Hi-VHF Monopole Whip (14-in high) TRUE-OMNI-Directional Antenna analyzed using 4nec2.
This antenna responds to Vertical and Circular/Elliptical (ONLY) Polarization.
TOTAL Raw Gain was calculated, which is the sum of Horizontal & Vertical Gain. If a station transmits equal power in H and V (CP=circular polarization), then the orientation of the antenna won't make TOO much difference.
More and more stations are firing up a second transmitter/antenna for CP broadcast to an expected explosion (???) of Mobile TV viewers. You can check the status of your local station here: http://www.rabbitears.info/ss/
However if a station is still only transmitting Horizontal Polarization, the antenna needs to be tilted on it's side (tip of whip to left or right). Otherwise the Gain will drop dramatically from what is listed below.
=================================== a) Whip (14-in high) with just a 2-inch circular disc ground plane, such as when placed on top of a stack of books/magazines on a wood table. Pretty pathetic.....
UHF: Raw Gain is 1 to -1 dBi for Ch14-30, but drops to -13 dBi on Ch51. SWR (75-ohm) is excessive (as high as 17 on low channels), dropping below 4 on Ch42-69. Hence Net Gain is non-existent.
Hi-VHF: Raw Gain is constant 1.7 dBi, but SWR is excessive (300-90), hence Net Gain is non-existent.
Ch2-6: Raw Gain is constant 1.6 dBi, but SWR is excessive (60,000-6,000), hence Net Gain is non-existent.
================================== Improved results with a small ground plane: b) Whip (14-in high) with a 19-in x 12-in rectangular ground plane, such as when placed on top of some electronic gear. Better, but still not much of an antenna.... [Location near electronic equipment NOT recommended due to electronic interference pick-up.]
UHF: Raw Gain is 1 to -1 dBi for Ch14-33, but drops to -7 dBi on Ch51. SWR (75-ohm) is excessive (as high as 9 on low channels and 5 on high channels), dropping below 4 on Ch27-53. Hence Net Gain is very low except on Ch27-53 it peaks at -3 dBi.
Hi-VHF: Raw Gain is constant 1.5 dBi, but SWR is excessive (10-4) on Ch7-9, hence Net Gain is only adequate on Ch11-13.
Ch2-6: Raw Gain is constant 1.7 dBi, but SWR is excessive (6000-660), so Net Gain is non-existent.
8 Mar 201016 items6496 visitsAlbum by holl_ands
enlarge 109KB, 1024x838 1 14" Whip w 19"x12" Base - 3D View
enlarge 77KB, 791x1024 2 14" Whip w 19"x12" Base - 4nec2 File
enlarge 108KB, 1024x648 3 14" Whip w 19"x12" Base - UHF Raw Gain
enlarge 130KB, 1024x648 4 14" Whip w 19"x12" Base - UHF SWR (75-ohm)
enlarge 123KB, 1024x648 5 14" Whip w 19"x12" Base - Hi-VHF Raw Gain
enlarge 130KB, 1024x648 6 14" Whip w 19"x12" Base - Hi-VHF SWR (75-ohm)
enlarge 114KB, 1024x648 7 14" Whip w 19"x12" Base - Ch2-6 Raw Gain
enlarge 136KB, 1024x648 8 14" Whip w 19"x12" Base - Ch2-6 SWR (75-ohm)
enlarge 18KB, 642x1024 9 14" Whip w 2" Base - 3D View
enlarge 29KB, 791x1024 10 14" Whip w 2" Base - 4nec2 File
enlarge 94KB, 1024x648 11 14" Whip w 2" Base - UHF Raw Gain
enlarge 131KB, 1024x648 12 14" Whip w 2" Base - UHF SWR (75-ohm)
enlarge 110KB, 1024x648 13 14" Whip w 2" Base - Hi-VHF Raw Gain
enlarge 122KB, 1024x648 14 14" Whip w 2" Base - Hi-VHF SWR (75-ohm)
enlarge 106KB, 1024x648 15 14" Whip w 2" Base - Ch2-6 Raw Gain
enlarge 132KB, 1024x648 16 14" Whip w 2" Base - Ch2-6 SWR (75-ohm)
