Topband: Looking for 160m narrow beam RX advice - an interesting combination of ideas

[Tom W8JI]

>
> 1. I can see the case for an array of loops. However, wouldn't it be less
> time-consuming --not to mention less expensive-- to just get an additional
> MFJ-1026 to effectively null the second noise source? Null out one noise 
> in
> the first 1026, and then null out the second noise source in the second
> 1026? (If not in this case, then in other situations?)

An array of loops is two loops for two directions.

A person could use two noise cancellers with two sense antennas, but the 
adjustment would be back and forth several times between the nullers unless 
the individual sense antennas heard only noise from one source and nothing 
from the other noise source.


> 2. I'm well aware that a separate noise antenna placed very close to the
> RFI source can be extremely effective. However, if that's not possible,
> then how about two identical RX antennas fed into a 1026? At one time, I
> was toying with the idea feeding my main Beverage, and a second, parallel
> Beverage, into my 1026.
> The idea was to try and phase out distant line noise, among other things.

It works like any phasing system with mixing level controls would work. The 
pattern you get depends on the antenna layout.

I have a calibrated system I use as an interferometer to DF.  I can also, 
like when a jammer from New England used to come on, null someone out.

It is also useful for measuring signal wave angle with the correct sense 
antennas. This takes two systems, so the crossing points of two different 
null cones (the null is rarely a single point, but almost always a "cone 
slice") can be plotted.

The key is always element layouts. The phasing is easy.

73 Tom