From: Chris Trayner <C.Trayner@leeds.ac.uk>
To: "rsgb_lf_group@blacksheep.org" <rsgb_lf_group@blacksheep.org>
Date: Mon, 22 Aug 2011 18:45:55 +0100
Thread-Topic: LF: Re: Re: Ferrite wideband antennas?
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Dear All,

>From an engineering point of view, a scientific theory does not have to be =
true.  It just has to be useful.

When a scientist builds a bridge it will collapse, but the scientist can pe=
rfectly explain why it collapsed. When an engineer builds a bridge it will =
not collapse, but the engineer will not have a clue why it does not collaps=
e.

I'm afraid some of these homely sayings seem to me to miss some of the poin=
ts.

If you have a 'theory' (e.g. a set of equations) which works, but you don't=
 understand why (or it's not true), then it's potentially dangerous. 'It wo=
rks' means that it works under the set of circumstances where it has been t=
ested. You could use it outside those circumstances and not realise you had=
 done so.

A scientist explaining bridge collapse isn't trying to build a good bridge:=
 (s)he is playing a different game (albeit one that may later benefit bridg=
e building).

An engineer who doesn't understand why their bridge stays up (i.e. hasn't b=
othered to undserstand the theory properly) may have built a bridge that wi=
ll later collapse under unpredicted circumstances.


Traditional electr(on)ic engineering had many areas where you can work well=
 from simple theories and experience. You can choose an audio inter-stage c=
oupling capacitor like that. But modern engineering also has many areas whi=
ch are far more complicated - you can't design stripline by rule of thumb a=
nd feel (unless you've designed something very similar before), nor 3-phase=
 AC-to-AC converters handling hundreds of megawatts.

"For now I see the true old days are gone." Cue chorus of old-timers blamin=
g it on beat music and the lack of capital punishment. Actually, I think th=
ey are still here; it's just that the forefront of electronics nowadays is =
the far more complicated stuff. Fortunately, as radio amateurs, we set our =
own agendas and can choose to work in whatever part of that spectrum we wis=
h.


73,
Chris G4OKW

-----------------------
Dr Chris Trayner
School of Electronic & Electrical Engineering,
The University of Leeds,
Leeds LS2 9JT, United Kingdom
Tel: +44 113 34 32053
Fax: +44 113 34 32032