raypsi wrote:
Hey OM

What you are saying is that I can take a 20 mW emitter and with an
infinite size dish I can get infinite power from a 20 mW emitter?

You can get infinite *Effective Isotropic Radiated Power* from 20 mW
with an infinite dish. Not practical, but theoretically correct.

You're misunderstanding EIRP, Effective Isotropic Radiated Power. If
you feed a 60 dB parabolic antenna with 20 mW you get the equivalent of
feeding a theoretical *isotropic* radiator with 20 kW, the key word
being 'isotropic,' meaning that 20 kW is being radiated in all
directions. Your 60 dB dish directs your 20 mW *in a specific
direction* with a *specific* beam width. *In that beam* the field
strength is the same as it would be from 20 kW *going in every
direction*. The ratio of every direction to your dish's beam width is
60 dB.

No way you can get infinite power from a 20 mW source unless the dish
is supplying the extra power. In other words it's not possible to get
infinite power focused from a 20 mW source, and that all that power is
coming from the 20 mW emitter.

You're not getting infinite power, you're getting 20 mW focused into a
finite beam width and in that beam width it has the same field strength
that 20 kW going in all directions would give you.

Take that 20 mW emitters' isotropic pattern, there is a potential of
an infinite amount of power in that pattern because it can be
focused?

Only if it can be focused into an infinitely small point which you won't
get from any finite gain antenna.

Frying that turkey only takes 20 mW of total power period. And it may
or may not be from focusing the 20 mW. The turkey gets cooked with 20
mW is still a fact that can't be refutted.

Part of that fact is it will take a long, long time to cook it with only
20 mW because you can only cook (defined as raising the temperature to
about 160 F) a very, very small portion of the turkey at a time with
only 20 mW.

- W8LNA



73 OM
de n8zu




You can't. You're just focusing that 20 mW of power in the "useful
direction"


-Bill- Hide quoted text -
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