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.
... 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.
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.
On 2025-12-11, Daniel James <daniel@me.invalid> wrote:
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.
I seem to remember hearing that there was an English building code that REQUIRED outside pipes for water (and sewage?) so that they could be
easily thawed with a blowtorch when they froze in the winter?
On 11/12/2025 18:16, Lars Poulsen wrote:
On 2025-12-11, Daniel James <daniel@me.invalid> wrote:
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.
I seem to remember hearing that there was an English building code that
REQUIRED outside pipes for water (and sewage?) so that they could be
easily thawed with a blowtorch when they froze in the winter?
No, it was only done to save money.
I've had to skip subject threading because of all
the new postings ... just datetime sorting now.
On 10/12/2025 10:02, c186282 wrote:
On 12/10/25 04:14, Andy Burns wrote:I stated for te record and for the interest of others doing outside wifi coupled IOT shit that rain wind and possibly cars made a difference.
c186282 wrote:
I think it was you ... said how a cam wouldNo, maybe TNP said his oil level monitor would drop out?
more or less drop out when the Big Red Truck
was there.
Posting traffic has considerably increased of late,
partly my "fault" ... but COSLM was kind of dying
and that would have been tragic. Forgive the sort
of off-topic stuff, but it DOES keep minds alive -
you can't ALWAYS think about Linux without kind
of seizing up :-)
Someone else remarked that so did fire trucks.
The downside of the new oil monitor is that is is so accurate - to
within a litre it seems - that I can visibly see how much a shower or washing the dishes costs me, and a cold night is very expensive. :-)
LOL.
Now off to write the software that will look at it for me and warn me of things by email.
So I can get on with the next project.
First of all thanks to all those who responded on my first efforts to
put a battery power Pi Pico W outside and have it phone home.
Having eliminated temperature and supply voltage as issues, I delved
into wifi and router logs, and it was clear that it was sometimes
getting a DHCP lease and even occasionally opening a TCP/IP connections
and sending data. And might be dependent on where I parked the car and
the weather.
I tried putting a tin tray behind the router and that made it worse.
Now the layout was that a ground floor router through the window and the garage was not very good at about 30m range.
Then I remembered I had put an Ethernet port in an upstairs bedroom by
the window in case I wanted to use it as an office.
It was further away - 35m or so - but much less cluttered path. It just
had to go through a corner of the garage.
Instantly the router reported about 8-10dB more signal and almost
reliable comms resulted.
And I knew all that trig would come in handy one day :-)
On 2025-12-10 11:24, The Natural Philosopher wrote:
On 10/12/2025 10:02, c186282 wrote:
On 12/10/25 04:14, Andy Burns wrote:I stated for te record and for the interest of others doing outside
c186282 wrote:
I think it was you ... said how a cam wouldNo, maybe TNP said his oil level monitor would drop out?
more or less drop out when the Big Red Truck
was there.
Posting traffic has considerably increased of late,
partly my "fault" ... but COSLM was kind of dying
and that would have been tragic. Forgive the sort
of off-topic stuff, but it DOES keep minds alive -
you can't ALWAYS think about Linux without kind
of seizing up :-)
wifi coupled IOT shit that rain wind and possibly cars made a difference.
Someone else remarked that so did fire trucks.
The downside of the new oil monitor is that is is so accurate - to
within a litre it seems - that I can visibly see how much a shower or
washing the dishes costs me, and a cold night is very expensive. :-)
LOL.
Now off to write the software that will look at it for me and warn me
of things by email.
So I can get on with the next project.
You mentioned thieves stealing fuel. You can also monitor for that. You would need a fuel flow meter on the fuel line, or a sensor telling when
the furnace is working. Compare with the tank level decreasing rapidly.
the sensor I built on the tank has no power except batteries: So it only wakes up occasionally and draws nanoamps in between.
I have completed the warning software that looks for low oil levels,
loss of communication, a failing battery and unexpected changes in oil level, BUT it cannot do that in real time as the unit is only powered up
for a minute or so every couple of hours.
Depending on how long the batteries last I may increase the frequency of operation.
On 2025-12-09 11:47, The Natural Philosopher wrote:
First of all thanks to all those who responded on my first efforts to
put a battery power Pi Pico W outside and have it phone home.
Having eliminated temperature and supply voltage as issues, I delved
into wifi and router logs, and it was clear that it was sometimes
getting a DHCP lease and even occasionally opening a TCP/IP
connections and sending data. And might be dependent on where I parked
the car and the weather.
I tried putting a tin tray behind the router and that made it worse.
Now the layout was that a ground floor router through the window and
the garage was not very good at about 30m range.
Then I remembered I had put an Ethernet port in an upstairs bedroom by
the window in case I wanted to use it as an office.
