Re: I am planning to beam radio signal into space.

[EMAIL PROTECTED] (P. Backus) wrote in message news:<[EMAIL PROTECTED]>...
> 1. With a 3 m antenna you will need a LOT of power to be detected at
> the distance of the nearest star system, about 4 light years.  The
> equivalent of the Arecibo antenna and the Project Phoenix SETI
> processor at 4 light years could detect a 36 kW transmitter on a 3 m
> dish.  If you want to reach 10 light years, you would need more than
> 200 kW.

> 2. Although directional, the antenna will dump a small fraction of the
> power in other directions, its "sidelobes".  I think for a typical
> antenna this will be about 0.1%.  For the 36 kW example above, you
> will have the equivalent of an omnidirectional antenna broadcasting a
> few watts.  People (the government) will notice.

I can built a bigger dish my self, similar to Arecibo, 
ofcouse not that big, maybe 10 m, or even 20 m.
It will have parabola curve, 
not hemisphere(Arecibo is hemisphere right?).
I believe I can do it.
This would reduce power needed and reduce sidelobes.

> 3. There are international agreements on radio spectrum usage.  You
> cannot just broadcast on any frequency at any power (especially
> kilowatts!), no matter how isolated you think you are.  If you
> transmit on a frequency assigned to a commercial service, you will
> hear from their lawyers and your government.

I will carefully select frequency so than it will no interfere
with any services on earth.
 
> 4. Running a generator to power a 36 kW transmitter will get
> expensive.  You will need about 4000 liters of fuel every two to three
> weeks.  That gets very expensive, very quickly.

Fuel in my country is quite cheap.

> So, as I think others have said, transmitting is not a practical way
> to participate in SETI.  However, you could put together a very nice
> SETI League station.

If the ET also think like you, they never transmit high power beam out.
Your SETI project will never pick-up any signal from the ET.
 
> Peter Backus
> Project Phoenix