Topband: beverage lobes

[k3bu at optonline.net]

>> K3BU:
> > Staggered Beverages narrow the horizontal lobe, to get low 
> > vertical lobes you need to go long beverages or long and 
> > stagerred, and down hill if possible.


>W8JI: 
> Not so. Staggered Beverages can place a null almost anywhere 
> depending on stagger distance and phase. With 180 degree 
> phase shift you can get a null straight up (and to the 
> sides). Generally the stagger works best to control or 
> improve F/B ratio or suppress high angle lobes. It actually 
> doesn't do as much at all for lobe width.
> 

IS So!
Using EZNEC file example of staggered Beverages from W8JI web site, they show 79.1 deg horizontal beamwidth at 35 deg elevation max angle, gain -14.9 dB  F/B 15.6 dB
Removing one Beverage, the single one shows 94.8 deg horizontal beamwidth at 40 deg elevation angle, gain -13.15 dB   F/B  6.49 dB
94.8 - 79.1 = 15.7 deg  - that doesn't seem like "doesn't do as much".


> The high angle lobe generally doesn't contribute much noise. 
> S/N is largely a function of directivity, and that is not 
> impacted much by a few narrow spurious lobes.
> 
> For Beverages in Echelon (stepped):
> 
> http://www.w8ji.com/echelon-log_beverages.htm
> 
> 73 Tom 

Also statement on W8JI web site that "It is not necessary, nor does it do any good, to go beyond 1-1/2 or 2 WL." is not true. I have used 3.5 wave beverages and they kill other shorter Beverages when signal angles are low. 

73  Yuri, K3BU