an unaided human.
Hopefully commercial aircraft aren't as 'advanced'. At least in the
Gimli generation a good pilot could set it down without engines or
instrumentation although I'm curious about the control surface
actuators. At least the hydraulics must not depend on both engines running.

Re: Large scale RF shielding

<cd305a7f-3351-c825-f703-98c076cb4512@electrooptical.net>

 copy mid

https://www.novabbs.com/tech/article-flat.php?id=96582&group=sci.electronics.design#96582

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Path: i2pn2.org!i2pn.org!eternal-september.org!reader02.eternal-september.org!.POSTED!not-for-mail
From: pcdhSpam...@electrooptical.net (Phil Hobbs)
Newsgroups: sci.electronics.design
Subject: Re: Large scale RF shielding
Date: Sun, 8 May 2022 22:24:53 -0400
Organization: A noiseless patient Spider
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 by: Phil Hobbs - Mon, 9 May 2022 02:24 UTC

rbowman wrote:
> On 05/08/2022 03:35 PM, jlarkin@highlandsniptechnology.com wrote:
>> On Sun, 8 May 2022 15:09:08 -0600, rbowman <bowman@montana.com> wrote:
>>
>>> On 05/08/2022 11:45 AM, jlarkin@highlandsniptechnology.com wrote:
>>>> On Sun, 8 May 2022 10:37:17 -0600, rbowman <bowman@montana.com> wrote:
>>>>
>>>>> On 05/08/2022 02:48 AM, Martin Brown wrote:
>>>>>> On 07/05/2022 17:23, rbowman wrote:
>>>>>>> On 05/07/2022 02:12 AM, Martin Brown wrote:
>>>>>>>> On 06/05/2022 17:31, Joe Gwinn wrote:
>>>>>>>>> On Fri, 6 May 2022 10:46:00 +0100, Martin Brown
>>>>>>>>> <'''newspam'''@nonad.co.uk> wrote:
>>>>>>>>>
>>>>>>>>
>>>>>>>>>> High end car theft gangs in Belgium did a pretty good job with
>>>>>>>>>> lining a
>>>>>>>>>> largish HVG with supermarket grade aluminium foil and if
>>>>>>>>>> memory serves
>>>>>>>>>> lead flashing seals on the opening joints. Good enough Faraday
>>>>>>>>>> cage to
>>>>>>>>>> steal high end cars with notional satellite tracking on them
>>>>>>>>>> anyway.
>>>>>>>>>
>>>>>>>>> Cute.  I assume that HVG is some kind of lorry.
>>>>>>>>
>>>>>>>> Its a typo!
>>>>>>>> For HGV = heavy goods vehicle 44T tractor trailer combo.
>>>>>>>> US  = big rig (but yours are max 64T?)
>>>>>>>
>>>>>>> 80,000 pounds, to avoid the ton ambiguity. Some states will license
>>>>>>> 105,000 for intrastate traffic.
>>>>>>
>>>>>> It is only really a problem in the US where short tons are used to
>>>>>> defraud the buyer of 10% of what they paid for. An Imperial or
>>>>>> British
>>>>>> ton and a metric Ton are close enough for most practical purposes.
>>>>>>
>>>>>> US short measure sharp practice gets you problems like the Gimli
>>>>>> glider.
>>>>>>
>>>>>
>>>>> A ton is defined as 20 hundredweights but a British hundredweight
>>>>> is 112
>>>>> pounds for some obscure reason going back to stones, another strange
>>>>> unit of measurement. Why there are 8 stones in a hundredweight also
>>>>> escapes me. Actually Canada uses short tons.
>>>>>
>>>>> They did use the imperial gallon so I always thought I was getting a
>>>>> bargain when buying gasoline in Canada. After going to the liter
>>>>> and the
>>>>> loonie (Canadian dollar) falling to .75 USD, I gave up trying to
>>>>> figure
>>>>> out how badly I was getting screwed. The US uses the Queen Anne's
>>>>> gallon
>>>>> and wasn't about to adopt the Imperial system in 1826. We also
>>>>> retained
>>>>> the Winchester bushel. I can't find a citation but it wouldn't
>>>>> surprise
>>>>> me if a hundredweight was 100 pounds before 1826 too.
>>>>>
>>>>> Anyway the Gimli Glider was the end result of many more problems
>>>>> than a
>>>>> simple conversion. It wasn't a high point for Air Canada. Boeing
>>>>> certainly didn't help. I once worked for a firm that did fuel
>>>>> measurement and management systems. We didn't assume the engines would
>>>>> be running to keep the system powered up. Admittedly the systems
>>>>> primarily went into military aircraft where a little wear and tear is
>>>>> expected, but still...
>>>>>
>>>>
>>>>
>>>> This is one of my designs, or at least the hardware part is:
>>>>
>>>> http://www.highlandtechnology.com/DSS/P330DS.shtml
>>>>
>>>> Fuel volume measurement is tricky with a funny-shaped tank in a
>>>> tiltable vehicle.
>>>>
>>>> Did you work for Simmonds?
>>>>
>>>>
>>>>
>>>
>>> Yes, briefly. That was my first and last brush with DoD projects. It
>>> didn't help that it was in the middle of the walker debacle and DISCO
>>> put everything on hold as far as clearances went. I'd been hired to work
>>> on the test kit software but when there's nothing to test...
>>>
>>> The upside was I had plenty of spare time to go down to Middlebury and
>>> learn how to fly. The FBO was run by an ag pilot whose family had
>>> originally built the strip for their spraying operation. It was
>>> interesting to say the least. He had a couple of elderly Larks, one of
>>> which added pumping up the brakes to the usual final approach protocol.
>>>
>>> I was moonlighting for another employee who had a side project going. He
>>> contacted me almost a year later about some tax paperwork. I asked if
>>> he'd written any code yet. The answer was no, they were still haggling
>>> over the design document. I can fully understand why projects like the
>>> F-35 have problems.
>>>
>>> I'd taken a contract at GE Ft. Wayne to develop a copier power supply
>>> testing system and it was very refreshing to actually make progress.
>>
>>
>> I did a tank gauging system for Simmonds, for LNG tanks on a giant
>> barge, when I was with someone else. I did later interview with them,
>> but I didn't think I'd like Vermont.
>
> Excellent decision! That was the longest winter of my life and since I
> grew up down around Troy NY, that's saying something.
>>
>> What I remembered was fabulous bbq ribs on some floating restaurant on
>> Lake Champlain. Ribs? In Vermont?
>>
>
> Burlington is, um, different. Part of it is NYC escapees like Bernie
> Sanders. UVM leavens the mixture, and IBM had a chip plant at Essex
> Junction that they sold to GlobalFoundries when they went out of the fab
> business.

