[TowerTalk] 4 Sq array Dx or Hi Z

[Jim Brown]

On 9/6/2012 5:36 PM, Joe Subich, W4TV wrote:
> flipping phase 

Joe,

Please use the right word -- POLARITY when you mean turning the wires 
over to invert the signal. Phase is a continuously variable function and 
increases directly proportional to frequency.  For example, a piece of 
transmission line that provides 180 degrees phase shift at one frequency 
provides a phase shift of 198 degrees at 1.1X that frequency, but 
reversing the POLARITY results turning the signal over at ALL 
frequencies.  The difference between how these two methods of feeding 
antennas can be HUGE in terms of the maintaining performance over a 
desired bandwidth.

Engineers working in pro audio had to learn this 30 years ago when 
modern instrumentation made the difference glaringly obvious, and 
although it's critically important to hams, most don't even have a clue 
about the difference.

73, Jim K9YC