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Re: [IRCA] [NRC-AM] DKAZ Antenna
At 12:40 21-08-15, you wrote:
Nick: See CAPS below
Mark Durenberger
-----Original Message----- From: Nick Hall-Patch
I haven't had experience with two D-Kaz Mark, but do I gather then
that you haven't seen evidence of null steering with the DKaz
alone? I HAVEN'T SEEN EVIDENCE OF STEERING, JUST DEPTH ADJUSTMENT
(PRESUMABLY INCLUDING RE-SHAPING OF SIDE-LOBES).
I'm not sure my use of "null steering" is entirely the correct term,
even for the Flag. The direction for minimum signal response moves
with adjustment of the termination (especially for vertical
polarization), but the depth of the null is not be as great as the
best null obtained directly off the back of the antenna.
I had observed similar (and <900 ohms) termination values for
Portland on 1190 and Seattle on 1000, one 50 degrees off the back
of the antenna, one 30 degrees, but realize that although Portland
on 620 and and Seattle on 710 also had similar values of
termination, that value was higher. And to throw it all out,
Portland area on
1640 and Seattle on 1680 had different values of termination altogether.
Now I think of it however, doesn't the fact that 1640 and 1680 had
different termination resistances for best nulls show a type of "null
steering" (or ?). In both cases, the null was around -25dB, and the
difference in termination resistance was a couple of hundred
ohms. I had no reference right off the back of the antenna at those
frequencies, but I assume that both values of termination resistance
couldn't have each been appropriate for the deepest null off the back
of the antenna.
I'll look into that further vacation time.
best wishes,
Nick
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