Re: LOGO-L> Playing with Logo

["Dale R. Reed" <dale-reed@worldnet.att.net>]

Dr. Martin A. Burschka wrote:
<snip> 
> valleys between. You make their superposition rule:
<snip>
> I do like very much your idea to reproduce interference patterns
<snip>
> Maybe one could model the amplitude of the partial wave of some
> first antenna by color coding. <snip>

All good points Martin.  I think another way of saying it is phase has
not been taken into account.  And as you say, things are either on or
off.  Digitized instead of analog as it really is in real life.  Even
though there is a main beam in the expected broadside direction(assuming
these are electromagnetic radiators) the 3dB beamwidth and sidelobes are
probably not correct.  I could get my dusty textbooks down from the
shelf but not now.  One thing you and Christoph can look for.  If the
sources were very close together then the resulting array beamwidth
should be equal to 50/(total spacing in wavelenths).  My
Electromagnetic's professor called it the Woolworth rule.  Woolworths
was a 5 and 10 cent store so…   Hey Martin which country are you and
Christoph in?  I think I might be losing you here.  

I am trying to write the programs so they are easily used in both
Microworlds and MSWLogo.  Must eliminate the "arc" and "for"
procedures.  Guess there will always be the setxy and setpos
differences. I am already getting questions about the "for" procedure
from people that are not using MSWLogo. Amazing how many different kinds
of people using all kinds of Logo in many different countries are on
this Logo list.  

The pixil thing is a problem to watch out for.  I suggest that you and
Christoph do what I am doing and turn whatever you are doing 90 degrees
once in awhile.  Certainly just simple images have little "fringes" that
are due I suspect to the limitations of our monitors.  

I made some improvements(for my purposes) in the code I sent you before
and include them below.  My purpose is to have the waves "radiate" from
where ever the turtle is but the waves be drawn by the turtle so its
position can be sensed for future reflections, etc.  And, as I said
above, I am trying to minimize the changes that must be made when
transporting code back and forth between MSWLogo and Microworlds.  So if
I am helping a little homeschooler with a problem I can help him(when I
say him I mean him or her, I am not a very politically correct kind of
guy) in whatever Logo he is working with.   

And tell Christoph that he and I share something besides an interest in
Logo.  

He being 11 and me being retired we can both do pretty much what we want
to do.  Almost no distractions from girls and not much work to do.  He
has another couple good years then things will be much different for him
for most of the rest of his life.  But if he saves his money and invests
it wisely and has married an understanding wife he will be free to play
with Logo again when he gets to be my age. 

And one more thing Martin.  There is engineering and there is art. I was
an Electromagnetics Engineer for 40 years and I was always very
uncomfortable when someone referred to the "Art of Engineering."  I
think art is one thing and engineering is another.  So I am not that
concerned that I am not accounting for phase or whatever.  Think of them
as moire patterns and simply enjoy their beauty.  At least that is what
I am doing at the moment.    Dale

to cross
setpencolor [0 0 0] setpensize[1 1]
fd 2 bk 4 fd 2
rt 90
fd 2 bk 4 fd 2
lt 90 
end

to manywaves
st cs home 
for [source 0 10 1][setxy :source 0 cross waves]
ht
GIFSAVE "manywaves1.gif
end

to wave
setpencolor [0 0 250] setpensize[1 1]
pu fd :R rt 90 pd
repeat 360[fd :R*pi/180 rt 1]
lt 90 pu bk :R pd
end

to waves
for [R 10 200 10][wave]
end
-- 
$  dale-reed@worldnet.att.net   Seattle, Washington U.S.A.  $