-----Messaggio Originale-----
Da: Tom Osborne <w7why@harborside.com>
A: TowerTalk <towertalk@contesting.com>
Data invio: venerdì 12 novembre 1999 6.31
Oggetto: [TowerTalk] Stacking question
>
>
> Hi Gang
>
> I've been wondering about some things. Say 2 3 element
> monobanders are stacked, the gain goes up 3 db (at least that's
> what I think). If there is 100 watts going to the antennas, when
> it reaches the splitter does 50 watts go to each antenna or does
> the full 100 watts reach each antenna. If only 50 watts, it
> doesn't seem like there is actually any gain in stacking antennas
> as the gain goes up but the ERP is the same as with one antenna.
There is gain because You transmit the same previous energy but
splitted into two antennas.
If the antennas are in the same point you have no gain (here you got
confused) if the antennas are enough apart to increase the capture
area there is gain.
> I know that the takeoff angle is supposed to be lower with a
> stack,
Not necessarily.
but how much would you have to raise a single antenna to
> get the same take off angle with 2 antennas in a stack.
> What got me to wondering is I'm going to play with a 10 meter
> antenna here. I'm now using a 2 element monobander on 10, driven
> element and reflector, and I want to put another driven element
> on the other end so I can switch directions with the beam. I also
> would like to be able to feed them both so I could beam NW and SE
> at the same time. Just wondering what would happen feeding them
> both.
Basically You beam two directions with half power. Other complex
pattern of minor amplitude grow or disappear.
Thanks and 73
> Tom W7WHY
73,
Mauri I4JMY
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