It was further away - 35m or so - but much less cluttered path. It
just had to go through a corner of the garage.
Instantly the router reported about 8-10dB more signal and almost
reliable comms resulted.
Two ideas.
Some routers can steer the signal horizontally; the technology is called "MIMO" (https://en.wikipedia.org/wiki/MIMO). You notice because the
router has multiple antenas, maybe four.
Then you can replace the antena on the router or the remote with a directional WiFi antena. Home made with a box of Pringles. just google
for "pringles wifi antenna". I made one and it actually works. But maybe they are sold, too.
...
And I knew all that trig would come in handy one day :-)
You can calculate it numerically on a computer, by calculating the aproximate integral ;-)
The Natural Philosopher wrote:
the sensor I built on the tank has no power except batteries: So it
only wakes up occasionally and draws nanoamps in between.
I have completed the warning software that looks for low oil levels,
loss of communication, a failing battery and unexpected changes in oil
level, BUT it cannot do that in real time as the unit is only powered
up for a minute or so every couple of hours.
Depending on how long the batteries last I may increase the frequency
of operation.
Worth trying to send the data as UDP rather than TCP? if it fits in a
single packet,the receiver doesn't have to track the position within a stream ...
On 2025-12-11 19:28, John R Walliker wrote:
On 11/12/2025 18:16, Lars Poulsen wrote:
On 2025-12-11, Daniel James <daniel@me.invalid> wrote:
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.
I seem to remember hearing that there was an English building code that
REQUIRED outside pipes for water (and sewage?) so that they could be
easily thawed with a blowtorch when they froze in the winter?
No, it was only done to save money.
It seems amazing to me doing that in Britain, were pipes can freeze. Now
I understand the description of an hotel (Devon) in a novel I'm reading (Ruth Rendell, The secret house of death).
On 11/12/2025 21:06, Carlos E.R. wrote:
On 2025-12-10 11:24, The Natural Philosopher wrote:
On 10/12/2025 10:02, c186282 wrote:
On 12/10/25 04:14, Andy Burns wrote:
c186282 wrote:
Now off to write the software that will look at it for me and warn me
of things by email.
So I can get on with the next project.
You mentioned thieves stealing fuel. You can also monitor for that.
You would need a fuel flow meter on the fuel line, or a sensor telling
when the furnace is working. Compare with the tank level decreasing
rapidly.
The problem is that the sensor I built on the tank has no power except batteries: So it only wakes up occasionally and draws nanoamps in between.
I have completed the warning software that looks for low oil levels,
loss of communication, a failing battery and unexpected changes in oil level, BUT it cannot do that in real time as the unit is only powered up
for a minute or so every couple of hours.
Depending on how long the batteries last I may increase the frequency of operation. But it can never be 'real time'
Two ideas.
Some routers can steer the signal horizontally; the technology is called "MIMO" (https://en.wikipedia.org/wiki/MIMO). You notice because the
router has multiple antenas, maybe four.
Then you can replace the antena on the router
directional WiFi antena.
Home made with a box of Pringles. just google
for "pringles wifi antenna". I made one and it actually works. But maybe they are sold, too.
Well the daemon runs under xinetd...for sheer laziness. I guess I could
make it UDP.
But I don't know what problem that would solve.
On 2025-12-12 11:26, The Natural Philosopher wrote:
On 11/12/2025 21:06, Carlos E.R. wrote:
On 2025-12-10 11:24, The Natural Philosopher wrote:
On 10/12/2025 10:02, c186282 wrote:
On 12/10/25 04:14, Andy Burns wrote:
c186282 wrote:
Now off to write the software that will look at it for me and warn
me of things by email.
So I can get on with the next project.
You mentioned thieves stealing fuel. You can also monitor for that.
You would need a fuel flow meter on the fuel line, or a sensor
telling when the furnace is working. Compare with the tank level
decreasing rapidly.
The problem is that the sensor I built on the tank has no power except
batteries: So it only wakes up occasionally and draws nanoamps in
between.
I have completed the warning software that looks for low oil levels,
loss of communication, a failing battery and unexpected changes in oil
level, BUT it cannot do that in real time as the unit is only powered
up for a minute or so every couple of hours.
Depending on how long the batteries last I may increase the frequency
of operation. But it can never be 'real time'
Ah.
What about a small solar panel and rechargeable batteries?
The Natural Philosopher wrote:
Well the daemon runs under xinetd...for sheer laziness. I guess I
could make it UDP.
But I don't know what problem that would solve.
The data would arrive if a single packet got through the fog, whereas
with tcp at least dour packets on sequence need to make it (or get
retried) with UDP you could afford to spray each packet half a dozen
times and if one of them makes it, you're good ...
