VK4WDM > 20-02-2018, 08:32 PM
VK4ADC > 20-02-2018, 09:16 PM
VK4WDM > 06-03-2018, 04:08 PM
(20-02-2018, 09:16 PM)VK4ADC Wrote: Wayne
Expect narrow SWR bandwidth with helical radials : the Diamond CP6 does have them but have a look at the freq response width at http://www.diamondantenna.net/pdfdocs/CP6A.pdf
To homebrew, try this calculator with the same values for min and max former diameters for straight wall PVC tube (non-shrinking) - it will at least get you into the 'frequency ballpark' :
http://www.vk4adc.com/web/hf-projects/45...-whip-calc
Doug