On Tue, 16 Dec 2008 07:51:02 -0800 (PST), Gary Slagel wrote:
>I had a couple comments that I would probably not notice much
>difference in the directivity with the 90 degree offset dipoles.
Whoever told you that is WRONG! I've got crossed dipoles in the
air at 90 degrees for 80 and 40, and there are DEEP NULLS off the
ends. I also have crossed dipoles on 20/15/10. Same result. In
each pair, one is broadside EU/VK/ZL (and also the east coast of
the US), while the other is broadside SA/JA (and WA, TX, AZ).
I do a lot of contesting, and have them on a switch. On any given
signal, switching can make the difference between hearing them or
not, and in being heard or not. I've also had crossed dipoles on
Field Day, with the same result.
I had an 80/40 HyPower in Chicago at only 40 ft, and it was dead
off the ends.
How much difference? Easily 6-10 dB, sometimes more. 10 dB is 10X
the power, the equivalent of adding a 1kW power amp to your 100W
radio. 6 dB is 4:1 power, equivalent to a 400W power amp. If the
other guy has an S6 noise level and that 6 dB gets you to S7, it
makes the difference. And, BTW, most REAL S-meters are NOT 6dB/S-
unit except right around S9. Below about S7, the ones I've
measured are more like 3dB/S-unit.
73,
Jim Brown K9YC
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