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More on wifi range - Pi PICO W Oil level sensor

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  More on wifi range - Pi PICO W Oil level sensor The Natural Philosopher <tnp@invalid.invalid> - 2025-12-09 10:47 +0000
    Re: More on wifi range - Pi PICO W Oil level sensor Andy Burns <usenet@andyburns.uk> - 2025-12-09 11:57 +0000
      Re: More on wifi range - Pi PICO W Oil level sensor The Natural Philosopher <tnp@invalid.invalid> - 2025-12-09 14:07 +0000
        Re: More on wifi range - Pi PICO W Oil level sensor Rich <rich@example.invalid> - 2025-12-09 19:14 +0000
          Re: More on wifi range - Pi PICO W Oil level sensor The Natural Philosopher <tnp@invalid.invalid> - 2025-12-09 19:17 +0000
      Re: More on wifi range - Pi PICO W Oil level sensor c186282 <c186282@nnada.net> - 2025-12-09 21:19 -0500
        Re: More on wifi range - Pi PICO W Oil level sensor Andy Burns <usenet@andyburns.uk> - 2025-12-10 05:18 +0000
          Re: More on wifi range - Pi PICO W Oil level sensor c186282 <c186282@nnada.net> - 2025-12-10 00:27 -0500
            Re: More on wifi range - Pi PICO W Oil level sensor Andy Burns <usenet@andyburns.uk> - 2025-12-10 05:38 +0000
              Re: More on wifi range - Pi PICO W Oil level sensor c186282 <c186282@nnada.net> - 2025-12-10 02:13 -0500
                Re: More on wifi range - Pi PICO W Oil level sensor Andy Burns <usenet@andyburns.uk> - 2025-12-10 08:12 +0000
                Re: More on wifi range - Pi PICO W Oil level sensor Andy Burns <usenet@andyburns.uk> - 2025-12-10 08:15 +0000
                  Re: More on wifi range - Pi PICO W Oil level sensor c186282 <c186282@nnada.net> - 2025-12-10 03:56 -0500
                    Re: More on wifi range - Pi PICO W Oil level sensor Andy Burns <usenet@andyburns.uk> - 2025-12-10 09:14 +0000
                      Re: More on wifi range - Pi PICO W Oil level sensor The Natural Philosopher <tnp@invalid.invalid> - 2025-12-10 09:59 +0000
                      Re: More on wifi range - Pi PICO W Oil level sensor c186282 <c186282@nnada.net> - 2025-12-10 05:02 -0500
                        Re: More on wifi range - Pi PICO W Oil level sensor The Natural Philosopher <tnp@invalid.invalid> - 2025-12-10 10:24 +0000
                          Re: More on wifi range - Pi PICO W Oil level sensor c186282 <c186282@nnada.net> - 2025-12-10 05:53 -0500
                            Re: More on wifi range - Pi PICO W Oil level sensor The Natural Philosopher <tnp@invalid.invalid> - 2025-12-10 11:45 +0000
                          Re: More on wifi range - Pi PICO W Oil level sensor "Carlos E.R." <robin_listas@es.invalid> - 2025-12-11 22:06 +0100
                            Re: More on wifi range - Pi PICO W Oil level sensor The Natural Philosopher <tnp@invalid.invalid> - 2025-12-12 10:26 +0000
                              Re: More on wifi range - Pi PICO W Oil level sensor Andy Burns <usenet@andyburns.uk> - 2025-12-12 10:39 +0000
                                Re: More on wifi range - Pi PICO W Oil level sensor The Natural Philosopher <tnp@invalid.invalid> - 2025-12-12 11:14 +0000
                                  Re: More on wifi range - Pi PICO W Oil level sensor Andy Burns <usenet@andyburns.uk> - 2025-12-12 11:41 +0000
                                    Re: More on wifi range - Pi PICO W Oil level sensor The Natural Philosopher <tnp@invalid.invalid> - 2025-12-12 12:10 +0000
                                    Re: More on wifi range - Pi PICO W Oil level sensor c186282 <c186282@nnada.net> - 2025-12-13 01:19 -0500
                              Re: More on wifi range - Pi PICO W Oil level sensor "Carlos E.R." <robin_listas@es.invalid> - 2025-12-12 12:19 +0100
                                Re: More on wifi range - Pi PICO W Oil level sensor The Natural Philosopher <tnp@invalid.invalid> - 2025-12-12 12:10 +0000
                                Re: More on wifi range - Pi PICO W Oil level sensor c186282 <c186282@nnada.net> - 2025-12-12 23:42 -0500
                                  Re: More on wifi range - Pi PICO W Oil level sensor "Carlos E.R." <robin_listas@es.invalid> - 2025-12-13 13:30 +0100
                        Re: More on wifi range - Pi PICO W Oil level sensor "Carlos E.R." <robin_listas@es.invalid> - 2025-12-11 22:03 +0100
                  Re: More on wifi range - Pi PICO W Oil level sensor The Natural Philosopher <tnp@invalid.invalid> - 2025-12-10 09:57 +0000
            Re: More on wifi range - Pi PICO W Oil level sensor The Natural Philosopher <tnp@invalid.invalid> - 2025-12-10 09:55 +0000
              Re: More on wifi range - Pi PICO W Oil level sensor c186282 <c186282@nnada.net> - 2025-12-10 05:36 -0500
                Re: More on wifi range - Pi PICO W Oil level sensor The Natural Philosopher <tnp@invalid.invalid> - 2025-12-10 11:33 +0000
        Re: More on wifi range - Pi PICO W Oil level sensor The Natural Philosopher <tnp@invalid.invalid> - 2025-12-10 09:47 +0000
          Re: More on wifi range - Pi PICO W Oil level sensor c186282 <c186282@nnada.net> - 2025-12-10 05:29 -0500
            Re: More on wifi range - Pi PICO W Oil level sensor The Natural Philosopher <tnp@invalid.invalid> - 2025-12-10 11:29 +0000
            Re: More on wifi range - Pi PICO W Oil level sensor Daniel James <daniel@me.invalid> - 2025-12-10 13:01 +0000
