To Dream the Impossible Dream

[Tom Kunich]

https://duckduckgo.com/?q=200+rpm+cadence&atb=v366-1&t=chromentp&iax=videos&ia=videos&iai=https%3A%2F%2Fwww.youtube.com%2Fwatch%3Fv%3DANgJ5e-VWok

https://www.youtube.com/watch?v=R8mP8Pjexfk

The problem with people who pretend to know how to ride is that they've never actually ridden enough to know what can be done.

I did 200 rpm with a very strong tailwind past Carnegie Cycle Park. Almost all of the way into the town of Tracy.

So why did the Great Pretenders here cry that it was impossible?

[Roger Merriman]

They didn’t say it was impossible more that it’s improbable that you’d
achieve that.

Track cyclists and I’m sure this was noted at the time I probably did my
self note that they can reach 200rpm personally I topped out at around the
130rpm mark, though this is from memory and over a decade now!

Roger Merriman

[Lou Holtman]

So some youtube clips of people just barely reach 200 rpm on rollers for a few seconds is proof you did 200 rpm all the way to who knows where. I don’t believe you did, sorry.


Lou.

[Catrike Rider]

On Sun, 29 Oct 2023 21:21:10 GMT, Roger Merriman <ro...@sarlet.com>
wrote:

My Garmin recorded max cadence numbers are full of errrors, but
disregarding the spikes the line runs between 95 and 115. I'm not a
spinner... My average cadence for 900+ rides over the last 14 years
is about 60.

[Lou Holtman]

Almost everyone tops out between 120 and 140 rpm on normal roads. On rollers maybe a bit higher.

Lou

[Sir Ridesalot]

Interesting to see the intense effort that Eddy Merckx made whilst spinning at a very high cadence on rollers where there was no headwind or other distractions.

https://www.youtube.com/watch?v=_BcHekNAfOo

Perhaps Tom has two magnets on his cadence counter and wheel which would explain his Prime Tour Quality cadence and speeds? LOL ;<)

Cheers

[Jeff Liebermann]

On Sun, 29 Oct 2023 13:56:01 -0700 (PDT), Tom Kunich
<cycl...@gmail.com> wrote:

>The problem with people who pretend to know how to ride is that they've never actually ridden enough to know what can be done.
>I did 200 rpm with a very strong tailwind past Carnegie Cycle Park. Almost all of the way into the town of Tracy.
>So why did the Great Pretenders here cry that it was impossible?

Google search couldn't find anything named Carnegie Cycle Park.
However, I did find a Carnegie State Vehicular Recreation Area near
Tracy CA.
<https://ohv.parks.ca.gov/?page_id=1172>
It seems to be for
"Rugged off-roading tracks in a 5,000-acre state park for motorcycles,
4X4s & ATVs plus campsites."
I found no mention of cycling in the park.

Checking the road distance between the Park and Tracy, it's listed as
"mostly flat" for 12.6 miles.
<https://maps.app.goo.gl/FsV7ZFKgboxWSTVGA>
That must have been a truly amazing ride with a VERY strong tailwind.

What day and time was this ride? Since you were kind enough to
disclose the location, I can check the past weather data for the
location, date and time. If there was a recorded hurricane in the
correct direction on that day, it would help you prove that there was
an appropriate tailwind.

I'm not sure what you mean by "past the park". Perhaps you woke up
this morning and discovered that you had actually started at the
entrance to the park. From the Tracy Hills Welcome Center, the ride
is about 6 miles.
<https://maps.app.goo.gl/Wk4pvwGbZVQfyL6o9>
That's half the distance but still a rather long ride for you to spin
at 200 rpm.

Are amazing stories like this why you closed your Strava account and
deleted all your data? Surely you would have recorded this activity
demonstrating your amazing performance and abilities and received
appropriate kudos for being the worlds fastest disabled person.

01/06/2023
<https://groups.google.com/g/rec.bicycles.tech/c/K-cG5lehtd0/m/X3FtbYbXAAAJ>
"I am permanently disabled and so is the cop who managed to get me
back from the last step from death."


--
Jeff Liebermann je...@cruzio.com
PO Box 272 http://www.LearnByDestroying.com
Ben Lomond CA 95005-0272
Skype: JeffLiebermann AE6KS 831-336-2558

[Sir Ridesalot]

On Sunday, October 29, 2023 at 4:30:09 p.m. UTC-5, Lou Holtman wrote:

Done indoors so no headwind or road pavement to slow one down as one steers etcetera. Nor any traffic or other things to watch out for.

I wonder just how many Grand Tours Tom has one? After all if he's this great at his present age he must have been better than the Grand Tour winners when he was in his twenties and thirties.

