I wonder if a stainless steel stock pot woulr be a useful RFI shield for
low level measurements, such as phase noise measurements.

The pot is available on Amazon and is the cheapest and largest I could
find. Here is the data. A picture is in the link:

Imusa Stainless Steel Stock Pot, 20 Quart

$46.77 FREE delivery July 17 - 18

Material : Stainless Steel
Colour : Silver
Capacity : 18.93 liters
Item dimensions : 37.5 x 28 cm : 37/2.54 = 14.5" X 11"

https://www.amazon.ca/Imusa-Stainless-Steel-Stock-Quart/dp/B0018EAMKA/

I am mainly interested in frequencies around 100 MHz. The lid is loose
fitting, but I could get some RF gasketing to make better contact.

The rf source is a local transmitter that obliterates all measurements.

Thanks for any help.

Mike

--
MRM

On Friday, 15 July 2022 at 19:29:02 UTC+2, Mike Monett wrote:
> I wonder if a stainless steel stock pot woulr be a useful RFI shield for
> low level measurements, such as phase noise measurements.
>
> The pot is available on Amazon and is the cheapest and largest I could
> find. Here is the data. A picture is in the link:
>
> Imusa Stainless Steel Stock Pot, 20 Quart
>
> $46.77 FREE delivery July 17 - 18
>
> Material : Stainless Steel
> Colour : Silver
> Capacity : 18.93 liters
> Item dimensions : 37.5 x 28 cm : 37/2.54 = 14.5" X 11"
>
> https://www.amazon.ca/Imusa-Stainless-Steel-Stock-Quart/dp/B0018EAMKA/
>
> I am mainly interested in frequencies around 100 MHz. The lid is loose
> fitting, but I could get some RF gasketing to make better contact.
>
> The rf source is a local transmitter that obliterates all measurements.
>
> Thanks for any help.
>
> Mike
>
>
> --
> MRM
expensive

Mike Monett wrote:
> I wonder if a stainless steel stock pot woulr be a useful RFI shield for
> low level measurements, such as phase noise measurements.
>
> The pot is available on Amazon and is the cheapest and largest I could
> find. Here is the data. A picture is in the link:
>
> Imusa Stainless Steel Stock Pot, 20 Quart
>
> $46.77 FREE delivery July 17 - 18
>
> Material : Stainless Steel
> Colour : Silver
> Capacity : 18.93 liters
> Item dimensions : 37.5 x 28 cm : 37/2.54 = 14.5" X 11"
>
> https://www.amazon.ca/Imusa-Stainless-Steel-Stock-Quart/dp/B0018EAMKA/
>
> I am mainly interested in frequencies around 100 MHz. The lid is loose
> fitting, but I could get some RF gasketing to make better contact.
>
> The rf source is a local transmitter that obliterates all measurements.
>
> Thanks for any help.
>
> Mike
>
>

If you can get good sealing on the lid, and get signals in and out.

Something like bulkhead-mount BNC F-F adapters for RF, and some
feedthrough caps for slower stuff.

I have a thousand or so Soviet 10 nF feedthroughs that I got on eBay
long ago--since I haven't sent your scintillator yet, I'll toss a
handful into the box.

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

On Friday, July 15, 2022 at 10:29:02 AM UTC-7, Mike Monett wrote:
> I wonder if a stainless steel stock pot woulr be a useful RFI shield for
> low level measurements, such as phase noise measurements.
>
> The pot is available on Amazon and is the cheapest and largest I could
> find.

Plain old soft tin-plate steel cans, like popcorn treats and saltines come in,
are good; any decent HVAC shop can bend up a galvanized box for you, and
at 100 MHz the seams shouldn't be a major problem. A big stock pot
is intermediate-sized by comparison. If you can put battery power inside
the box, and avoid DC/DC converters or clocked logic, that's a win.

