[Elecraft] diversity receive what bands

[Bill W4ZV]

Jim Brown-10 wrote
> Beverages tend to favor higher wave angles, while verticals favor low 
> angles.  Those who have lots of land like to install both Beverages and 
> vertical RX arrays (Hi-Z Antennas, DX Engineering are US companies that 
> sell them). I've seen reports of signals appearing an hour earlier on 
> one antenna than the other, then disappearing from the first antenna.

Beverages and vertical arrays actually have very similar takeoff angles
(e.g. 25-40 degrees).  Salt water dramatically lowers the lowest takeoff for
verticals and a poor ground will raise it.  Lengthening Beverages will also
lower the takeoff angle.  See Graph 3 below for an example of the latter on
160:

http://www.seed-solutions.com/gregordy/Amateur%20Radio/Experimentation/Beverage.htm

At 1 wavelength (~540' which is about the minimum useful Beverage length)
the takeoff angle is 42 degrees.  Lengthening it to 2 wavelengths lowers the
angle to 27 degrees.  

Below are two plots (top and very bottom) of my antennas which demonstrate
the difference between a low dipole (90 degree takeoff), a vertical array
(22 degree takeoff) and a 2 wavelength Beverage (24 degree takeoff):

http://users.vnet.net/btippett/new_page_10.htm

I normally use Beverages on one port and an RX4SQ on the other port.  I can
also switch between the RX4SQ and my TX array (Spitfire variant).  On 80 and
160 I use diversity almost 100% of the time.

73,  Bill  W4ZV





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