Topband: STEERING

[Tom W8JI]

>I have a MFJ-1025 and I have seen some past post about using this unit for 
>direction steering using two separate antennas.  I am installing a new two 
>wire beverage and wonder if there would be any steering possible using the 
>two inputs from the beverage into the MFJ.  I had to ask........
>>>

If you model a single wire Beverage with two sources and no termination, and 
step the termination through all levels and phases, you will see exactly 
what is possible.

The level will control null depth, the phase will control null position. 
Null movement is limited, but you can move nulls around a little bit. You 
can get deep nulls if the level is right, but they do not steer like people 
think or old articles claim.

For example a 1 wl Beverage likes roughly around 160 degrees phase shift 
(-30 if you flip phase by transposing wire directions) and about a 1.4:1 
current ratio from feedpoint to termination. You can make the pattern deeper 
or more shallow, and move nulls around near the back, but it basically stays 
about the same overall pattern with varying null depths in the same general 
areas.

This isn't saying it isn't useful to move the nulls around a little, but 
don't expect to actually steer or narrow the beam. That would take two 
antenna with some significant physical spacing in wavelengths.