From Newsgroup: comp.sys.raspberry-pi

On 12/24/25 15:07, The Natural Philosopher wrote:

On 24/12/2025 17:00, Kerr-Mudd, John wrote:

On Wed, 24 Dec 2025 14:23:45 +0000
The Natural Philosopher <tnp@invalid.invalid> wrote:

[]

What I learned was that theory is too simplified to actually be able to
design a real antenna: All our designs were field tested and adjusted.

I am not advocating Pringle cans.-a I wouldnt use one myself. But I am
not so quick to rubbish them as you are.

RF propagation is tricky, and real world objects of no apparent value
often have enormous effects.

Prsumably you're saying Mythbusters-style "not proven"?

I am saying that a blanket denial 'because the theory says no' is not
good enough for me, personally.

To make a waveguide, which is analysable, is quite tricky. To throw something in place that 'does something' and clearly is *not* a
waveguide, and is essentially unanalysable, is another matter.

With Gigahertz, as with Heffalumps, you never know...

Yep, once you get into gHz things get really weird.

"Solutions" here can work for NO GOOD REASON, pure
chance, funky reflections.

Moved a unit literally four inches the other day and
the data rate went up nearly 5X.

Yes, a cheapo foil-lined tube CAN be a a waveguide,
but the math has to work out.

Me, I can't use waveguides because I need an OMNI
signal the way things are spaced out in my home.
I use one, sometimes two, wifi repeaters instead.
Fairly cheap, work well.

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From Newsgroup: comp.sys.raspberry-pi

On Wed, 24 Dec 2025 12:16:27 +0000, The Natural Philosopher wrote:

On 24/12/2025 07:58, mm0fmf wrote:

On 11/12/2025 21:18, Carlos E.R. wrote:

Home made with a box of Pringles. just google for "pringles wifi
antenna".

Also Google cutoff frequency and see that the Pringle tube is too small
in diameter to be effective at 2.4GHz.

Assuming that is a relevant issue.

Shouting down a pipe whose diameter is way less than the wavlength of
voice frequencies, still works....

True, but the benefits of impedance matching with a megaphone were
discovered long ago.
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From Newsgroup: comp.sys.raspberry-pi

On 24/12/2025 23:17, mm0fmf wrote:

On 24/12/2025 20:07, The Natural Philosopher wrote:

With Gigahertz, as with Heffalumps, you never know...

Some of us do know.

Some of us have worked with RF.
--
rCLI know that most men, including those at ease with problems of the greatest complexity, can seldom accept even the simplest and most
obvious truth if it be such as would oblige them to admit the falsity of conclusions which they have delighted in explaining to colleagues, which
they have proudly taught to others, and which they have woven, thread by thread, into the fabric of their lives.rCY

rCo Leo Tolstoy

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From Newsgroup: comp.sys.raspberry-pi

On 2025-12-24, mm0fmf <none@invalid.com> wrote:

On 11/12/2025 21:18, Carlos E.R. wrote:

Home made with a box of Pringles. just google for "pringles wifi antenna".

Also Google cutoff frequency and see that the Pringle tube is too small
in diameter to be effective at 2.4GHz.

Of course, designs on the internet do not have to follow the laws of physics! :-)

If you need a different diameter and know what diameter you need,
any decent hardware store or home improvement big-box store in
the US and perhaps elsewhere will have a wide assortment of sizes
of PVC, ABS, and metal pipes and round conduits. Some adhesive
and copper foil would seem likely to be useful for making the
plastic types useable.
--
Robert Riches
spamtrap42@jacob21819.net
(Yes, that is one of my email addresses.)
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From Newsgroup: comp.sys.raspberry-pi

On 25/12/2025 03:25, Robert Riches wrote:

On 2025-12-24, mm0fmf <none@invalid.com> wrote:

On 11/12/2025 21:18, Carlos E.R. wrote:

Home made with a box of Pringles. just google for "pringles wifi antenna". >>

Also Google cutoff frequency and see that the Pringle tube is too small
in diameter to be effective at 2.4GHz.

Of course, designs on the internet do not have to follow the laws of
physics! :-)

If you need a different diameter and know what diameter you need,
any decent hardware store or home improvement big-box store in
the US and perhaps elsewhere will have a wide assortment of sizes
of PVC, ABS, and metal pipes and round conduits. Some adhesive
and copper foil would seem likely to be useful for making the
plastic types useable.

If I felt that a design of any sort could be connected to a Pi Pico W I
would 3D print it.
But in the end the simpler approach was to create a wifi point higher up.

Signal strength varies wildly, but enough transmissions get through...
--
"Strange as it seems, no amount of learning can cure stupidity, and
higher education positively fortifies it."