              Re: More on wifi range - Pi PICO W Oil level sensor The Natural Philosopher <tnp@invalid.invalid> - 2025-12-10 13:05 +0000
                Re: More on wifi range - Pi PICO W Oil level sensor c186282 <c186282@nnada.net> - 2025-12-10 23:19 -0500
              Re: More on wifi range - Pi PICO W Oil level sensor c186282 <c186282@nnada.net> - 2025-12-10 23:12 -0500
                Re: More on wifi range - Pi PICO W Oil level sensor The Natural Philosopher <tnp@invalid.invalid> - 2025-12-11 08:48 +0000
                  Re: More on wifi range - Pi PICO W Oil level sensor c186282 <c186282@nnada.net> - 2025-12-11 04:19 -0500
                  Cable chasing (Was: More on wifi range - Pi PICO W Oil level sensor) Daniel James <daniel@me.invalid> - 2025-12-11 10:15 +0000
                Inside out (Was: More on wifi range - Pi PICO W Oil level sensor) Daniel James <daniel@me.invalid> - 2025-12-11 10:23 +0000
                  Re: Inside out (Was: More on wifi range - Pi PICO W Oil level sensor) Lars Poulsen <lars@beagle-ears.com> - 2025-12-11 18:16 +0000
                    Re: Inside out (Was: More on wifi range - Pi PICO W Oil level sensor) John R Walliker <jrwalliker@gmail.com> - 2025-12-11 18:28 +0000
                      Re: Inside out (Was: More on wifi range - Pi PICO W Oil level sensor) "Carlos E.R." <robin_listas@es.invalid> - 2025-12-11 21:59 +0100
                        Re: Inside out (Was: More on wifi range - Pi PICO W Oil level sensor) The Natural Philosopher <tnp@invalid.invalid> - 2025-12-12 11:21 +0000
                          Re: Inside out (Was: More on wifi range - Pi PICO W Oil level sensor) "Carlos E.R." <robin_listas@es.invalid> - 2025-12-13 13:45 +0100
                            Re: Inside out (Was: More on wifi range - Pi PICO W Oil level sensor) Bob Martin <bob.martin@excite.com> - 2025-12-14 06:38 +0000
                              Re: Inside out (Was: More on wifi range - Pi PICO W Oil level sensor) The Natural Philosopher <tnp@invalid.invalid> - 2025-12-15 19:19 +0000
    Re: More on wifi range - Pi PICO W Oil level sensor "Carlos E.R." <robin_listas@es.invalid> - 2025-12-11 22:18 +0100
      Re: More on wifi range - Pi PICO W Oil level sensor The Natural Philosopher <tnp@invalid.invalid> - 2025-12-12 10:41 +0000
        Re: More on wifi range - Pi PICO W Oil level sensor "Carlos E.R." <robin_listas@es.invalid> - 2025-12-13 13:57 +0100
      Re: More on wifi range - Pi PICO W Oil level sensor The Natural Philosopher <tnp@invalid.invalid> - 2025-12-12 11:28 +0000
        Re: More on wifi range - Pi PICO W Oil level sensor "Carlos E.R." <robin_listas@es.invalid> - 2025-12-13 13:56 +0100
          Re: More on wifi range - Pi PICO W Oil level sensor John R Walliker <jrwalliker@gmail.com> - 2025-12-14 19:22 +0000
      Re: More on wifi range - Pi PICO W Oil level sensor mm0fmf <none@invalid.com> - 2025-12-24 07:58 +0000
        Re: More on wifi range - Pi PICO W Oil level sensor The Natural Philosopher <tnp@invalid.invalid> - 2025-12-24 12:16 +0000
          Re: More on wifi range - Pi PICO W Oil level sensor John R Walliker <jrwalliker@gmail.com> - 2025-12-24 14:04 +0000
            Re: More on wifi range - Pi PICO W Oil level sensor The Natural Philosopher <tnp@invalid.invalid> - 2025-12-24 14:23 +0000
              Re: More on wifi range - Pi PICO W Oil level sensor "Kerr-Mudd, John" <admin@127.0.0.1> - 2025-12-24 17:00 +0000
                Re: More on wifi range - Pi PICO W Oil level sensor The Natural Philosopher <tnp@invalid.invalid> - 2025-12-24 20:07 +0000
                  Re: More on wifi range - Pi PICO W Oil level sensor mm0fmf <none@invalid.com> - 2025-12-24 23:17 +0000
                    Re: More on wifi range - Pi PICO W Oil level sensor The Natural Philosopher <tnp@invalid.invalid> - 2025-12-25 03:23 +0000
                      Re: More on wifi range - Pi PICO W Oil level sensor rbowman <bowman@montana.com> - 2025-12-25 07:32 +0000
                  Re: More on wifi range - Pi PICO W Oil level sensor c186282 <c186282@nnada.net> - 2025-12-24 21:16 -0500
              Re: More on wifi range - Pi PICO W Oil level sensor "Carlos E.R." <robin_listas@es.invalid> - 2025-12-27 21:51 +0100
                Re: More on wifi range - Pi PICO W Oil level sensor The Natural Philosopher <tnp@invalid.invalid> - 2025-12-27 23:31 +0000
                  Re: More on wifi range - Pi PICO W Oil level sensor rbowman <bowman@montana.com> - 2025-12-27 23:58 +0000
            Re: More on wifi range - Pi PICO W Oil level sensor Lars Poulsen <lars@beagle-ears.com> - 2025-12-24 23:01 +0000
          Re: More on wifi range - Pi PICO W Oil level sensor rbowman <bowman@montana.com> - 2025-12-25 02:29 +0000
        Re: More on wifi range - Pi PICO W Oil level sensor Lars Poulsen <lars@beagle-ears.com> - 2025-12-24 22:53 +0000
        Re: More on wifi range - Pi PICO W Oil level sensor Robert Riches <spamtrap42@jacob21819.net> - 2025-12-25 03:25 +0000
          Re: More on wifi range - Pi PICO W Oil level sensor The Natural Philosopher <tnp@invalid.invalid> - 2025-12-25 03:34 +0000
            Re: More on wifi range - Pi PICO W Oil level sensor "Kerr-Mudd, John" <admin@127.0.0.1> - 2025-12-25 10:43 +0000
              Re: More on wifi range - Pi PICO W Oil level sensor The Natural Philosopher <tnp@invalid.invalid> - 2025-12-25 11:43 +0000
              Re: More on wifi range - Pi PICO W Oil level sensor rbowman <bowman@montana.com> - 2025-12-25 18:44 +0000