If only. IBM had to _pay_ GF $1.5B to haul their fabs away. :(

I did a bunch of work with the Fishkill and Burlington folks BITD.

>
Cheers

Phil Hobbs
>
>

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

http://electrooptical.net
http://hobbs-eo.com

Re: Large scale RF shielding

<jdrm4vF5tviU1@mid.individual.net>

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From: bow...@montana.com (rbowman)
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Subject: Re: Large scale RF shielding
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 by: rbowman - Mon, 9 May 2022 05:11 UTC

On 05/08/2022 08:24 PM, Phil Hobbs wrote:
> If only. IBM had to _pay_ GF $1.5B to haul their fabs away. :(

I didn't get that part of the story. A high school/college friend spent
his career in Essex Junction and retired prior too the sale. He
mentioned IBM was out but didn't go into details.

https://www.poughkeepsiejournal.com/story/news/local/2021/06/21/ibm-globalfoundries-suing-over-east-fishkill-deal/7768785002/

It sounds like it's getting chewy.

My cousin worked there in Burlington in the '70s. There was a space
problem so her group was temporarily located in a former supermarket.
They would get the random person wandering in looking for pork chops.
True to the I've Been Moved philosophy she wound up in Tucson. At least
it doesn't snow there very often if you stay out of the mountains.

> I did a bunch of work with the Fishkill and Burlington folks BITD.

My friend worked at Fishkill on sort of a work/study program. As might
be expected RPI had close ties with IBM. Between IBM and the little
companies they spun off to avoid monopoly scrutiny it helped to offset
the manufacturing fleeing NYS.

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