[TowerTalk] beverage doubts

[rick@area.com]

> > So far, I'm not terribly impressed.  Signals in the desired direction are
> > down a couple of S-units, which is tolerable, and the thing appears to have
> > some directivity (i.e. signals in non-desired directions are down more) but
> > the signal-to-noise ratio does not seem significantly better than on my
> > vertically-polarized 4-element parasitic array.

We put up a 1300 foot Beverage, and were not all that impressed
in general either, although it had excellent front to back ratio.
Might be good from the West Coast to the Pacific if you need to
reject the USA.

> But if I don't terminate a Beverage, or terminate it incorrectly, the 
> extra length makes a big improvement in F/B and often in S/N. That's 
> because the F/B ratio of a long wire is directly related to the 
> return loss of the antenna, and the longer antenna has more return 
> loss when the system is improperly terminated.
> 
> I measured current in several Beverages over the years. At the end 
> of 500 ft on 160, with a 7 ft high antenna, 25 to 50% of the current 
> is gone at the far end. That's 3 to 6 dB of power loss, and 6 to 
> 12 dB of return loss.
> 
> Measurements like mine are confirmed in textbooks, where long wires 
> close to real earth have been measured.
> 73, Tom W8JI
> w8ji.tom@MCIONE.com


My 1300 foot Beverage tends to confirm Tom's experience.  It didn't
matter whether it was terminated or not, it had always had good F/B
ratio.  Based on a conversation with Tom, I am going to try 585 foot
Beverages in a phased array instead.

Rick Karlquist N6RK
rick@area.com

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