Re: RE: Re: Garmin altitude problems

On 11/8/2024 2:23 PM, cyclintom wrote:

On Sun Aug 11 13:26:43 2024 Frank Krygowski  wrote:

On 8/10/2024 8:38 PM, Jeff Liebermann wrote:

  As I understand it, all aviation barometric altimeters are temperature
compensated.  I would think the aviation temperature compensation for
air density method is somewhat similar to a marine barometer:
<https://www.faa.gov/air_traffic/publications/atpubs/aip_html/part2_enr_section_1.8.html>
I couldn't find anything that shows how the various gears work and
where the bi-metallic temperature compensator is located (because of
numerous interruptions today).

I just opened up the wall mounted aneroid barometer here in my study, an
antique I inherited. It's an extremely simple lever mechanism, no gears
involved. The capsule pushes up or down on a long thin lever arm. The
vertical motion of the lever's end is converted to a horizontal motion
of a tall thin post, which anchors the end of the smallest roller-style
chain I've ever seen, maybe 0.050" pitch. That wraps around the needle's
pivot shaft.  Here's a photo:
https://www.flickr.com/photos/16972296@N08/53916400376/in/dateposted-public/
   (Sorry, the "tall thin post" is in shadow.)
>
The left end of the lever system is not a pivot point, but instead is a
rather wide brass stamping. I'd think that part could be made bimetallic
to provide temperature compensation.
>
>
-- - Frank Krygowski

    Remember that ALL metals expand when heated but they expand at different rates so the mechanism has to correct the expansion of one metal against the expansion of the other for compensation so there has to be a mechanism that puts one point of rotation against another.
 I wish that Liebermann would stop trying to be an expert at things he doesn't understand. He said that my way of using a pulse width to measure a line length so that you can zero in on the reflection point is wrong

Yes, it was wrong. You claimed you were using PWM, but you were describing TDR, and describing it incorrectly. And no, TDR does not use PWM to manipulate the pulse width.

but offered NO alternative

Yes, he and I both did, explaining the _correct_ way to use TDR without a specific TDR tester.

and then just the other day showed a TV90 and pretended that to be the alternative.

It's a TDR test set. It's what we've been stating you were doing all along, not PWM. IT says so right on the page
https://www.atecorp.com/products/tektronix/tv90

He has NO idea of how a TV90 works

He described TDR rather well, you're just too stupid to understand it. you on the OTH didn't even know what TDR actually meant until it was explained to you (you called it "time delay reflection", lol https://groups.google.com/g/rec.bicycles.tech/c/f_tByXh5jXo/m/CNLtZacUCAAJ)

which just happens to be a sophisticated copy of my way that is used to find cable faults in underground lines. Tektronics makes the TV100 which is a further sophistication.

And you won't find PWM anywhere in any description of TDR.

 He did the same thing when I wrote the formula of how altitude via air pressure is calculated. He writes the same thing and claims that I am wrong because it doesn't include compensation. If sea level pressure is unchanged there needs be no compensation.

lol - the barometeric pressure at sea level changes by the hour, sometimes faster, so yes, you need compensation.

And you can't be in two places at one time. Wait, Lieberrmann can, just ask him.
 The world is simulaneously complicated and simple. The deeper you look the more complicated it becomes but for most things a very simple observation is all you need. You are happy with your steel bike. I prefer a more complex bike. I use 10 speed (once I used Campy 12 speed and Shimano Di2) because it is good enough for the way in which I ride. Your 7 speeds are fine for you. We agree to disagree about helmets and bike lanes. As long as you do not oppose people's choices in your state, that's good enough. I'm sure that you're riding is safe without a helmet though it is my opinion that the very term accident carries the meaning that you cannot be perfectly safe. And I have learned the hard way that is better to be safe than sorry.
 May you live to a healthy old age in a time of the party of Lincoln.

New meds?
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