Topband: New 160M high performance receiving antenna at W3LPL

[Tom W8JI]

I want to correct this:


>> I experimented here with very large arrays years ago by watching signals
>> and watching phase, and I found skywave 160 signals commonly have phase 
>> and
>> level variations between arrays centered about 1-2 wavelengths apart. 
>> This
>> is at the root of the very reason we use spatial diversity, and why 
>> spatial
>> diversity works. It stands to reason if phase and level were stable,
>> spatial diversity would not work.

The spacing I typed could have been worded better. At 1 wavelength spatial 
separation phase and level was pretty stable. At 2 wavelengths spatial 
separation phase and level started to show issues on skywave.

This is NOT an abrupt transition like flipping a switch. It is a progressive 
transition where the likelihood of skywave not being in phase increases, or 
the chance of not having the same levels from each area increases. This 
increases fading when antennas are directly combined, or when one antenna is 
VERY large spatially.

While this varies with propagation conditions and array spacing, and I'm 
assuming it is sensitive to latitude and direction of path, it was bad 
enough here that I never combined small arrays directly into a "giant array" 
or used a really long Beverage antenna.

73 Tom