My chemical engineering professor at UCLA said last Thursday something like the following.

Upto now in science classes you have studied theoretical science and dealt almost exclusively in SI units. However, AES [American engineering units] are still the dominant units in engineering, so we will be using them in this class.

I was always under the impression that science was totally metric... I guess this isn't true.

Bud wrote

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Upto now in science classes you have studied theoretical science and dealt almost exclusively in SI units. However, AES [American engineering units] are still the dominant units in engineering, so we will be using them in this class.
>>

In the US maybe, but outside the US No!.

You have just spoken on behalf of all countries other than the US.

Truly you are a man of knowledge.

I use both English and metric units in electronics work.

Some quantities have been universally expressed in metric units, in both Britain and the U.S., since early times. For example, radio wavelengths are always quoted in meters.

There are certainly those engineers in modern-day Britain who work almost wholly in metric, but many of us do not. If I take those metric wavelengths and do the calculations to determine antenna or feeder lengths, I use a formula which gives the answers directly in feet.

^ why not inches instead?

Herein lies the beauty of the metric system - Paul calculates his antenna sizes in feet, Bryan asks why not inches. It takes a bit of mental effort to convert 15.85 feet to inches.

If however he was working in metres, the conversion to millimetres is automatic - shift the decimal point three. The metric version of Bryan would not need to ask the metric version of Paul why he had not used millimetres - it would be unimportant.

Well, actually I DO calculate in inches when working with very high frequencies (and thus very short wavelengths).

There's no big problem with using metric wavelengths and English measurements for antennas and feeders. The wavelengths are something intangible, a physical property of an unseen electromagnetic wave. The feeders and antennas are tangible, metal objects which can be seen and touched.

I grew up measuring such things in feet and inches, and I simply find it more convenient to use units which I can visualize easily.