Re: Opinions on SI

"Rick Muething" <rmuething@...>

Well Bryan,
The international screw thread committee was supposed to standardize screw sizes and threads in the early 19th century ....of course they didn’t do too good a job so now we have US Fine, US Coarse, Metric, each with many variations etc.  much to the benefit of those making wrenches, sockets and drivers!)  As long as you are communicating clearly I don’t think it is a big deal.  For me: (a US educated Engineer)There is no confusion with:
70cm vs. 70 cm,
12VDC  vs DC 12 V  (I am sure 12VDC is more common)
bps vs. b/s
or ppm (most xtals and oscillators are specified in ppm)
So I would vote use standards where appropriate (please avoid furlongs per forte night when possible! )  and push on!  Those that want to retranslate to the latest “approved” standards can contribute by doing a translation if necessary.
Keep up the good work!
Rick Muething, KN6KB

From: k7udr
Sent: Saturday, November 24, 2012 12:37 PM
Subject: [UniversalDigitalRadio] Opinions on SI

After a recent presentation I was approached by a fellow Ham who noted that my presentation did not conform to SI (International system of units). He offered a training exercise in the proper usage which I accepted. I must admit, I was ignorant of SI prior to that time.

Apparently, SI is taught in grade school throughout the world, whereas my US education seems to be lacking.

So I went through my material fixing obvious offenders, like proper capitalization and the use of a space between value and units.

the K in kilo should be lowercase
70cm should be 70 cm
12VDC should be DC 12 V (looks pretty awkward to me)

I then learned that bps should be b/s and dBm don't exist. Further ppm is incorrect.

Now I've never seen b/s used by anyone, anywhere and I certainly wouldn't want a table of values expressed as:

dB referenced to 1 mW

instead of dBm

When I purchase an oscillator, tolerance is expressed in ppm, so apparently the manufacturers are unaware of their non-conforming usage.

Am I out of touch with reality? Are you offended by 56 kbps?

I'd like to hear others thoughts on this, particularly those of you educated somewhere other than the US


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