On Mon,2/16/2015 9:18 AM, wb6r...@mac.com wrote:
The CPU between my ears is what the L vs R phase difference processes in Diversity mode. I can get a somewhat similar affect using AFX (or the equivalent with a Heil headset that has a phase reversal switch) but significantly without the benefit of the phase difference of the received signal from two different antennas in Diversity RX.
You (and Heil) are using the word "phase" incorrectly when you talk about "reversing" it. What that switch is doing is reversing the POLARITY. Polarity has two values -- normal and inverted. Polarity is the same for all frequencies. Bob Heil, who claims to be the audio guru should know better -- the word polarity has been used in this manner in pro audio for nearly 40 years.
Phase is a continuously variable function measured in degrees (or radians), has the range of +/- infinity. Phase has no meaning for signals of different frequencies. When phase differences are the result of time differences between two signals of the same frequency (for example, a direct signal and a reflected one), the phase difference is proportional to the time difference. These multiple arrivals cause what we hear as "picket fencing" at VHF and UHF, and long slow fades on the lower frequency bands (including 160M). The peaks occur when direct and reflected are more nearly in phase, the dips occur when direct and reflected are nearly equal in amplitude but close to 180 degrees out of phase.
Another example -- when we use lengths of feedline to provide phase shift for antenna arrays, the amount of phase shift depends on the frequency. If we want two antennas to be driven precisely in phase over a broad frequency range (for example, wide bands like 160M, 80M, and 10M), we should use two lines of equal length. A half-wave (or multiple of half-waves) will provide the desired phase relationship at a single design frequency, but a different value away from that frequency.
73, Jim K9YC ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