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#37485

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...
-- 
"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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#37486

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.  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

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#37487

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.  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.  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.  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.


-- 
The lifetime of any political organisation is about three years before 
its been subverted by the people it tried to warn you about.

Anon.

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#37488

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.  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"?



-- 
Bah, and indeed Humbug.

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#37489

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.  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...
> 

-- 
If I had all the money I've spent on drink...
..I'd spend it on drink.

Sir Henry (at Rawlinson's End)

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#37492

On 24/12/2025 20:07, The Natural Philosopher wrote:
> 
> With Gigahertz, as with Heffalumps, you never know...

Some of us do know.

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#37498

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.

-- 
     “I 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.”

     ― Leo Tolstoy

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#37502

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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#37495

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.  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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#37513

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.  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.  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.  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.
ES🇪🇸, EU🇪🇺;

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#37514

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.  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.  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.  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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#37515

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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#37491

[See also my previous followup - also shifting to alt.

On 2025-12-24, John R Walliker <jrwalliker@gmail.com> 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.  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
>


-- 
Lars Poulsen - an old geek in Santa Barbara, California

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#37496

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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#37490

[Folloup-to alt.unix.geeks]

> On 11/12/2025 21:18, Carlos E.R. wrote:
>> Home made with a box of Pringles. just google for "pringles wifi antenna".

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

As a wireless applications engineer, I have always shaken my head
at the pringles can antenna, which if well made can have a gain up
to at most 8 dBi or so. For less than $50, you can buy a professinally
made flat patch antenna with 8 dBi gain at L-com.com. Apparently, you
can find used ones on eBay for under $30, but why take the risk?
If you need circular polarization, it will be closer to $75.
-- 
Lars Poulsen - an old geek in Santa Barbara, California

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#37499

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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#37500

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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#37503

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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#37504

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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#37505

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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