[TowerTalk] R8 vs 6BTV, etc.

[Joe Subich, K4IK]

> I've had various verticals, trapped and non-trapped, for HF.  
> Right now, I'm using the R8, which has been a good performer. 
>  (The new Yagis, which replace wind damaged units will go up 
> this spring.)  No, it will not give you the strongest signal 
> on the band or beat out a good Yagi on a reasonable tower.  
> (I think Cushcraft's gain figures are overly optimistic.)  
> When the band is open, however, it performs credibly; I've 
> worked DXCC on 30M and KL7 and KH6 on 6M.  As Cushcraft 
> states, it should be mounted at least 10 feet above the 
> ground.  However, much higher mounting will emphasize 
> high-angle radiation.

The height is a compromise between ground induced losses on the 
lower bands and elevation issues on the higher bands. 

With an elevated vertical (ground plane) mounted 1/4 wave above 
ground the peak gain is about 1.0 dBi at 16 degree t.o. angle. 

As the height moves above 1/4 wave a higher angle lobe forms - 
at 3/8 wave the high angle lobe is 0.3 dB at about 55 degrees 
t.o. angle and the primary lobe is about 1.3 dB at 15 degrees. 
There vertical pattern dips about 4 dB between the two lobes. 

When the height reaches 1/2 have above ground the "high angle" 
lobe is 1.8 dBi at 48 degrees ... the low angle lobe is around 
1.0 dBi at 13 degrees.  

As one goes above 1/2 wave a third lobe is formed but it remains
5 to 6 dB below the two lower angle lobes. 

All this assumes that the support and feedline are properly 
decoupled from the radials (or counterpoise) and do not radiate! 

73, 

   ... Joe, K4IK