On Fri, 15 Jul 2022 17:28:55 -0000 (UTC), Mike Monett <spamme@not.com>
wrote:

>I wonder if a stainless steel stock pot woulr be a useful RFI shield for
>low level measurements, such as phase noise measurements.
>
>The pot is available on Amazon and is the cheapest and largest I could
>find. Here is the data. A picture is in the link:
>
>Imusa Stainless Steel Stock Pot, 20 Quart
>
>$46.77 FREE delivery July 17 - 18
>
>Material : Stainless Steel
>Colour : Silver
>Capacity : 18.93 liters
>Item dimensions : 37.5 x 28 cm : 37/2.54 = 14.5" X 11"
>
>https://www.amazon.ca/Imusa-Stainless-Steel-Stock-Quart/dp/B0018EAMKA/
>
>I am mainly interested in frequencies around 100 MHz. The lid is loose
>fitting, but I could get some RF gasketing to make better contact.
>
>The rf source is a local transmitter that obliterates all measurements.
>
>Thanks for any help.
>
>Mike

Yes, but not any help for magnetic fields.

You could seal the lid fairly well with a wide strip of copper or
aluminum tape, like the stuff sold at Lowes.

And use it to make chicken broth. No canned junk approaches good
home-made broth.

Too bad it won't solder, but you can install SMA or BNC connectors.

https://www.dropbox.com/s/2uoeruouhcoz6al/Z482_Can.jpg?raw=1

https://www.dropbox.com/s/30c6aesh4tzjg56/Z496_Can.jpg?raw=1

whit3rd <whit3rd@gmail.com> wrote in
news:859ca810-27c1-47c5-9dad-76d605fb8554n@googlegroups.com:

> On Friday, July 15, 2022 at 10:29:02 AM UTC-7, Mike Monett wrote:
>> I wonder if a stainless steel stock pot woulr be a useful RFI
>> shield for low level measurements, such as phase noise
>> measurements.
>>
>> The pot is available on Amazon and is the cheapest and largest I
>> could find.
>
> Plain old soft tin-plate steel cans, like popcorn treats and
> saltines come in, are good; any decent HVAC shop can bend up a
> galvanized box for you, and at 100 MHz the seams shouldn't be a
> major problem. A big stock pot is intermediate-sized by
> comparison. If you can put battery power inside the box, and
> avoid DC/DC converters or clocked logic, that's a win.
>

Without any rf gasketing between the pot and the removeable lid, you
may want to buy a roll of copper tape to seal it up with. Tape it up
after closure remove after testing.

John Larkin <jlarkin@highland_atwork_technology.com> wrote in
news:ahi3dhllsmv72phkvg9332d659eof1bnph@4ax.com:

> On Fri, 15 Jul 2022 17:28:55 -0000 (UTC), Mike Monett
> <spamme@not.com> wrote:
>
>>I wonder if a stainless steel stock pot woulr be a useful RFI
>>shield for low level measurements, such as phase noise
>>measurements.
>>
>>The pot is available on Amazon and is the cheapest and largest I
>>could find. Here is the data. A picture is in the link:
>>
>>Imusa Stainless Steel Stock Pot, 20 Quart
>>
>>$46.77 FREE delivery July 17 - 18
>>
>>Material : Stainless Steel
>>Colour : Silver
>>Capacity : 18.93 liters
>>Item dimensions : 37.5 x 28 cm : 37/2.54 = 14.5" X 11"
>>
>>https://www.amazon.ca/Imusa-Stainless-Steel-Stock-Quart/dp/B0018EAM
>>KA/
>>
>>I am mainly interested in frequencies around 100 MHz. The lid is
>>loose fitting, but I could get some RF gasketing to make better
>>contact.
>>
>>The rf source is a local transmitter that obliterates all
>>measurements.
>>
>>Thanks for any help.
>>
>>Mike
>
> Yes, but not any help for magnetic fields.
>
> You could seal the lid fairly well with a wide strip of copper or
> aluminum tape, like the stuff sold at Lowes.
>
> And use it to make chicken broth. No canned junk approaches good
> home-made broth.
>
> Too bad it won't solder, but you can install SMA or BNC
> connectors.
>
> https://www.dropbox.com/s/2uoeruouhcoz6al/Z482_Can.jpg?raw=1
>
> https://www.dropbox.com/s/30c6aesh4tzjg56/Z496_Can.jpg?raw=1

He could line out the pot with 2 inch wide strips of Mu metal.
Even transformer lamination media would work.

Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote:

> If you can get good sealing on the lid, and get signals in and out.
>
> Something like bulkhead-mount BNC F-F adapters for RF, and some
> feedthrough caps for slower stuff.
>
> I have a thousand or so Soviet 10 nF feedthroughs that I got on eBay
> long ago--since I haven't sent your scintillator yet, I'll toss a
> handful into the box.
>
> Cheers
>
> Phil Hobbs

Thanks for the reply.

Amazon reviewers complain the lid is warped, but it could probably be
straightened. Maybe a weight on the lid might help, and some RF gasketing.

I was planning on BNC's, but the shielding on RG-58 is not very good:

"The state-of-the-art for RF leakage of flexible cables is given as
nominally �40 dBc for a single round wire braid, RG-8 and RG-58, and �60
dBc for double braid outer conductors", from

https://www.microwavejournal.com/articles/6007-improving-shielding-
effectiveness-of-flexible-coaxial-cables

From previous experience, the first 90% is easy. It's the last 10% that
drives you nuts. So with a FM station blasting rock on your doorstep, I
expect a serious fight.

Thanks for the news on the scintillator. I have some good information on
getting it up and running that I will put in a separate post. I know
everyone is just dying to learn how much radon gas is in their basement.

Let me know how much it costs so I can send you the money.

Thanks,

Mike

--
MRM

whit3rd <whit3rd@gmail.com> wrote:

> On Friday, July 15, 2022 at 10:29:02 AM UTC-7, Mike Monett wrote:
>> I wonder if a stainless steel stock pot woulr be a useful RFI shield
>> for low level measurements, such as phase noise measurements.
>>
>> The pot is available on Amazon and is the cheapest and largest I could
>> find.
>
> Plain old soft tin-plate steel cans, like popcorn treats and saltines
> come in, are good; any decent HVAC shop can bend up a galvanized box for
> you, and at 100 MHz the seams shouldn't be a major problem. A big
> stock pot is intermediate-sized by comparison. If you can put battery
> power inside the box, and avoid DC/DC converters or clocked logic,
> that's a win.

Thanks for the info. There will be some noisy things inside the pot, but it's
the outside interference that will be difficult. There's a FM station not far
away that obliterates all measurements.

--
MRM

fredag den 15. juli 2022 kl. 22.20.18 UTC+2 skrev John Larkin:
> On Fri, 15 Jul 2022 17:28:55 -0000 (UTC), Mike Monett <spa...@not.com>
> wrote:
> >I wonder if a stainless steel stock pot woulr be a useful RFI shield for
> >low level measurements, such as phase noise measurements.
> >
> >The pot is available on Amazon and is the cheapest and largest I could
> >find. Here is the data. A picture is in the link:
> >
> >Imusa Stainless Steel Stock Pot, 20 Quart
> >
> >$46.77 FREE delivery July 17 - 18
> >
> >Material : Stainless Steel
> >Colour : Silver
> >Capacity : 18.93 liters
> >Item dimensions : 37.5 x 28 cm : 37/2.54 = 14.5" X 11"
> >
> >https://www.amazon.ca/Imusa-Stainless-Steel-Stock-Quart/dp/B0018EAMKA/
> >
> >I am mainly interested in frequencies around 100 MHz. The lid is loose
> >fitting, but I could get some RF gasketing to make better contact.
> >
> >The rf source is a local transmitter that obliterates all measurements.
> >
> >Thanks for any help.
> >
> >Mike
> Yes, but not any help for magnetic fields.
>
> You could seal the lid fairly well with a wide strip of copper or
> aluminum tape, like the stuff sold at Lowes.
>
> And use it to make chicken broth. No canned junk approaches good
> home-made broth.
>
> Too bad it won't solder, but you can install SMA or BNC connectors.
>
> https://www.dropbox.com/s/2uoeruouhcoz6al/Z482_Can.jpg?raw=1
>
> https://www.dropbox.com/s/30c6aesh4tzjg56/Z496_Can.jpg?raw=1

with a more aggressive fluss stainless solder easily with a normal soldering iron and solder

but it is probably not easy to something as substantial as a pot hot enough without melting the connector

much easier to get some of these:

https://www.amazon.com/outstanding-SMA-Female-Waterproof-Bulkhead-Connector/dp/B07BXZ2NDV

On 2022-07-15, Mike Monett <spamme@not.com> wrote:
> I wonder if a stainless steel stock pot woulr be a useful RFI shield for
> low level measurements, such as phase noise measurements.

