[TowerTalk] Inverted L on three low bands

[Nick Pair]

Assuming you have at least a quarter wavelength of wire vertical on 40 mtrs.you need to have separate radiators or at least stubs for each band to have a easy to feed antenna on three bands as 40, 80, and 160. One quick way is to leave the 160 L as is and put out another wire in the opposite direction to resonate it as a 80 L. Then all you need to do is add a second vertical at your feed point for a quarter on 40 with 4 in. or more spacing from 80/160 vertical of the L.This gives you a low impedance element on band of interest and the other two are at high impedance 1/8 or 1/2 lengths. 
  This type of antenna must be worked against a radial system for efficiency. The higher you can get the radials the fewer you can get away with but less than 4 is not a good idea unless a compromising layout necessitates.(I have have used just a ground connection in portable operation but it was more of a cloud burner than a distance communication antenna. Just 1 radial was a improvement with the radial a foot or more off ground.) Also the more vertical you can get for the L the lower the takeoff angle will be as it approaches the angle of a true vertical 1/4 wave.
  Radials for each band is better but you compromise to fit your situation. If you get a very low SWR with 50 ohm coax direct feed be very suspicions that you could use more radials or off ground ones!
   
  This just a few ramblings on how to answer your question on 3 bands one L.
  73
  Nick
  WB7PEK

 		
---------------------------------
Yahoo! Music Unlimited - Access over 1 million songs.Try it free.