[NLRS] Alford slot antenna formulas?

[Scott]

After searching through many search pages, I have not been able to find 
formulas for calculating dimensions (tube diameter, slot width, slot 
length--well length of slot has been indicated as 1/2 and 2 wavelengths, 
etc.).  I would assume that the circumference of the tube would be 
something like 1 wavelength (but the published measurements I did find 
for a couple bands don't seem to corroborate that!) since most of the 
theory I found indicates you treat the alford slot as an infinite number 
of horizontal loops all stacked on top of each other (yea calculus!). 
Anybody have any more info on these antennas?

-- 
Scott N0EDV
http://corbenflyer.tripod.com/
Building RV-4
Gotta Fly or Gonna Die