TopBand: Radiation Angle vs. System Losses

[Jon K. Jones]

Bill, K0HA brings up a good point regarding "how well"
verticals of various wave lengths work on 160 may not be 
due the radiation angle but rather the efficiency of the feed
system and feedline losses. System losses are critical
and may offset attempts to lower the angle of radiation. 
The quarter wave vertical is a good match to 50 ohm coax
and at 160 meters will have negligible feedline loss.
The 1/2 wave vertical has an impedance of several thousand
ohms and will have high line losses even at 1.8 MHz if connected
directly to 50 ohm coaxial feedline and matched with a tuner
in the shack due to the extremely high SWR.
(I tried this with a 1/2 wave balloon vertical last winter) Using a matching unit at the base of the vertical itself, setting it
up as a "J-pole" or using open wire feedline are ideas to 
reduce the feedline loss. 
The 1/2 wave vertical's high radiation resistance offers greater efficiency over poor ground systems than the 1/4 wave if line
and matching losses can be kept reasonable.


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