Two magnets instead of one on your wheel and crankarms can really boost cadence and speed readings without any extra effort from the rider. ;<) LOL

Cheers

[Sir Ridesalot]

On Sunday, October 29, 2023 at 5:47:57 p.m. UTC-5, Sir Ridesalot wrote:
> On Sunday, October 29, 2023 at 4:30:09 p.m. UTC-5, Lou Holtman wrote:
> > On Sunday, October 29, 2023 at 9:56:03 PM UTC+1, Tom Kunich wrote:
> > > https://duckduckgo.com/?q=200+rpm+cadence&atb=v366-1&t=chromentp&iax=videos&ia=videos&iai=https%3A%2F%2Fwww.youtube.com%2Fwatch%3Fv%3DANgJ5e-VWok
> > >
> > > https://www.youtube.com/watch?v=R8mP8Pjexfk
> > >
> > > The problem with people who pretend to know how to ride is that they've never actually ridden enough to know what can be done.
> > >
> > > I did 200 rpm with a very strong tailwind past Carnegie Cycle Park. Almost all of the way into the town of Tracy.
> > >
> > > So why did the Great Pretenders here cry that it was impossible?
> > So some youtube clips of people just barely reach 200 rpm on rollers for a few seconds is proof you did 200 rpm all the way to who knows where. I don’t believe you did, sorry.
> >
> >
> > Lou.
> Done indoors so no headwind or road pavement to slow one down as one steers etcetera. Nor any traffic or other things to watch out for.
>

> I wonder just how many Grand Tours Tom has won? After all if he's this great at his present age he must have been better than the Grand Tour winners when he was in his twenties and thirties.

[Tom Kunich]

Lou, I told you at the time that when you're riding in a hard following wind you get the chance to loosen up your legs and holding that sort of cadence is not difficult. Just because you can't do it doesn't mean that it can't be done. It requires a set of special circumstances and I had it for about 5 miles spun out in a 50-11.

The fact that without a warmup and on rollers you think that means that it is unlikely doesn't mean that it is.

[Tom Kunich]

How many miles do you have this year and how many feet of climbing? I'm at 5,000 miles and 180,000 feet of climbing and most of the climbing roads are still closed down do that I don't have access to longer miles and more climbing. And funny that I'm not calling myself "ridesalot".

[Jeff Liebermann]

On Sun, 29 Oct 2023 15:47:55 -0700 (PDT), Sir Ridesalot
<i_am_cyc...@yahoo.ca> wrote:

>Two magnets instead of one on your wheel and crankarms can really boost cadence and speed readings without any extra effort from the rider. ;<) LOL
>Cheers

I don't think that will work with Tom's Garmin setup. I vaguely
recall that Tom has a Garmin speed and cadence sensor. It uses an
accelerometer instead of a magnet:
<https://www.cardiosport.co.uk/cardiosport-speed-cadence-sensor>
<https://www.garmin.com/en-US/p/641221>
Please ask Tom which sensor he was using. He doesn't answer my
questions. Also ask what wheel size and gears he was using. With
that information, I can calculate how fast he was going when he hit
200 rpm.

Also, I don't see how he could watch the Garmin cadence display while
riding on public roads at top speed in what looks like a built up
area.

I like your idea of adding a magnet. If one extra magnet can double
Tom's performance, imagine what adding a magnet on every spoke could
do.

[John B.]

Well, power, i.e. Horsepower is a calculation based on RPM and Torque
so increasing RPM with the same force on the pedals results in more
power.

But then, there is no such thing as a "free lunch" so increasing RPM
likely results in an increase in exhausting (:-)
--
Cheers,

John B.

[Frank Krygowski]

On 10/29/2023 5:21 PM, Roger Merriman wrote:
> Tom Kunich <cycl...@gmail.com> wrote:
>> https://duckduckgo.com/?q=200+rpm+cadence&atb=v366-1&t=chromentp&iax=videos&ia=videos&iai=https%3A%2F%2Fwww.youtube.com%2Fwatch%3Fv%3DANgJ5e-VWok
>>
>> https://www.youtube.com/watch?v=R8mP8Pjexfk
>>
>> The problem with people who pretend to know how to ride is that they've
>> never actually ridden enough to know what can be done.
>>
>> I did 200 rpm with a very strong tailwind past Carnegie Cycle Park.
>> Almost all of the way into the town of Tracy.
>>
>> So why did the Great Pretenders here cry that it was impossible?
>>
> They didn’t say it was impossible more that it’s improbable that you’d
> achieve that.

Exactly. I've seen it done in a roller demonstration. I timed it myself,
and I've described that here before.

I just don't believe Tom has done it, not even on rollers, let alone on
the road.

(Yet again, Tom's original post does not appear in my Eternal September
feed.)

--
- Frank Krygowski

[Lou Holtman]

Riding at a cadence of 200 rpm is not loosining your legs. That is a serious effort that needs concentration. Tom you did not do 200 rpm just because you had a tail wind. Ridiculous.

Lou

[Lou Holtman]

On Monday, October 30, 2023 at 12:38:22 AM UTC+1, Jeff Liebermann wrote::

>
> I like your idea of adding a magnet. If one extra magnet can double
> Tom's performance, imagine what adding a magnet on every spoke could
> do.
> --

As a joke we added a magnet on a ridings buddy bike at a coffee stop. It was his birthday. Man he was confused ;-). I have a Garmin speed sensor that somehow detects the earth magnetic field. On certain overpasses the speed drop to a very low value. From 30 km/hr to lets say 12 km/hr. Every time.

Lou

[Roger Merriman]

Only post that have disappeared on my feed have been two of yours but
possibly that was local network error, ie areas with WiFi that isn’t
connected and so on.

Roger Merriman

[Catrike Rider]

On Mon, 30 Oct 2023 07:21:00 +0700, John B. <sloc...@gmail.com>

Just like a big diesel engine would come apart if it went to the same
RPM as Formula 1 race car engines, my hips and knees would likely come
apart if got my cadence up over 150 RPM.