Is there a reason why you're not considering paint cans?

--
Jasen.

On Friday, July 15, 2022 at 1:40:07 PM UTC-7, DecadentLinux...@decadence.org wrote:
> whit3rd <whi...@gmail.com> wrote in
> news:859ca810-27c1-47c5...@googlegroups.com:
> > On Friday, July 15, 2022 at 10:29:02 AM UTC-7, Mike Monett wrote:
> >> I wonder if a stainless steel stock pot woulr be a useful RFI
> >> shield for low level measurements, such as phase noise
> >> measurements.

> > Plain old soft tin-plate steel cans, like popcorn treats and
> > saltines come in, are good; any decent HVAC shop can bend up a
> > galvanized box for you, and at 100 MHz the seams shouldn't be a
> > major problem. A big stock pot is intermediate-sized by
> > comparison. If you can put battery power inside the box, and
> > avoid DC/DC converters or clocked logic, that's a win.

> Without any rf gasketing between the pot and the removeable lid, you
> may want to buy a roll of copper tape to seal it up with. Tape it up
> after closure remove after testing.

Or, have the lid brazed into its seat; build a bolt-able flange door into the flat kettle bottom, if easy entry
is required. A domed lid wouldn't be easy to seal. I wonder if a salt-water bath containing
the lid would be good enough conductivity, just drop the kettle on top of that... quick and dirty.

There once was a reciprocating mechanism to be fitted to a motor, that we just terminated in
a brass cup. The motor got a brass ball, and we soft-soldered 'em to connect (and disconnected
with a torch). We liked rigidity with minimal moving mass.

Lasse Langwadt Christensen <langwadt@fonz.dk> wrote:

[...]

> with a more aggressive fluss stainless solder easily with a normal
> soldering iron and solder
>
> but it is probably not easy to something as substantial as a pot hot
> enough without melting the connector
>
> much easier to get some of these:
>
> https://www.amazon.com/outstanding-SMA-Female-Waterproof-Bulkhead-Connect
> or/dp/B07BXZ2NDV

Thanks for the link on SMA.

The problem with RG-58 is it only gives 40-60dB of attenuation to leakage:

https://www.microwavejournal.com/articles/6007-improving-shielding-
effectiveness-of-flexible-coaxial-cables

There are a few manufacturers of coax with foil plus braid shield. It's not
expensive. I'll get some and try it:

https://www.pimfg.com/product-detail/RG-58-U
https://www.summitsource.com/RG-58-Dual-Shielded-C646.aspx
https://www.tessco.com/product/rg58-size-coaxial-cable-10849

Thanks,

Mike

--
MRM

whit3rd <whit3rd@gmail.com> wrote:

[...]

> Or, have the lid brazed into its seat; build a bolt-able flange door
> into the flat kettle bottom, if easy entry is required. A domed lid
> wouldn't be easy to seal. I wonder if a salt-water bath containing
> the lid would be good enough conductivity, just drop the kettle on top
> of that... quick and dirty.

Thanks for the idea. There's plenty of RF gasket available.

