Hi Wolf,
> This is a first brief report on my bew phased beverages.
> Consisting of two 800 ft bevs.
How far apart are they Wolf, and is there any Echelon staggering?
If they are closer than 280 or 300 feet spacing and purely
broadside, the advantage of broadside (co-phasing) is minimal at
best. Using end-stagger (Echelon) allows close spacings like 35
feet to improve F/B and F/S and can help S/N much more
consistently, but on a quiet night S/N improvement is minimal at
best because directivity doesn't narrow up that much. F/B ratio
improves the most with Echelon stacking and end-fire phasing.
Large spacings improve S/N under wider ranges of conditions, but
are more critical and often require constant re-adjustment of phase.
I have to change phase between two Beverages spaced 500 feet as
much as 130 degrees during the course of one opening at times!!!
With wide spaced arrays, a phasing control is a MUST if you are
going to use them night after night. Some nights phasing them will
be useless or actually hurt because phase will be shifting so fast it
will be impossible to add the desired signals.
This morning was one of those cases! A single Beverage worked
better than an array of two or three (spaced 500 feet apart between
each antenna), because the phase shift was changing second by
second between the antennas! My four-square was the same as
the single Beverage for receive, and nothing would phase together
without hurting S/N.
On calm stable propagation nights large arrays work exceptionally
well, but on nights where we are having geomagnetic storms they
are mostly useless!
I get good results with AM transmitters in
> the right direction,signals go up 3 to 4 dbs.Side rejection goes up as
> well.I can switch very fast from phased to unphased status.As conditions
> were poor this week i only have a small database from experience.But one
> thing can be said = the dx signals DONT go up the way that the AM bc
> signals do !
Phase shift might be different, or phase requirements different.
Also, some nights large physical size arrays just won't work well
because phase of signals at each antenna is too turbulent.
73, Tom W8JI
w8ji@contesting.com
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