On 2025-12-12 11:26, The Natural Philosopher wrote:
On 11/12/2025 21:06, Carlos E.R. wrote:
On 2025-12-10 11:24, The Natural Philosopher wrote:
On 10/12/2025 10:02, c186282 wrote:
On 12/10/25 04:14, Andy Burns wrote:
c186282 wrote:
Now off to write the software that will look at it for me and warn
me of things by email.
So I can get on with the next project.
You mentioned thieves stealing fuel. You can also monitor for that.
You would need a fuel flow meter on the fuel line, or a sensor
telling when the furnace is working. Compare with the tank level
decreasing rapidly.
The problem is that the sensor I built on the tank has no power except
batteries: So it only wakes up occasionally and draws nanoamps in
between.
I have completed the warning software that looks for low oil levels,
loss of communication, a failing battery and unexpected changes in oil
level, BUT it cannot do that in real time as the unit is only powered
up for a minute or so every couple of hours.
Depending on how long the batteries last I may increase the frequency
of operation. But it can never be 'real time'
Ah.
What about a small solar panel and rechargeable batteries?
The Natural Philosopher wrote:
Well the daemon runs under xinetd...for sheer laziness. I guess I
could make it UDP.
But I don't know what problem that would solve.
The data would arrive if a single packet got through the fog, whereas
with tcp at least dour packets on sequence need to make it (or get
retried) with UDP you could afford to spray each packet half a dozen
times and if one of them makes it, you're good ...
On 12/12/25 06:19, Carlos E.R. wrote:
On 2025-12-12 11:26, The Natural Philosopher wrote:
On 11/12/2025 21:06, Carlos E.R. wrote:
On 2025-12-10 11:24, The Natural Philosopher wrote:
On 10/12/2025 10:02, c186282 wrote:
On 12/10/25 04:14, Andy Burns wrote:
What about a small solar panel and rechargeable batteries?
Seeed sells the "LiPo Rider Plus". After checking
several brands of 'solar charge controllers' these
were the ones I chose to power my field projects.
Most of the others did NOT cap the voltage very
well, or at all, so the sun comes out bright and you
might send 6+ into your 3.1v device.
Combined with a 3 to 5 watt panel they'll keep even
intermittent non-nano-power projects going.
Beware the quality of the batteries though ... got
some no-names, about 50x50x10mm square, that were
generally good - but one DID explode on me, inside
the office building, when I barely touched it. Had
not been charged for months either. Oh well, nothing
to do but watch the big crimson flame .......
Fire control IS a priority with lithiums.
On 11/12/2025 20:59, Carlos E.R. wrote:
On 2025-12-11 19:28, John R Walliker wrote:
On 11/12/2025 18:16, Lars Poulsen wrote:
On 2025-12-11, Daniel James <daniel@me.invalid> wrote:
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.
I seem to remember hearing that there was an English building code that >>>> REQUIRED outside pipes for water (and sewage?) so that they could be
easily thawed with a blowtorch when they froze in the winter?
No, it was only done to save money.
It seems amazing to me doing that in Britain, were pipes can freeze.
Now I understand the description of an hotel (Devon) in a novel I'm
reading (Ruth Rendell, The secret house of death).
I think the issue is that pre war, many many houses had no water, no
inside toilet, no heating beyond a coal fire no electricity and so on.
Hence they were upgraded to a water tank in the roof and some form of sporadic mains water supply, fed via something coming out of the ground
and into the house.
Drainage was often external - room size was small and the pipes were
just routed outside for ease of installation. And indeed access for
clearing blockages.
Retrofitting modern infrastructure to old houses is massively expensive.
On 11/12/2025 21:18, Carlos E.R. wrote:
On 2025-12-09 11:47, The Natural Philosopher wrote:I sorta tried that without huge success, In fact I am getting up to 12dB variation in signal due to who knows what?
First of all thanks to all those who responded on my first efforts to
put a battery power Pi Pico W outside and have it phone home.
Having eliminated temperature and supply voltage as issues, I delved
into wifi and router logs, and it was clear that it was sometimes
getting a DHCP lease and even occasionally opening a TCP/IP
connections and sending data. And might be dependent on where I
parked the car and the weather.
I tried putting a tin tray behind the router and that made it worse.
Now the layout was that a ground floor router through the window and
the garage was not very good at about 30m range.
Then I remembered I had put an Ethernet port in an upstairs bedroom
by the window in case I wanted to use it as an office.
It was further away - 35m or so - but much less cluttered path. It
just had to go through a corner of the garage.
Instantly the router reported about 8-10dB more signal and almost
reliable comms resulted.
Two ideas.
Some routers can steer the signal horizontally; the technology is
called "MIMO" (https://en.wikipedia.org/wiki/MIMO). You notice because
the router has multiple antenas, maybe four.