[Rolf Mantel]

Am 29.10.2023 um 22:21 schrieb Roger Merriman:

> Track cyclists and I’m sure this was noted at the time I probably did my
> self note that they can reach 200rpm personally I topped out at around the
> 130rpm mark, though this is from memory and over a decade now!

When I had my first bike computer with cadence sensor around 1995, I
once sprinted out of the way of a double decker bus approaching behind
me, not thinking about shifting. By the time I managed to reach my
turn-off, the cadence sensor was showing 152 rpm. In those days, I
usually aimed for 110 to 120 rpm as 'cuising speed', normally leading to
peaks around 130 rpm.

These days, I usually have a max around 120 rpm peaks and an average
around 90-100 rpm.

[Tom Kunich]

If you're having that much trouble with the English language perhaps you should refrain from commenting.

[Lou Holtman]

Maybe you should stop making BS claims: 141 km/hr downhill speed and 200 rpm cadence (for 5 miles?).

Lou

[Tom Kunich]

According to you. You're sounding more and more like Flunky and you know better. And I think my claim was for 60 mph and not 87. If you haven't been on the descent I was, don't tell me it can't be done.

[Lou Holtman]

Nope it was in the 80 ties mph and that caught my attention. 60 would be unlikely for a 79 yo but possible if everything was optimal but not 80 something mph. After a lot of discussions with a lot of BShiting you admitted that it had to be a glitch of your Garmin or whatever like a lot of your BS claims end. A 200 rpm cadence you can’t reach out of the blue just because someone has a tailwind. Your link to that youtube clip proves that. Ask anyone here if he or she ever hit 200 rpm in a normal ride on normal streets. I’m waiting. That downhill guy that tries to set records on downhills hit 130 rpm IIRC pedalling fiercely on a 12% grade and you hit 200 rpm, yeah rightI was not on that descent but I’m sure you didn’t do it. Prove me wrong with data or a descent clip like the downhill guy. I will buy you a beer and a donut. I will end here because it is tiring arguing with you.

Lou

[Jeff Liebermann]

On Mon, 30 Oct 2023 00:45:57 -0700 (PDT), Lou Holtman
<lou.h...@gmail.com> wrote:

>On Monday, October 30, 2023 at 12:38:22?AM UTC+1, Jeff Liebermann wrote::
>> I like your idea of adding a magnet. If one extra magnet can double
>> Tom's performance, imagine what adding a magnet on every spoke could
>> do.

>As a joke we added a magnet on a ridings buddy bike at a coffee stop. It was his birthday. Man he was confused ;-). I have a Garmin speed sensor that somehow detects the earth magnetic field. On certain overpasses the speed drop to a very low value. From 30 km/hr to lets say 12 km/hr. Every time.
>Lou

"How do Garmin Speed Sensors Measure Speed?"
<https://support.garmin.com/en-US/?faq=9NL91YJSJd3Tnyif9jRSy6>
"The Garmin Bike Speed Sensor and Speed Sensor 2 both contain a
magnetometers that measures the three dimensional components of the
ambient magnetic field (similar to an accelerometer measuring
acceleration)..."

That's less than useful. I couldn't find anything specific with a
patent search. Measuring the earth's magnetic field is easy enough
with a Hall Effect device. However, I don't know how it might be used
to measure the velocity through this field. I need to think about
this.

My guesses(tm):
1. The rebar in the concrete was magnetized.
2. There was a vehicle detector loop buried in the road to operate a
vehicle counter or traffic signal.
3. There was a transmit loop in the road for a 1970's "sign post"
vehicle location system.
4. Someone buried a de-magnetizer (degausser) in the road.

If the sensor was mounted on the hub or fork, it would probably be too
far away from the buried loop for magnetic field coupling. However,
if it was mounted on the crank, it might be sufficiently close.

[Tom Kunich]

That speed was 10 years ago when I first recovered from my concussion and still didn't have good sense and I would COMMONLY outrun everyone in a 15 member group two or three of which were excellent descenders.

But I must have been a very fast descender before my concussion because after my concussion when I still hadn't been properly treated they would find me laying on the ground or in a ditch and assume that I had made a mistake and not that I had had a seizure despite the fact that I could often still be having the seizure when they arrived. On the Redwood Road descent from Mariel Gate, it is only 2 miles or so and I would often be up the 1/4 mile 12% climb 2 miles further on waiting for them to arrive.

I climb like a snail now and I am very careful descending after some very close calls.

[Lou Holtman]

Strange thing is not all overpasses cause this drop in speed but more than one.

Lou

[Jeff Liebermann]

On Mon, 30 Oct 2023 11:07:40 -0700 (PDT), Tom Kunich
<cycl...@gmail.com> wrote:

>That speed was 10 years ago when I first recovered from my concussion

That would be 13 years ago:

<https://www.linkedin.com/feed/update/urn:li:ugcPost:6912346811772932096/>
"I got a severe concussion in 2010 that led to a type of seizures that
I didn't remember afterwards. This wasn't discovered and treated
properly until 2012 after 4 car wrecks luckily without any injuries"

>and still didn't have good sense and I would COMMONLY outrun everyone
>in a 15 member group two or three of which were excellent descenders.