- Stephen Vizinczey


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From Newsgroup: comp.sys.raspberry-pi

On Thu, 25 Dec 2025 03:23:15 +0000, The Natural Philosopher wrote:

On 24/12/2025 23:17, mm0fmf wrote:

On 24/12/2025 20:07, The Natural Philosopher wrote:

With Gigahertz, as with Heffalumps, you never know...

Some of us do know.

Some of us have worked with RF.

That was my first real job -- 15 kw of it at around 100 MHz. Why is that fluorescent tube lighting with nothing attached to it?
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From Newsgroup: comp.sys.raspberry-pi

On Thu, 25 Dec 2025 03:34:30 +0000
The Natural Philosopher <tnp@invalid.invalid> wrote:

On 25/12/2025 03:25, Robert Riches wrote:

On 2025-12-24, mm0fmf <none@invalid.com> wrote:

On 11/12/2025 21:18, Carlos E.R. wrote:

Home made with a box of Pringles. just google for "pringles wifi antenna".

Also Google cutoff frequency and see that the Pringle tube is too small
in diameter to be effective at 2.4GHz.

Of course, designs on the internet do not have to follow the laws of
physics! :-)

If you need a different diameter and know what diameter you need,
any decent hardware store or home improvement big-box store in
the US and perhaps elsewhere will have a wide assortment of sizes
of PVC, ABS, and metal pipes and round conduits. Some adhesive
and copper foil would seem likely to be useful for making the
plastic types useable.

If I felt that a design of any sort could be connected to a Pi Pico W I would 3D print it.
But in the end the simpler approach was to create a wifi point higher up.

Signal strength varies wildly, but enough transmissions get through...

But what do I do with all these spare Pringle tubes:-?
--
Bah, and indeed Humbug.
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From Newsgroup: comp.sys.raspberry-pi

On 25/12/2025 10:43, Kerr-Mudd, John wrote:

But what do I do with all these spare Pringle tubes:-?

Tell them to marry Meghan Markle and write a whiny book
--
"It was a lot more fun being 20 in the 70's that it is being 70 in the 20's" Joew Walsh

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From Newsgroup: comp.sys.raspberry-pi

On Thu, 25 Dec 2025 10:43:18 +0000, Kerr-Mudd, John wrote:

But what do I do with all these spare Pringle tubes:-?

Build a Hamster Habitat.

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From Newsgroup: comp.sys.raspberry-pi

On 2025-12-24 15:23, The Natural Philosopher wrote:

On 24/12/2025 14:04, John R Walliker wrote:

On 24/12/2025 12:16, The Natural Philosopher wrote:

On 24/12/2025 07:58, mm0fmf wrote:

On 11/12/2025 21:18, Carlos E.R. wrote:

Home made with a box of Pringles. just google for "pringles wifi
antenna".

Also Google cutoff frequency and see that the Pringle tube is too
small in diameter to be effective at 2.4GHz.

Assuming that is a relevant issue.

Shouting down a pipe whose diameter is way less than the wavlength of
voice frequencies, still works....

Of course, designs on the internet do not have to follow the laws of
physics! :-)

..especially for people who don't fully understand them...

Indeed.-a And I'm sure you are perfectly well aware of the difference
between longitudinal sound waves propagating down a narrow pipe and
transverse electromagnetic waves in a waveguide.

An antenna is not a waveguide.

If a Pringles can were highly conductive it would have a cutoff
frequency of close to 2.4GHz so the attenuation would be very high.
However, a very thin layer of aluminium on the inside of a cardboard
tube will be so resistive that it will not make a lot of difference.

A statement which clearly contradicts the well known skin effect of conductirs at high frequencies.

For many purposes a well made half-wave dipole or quarter-wave
monopole gives excellent results which are far better than anything
that can be achieved with small pcb antennas.

Sure. Most routers come with wavelength sized wobbly penises that give
you a few dB.

A quarter wave monopole made from relatively thick wire or rod can
be an excellent match to 50 ohm coax so long as the ground plane
is at least a few wavelengths across.

A half-wave dipole combined with a coaxial balun can also be a very
good match but has a slightly narrower bandwidth due to the
frequency dependency of the coax balun.-a The choice of which one to
use depends mostly on how the antenna is to be mounted.

An almost omnidirectional antenna with very low losses can be
more effective than a lossy directional one.

John

Nevertheless I have seem that sort of design work.
I worked around radar antennae briefly in the 1960s.

What I learned was that theory is too simplified to actually be able to design a real antenna: All our designs were field tested and adjusted.

I am not advocating Pringle cans.-a I wouldnt use one myself. But I am
not so quick to rubbish them as you are.

RF propagation is tricky, and real world objects of no apparent value
often have enormous effects.

I just say that once I built a Pringles antenna at a training course,
and it does work. Inside the tube there is a threaded metal rod with a
number of nuts and washers that had to be put at precise distances
according to the instructions we followed.

