How do civil engineers use grad to measure slopes in construction?

[jim hardy]

Ever run across the Poundal ? Accelerates 1lbm 1 ft/sec²
for me it beats using slugs...

Who has ever used "grad" to express angles, and why was it put in every calculator ever made?

The HP35 calculator instruction book explained where Grads are useful. I used them a few times in early 70's but have forgot why.

Asimov once pointed out our base 360 for angular measurement comes from an archaic (i think)Sumerian number system. They picked 360 because it's evenly divisible by so many numbers

The divisors of 360 are 1, 2, 3, 4, 5, 6, 8, 9, 10, 12, 15, 18, 20, 24, 30, 36, 40, 45, 60, 72, 90, 120, 180 and 360, making a total of 24 divisors. 360 is a highly composite number.
360 (number) - Wikipedia

https://en.wikipedia.org/wiki/360_(number)

There was once a movement to change angular measurement to decimal , milliturns . A grad would be 2.5 militurns.
But as you suggest, "Newer" does not equate to "Better".

i DO miss RPN calculators , much preferred them.

But i digress.

old jim

 

[sophiecentaur]

The HP35 calculator instruction book explained where Grads are useful. I used them a few times in early 70's but have forgot why.

Grads are ideal for calculations involving rotations. `There is no need to introduce 360, 60 and 60 into your calculations. But Grads are a bit on the big side even for rough practical work so they are not a very intuitive size. (Same objection as you guys have about kg - too big and g - too small. The oz is pretty much right for most things, I have to admit)
Interestingly, in navigation, it is the practice nowadays to use degrees, minutes and decimals of minutes instead of using degrees, minutes and seconds which was past practice. Your GPS hand held will almost certainly have both options available. I was at sea with a pal and we were busy disagreeing with where we were and I realized he was using mins and secs and I was using decimal mins. The chart, of course was in decimal mins because it was not printed in Victorian times.

 

[wirefree]

Christmas Greetings to All - whichever part of the world you are in. I hope it’s a good end to the year for everyone.

— see below the part of the solution to the question after all the mechanics of the DC are complete and all power values have been calculated.
wirefree

@tech99 @jim hardy @davenn @f95toli @sophiecentaur
Thank you for sticking around.My effort here has been to not expose you to the inner workings of the Directional Coupler. Related to it are concepts such as Coupling (C) and Directivity (D). How they are calculated and what their magnitudes are in this particular question, I hoped, wouldn’t concern you as long as their units were mentioned.The relevant terms remain P_x’s , units of which have been clearly mentioned.Warm regards,

wirefree

 

[jim hardy]

Coupling (C) and Directivity (D). How they are calculated and what their magnitudes are in this particular question, I hoped, wouldn’t concern you as long as their units were mentioned.

Well Thanks for the feedback and kind wishes - they are reciprocal

i only tried to address this query

I am here to clear my doubt about the dB scale, in general, and it’s use in calculating received power

but asked about D and C for fear i had missed something fundamental

i hope you're more confident with db now.

Myself, i was glad to see db is still on the Simpson 260 meter face.
It's the only piece of nostalgia i know that's "still made just like they used to."

old jim

 

[Tom.G]

3) Who has ever used "grad" to express angles, and why was it put in every calculator ever made?

Back when the first pocket scientific calculator became available, a large part of the market was the Civil Engineers.

IIRC, that 'orphan', the grad, is rather handy in infrastructure plumbing such as sewer lines, even when building a home. When laying a sewer line, the construction folks build in a slope so the water will flow down hill rather than just lay in the bottom of the pipe. They refer to the slope as Rise/Run, x feet of rise per 100 feet of run. One foot of rise (or fall) per 100 feet = 1grad.

(irrelevant side story)
As you may have heard, here in California we run into a water shortage on occassion. This of course triggers calls for everyone to use less water, don't water their lawns, flush their toilets less often, etc. Well the sewers, both storm and sanitary, were built ages ago when water was used freely, and they were built with a slope adequate to move the expected solids along with the water flow. Under drought conditions there were problems with the sewers clogging due to the reduced water flow.

Cheers,
Tom