Domenico: I suspect that the difference of opinion has to do with the difference in punctuation (',' vs. '.') used with large numbers.
In typical American usage, 243,902,443 Million Watts = 243,902,443,000,000 watts = 243.9 trillion watts 243.902 443 million watts = 243,902,443 watts = 243.9 million watts
without the punctuation ->
243 902 443 million watts = 243 902 443 000 000 watts = almost 244 trillion watts.
So, I think that if the comma is used as a 3-decade separator and not a decimal point, that the original posting was in fact a million times overstated. I hope that clarifies it.
If not, then think of it this way.
400 watts x 0 dB = 400 watts 400 watts x 10 dB = 4000 watts = 4 kilowatts 400 watts x 20 dB = 40000 watts = 40 kilowatts 400 watts x 30 dB = 400000 watts = 400 kilowatts 400 watts x 40 dB = 4000000 watts = 4000 kilowatts = 4 megawatts 400 watts x 50 dB = 40000000 watts = 40000 kilowatts = 40 megawatts 400 watts x 60 dB = 400000000 watts = 400000 kilowatts = 400 megawatts
They were nowhere close to 400 000 000 (400 million) megawatts of ERP.
400,000,000 million = 400 million million = 400 terawatts 400.000.000 million = 400 million = 400 megawatts
73 de W0JT
On Apr 21 2010, i8cvs wrote:
----- Original Message ----- From: "Nigel Gunn G8IFF/W8IFF" nigel@ngunn.net To: "i8cvs" domenico.i8cvs@tin.it Cc: "Fabio A" iw8qku@amsat.org; "AMSAT-BB" amsat-bb@amsat.org; "Mateusz" sq7dqx@poczta.onet.pl Sent: Wednesday, April 21, 2010 9:07 PM Subject: Re: [amsat-bb] Re: Arecibo on 432 MHz Moon Bounce (some calculations)
Of course, this ia all rubbish as the stated power of 243TeraWatts (READ
BELOW CAREFULLY) is clearly not true.
That would require an antenna gain of, in the regeon of, 120dB.
On 21-Apr-10 17:49, i8cvs wrote:
The only official data given for Arecibo by WF1F are the following :
The 1,000 foot dish has 60 dBi on 432 mc and 400 watts. That comes out to be approximately 243,902,443 Million Watts ERP.
Hi Nigel, G8IFF/W8IFF
I disagree with your numbars:
1 tera watt =1 TW = 1 x 10^12 watt or 1,000,000,000,000 watt
1 mega watt = 1MW = 1 x 10^6 watt or 1,000,000 watt or 1 million watt
So 243,902,443 million watt ERP = 243,902,443 MW ERP as WF1F writes is CORRECT
By the way the gain of Arecibo is 60 dBi or 1.000.000 time in power and not 120 dB = 1. x 10^12 or 1.000.000.000.000 time in power
73" de
i8CVS Domenico