Black magic.

We did not have any tool to measure gain, but indeed the router read a
higher signal that with its manufacturer antena. And it was directional.
I can not give any number because I don't remember where my notes are.


Back to the original subject of the thread and to topic; Some of the
designs out there just put an USB dongle inside the tube, and they work, somehow. No need to actually have a wifi card with socket for the
antenna. If the Pi is small enough (I have no idea) there will be
designs out there using it.
--
Cheers, Carlos.
ESEfc-Efc+, EUEfc-Efc|;
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From Newsgroup: comp.sys.raspberry-pi

On 27/12/2025 20:51, Carlos E.R. wrote:

On 2025-12-24 15:23, The Natural Philosopher wrote:

On 24/12/2025 14:04, John R Walliker wrote:

On 24/12/2025 12:16, The Natural Philosopher wrote:

On 24/12/2025 07:58, mm0fmf wrote:

On 11/12/2025 21:18, Carlos E.R. wrote:

Home made with a box of Pringles. just google for "pringles wifi
antenna".

Also Google cutoff frequency and see that the Pringle tube is too
small in diameter to be effective at 2.4GHz.

Assuming that is a relevant issue.

Shouting down a pipe whose diameter is way less than the wavlength
of voice frequencies, still works....

Of course, designs on the internet do not have to follow the laws
of physics! :-)

..especially for people who don't fully understand them...

Indeed.-a And I'm sure you are perfectly well aware of the difference
between longitudinal sound waves propagating down a narrow pipe and
transverse electromagnetic waves in a waveguide.

An antenna is not a waveguide.

If a Pringles can were highly conductive it would have a cutoff
frequency of close to 2.4GHz so the attenuation would be very high.
However, a very thin layer of aluminium on the inside of a cardboard
tube will be so resistive that it will not make a lot of difference.

A statement which clearly contradicts the well known skin effect of
conductirs at high frequencies.

For many purposes a well made half-wave dipole or quarter-wave
monopole gives excellent results which are far better than anything
that can be achieved with small pcb antennas.

Sure. Most routers come with wavelength sized wobbly penises that give
you a few dB.

A quarter wave monopole made from relatively thick wire or rod can
be an excellent match to 50 ohm coax so long as the ground plane
is at least a few wavelengths across.

A half-wave dipole combined with a coaxial balun can also be a very
good match but has a slightly narrower bandwidth due to the
frequency dependency of the coax balun.-a The choice of which one to
use depends mostly on how the antenna is to be mounted.

An almost omnidirectional antenna with very low losses can be
more effective than a lossy directional one.


John

Nevertheless I have seem that sort of design work.
I worked around radar antennae briefly in the 1960s.

What I learned was that theory is too simplified to actually be able
to design a real antenna: All our designs were field tested and adjusted.

I am not advocating Pringle cans.-a I wouldnt use one myself. But I am
not so quick to rubbish them as you are.

RF propagation is tricky, and real world objects of no apparent value
often have enormous effects.

I just say that once I built a Pringles antenna at a training course,
and it does work. Inside the tube there is a threaded metal rod with a number of nuts and washers that had to be put at precise distances
according to the instructions we followed.

Black magic.

Sounds like a primitive Yagi...

We did not have any tool to measure gain, but indeed the router read a higher signal that with its manufacturer antena. And it was directional.
I can not give any number because I don't remember where my notes are.

Always hard to tell anyway.

Back to the original subject of the thread and to topic; Some of the
designs out there just put an USB dongle inside the tube, and they work, somehow. No need to actually have a wifi card with socket for the
antenna. If the Pi is small enough (I have no idea) there will be
designs out there using it.

As I said, I took the shortest route to success - relocated the wifi
point to higher up with less obstructions, and added a suicide alarm to
kill the receiving process if the signal fails mid message...

I will have to add another wifi point to replace the one I stole, for
next summer when that part of the garden is in use :-)
--
"Anyone who believes that the laws of physics are mere social
conventions is invited to try transgressing those conventions from the
windows of my apartment. (I live on the twenty-first floor.) "

Alan Sokal

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From Newsgroup: comp.sys.raspberry-pi

On Sat, 27 Dec 2025 23:31:48 +0000, The Natural Philosopher wrote:

Sounds like a primitive Yagi...

I build a 2m quagi at one point, speaking of primitive.

http://www.overbeck.com/quagi.htm

It didn't look like much but I could hit a repeater 160 miles away with a
5w Radio Shack handi-talki. There's an advantage to having a 7800'
mountain to put you're repeater on.



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From Newsgroup: comp.sys.raspberry-pi

On 12/10/25 08:01, Daniel James wrote:

On 10/12/2025 10:29, c186282 wrote:

What we WANT is for a device connection to use
the BEST signal - whether that's the primary
router or an extender - and switch back and
forth automatically depending on the connection
quality. Looks like it CAN be done ... but ....