You could outrun everyone while still having seizures and crashing
cars? I don't think so.

>But I must have been a very fast descender before my concussion because after my concussion when I still hadn't been properly treated they would find me laying on the ground or in a ditch and assume that I had made a mistake and not that I had had a seizure despite the fact that I could often still be having the seizure when they arrived. On the Redwood Road descent from Mariel Gate, it is only 2 miles or so and I would often be up the 1/4 mile 12% climb 2 miles further on waiting for them to arrive.

Amazing. All those details while you were having seizures and "I
didn't remember afterwards"? I don't think so.

>I climb like a snail now and I am very careful descending after some very close calls.

[Jeff Liebermann]

On Mon, 30 Oct 2023 11:28:14 -0700 (PDT), Lou Holtman
<lou.h...@gmail.com> wrote:

>Strange thing is not all overpasses cause this drop in speed but more than one.
>Lou

That suggests that there's something unique about the rebar, it's
magnetic properties, how the rebar was handled, and how it was
non-destructively tested. I vaguely recall reading something about
magnetizing rebar and making a magnetic field intensity map when
construction is almost done. As the rebar rusts, the magnetic field
intensity map will change. Breaks will also be highlighted. I did
some Google searching for information and didn't find much. This
article lists and describes some of the methods used for
non-destructive testing:

"Impact of Magnetization on the Evaluation of Reinforced Concrete
Structures Using DC Magnetic Methods"
<https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8838079/>

Also, a large lifting electromagnet is used for moving large bundles
of rebar. Such a device runs on DC and might have magnetized the
rebar. For example:
<http://www.tekbem.com/eng/products-and-services/iron-and-steel/lifting-crane-magnets/rebar-magnets/>

It might be interesting to walk over the bridges with a magnetic
compass.

[Tom Kunich]

A magnetometer is a two dimension device. On the Garmin it only measure a 180 degree rotation. None of this has to do with the EXTREMELY minor changes in the magnetic field of the Earth at different locations. If you are measuring a reduction in speed it is because you're going slower and not because of local magnetic anomalies which are on the order of 1% or so. Remember, you're getting information from Liebermann.

[Lou Holtman]

Again you pretend to know it better (I going slower) and again you are wrong.

Lou

[Tom Kunich]

Let me get this straight, your speed indicator says that you are going slower but you deny that. And it only occurs on some overpasses, like at the end of a hard ride on the steeper ones. OK. Gotcha.

[Lou Holtman]

No, I,m riding 25-30 km/hr at the beginning of the overpass. At the moment when I am at somewhere at the highest point I see the speed drop suddenly to a very low value and when I have the autostop function enabled on my Garmin it stops recording. I set the autostop speed at 7 km/hr btw. 5-10 meters further the speed is 25-30 km/hr again and the recording starts again. I don’t brake nor accelerate. It is something with the speedsensor and that overpass. Got it? This is the overpass

https://www.google.com/maps/place/A73,+Venlo/@51.365689,6.124701,3a,75y,124.84h,90t/data=!3m4!1e1!3m2!1s6RtGkRMQKU_E93-loU_Kvg!2e0!4m6!3m5!1s0x47c7455d34dab33b:0x1f3b84e67c43955e!8m2!3d51.365769!4d6.1247087!16s%2Fg%2F11tnftl0p7

Lou

[Jeff Liebermann]

On Mon, 30 Oct 2023 12:07:18 -0700, Jeff Liebermann <je...@cruzio.com>

Yet another possibility is 2.4 GHz RF interference(1). ANT+ and BLE
share the 2.4 GHz band. If there was any interference, the link
between the sensor and the bicycle logging computer could be
momentarily lost. I don't know if Garmin uses some kind of error
correction protocol. That would help with short bursts of RF, but
fail badly with large numbers of consecutive lost packets.

So what could be mounted on some bridges, but not on others? Some
kind of traffic information system? Short bursty wi-fi data to track
trucks, public transport, public safety vehicles, etc that doesn't
require long range VHF/UHF wide area communications? Or, it could be
one these devices that kept me busy about 20 years ago:
<https://groups.google.com/g/alt.internet.wireless/c/SpB0jCovYWY/m/_GVlxFmaS2sJ>

My favorite was the RF excited sulfur lamp and wide area jammer:
<https://en.wikipedia.org/wiki/Sulfur_lamp>
<https://archive.ph/20010209135028/http://www.fusionlighting.com/>

(1) Remind me to apply Occam's Razor before I post any more
guesses(tm).

[Tom Kunich]

Lou, I have no idea of what is happening but the Garmin phase 2 speed and cadence are not to blame. They can detect a 180 degree rotation and that is all. There are no magnetic anomalies more than 3 feet away that would effect it. Rebar used in construction can be magnetized by magnetic handling devices but this is an extremely low grade of steel that barely holds a magnetic charge and in addition is laid in, with a cross hatch arrangement largely neutralizing anything that is there. Whatever the problem is it has nothing to do with any bullshit that Liebermann may be feeding you.

[Tom Kunich]

I should add that ANT+ is encoded and cannot be interfered with.

[Lou Holtman]

So what is your hypothesis ? I only reported what happens. So rotational detection can’t be disturbed and also not the transmission. What is left?

