Home made with a box of Pringles. just google for "pringles wifi antenna".
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 toPrsumably you're saying Mythbusters-style "not proven"?
design a real antenna: All our designs were field tested and adjusted.
I am not advocating Pringle cans. 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.
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! :-)
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. 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.
On 24/12/2025 07:58, mm0fmf wrote:
On 11/12/2025 21:18, Carlos E.R. wrote:Assuming that is a relevant issue.
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.
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...
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:Assuming that is a relevant issue.
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.
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.ÿ 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.
If a Pringles can were highly conductive it would have a cutoffA statement which clearly contradicts the well known skin effect of
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.
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.
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.ÿ 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
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! :-)
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:Assuming that is a relevant issue.
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.
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. 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.
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.
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.
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. 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
With Gigahertz, as with Heffalumps, you never know...
On 24/12/2025 20:07, The Natural Philosopher wrote:
With Gigahertz, as with Heffalumps, you never know...
Some of us do know.
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.
On 24/12/2025 17:00, Kerr-Mudd, John wrote:
On Wed, 24 Dec 2025 14:23:45 +0000I am saying that a blanket denial 'because the theory says no' is not
The Natural Philosopher <tnp@invalid.invalid> wrote:
[]
What I learned was that theory is too simplified to actually be able toPrsumably you're saying Mythbusters-style "not proven"?
design a real antenna: All our designs were field tested and adjusted.
I am not advocating Pringle cans.ÿ 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.
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...
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! :-)
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...
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:Assuming that is a relevant issue.
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.
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.ÿ 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 cutoffA statement which clearly contradicts the well known skin effect of
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.
conductirs at high frequencies.
For many purposes a well made half-wave dipole or quarter-waveSure. Most routers come with wavelength sized wobbly penises that give
monopole gives excellent results which are far better than anything
that can be achieved with small pcb antennas.
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.ÿ 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.ÿ 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.
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:Assuming that is a relevant issue.
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.
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.ÿ 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 cutoffA statement which clearly contradicts the well known skin effect of conductirs at high frequencies.
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.
For many purposes a well made half-wave dipole or quarter-waveSure. Most routers come with wavelength sized wobbly penises that give
monopole gives excellent results which are far better than anything
that can be achieved with small pcb antennas.
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.ÿ 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.ÿ 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.
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