[TowerTalk] Two 15M stacking
btippett at alum.mit.edu
Sun Feb 25 07:28:44 EST 2007
>My point was, that in order to compare two antennas
to know whether you could possibly lose anything because
of the narrow beamwidth, you would have to look at the
3 dB beamwidth of the one with X gain and then compare it
to the 6 dB beamwidth of one with X + 3 dB of gain.
I understand Stan, but 3 dB is very hard to
come by once a single antenna reaches a certain size
because you must MORE than double boom length to get
3 dB. I know you recently built a monster 40m Yagi,
but I personally would prefer two stacked 3-el Yagis.
The flexibility of pointing in different directions
plus the ability to steer takeoff angle in varying
conditions is a plus IMHO...not to mention mechanical
reliability issues such as tower and rotator torque.
Now that you've used your monster 40m in a
few contests, what do you think of it? Was it worth
the effort? How are your 40m scores comparing to
the big 3 versus before?
Regarding comments about extremely high
antennas, maybe my top one at 105' is not high enough
to really see advantages. It's good in a few cases
but I really doubt I would miss it much other than
the directional diversity it gives me. That could
also be due to my not operating 10m much when the
sunspots are really down. Maybe that is when really
high antennas work so much better.
73, Bill W4ZV
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