--
MRM

On Fri, 15 Jul 2022 20:42:45 -0000 (UTC),
DecadentLinuxUserNumeroUno@decadence.org wrote:

>John Larkin <jlarkin@highland_atwork_technology.com> wrote in
>news:ahi3dhllsmv72phkvg9332d659eof1bnph@4ax.com:
>
>> On Fri, 15 Jul 2022 17:28:55 -0000 (UTC), Mike Monett
>> <spamme@not.com> wrote:
>>
>>>I wonder if a stainless steel stock pot woulr be a useful RFI
>>>shield for low level measurements, such as phase noise
>>>measurements.
>>>
>>>The pot is available on Amazon and is the cheapest and largest I
>>>could find. Here is the data. A picture is in the link:
>>>
>>>Imusa Stainless Steel Stock Pot, 20 Quart
>>>
>>>$46.77 FREE delivery July 17 - 18
>>>
>>>Material : Stainless Steel
>>>Colour : Silver
>>>Capacity : 18.93 liters
>>>Item dimensions : 37.5 x 28 cm : 37/2.54 = 14.5" X 11"
>>>
>>>https://www.amazon.ca/Imusa-Stainless-Steel-Stock-Quart/dp/B0018EAM
>>>KA/
>>>
>>>I am mainly interested in frequencies around 100 MHz. The lid is
>>>loose fitting, but I could get some RF gasketing to make better
>>>contact.
>>>
>>>The rf source is a local transmitter that obliterates all
>>>measurements.
>>>
>>>Thanks for any help.
>>>
>>>Mike
>>
>> Yes, but not any help for magnetic fields.
>>
>> You could seal the lid fairly well with a wide strip of copper or
>> aluminum tape, like the stuff sold at Lowes.
>>
>> And use it to make chicken broth. No canned junk approaches good
>> home-made broth.
>>
>> Too bad it won't solder, but you can install SMA or BNC
>> connectors.
>>
>> https://www.dropbox.com/s/2uoeruouhcoz6al/Z482_Can.jpg?raw=1
>>
>> https://www.dropbox.com/s/30c6aesh4tzjg56/Z496_Can.jpg?raw=1
>
> He could line out the pot with 2 inch wide strips of Mu metal.
>Even transformer lamination media would work.

It's really hard to shield a substantial volume from low frequency mag
fields. A chunky steel Hoffman box is basically transparent. Mumetal
foil is useless.

Thick copper eddy-current shielding sort of works, but that ss pot
won't do much.

On Fri, 15 Jul 2022 14:21:28 -0700 (PDT), Lasse Langwadt Christensen
<langwadt@fonz.dk> wrote:

>fredag den 15. juli 2022 kl. 22.20.18 UTC+2 skrev John Larkin:
>> On Fri, 15 Jul 2022 17:28:55 -0000 (UTC), Mike Monett <spa...@not.com>
>> wrote:
>> >I wonder if a stainless steel stock pot woulr be a useful RFI shield for
>> >low level measurements, such as phase noise measurements.
>> >
>> >The pot is available on Amazon and is the cheapest and largest I could
>> >find. Here is the data. A picture is in the link:
>> >
>> >Imusa Stainless Steel Stock Pot, 20 Quart
>> >
>> >$46.77 FREE delivery July 17 - 18
>> >
>> >Material : Stainless Steel
>> >Colour : Silver
>> >Capacity : 18.93 liters
>> >Item dimensions : 37.5 x 28 cm : 37/2.54 = 14.5" X 11"
>> >
>> >https://www.amazon.ca/Imusa-Stainless-Steel-Stock-Quart/dp/B0018EAMKA/
>> >
>> >I am mainly interested in frequencies around 100 MHz. The lid is loose
>> >fitting, but I could get some RF gasketing to make better contact.
>> >
>> >The rf source is a local transmitter that obliterates all measurements.
>> >
>> >Thanks for any help.
>> >
>> >Mike
>> Yes, but not any help for magnetic fields.
>>
>> You could seal the lid fairly well with a wide strip of copper or
>> aluminum tape, like the stuff sold at Lowes.
>>
>> And use it to make chicken broth. No canned junk approaches good
>> home-made broth.
>>
>> Too bad it won't solder, but you can install SMA or BNC connectors.
>>
>> https://www.dropbox.com/s/2uoeruouhcoz6al/Z482_Can.jpg?raw=1
>>
>> https://www.dropbox.com/s/30c6aesh4tzjg56/Z496_Can.jpg?raw=1
>
>with a more aggressive fluss stainless solder easily with a normal soldering iron and solder
>
>but it is probably not easy to something as substantial as a pot hot enough without melting the connector
>
>much easier to get some of these:
>
>https://www.amazon.com/outstanding-SMA-Female-Waterproof-Bulkhead-Connector/dp/B07BXZ2NDV

Those are cool. You can screw an SMA lowpass filter or attenuator on
one side for better isolation.