Lou

[Rolf Mantel]

5. The speed sensor screws up on overpasses over electrified railway lines.

[Tom Kunich]

That is not a bad theory but here's the problem - the speed detector is over the wheel hub on the front of the bike. What a magnetic storm from a passing electric train would do is actually work in the same direction as the Earth's magnetic field if indeed this is an "overpass". I think that the ANT+ signal could be blocked by the electronic field from a passing train and if the signal is shut down long enough, the speed will drop depending upon the sample rate which I don't know. But it would be the same as coming to a stop.

So rather than a magnetic problem it could simply be interference destroying the connection. This is likely Lou's problem but I would think that it would occur to Lou that this occurred only on overpasses crossing electric train tracks (the overhead wires are well within the range of causing electronic interference,) If it is a bullet-like train with the wiring down at track level, it would be more unlikely unless a train was passing and absorbing a great deal of energy. I am unfamiliar with the Dutch train systems.

[Lou Holtman]

Nope the overpass is not over a train track. It occurs with both my speed sensors and both my Garmins (edge 1030 and edge 840) in all the combinations.

Lou

[Tom Kunich]

Why then it must be magic. The ONLY possibility is either you're actually going slower than you think or there is interference in the radio transmission of the ANT+ signal.

[Tom Kunich]

On the ride today I tried to judge the sample rate of the 830 and it was several times a second as far as I could tell. So any inte4rference would have to be pretty severe to not hold a speed.

[Lou Holtman]

I’m not going slower. I see if I can get a recording tomorrow with a disabled autostop. Maybe film the displayed speed.

Lou

[Tom Kunich]

I accept your statement that you're not slowing down. Is it possible that where you're seeing this you're passing a cell phone tower or the like?

[Lou Holtman]

I don’t think so but not 100% sure. On my rides I pass a lot of cell phone towers without problems. We have the best cell phone coverage in Europe IIRC.

Lou

[Tom Kunich]

With several transmissions per second. It would take a lot of power to block those signals. Is it possible that the speed detector is slipping on the hub when you're pedaling hard? This is hardly likely but let's rule it out.

[Lou Holtman]

Nope. If that would be the case it would happen all the time. It is on specific locations. It has to do with disturbance of the transmission or magnetic field. Lets wait for my test tomorrow if it doesn’t rain.

Lou

[Tom Kunich]

Did you get a chance to observe in more detail what was occurring for your registered speed to drop?

A wheel circumference is about 88 inches or 7 1/3rd feet. At 20 mph this is one revolution every 34 milliseconds. If as I estimated from observation that the speed is reporting about 10 times a second, that makes the speed detector only time to calculate the speed 4 times a second. So the speed of the bike is reported many times before the calculation catches up with the actual speed. Likewise the speed drop. So it wouldn't be too many gaps in the speed detection before the speed starts dropping

So it would seem to me that something is interfering with the ANT+ transmission from the sensors pretty regularly to have your speed show much diminishment.

[Lou Holtman]

Yes I have yesterday. I have to analyse the fit file. Will do it this evening. First glance at the data shows that only the speedsensor showed weird values for a couple of samples. My HRM, Di2 and power Ant+ sensors didn't show any strange behavior.

Lou

[Lou Holtman]

Well I exported the fit file data in Excel and made a graph of the speed where it drops. Also put the cadence in the same graph to prove that my real speed didn't drop:

https://photos.app.goo.gl/8bNSBACRJKjbNRzD8

It happens here:

https://photos.app.goo.gl/V5d2591uWrmGqR8V7

I approach that sport from the North:

https://photos.app.goo.gl/BEzCGDAkPZBdaN1Q7

and from the South:

https://photos.app.goo.gl/RTKVzNaWfk4NXp5HA

every time the speed drops on the same spot. As mentioned earlier, only the speedsensor shows strange behavior, not the other Ant+ sensors (HRM, Power meter, Di2 sensor).

Lou

[Tom Kunich]

I don't know when you bought that pickup but I think that they have a two year warranty. I would think that you could be having the speed sensor slipping on bumps, but that is perhaps the smoothest bike lane I've ever seen.

I cannot think what could go wrong in the sensor since I think that there's only a coil of wire and an amplifier in there to magnify the flux change from one direction to the other. The magnitude doesn't matter, only the change. I would think that it would be nothing but an overcompensated operational amplifier that simply goes from on extreme to the other. And of course the ANT+ transmitter unit.

When was the last time you changed the battery?

[Jeff Liebermann]

On Thu, 2 Nov 2023 09:52:32 -0700 (PDT), Lou Holtman
<lou.h...@gmail.com> wrote:

>Well I exported the fit file data in Excel and made a graph of the speed where it drops. Also put the cadence in the same graph to prove that my real speed didn't drop:
>https://photos.app.goo.gl/8bNSBACRJKjbNRzD8

That would seem to indicate that the problem is NOT caused by an
interruption or interference in ANT+ or BLE data. However, I'm not so
sure. See below.

>It happens here:
>https://photos.app.goo.gl/V5d2591uWrmGqR8V7

Note that there's no data on lines 704-706 and 713-714. The 704-706
lines are within the range where the speed graph became erratic. The
713-714 lines are just outside the range of the graph. I would think
that the loss of data in these areas might indicate an interruption or
some interference. If a lost data point is being reconstructed by
doing an XOR (exclusive OR) on the preceding and succeeding data
points, then you might be seeing the result of this type of error
correction.