I have a bunch of Ubiquity UbiFi access points around the house with
wired backhaul to the router. They can also work with wireless backhaul,
but we were having the house rewired so putting a load of CAT6 in, and a
POE switch, was a no-brainer.

They do exactly that. As a device moves between areas with different APs
the APs detect which has the best signal and the one with the lower
signal strength drops the connection. The device then reconnects and
picks the one with the stronger signal.

They've been in place about four years, now, and seem to work well.

Alas I had to re-wire some commercial structures
for net/etc over the years, back when I was still
young enough to crawl around in ceilings. What a
pain in the ass ! The structures were made to spec,
1950s spec, electric and standard telephone, and
NO slack for add-ons.

I've seen pix of British castles ... they just run
lots of pipes on the outsides of the thick stone
walls. Works, but you'd never get away with that
in modern commercial buildings. Things have to
look all neat and tidy.

My house is early 50s ... mostly concrete and heavy
wood, now a metal roof. Again it was NOT meant for
running NEW stuff around. Half the bricks were
solid-poured full of concrete. Everybody thought
that the 1950s were the pinnacle of modern civ ...
"What else WOULD you need to add in ???".

I've had good success with wifi 'extenders' - and
they're pretty cheap unless you want today's VERY
fastest specs. Running two of them now ... one
for out-buildings, another for a convoluted corner
of the main house with the desktop I never use.

Anyway, for the OP, one extender is the solution
to his problem.

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From Newsgroup: comp.sys.raspberry-pi

On 11/12/2025 04:12, c186282 wrote:

Everybody thought
-a that the 1950s were the pinnacle of modern civ ...
-a "What else WOULD you need to add in ???".

Reminds me of a brand new factory in Jo'burg. Solid concrete walls and a
tin roof. And nnot a single socket or light that worked.

The contractor brought in to fix it spent 20 minutes looking and then
said 'Fuck that - get the Kangas' and simply chipped new channels for *everything*. Laid in pipe conduit and got wiring.

Before the days of computers that was, let alone networking. We used Telex.
--
The urge to save humanity is almost always a false front for the urge to
rule.
rCo H. L. Mencken, American journalist, 1880-1956

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From Newsgroup: comp.sys.raspberry-pi

On 12/11/25 03:48, The Natural Philosopher wrote:

On 11/12/2025 04:12, c186282 wrote:

Everybody thought
-a-a that the 1950s were the pinnacle of modern civ ...
-a-a "What else WOULD you need to add in ???".

Reminds me of a brand new factory in Jo'burg. Solid concrete walls and a
tin roof. And nnot a single socket or light that worked.

The contractor brought in to fix it spent 20 minutes looking and then
said 'Fuck that - get the Kangas' and simply chipped new channels for *everything*. Laid in pipe conduit and got wiring.

Before the days of computers that was, let alone networking. We used Telex.

Esp in the 50s, well, they DID really think they
were The Pinnacle. Everyone would always have
their rotary-dial telephones, only a few, and
need just a very few lights and sockets. So, they
built, often large, structures reflecting that
philosophy.

Solid concrete ... or at least with gaps you could
not GET to once construction finished.

My last office, they wanted to add a couple of
extensions. Had to force the builders to drill
a couple of 2" holes through solid concrete
lintels just so we could run comm/net cables.
The lintels didn't really hold up much weight
but were huge regardless. Took them like half
a day to put the two holes though the lintels,
and they hit a piece of rebar in the process.

This was well before crap gypsum-board walls and
drop ceilings.



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From Newsgroup: comp.sys.raspberry-pi

On 11/12/2025 08:48, The Natural Philosopher wrote:

The contractor brought in to fix it spent 20 minutes looking and then
said 'Fuck that - get the Kangas' and simply chipped new channels for *everything*. Laid in pipe conduit and got wiring.

That was the sparky's method when we had our (1830-ish, solid brick
walls) house rewired a few years ago -- smash out channels in the
bricks, lay the cables, plaster over ... and hope the walls still have
the strength to hold the roof on.

Fortunately we had CAT-6 cables (and some coax TV aerial cables) as well
as mains power put in, so most of what we want works more-or-less where
we want it.
--
Cheers,
Daniel.
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From Newsgroup: comp.sys.raspberry-pi

On 11/12/2025 04:12, c186282 wrote:

... they just run lots of pipes on the outsides of the thick stone
walls. Works, but you'd never get away with that in modern
commercial buildings. Things have to look all neat and tidy.

Have you SEEN the Centre Georges Pompidou in Paris?

... or the Lloyds Insurance building in London, for that matter.
--
Cheers,
Daniel.
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