Actually, another possibility would be to normalize to 1500
watts radiated power (vs. effective isotropic radiated power).
This would allow the person with small lossy antennna
elements (e.g. your HOA phased array) or somone with a
really long feedline run to normalize for system ohmic losses.
You would essentially prorate your RF output power by
the difference between your antenna gain and its directivity
plus any feedline losses. For an antenna that had -3dBi
overall gain and 7dB of directivity, you could run 15 KW
into the input connector. This would radiate the same power
into space as a +7dBi gain antenna with 7dB of directivity
excited with 1500 watts.
73 de Mike, W4EF................................
----- Original Message -----
From: "Jim Lux" <jimlux@earthlink.net>
To: "Michael Tope" <W4EF@dellroy.com>; <va3pl@cuic.ca>;
<towertalk@contesting.com>
Sent: Tuesday, September 02, 2003 3:24 PM
Subject: Re: [TowerTalk] Smart antennas
> Or, one could run a 10 kW "active antenna tuner", on each of the 10
> elements in the array.
>
> While the current regulatory model lets me have 1500 joules/second, I
can't
> exactly distribute them as I see fit for other regulatory reasons. 30 odd
> years ago, the rules were changed from DC power to the final to PEP
largely
> to adapt to the "new fangled" SSB.
>
> I would suggest, as a starting point, that the DC/feedline power limit be
> increased, while keeping the nominal EIRP the same as it is. That is,
> assume that currently, one could put up a 10 dBi antenna and feed 1500W to
> it, for 15 kW EIRP. I could then put a -10 dBi compact loop sitting on
the
> grass and ram 150 kW into it. (Granted, I could probably see the blurred
> electric meter wheel spinning by the glow from the antenna before the
grass
> caught fire)
>
> One would still have an incentive to improve one's antenna system;
> amplifiers aren't free, after all. My model is more comparing the 5 dBi
> from an inefficent 4 square type array (which I could erect in my HOA
> controlled lot: flagpoles!) against the 8 dBi Yagi on a 100 foot
> tower. You can run 1500W into your Yagi, I'd like to run 750W into each
> element...
>
>
> At 02:59 PM 9/2/2003 -0700, Michael Tope wrote:
> >Seems like an EIRP scheme would take away incentive
> >to make ones antenna better. Why put up a 4-square to get
> >5dB of extra TX gain, when you would have to derate your
> >transmitter power by that same amount for a zero net gain.
> >Right now the FCC gives you 1500 joules/second to work
> >with. You are then free to distribute them across the heavens
> >any way you see fit (in keeping with safety limits of course).
> >If you want to spray them all in one direction with a high
> >gain antenna or distribute them uniformly with a omni, you
> >are free to do so. Other services have EIRP limits because
> >they have frequency reuse concerns that we don't have
> >(except for repeater service where we do have EIRP
> >constraints).
> >
> >Sorry, Jim, but I like big transmitters AND big antennas :):)
> >
> >73 de Mike, W4EF..............................
> >
> >----- Original Message -----
> >From: "Jim Lux" <jimlux@earthlink.net>
> >To: <va3pl@cuic.ca>; <towertalk@contesting.com>
> >Sent: Tuesday, September 02, 2003 2:03 PM
> >Subject: Re: [TowerTalk] Smart antennas
> >
> > > more of that power into the dirt or the clouds overhead. In pretty
much
> > > the rest of the radio world the licensing and power limits is in terms
of
> > > ERP. Maybe we should push for the FCC to do the same for hams? It's
not
> > > that different than how RF exposure is handled, or the limits on the 5
MHz
> > > band. You can either guarantee compliance by an antenna of known gain
> > > (i.e. a dipole) and limited transmit power, or by analysis/measurement
of
> > > actual field strength.
> > >
> > > In reality, the rule requires use of the least power to communicate,
and
> > > from a theoretical standpoint, that's the radiated far field. If you
use
> >a
> > > 1000W transmitter and a dipole or a 100W transmitter and a 12 dBi
> >directive
> > > antenna, the field strength is the same. Philosophically, I should be
> >able
> > > to allocate my resources how I see fit, subject to the radiated power
> > > limit.. If I want to invest in big high gain antennas and small
> > > transmitters or small antennas and big transmitters, that should be my
> > > choice (subject to safety rules, etc.)
> > >
> > > Of course, there are those who run big antennas AND big transmitters
who
> > > may not agree.
> > >
> > > Jim, W6RMK
> > > (http://home.earthlink.net/~w6rmk/antenna/phased/index.htm)
> > >
> > > At 03:19 PM 9/2/2003 -0400, VeeAthreePL wrote:
> > > >There is interesting article by Martin Cooper in July 2003 issue of
> > > >Scientific American pages 49 to 55. He is talking about Smart and
> > > >Adaptive antennas. This basically is aimed at cell phones but who
knows.
> > > >Worth the reading.
> > > >73 de Andy - VA3PL
> > > >
> > > >_______________________________________________
> > > >
> > > >See: http://www.mscomputer.com for "Self Supporting Towers",
"Wireless
> > > >Weather Stations", and lot's more. Call Toll Free, 1-800-333-9041
with
> > > >any questions and ask for Sherman, W2FLA.
> > > >
> > > >_______________________________________________
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> > > >http://lists.contesting.com/mailman/listinfo/towertalk
> > >
> > > _______________________________________________
> > >
> > > See: http://www.mscomputer.com for "Self Supporting Towers",
"Wireless
> >Weather Stations", and lot's more. Call Toll Free, 1-800-333-9041 with
any
> >questions and ask for Sherman, W2FLA.
> > >
> > > _______________________________________________
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> > > TowerTalk@contesting.com
> > > http://lists.contesting.com/mailman/listinfo/towertalk
> > >
> >
> >
> >
> >_______________________________________________
> >
> >See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless
> >Weather Stations", and lot's more. Call Toll Free, 1-800-333-9041 with
> >any questions and ask for Sherman, W2FLA.
> >
> >_______________________________________________
> >TowerTalk mailing list
> >TowerTalk@contesting.com
> >http://lists.contesting.com/mailman/listinfo/towertalk
>
> _______________________________________________
>
> See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless
Weather Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any
questions and ask for Sherman, W2FLA.
>
> _______________________________________________
> TowerTalk mailing list
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>
_______________________________________________
See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless Weather
Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any questions
and ask for Sherman, W2FLA.
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