Also, if there is data loss only in the speed sensor, which
essentially measures the strength of the earth's magnetic field, I
would expect it to be most sensitive to a static magnetic field, such
as one produce by DC current through a power cable in the roadway. The
older road lamps are all AC powered, but the new and improved LED
lighting is mostly powered by DC. To prevent radiating stray magnetic
fields, the two wires of the DC cable are run in parallel and close to
each other. Done correctly, there's no stray magnetic field produced.
However, I notice in the photo below, there is an inspection plate in
the curb which might contain a DC power cable. If it was installed in
a splice box or with the two wires spread apart, it might product a
stray magnetic field.

I suggest you carry a magnetic compass and look for a very strong
magnetic field in the vicinity of the inspection plate.

>I approach that sport from the North:
>https://photos.app.goo.gl/BEzCGDAkPZBdaN1Q7
>
>and from the South:
>https://photos.app.goo.gl/RTKVzNaWfk4NXp5HA
>
>every time the speed drops on the same spot. As mentioned earlier,
>only the speedsensor shows strange behavior, not the other Ant+
>sensors (HRM, Power meter, Di2 sensor).

As I understand the Di2 system, each sensor has its own 2.4GHz ANT+
link to the Garmin Edge 830(?). Data loss in the speed sensor should
not produce a corresponding data loss in the other sensors.

[Lou Holtman]

On Friday, November 3, 2023 at 5:11:38 AM UTC+1, Jeff Liebermann wrote:
> On Thu, 2 Nov 2023 09:52:32 -0700 (PDT), Lou Holtman
> <lou.h...@gmail.com> wrote:
>
> >Well I exported the fit file data in Excel and made a graph of the speed where it drops. Also put the cadence in the same graph to prove that my real speed didn't drop:
> >https://photos.app.goo.gl/8bNSBACRJKjbNRzD8
> That would seem to indicate that the problem is NOT caused by an
> interruption or interference in ANT+ or BLE data. However, I'm not so
> sure. See below.
> >It happens here:
> >https://photos.app.goo.gl/V5d2591uWrmGqR8V7
> Note that there's no data on lines 704-706 and 713-714. The 704-706
> lines are within the range where the speed graph became erratic. The
> 713-714 lines are just outside the range of the graph. I would think
> that the loss of data in these areas might indicate an interruption or
> some interference. If a lost data point is being reconstructed by
> doing an XOR (exclusive OR) on the preceding and succeeding data
> points, then you might be seeing the result of this type of error
> correction.

This has something to do with the power. I applied no power at those moments 'power_watt' is zero. I think from the power some other metrics are calculated that will give no values when the power is zero. Also the cadence is derived from the applied power. Sometime the cadence is zero when power is zero sometimes no value.

>
> Also, if there is data loss only in the speed sensor, which
> essentially measures the strength of the earth's magnetic field, I
> would expect it to be most sensitive to a static magnetic field, such
> as one produce by DC current through a power cable in the roadway. The
> older road lamps are all AC powered, but the new and improved LED
> lighting is mostly powered by DC. To prevent radiating stray magnetic
> fields, the two wires of the DC cable are run in parallel and close to
> each other. Done correctly, there's no stray magnetic field produced.
> However, I notice in the photo below, there is an inspection plate in
> the curb which might contain a DC power cable. If it was installed in
> a splice box or with the two wires spread apart, it might product a
> stray magnetic field.

I too think it has something to do with the (interrupted) magnetic field.

>
> I suggest you carry a magnetic compass and look for a very strong
> magnetic field in the vicinity of the inspection plate.
> >I approach that sport from the North:
> >https://photos.app.goo.gl/BEzCGDAkPZBdaN1Q7
> >
> >and from the South:
> >https://photos.app.goo.gl/RTKVzNaWfk4NXp5HA
> >
> >every time the speed drops on the same spot. As mentioned earlier,
> >only the speedsensor shows strange behavior, not the other Ant+
> >sensors (HRM, Power meter, Di2 sensor).
> As I understand the Di2 system, each sensor has its own 2.4GHz ANT+
> link to the Garmin Edge 830(?). Data loss in the speed sensor should
> not produce a corresponding data loss in the other sensors.

The Di2 system includes a wireless unit. This unit communicates with the Garmin head unit (in this case Edge 840), so it can display the gear you are in, the battery level, the position of the derailleurs during adjustment and you can scroll through the different data-fields by pushing a hidden button on the hoods so you don't have to swipe on the screen or push buttons on the headunit on a bumpy road.