On Sat, 16 Jul 2022 04:37:51 -0000 (UTC), Mike Monett <spamme@not.com>
wrote:

>Lasse Langwadt Christensen <langwadt@fonz.dk> wrote:
>
>[...]
>
>> with a more aggressive fluss stainless solder easily with a normal
>> soldering iron and solder
>>
>> but it is probably not easy to something as substantial as a pot hot
>> enough without melting the connector
>>
>> much easier to get some of these:
>>
>> https://www.amazon.com/outstanding-SMA-Female-Waterproof-Bulkhead-Connect
>> or/dp/B07BXZ2NDV
>
>Thanks for the link on SMA.
>
>The problem with RG-58 is it only gives 40-60dB of attenuation to leakage:
>
>https://www.microwavejournal.com/articles/6007-improving-shielding-
>effectiveness-of-flexible-coaxial-cables
>
>There are a few manufacturers of coax with foil plus braid shield. It's not
>expensive. I'll get some and try it:
>
>https://www.pimfg.com/product-detail/RG-58-U
>https://www.summitsource.com/RG-58-Dual-Shielded-C646.aspx
>https://www.tessco.com/product/rg58-size-coaxial-cable-10849
>
>Thanks,
>
>Mike
>

Tinned braid coax, semi-hardline, is great. ebay has assortments,
probably pulled from old RF gear or leftover custom stuff.

On Sat, 16 Jul 2022 01:57:27 -0000 (UTC), Jasen Betts
<usenet@revmaps.no-ip.org> wrote:

>On 2022-07-15, Mike Monett <spamme@not.com> wrote:
>> I wonder if a stainless steel stock pot woulr be a useful RFI shield for
>> low level measurements, such as phase noise measurements.
>
>Is there a reason why you're not considering paint cans?

Danish butter cookies and chocolates taste better than paint.

John Larkin wrote:
> On Fri, 15 Jul 2022 17:28:55 -0000 (UTC), Mike Monett <spamme@not.com>
> wrote:
>
>> I wonder if a stainless steel stock pot woulr be a useful RFI shield for
>> low level measurements, such as phase noise measurements.
>>
>> The pot is available on Amazon and is the cheapest and largest I could
>> find. Here is the data. A picture is in the link:
>>
>> Imusa Stainless Steel Stock Pot, 20 Quart
>>
>> $46.77 FREE delivery July 17 - 18
>>
>> Material : Stainless Steel
>> Colour : Silver
>> Capacity : 18.93 liters
>> Item dimensions : 37.5 x 28 cm : 37/2.54 = 14.5" X 11"
>>
>> https://www.amazon.ca/Imusa-Stainless-Steel-Stock-Quart/dp/B0018EAMKA/
>>
>> I am mainly interested in frequencies around 100 MHz. The lid is loose
>> fitting, but I could get some RF gasketing to make better contact.
>>
>> The rf source is a local transmitter that obliterates all measurements.
>>
>> Thanks for any help.
>>
>> Mike
>
> Yes, but not any help for magnetic fields.
>
> You could seal the lid fairly well with a wide strip of copper or
> aluminum tape, like the stuff sold at Lowes.
>
> And use it to make chicken broth. No canned junk approaches good
> home-made broth.
>
> Too bad it won't solder, but you can install SMA or BNC connectors.
>
> https://www.dropbox.com/s/2uoeruouhcoz6al/Z482_Can.jpg?raw=1
>
> https://www.dropbox.com/s/30c6aesh4tzjg56/Z496_Can.jpg?raw=1

If your gizmo will fit, gallon paint cans are a lot cheaper and have
really excellent RF sealing.

