archive: Re: SETI Helix antenna formulas-

Re: SETI Helix antenna formulas-

MarcusJohn@aol.com
Sun, 20 Sep 1998 23:04:59 EDT

Thanks Paul and Ed,

Ed Larsen's formula's have fixed the Half Power Beam Width on my
spreadsheet. If anyone wants a copy, it is about 4 kilobytes as excel 4, or
20kb as excel 97. I will email it if anyone wants it. It is useful for looking
at the changes in gain and HPBW when you vary circumference, turn number, and
axial length of turn, etc. If anyone want's to add functions, no prob.

Thanks,

John Marcus,
KE3SW

> My spreadsheet, and the website quoted, gives .015 degrees as the HPBW. Even
> if I assumed the Radians as an error, I still get 0.8 degree, which is not
> credible. I am off by an order of magnitude, so there is some major error
> here. I have the email from Ed Larson with his formulas, and I'm going to
> compare his formulas to my spread sheet to see were my error is.