Lou

[Jeff Liebermann]

On Fri, 3 Nov 2023 02:59:32 -0700 (PDT), Lou Holtman
<lou.h...@gmail.com> wrote:

>On Friday, November 3, 2023 at 5:11:38?AM UTC+1, Jeff Liebermann wrote:
>> On Thu, 2 Nov 2023 09:52:32 -0700 (PDT), Lou Holtman
>> <lou.h...@gmail.com> wrote:
>>
>> >Well I exported the fit file data in Excel and made a graph of the speed where it drops. Also put the cadence in the same graph to prove that my real speed didn't drop:
>> >https://photos.app.goo.gl/8bNSBACRJKjbNRzD8
>> That would seem to indicate that the problem is NOT caused by an
>> interruption or interference in ANT+ or BLE data. However, I'm not so
>> sure. See below.
>> >It happens here:
>> >https://photos.app.goo.gl/V5d2591uWrmGqR8V7
>> Note that there's no data on lines 704-706 and 713-714. The 704-706
>> lines are within the range where the speed graph became erratic. The
>> 713-714 lines are just outside the range of the graph. I would think
>> that the loss of data in these areas might indicate an interruption or
>> some interference. If a lost data point is being reconstructed by
>> doing an XOR (exclusive OR) on the preceding and succeeding data
>> points, then you might be seeing the result of this type of error
>> correction.
>
>This has something to do with the power. I applied no power at those moments 'power_watt' is zero. I think from the power some other metrics are calculated that will give no values when the power is zero. Also the cadence is derived from the applied power. Sometime the cadence is zero when power is zero sometimes no value.

Argh. If you stopped pedaling as you passed the area where the speed
became erratic, I can't determine if the speed variations were caused
by your pedaling changes or by external influences such as induced
magnetic fields or 2.4GHz interference. If you have any interest in
pursuing this further, another ride past the area, at constant power
and cadence, would be really nice.

>> Also, if there is data loss only in the speed sensor, which
>> essentially measures the strength of the earth's magnetic field, I
>> would expect it to be most sensitive to a static magnetic field, such
>> as one produce by DC current through a power cable in the roadway. The
>> older road lamps are all AC powered, but the new and improved LED
>> lighting is mostly powered by DC. To prevent radiating stray magnetic
>> fields, the two wires of the DC cable are run in parallel and close to
>> each other. Done correctly, there's no stray magnetic field produced.
>> However, I notice in the photo below, there is an inspection plate in
>> the curb which might contain a DC power cable. If it was installed in
>> a splice box or with the two wires spread apart, it might product a
>> stray magnetic field.
>
>I too think it has something to do with the (interrupted) magnetic field.

Well, let's see if the numbers make any sense.

I'll assume that the distance between the buried wires and the speed
sensor is 1 meter. I'll also guess(tm) that the nearby lamps are
something like this:
<https://commercialledlights.com/led-street-light-cobrahead-roadway-fixture-mrl02-series-cll/>
and are powered by 240 VDC. At 105 watts, the current draw per lamp
would be:
105w / 240VDC = 0.44 amps
The big question is how many lamps per branch circuit. Assuming the
branch circuit is protected by a 20A breaker and 10A is considered a
safe load, the could be up to 23 lamps powered by one branch circuit.
Therefore, the buried wires near the power source (and circuit
breaker) will "see" all 23 lamps for a current of 20A, while the
buried wires at the end of the branch circuit will "see" only 1 lamps
or 0.44A. I think it's a fair assumption that the power is NOT fed
from the middle of an overpass bridge, so maybe half of the lights fed
from the junction box (visible in the photos). That will be 5A
current.

So, how large a static magnetic field will 5A DC produce at 1 meter?

B = 2 * Pi * r * u0
where:
B = magnetic field in Teslas
Pi = 3.14
u0 = permeability of free space = 4 * Pi * 10^-7 Teslas m/A
where A = current in amps.
r = radius or the distance between the wire and sensor (1 meter).

For 1A current and 1meter distance:
B = 2*Pi * 1m * (4Pi * 10^-7 T m/A) * 1A
B = 2 * 10^-7 Tesla
Therefore, for 5Amps and 1meter, B = 1 * 10^-6 Tesla

The earth's magnetic field is about 5 gauss
or 0.00005 Tesla or 5 * 10^-5 Tesla
Therefore the magnetic field created by the buried wiring is 20 times
larger than the earth's magnetic field at one meter.

By itself, that would be sufficient to declare that the current
through the buried wiring is sufficiently large to cause some type of
interference. However, there are two big problems. Buried power
wires are usually buried in pairs, where the opposing magnetic field
from each wire dramatically reduces the production of stray magnetic
fields. In order for the wiring to interfere, the pairs of wires must
be separated or the pairs of wires be arranged in a "T" pattern. The
other problem is that almost every number I've mentioned is
accompanied by a guess(tm) tag, which indicates that it's not to be
trusted. The only way to be certain is to either obtain some details
on how the lighting is powered and connected, or to make some
measurements with a DC Gaussmeter.
<https://www.alphalabinc.com/products/gm1-hs/>
For now, methinks a simple magnetic compass will show the presence of
a magnetic field. The deflection can be compared with a long wire and
a constant current source set at 5 amps with the compass 1 meter away.

>> I suggest you carry a magnetic compass and look for a very strong
>> magnetic field in the vicinity of the inspection plate.
>> >I approach that sport from the North:
>> >https://photos.app.goo.gl/BEzCGDAkPZBdaN1Q7
>> >
>> >and from the South:
>> >https://photos.app.goo.gl/RTKVzNaWfk4NXp5HA
>> >
>> >every time the speed drops on the same spot. As mentioned earlier,
>> >only the speedsensor shows strange behavior, not the other Ant+
>> >sensors (HRM, Power meter, Di2 sensor).
>> As I understand the Di2 system, each sensor has its own 2.4GHz ANT+
>> link to the Garmin Edge 830(?). Data loss in the speed sensor should
>> not produce a corresponding data loss in the other sensors.