Cheers

Phil Hobbs

Mike Monett wrote:
> Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote:
>
>> If you can get good sealing on the lid, and get signals in and out.
>>
>> Something like bulkhead-mount BNC F-F adapters for RF, and some
>> feedthrough caps for slower stuff.
>>
>> I have a thousand or so Soviet 10 nF feedthroughs that I got on eBay
>> long ago--since I haven't sent your scintillator yet, I'll toss a
>> handful into the box.
>>
>> Cheers
>>
>> Phil Hobbs
>
> Thanks for the reply.
>
> Amazon reviewers complain the lid is warped, but it could probably be
> straightened. Maybe a weight on the lid might help, and some RF gasketing.
>
> I was planning on BNC's, but the shielding on RG-58 is not very good:
>
> "The state-of-the-art for RF leakage of flexible cables is given as
> nominally –40 dBc for a single round wire braid, RG-8 and RG-58, and –60
> dBc for double braid outer conductors", from
>
> https://www.microwavejournal.com/articles/6007-improving-shielding-
> effectiveness-of-flexible-coaxial-cables
>
> From previous experience, the first 90% is easy. It's the last 10% that
> drives you nuts. So with a FM station blasting rock on your doorstep, I
> expect a serious fight.
>
> Thanks for the news on the scintillator. I have some good information on
> getting it up and running that I will put in a separate post. I know
> everyone is just dying to learn how much radon gas is in their basement.
>
> Let me know how much it costs so I can send you the money.

Nah, no worries--it's very short money. We techies have to stick
together. I'll send it Monday.

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

Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote:

> Mike Monett wrote:

[...]

>> Let me know how much it costs so I can send you the money.
>
> Nah, no worries--it's very short money. We techies have to stick
> together. I'll send it Monday.
>
> Cheers
>
> Phil Hobbs

That's great news. Thanks Very Much!

--
MRM

On Fri, 15 Jul 2022 17:28:55 -0000 (UTC), Mike Monett <spamme@not.com>
wrote:

>I wonder if a stainless steel stock pot woulr be a useful RFI shield for
>low level measurements, such as phase noise measurements.
>
>The pot is available on Amazon and is the cheapest and largest I could
>find. Here is the data. A picture is in the link:
>
>Imusa Stainless Steel Stock Pot, 20 Quart
>
>$46.77 FREE delivery July 17 - 18
>
>Material : Stainless Steel
>Colour : Silver
>Capacity : 18.93 liters
>Item dimensions : 37.5 x 28 cm : 37/2.54 = 14.5" X 11"
>
>https://www.amazon.ca/Imusa-Stainless-Steel-Stock-Quart/dp/B0018EAMKA/
>
>I am mainly interested in frequencies around 100 MHz. The lid is loose
>fitting, but I could get some RF gasketing to make better contact.
>
>The rf source is a local transmitter that obliterates all measurements.
>
>Thanks for any help.
>
>Mike

For anything that had to leave the lab without a red face,
I've resorted to surplus steel ammo boxes. The contacting
surfaces can be ground and there's plenty of force-fit area
in the hermetic gasket to include em-compatible material.

RL

jlarkin@highlandsniptechnology.com wrote in
news:isi5dh90k2s11p9b68ppec1psmkiqeso58@4ax.com:

> On Fri, 15 Jul 2022 20:42:45 -0000 (UTC),
> DecadentLinuxUserNumeroUno@decadence.org wrote:
>
>>John Larkin <jlarkin@highland_atwork_technology.com> wrote in
>>news:ahi3dhllsmv72phkvg9332d659eof1bnph@4ax.com:
>>
>>> On Fri, 15 Jul 2022 17:28:55 -0000 (UTC), Mike Monett
>>> <spamme@not.com> wrote:
>>>
>>>>I wonder if a stainless steel stock pot woulr be a useful RFI
>>>>shield for low level measurements, such as phase noise
>>>>measurements.
>>>>
>>>>The pot is available on Amazon and is the cheapest and largest I
>>>>could find. Here is the data. A picture is in the link:
>>>>
>>>>Imusa Stainless Steel Stock Pot, 20 Quart
>>>>
>>>>$46.77 FREE delivery July 17 - 18
>>>>
>>>>Material : Stainless Steel
>>>>Colour : Silver
>>>>Capacity : 18.93 liters
>>>>Item dimensions : 37.5 x 28 cm : 37/2.54 = 14.5" X 11"
>>>>
>>>>https://www.amazon.ca/Imusa-Stainless-Steel-Stock-Quart/dp/B0018E
>>>>AM KA/
>>>>
>>>>I am mainly interested in frequencies around 100 MHz. The lid is
>>>>loose fitting, but I could get some RF gasketing to make better
>>>>contact.
>>>>
>>>>The rf source is a local transmitter that obliterates all
>>>>measurements.
>>>>
>>>>Thanks for any help.
>>>>
>>>>Mike
>>>
>>> Yes, but not any help for magnetic fields.
>>>
>>> You could seal the lid fairly well with a wide strip of copper
>>> or aluminum tape, like the stuff sold at Lowes.
>>>
>>> And use it to make chicken broth. No canned junk approaches good
>>> home-made broth.
>>>
>>> Too bad it won't solder, but you can install SMA or BNC
>>> connectors.
>>>
>>> https://www.dropbox.com/s/2uoeruouhcoz6al/Z482_Can.jpg?raw=1
>>>
>>> https://www.dropbox.com/s/30c6aesh4tzjg56/Z496_Can.jpg?raw=1
>>
>> He could line out the pot with 2 inch wide strips of Mu metal.
>>Even transformer lamination media would work.
>
> It's really hard to shield a substantial volume from low frequency
> mag fields.

You spelled "impossible" wrong. Instead of "None shall pass", it
is "All shall pass"... The trick is diversion.

> A chunky steel Hoffman box is basically transparent.
> Mumetal foil is useless.
>
> Thick copper eddy-current shielding sort of works, but that ss pot
> won't do much.
>

I made a ground penetrating radio once... it was a very low
frequency, and a very low 'baud rate'.

It can pass through planets (fields)... I think a little steel pot
wont stop it either. Redirection or diversion is the key to
obtaining an attenuated level of influence.

On Friday, July 15, 2022 at 1:29:02 PM UTC-4, Mike Monett wrote:
> I wonder if a stainless steel stock pot woulr be a useful RFI shield for
> low level measurements, such as phase noise measurements.
>
> The pot is available on Amazon and is the cheapest and largest I could
> find. Here is the data. A picture is in the link:
>
> Imusa Stainless Steel Stock Pot, 20 Quart
>
> $46.77 FREE delivery July 17 - 18
>
> Material : Stainless Steel
> Colour : Silver
> Capacity : 18.93 liters
> Item dimensions : 37.5 x 28 cm : 37/2.54 = 14.5" X 11"
>
> https://www.amazon.ca/Imusa-Stainless-Steel-Stock-Quart/dp/B0018EAMKA/
>
> I am mainly interested in frequencies around 100 MHz. The lid is loose
> fitting, but I could get some RF gasketing to make better contact.
>
> The rf source is a local transmitter that obliterates all measurements.
>
> Thanks for any help.

You can get a 6-gallon galvanized steel garbage can with lid for under $20 (Behrens). You're going to need a gasket whichever type you use.
You can spiral wrap some weather stripping with this for the lid gasket- about 45 inches.
https://www.amazon.com/ANGKEEL-Conductive-Grounding-Interference-Electrical/dp/B097HPSLTH/ref=sr_1_3
>
> Mike
>
>
> --
> MRM

Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote:

[...]

> If your gizmo will fit, gallon paint cans are a lot cheaper and have
> really excellent RF sealing.
>
> Cheers
>
> Phil Hobbs

Superb suggestion. A paint can from Home Depot will fit inside the stock
pot:

BEAUTITONE Empty Paint Can - with Lid & Handle, 4 L

6.50" Dia, 7.70" High

$7.99 /EA + shipping $13.15

https://www.homehardware.ca/en/4l-empty-paint-can-with-lid-and-
handle/p/1610806

This will give double shielding, like the old Marconi signal generators. It
will certainly help solve the problem of coax leakage for some of the
signals.

Thanks,

Mike

--
MRM