Then you can replace the antena on the router or the remote with a
directional WiFi antena. Home made with a box of Pringles. just google
for "pringles wifi antenna". I made one and it actually works. But
maybe they are sold, too.
The setup is all somewhat experimental. At least for now the software
is more or less stable - I have a few hanging daemons if the link goes
down mid message - but that is easily fixed .
...Huh? it can be as exact as your measurements are.
And I knew all that trig would come in handy one day :-)
You can calculate it numerically on a computer, by calculating the
aproximate integral ;-)
No 'approximations' here...
diameter= tankDepth - offset;
radius = diameter * 0.5;
y = echoDepth - offset -radius;
theta = asin( y / radius);
x = radius * cos(theta);
pie= radius * radius * theta;
delta = x * y;
area= (M_PI * radius *radius)/2 - (pie + delta);
volume=(area/(M_PI * radius *radius ))*tankVolume;
That is about ultimately three days of work. It is redundant but I think
gcc can optimise out the intermediary variables that I used to make sure even I could understand it.
What has been encouraging is the pinpoint accuracy of the measurements.
Once in a stable environment the ultrasonics are very precise. something like a mm or two in a couple of metres. Probably more precise than the
speed of sound in air of variable pressures would justify, or indeed the expansion of the oil in warmer temperatures.
LOL.
Maybe I have built the world's most complicated barometer.
On 11/12/2025 21:18, Carlos E.R. wrote:
Two ideas.
Some routers can steer the signal horizontally; the technology is
called "MIMO" (https://en.wikipedia.org/wiki/MIMO). You notice because
the router has multiple antenas, maybe four.
Then you can replace the antena on the router
What antenna on the router?
It's just a wifi bridge with an internal something or other.
https://www.netxl.com/wifi-access-points/mikrotik-routerboard- rb951ui-2nd-wifi-4-access-point/
Its actually very very cheap and has been 'good enough'
; or the remote with a
directional WiFi antena.
That gets complicated. I am trying easy shit first :-)
P Pico W doesn't have an 'antenna' either. Just some PCB traces.
Home made with a box of Pringles. just google for "pringles wifi
antenna". I made one and it actually works. But maybe they are sold, too.
Everything is possible. I am lazy. I do what is necessary to achieve
desired result and no more.
For now I seem to have adequate connectivity.
My city is ancient, three thousand years, but there is no river. Well
water tends to be salty, from the sea; mixed often. I don't know how
they survived. I think the water in sufficient quantities arrived in
1945, from a river 170 Km to the north. So before that year, houses here
had no bathrooms, they were built since then as houses were provided
with running water. Yet, I have not seen that network of pipes on the outside, except for rain water from the roof.
On 2025-12-12 12:28, The Natural Philosopher wrote:
On 11/12/2025 21:18, Carlos E.R. wrote:
Two ideas.
Some routers can steer the signal horizontally; the technology is
called "MIMO" (https://en.wikipedia.org/wiki/MIMO). You notice
because the router has multiple antenas, maybe four.
Then you can replace the antena on the router
What antenna on the router?
It's just a wifi bridge with an internal something or other.
Ah, pity. Many AP have external antenas that are screwed on a socket.
https://www.netxl.com/wifi-access-points/mikrotik-routerboard-
rb951ui-2nd-wifi-4-access-point/
Its actually very very cheap and has been 'good enough'
Barely :-)
> or the remote with a
directional WiFi antena.
That gets complicated. I am trying easy shit first :-)
P Pico W doesn't have an 'antenna' either. Just some PCB traces.
Yeah, well.
Home made with a box of Pringles. just google for "pringles wifi
antenna". I made one and it actually works. But maybe they are sold,
too.
Everything is possible. I am lazy. I do what is necessary to achieve
desired result and no more.
For now I seem to have adequate connectivity.
Of course, that is enough.
On 13 Dec 2025 at 12:45:41, "Carlos E.R." <robin_listas@es.invalid> wrote:
My city is ancient, three thousand years, but there is no river. Well
water tends to be salty, from the sea; mixed often. I don't know how
they survived. I think the water in sufficient quantities arrived in
1945, from a river 170 Km to the north. So before that year, houses here
had no bathrooms, they were built since then as houses were provided
with running water. Yet, I have not seen that network of pipes on the
outside, except for rain water from the roof.
Would that be Cadiz?
Home made with a box of Pringles. just google for "pringles wifi antenna".
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 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. 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. 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
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 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! :-)
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 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. 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 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....
On 24/12/2025 20:07, The Natural Philosopher wrote:
With Gigahertz, as with Heffalumps, you never know...
Some of us do 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 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 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.
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:-?
But what do I do with all these spare Pringle tubes:-?
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. 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. 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.
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. 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. 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.
Sounds like a primitive Yagi...
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