>The Di2 system includes a wireless unit. This unit communicates with the Garmin head unit (in this case Edge 840), so it can display the gear you are in, the battery level, the position of the derailleurs during adjustment and you can scroll through the different data-fields by pushing a hidden button on the hoods so you don't have to swipe on the screen or push buttons on the headunit on a bumpy road.
>
>Lou

I think you may have missed my point. With the EW-WU111 Wireless
Unit, any data loss between one remote sensor and the EW-WU111 will
not produce a simultaneous data loss from any of the other sensors.
Only a loss of connectivity between the Garmin Edge 840 and the
EW-WU111 could produce simultaneous data loss from multiple sensors.
However, because the speed and cadence sensors are in the same
package, there might be some interaction.

[Lou Holtman]

The EW-WU111 IS the sensor. It does not communicate with other sensors. In communicates with the control unit of the Di2 system by wire and transmits certain values to the headunit (Edge 840) wireless. It is not a combined speed/cadence sensor; it is a speed sensor only. Cadence is derived from the power meter/values. Bottom line is I can life with a few seconds of erratic speed values on few places. I just want to prove that the Garmin data can have erratic outliers, something Tom seems to forget sometimes.

Lou

[Tom Kunich]

Lou, what you're talking about is not an outlier. For the speed to come down either the transmission has to be completely missing for several seconds or there has to be a magnetic field that overrides the detector. THAT is unlikely since you are riding OVER the road and any magnetic fields would tend to simply increase the reaction of the sensor in the same direction.

And your graph plainly showed the something interfered with the transmission of the speed detector alone. I would guess that either the battery was getting weak or there is something specifically wrong with the speed sensor itself. That this occurs only in the same place is curious. It could not be RF interference since the other links are not effected. I would suspect bumps but your photos show that not to be the case. So if you have a spare sensor I would you suggest that you try it.

[Lou Holtman]

As I explained before I have two sensors on two different bikes and they show the same behaviour also with a fresh batteries. Every time I pass that spot, and I do that a lot because it is on my way home, without fail the speed drops for a few seconds.

Lou

[Tom Kunich]

OK, that eliminates the possibility of the sensor or the power being the problem. I am now wondering - if you have a disc brake, and you ride near a heavily magnetized object, with this interfere with the change of field? I think that you said that you have a rim brake bike. Is that so or are both of your test vehicles disc brakes?

[Lou Holtman]

No, one disk the other rim brakes. I will try one of the sensors with a Wahoo headunit. See if that makes a difference.

Lou

[Tom Kunich]

You said that both (the disc and the rim brake) have precisely the same problem of failing in the same area. This leaves me with the idea that something very strange is occurring. I would expect that if there was a very strong magnetic field or a very strong radio transmission in that area, that it would effect all of your sensors pretty much alike. But the failure ONLY of the speed sensor suggests a strong magnetic field with little range so that the cadence sensor isn't effected much since it is at the top of the crank arm at the change in -polarity.

Usually a magnetic fiend strong enough to effect the sensors in that manner would be rather large. But I could theorize that you could have a bipolar magnetic field that keeps most of its effects close to the ground. Something like a bar magnet. The concrete reinforcing rods are highly unlikely to do this because the constant vibration of passing traffic would shake any magnetic field out of them in rather short order.

You know, it just occurred to me that we used to use concrete containing magnetite and lead as shielding against high energy radiation. Do you suppose that in construction of that specific overpass that they ran out of normal concrete and used some of that type? I would think that a large enough magnetic field CROSSING the sensor would cause it to fail to detect up from down.

[Lou Holtman]

Like I said I have no cadence sensor. Cadence is derived from the power meter readings.

Lou

[Tom Kunich]

Since you have no actual cadence sensor, you wouldn't be able to compare the operation of the speed sensor to the cadence sensor. So rather than any other reasons that may simply be a focal point for radio interference in the what, 2.5 MHz range? These I believe are in the medium to international commercial aircraft communications spectrum.

[Jeff Liebermann]

On Sun, 5 Nov 2023 13:46:26 -0800 (PST), Tom Kunich
<cycl...@gmail.com> wrote:

>Since you have no actual cadence sensor, you wouldn't be able to compare the operation of the speed sensor to the cadence sensor. So rather than any other reasons that may simply be a focal point for radio interference in the what, 2.5 MHz range? These I believe are in the medium to international commercial aircraft communications spectrum.

That should be the 2.4 GHz (not 2.5 MHz) ISM (industrial scientific
medical) band which includes microwave ovens, point to point links,
wi-fi, Bluegoof, Zigbee, keyfobs, door bells, wireless video, some
remote controls, model aircraft, and just about everything else that
the FCC doesn't want to have cluttering other service bands.

FCC frequency allocations table (July 2022)
<https://transition.fcc.gov/oet/spectrum/table/fcctable.pdf>

NTIA 2016 version:
<https://www.ntia.doc.gov/files/ntia/publications/2003-allochrt.pdf>

Back to patching the roof, welding my wood stove back together,
building a burn pile, paying bills, general house cleanup, etc. I
should be mostly done in about a week. Make that two weeks. I'm
about 500 messages behind and it might take me a week to catch up on
the latest bicycle trivia.