NEC-LIST: Stripe Model of Two-Arms Conical Spiral Log Antenna

Hi ...

Where it can be mathematically described, the easiest way of creating
'large' geometry for NEC (or indeed any other modelling code that
accepts ascii input) is to write a program to create the appropriate
GW cards. Being a Luddite from way back my preference is Turbo Pascal
running in DOS, but you could use your favorite language - Basic,
Fortran or even C++.

eg ...
*
*
*
  for n:=1 to 200 do begin
    theta1:=n*pi/20; theta2:=(n+1)*pi/20;
    x1:=r*cos(theta1); y1:=r*sin(theta1);
    x2:=r*cos(theta2); y2:=r*sin(theta2);
    z1:=n*p; z2:=(n+1)*p;
 
writeln(output,'GW',seg:3,tag1:5,x1:10:3,y1:10:3,z1:10:3,x2:10:3,y2:10:3,z2:
10:3,dia:10:3);

    x1:=r*cos(theta1+pi); y1:=r*sin(theta1+pi);
    x2:=r*cos(theta2+pi); y2:=r*sin(theta2+pi);
    z1:=n*p; z2:=(n+1)*p;
 
writeln(output,'GW',seg:3,tag2:5,x1:10:3,y1:10:3,z1:10:3,x2:10:3,y2:10:3,z2:
10:3,dia:10:3);
  end;

The above crudely written code will generate cards for two five turn
spirals with 200 segments with a radius of r, with 40 segments per
turn, and a pitch of p/40. Wire diameter is dia.

Cheeeeeeeeeeeeeeeerz

Alan

**************************************
Alan Nott BEE, CEng, MIEE
Senior Technical Specialist Engineer
Electromagnetic Modelling
Fire Support Systems
Land Engineering Agency
Department of Defence
Australia
Tel + 61 3 9622 2835

email: alan.nott_at_defence.gov.au
Received on Sun Mar 04 2001 - 11:11:21 EST