Topband: beverage lobes

[k3bu at optonline.net]

> "Richard (Rick) Karlquist" wrote:I once 
> tried a 1300 ft beverage. It needed
> no terminating resistor to get very high F/B ratio because the 
> signal to be rejected was totally dissipated by the time it bounced
> off the end and traveled another 1300 ft to the feedpoint. YMMV.
> YMMV is certainly the concept in play here. I have run Beverages 
> from 180 foot long all the way out to 1100+ feet in length. I 
> can see definite improvement for every additional foot of 
> length. The observed difference in usable performance between a 
> 550 footer and an 1100 footer is about the same as the 
> difference between a 500 footer and the TX vertical. 800 footers 
> are very much inferior to the 1100 footers. Proper terminations 
> are required for optimum performance in EVERY case here. I could 
> run out to 2000 feet but haven't because I can hear so much more 
> than I can work with the 1100 footers, I don't want to be even 
> more depressed!
> 
> Perhaps the difference is due to ground. My dirt is about as bad 
> as you can get and still call it dirt. The top soil varies in 
> depth from a few inches to a few feet with a mix of solid 
> basalt, river rock, sand, and caliche underneath. My verticals 
> are barely better than low dipoles most of the time.
> 
> Yes, YMMV!!
> 
> 73, Larry
> 
> Larry - W7IUV 
> DN07dg - central WA
> http://w7iuv.com
> 

One has to realize the properties of the long Beverages, they lower the vertical angle and narrow the horizontal beamwidth. For example (according to EZNEC) going from 500 ft Beverage to 2000 ft, V angle gets down to about 20 deg and gain goes up about 10dB. Where there was a wide lobe at about 40 deg. with 500 footer, there is a 20 dB null at about 45 deg. H beam goes down to about 40 deg. So for one, they have to be "aimed" more cerefully (bevare of skewed path) and when the low angle propagation is happening (not too often). So casual tests might not show up the advantage, but when low angles happen, the difference is very pronounced. 
It is important to use decent gauge wire to minimize the ohmic losses.
First time I used 1600 ft down hill Beverages, I concluded that they were "useless" too. Having the long ones during contests with low angle prop, they played, when most stations complained about "lousy" propagation.

73 Yuri, K3BU