The anomoly you see is because the 60dB gain given is dBi and the "real" gain used to calculate the power is dBd (gain referenced to a dipole and not isotropic). The difference is around 2.4dB.
On 21-Apr-10 11:46, Fabio Azzarello wrote: > Hello, > thanks for the reply, but now I have another question. > I'm not good enough with those numbers! > > If the calculated ERP is about 243 MW... which derives from changing from > dBi to dBd (60dBi - 2.14), > the part I don't understand is: > > "*Since the given ERP is 243,902,443 Million Watts (see below) > and since 60 dB is equivalent to 1000000 (one Million) time in > power it comes out that the power reaching the feed of the dish is: > 243902443 / 1000000 = 243 watt > > The rest of the power 400-243 = 157 watt is lost in the feed line.*" > > How do they have feeder losses? > thanks in advance, > > 73s > Fabio > iw8qku > > > > On Wed, Apr 21, 2010 at 8:45 AM, Mateusz<sq7...@poczta.onet.pl> wrote: > >> >> 60dBi is abt 57dB >> It means 10exp5,7 >> ERP was 400x10exp5,7 W >> >> ----- Original Message ----- From: "Fabio A"<iw8...@amsat.org> >> To:<AMSAT-BB@amsat.org> >> Sent: Tuesday, April 20, 2010 8:26 PM >> Subject: [amsat-bb] Re: Arecibo on 432 MHz Moon Bounce (some calculations) >> >> >> Hello all, >>> just a curiosity, how did you found that the ERP is "... 243,902,443 >>> Million >>> Watts". >>> >>> Thanks >>> >>> 73s >>> Fabio >>> iw8qku >>> >>> ----- Original Message ----- >>> From: "MM"<ka1...@yahoo.com> >>> To:<amsat-bb@amsat.org> >>> Sent: Wednesday, April 07, 2010 3:06 PM >>> Subject: [amsat-bb] Arecibo on 432 MHz Moon Bounce >>> >>> >>> Hi all: >>>> Here is a EME event you cant miss. >>>> Dust off your CW key, its time for Satellite, QRP EME. >>>> >>>> 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. >>>> >>>> enjoy >>>> >>>> wf1f >>>> www.marexgm.org >>>> >>>> (thanks to KB1MGI for passing on this data) >>>> ... snip ... >>>> >>> > _______________________________________________ > Sent via amsat...@amsat.org. Opinions expressed are those of the author. > Not an AMSAT-NA member? Join now to support the amateur satellite program! > Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb > > > > > No virus found in this incoming message. > Checked by AVG - www.avg.com > Version: 9.0.814 / Virus Database: 271.1.1/2825 - Release Date: 04/21/10 > 06:31:00 > -- Nigel A. Gunn, 1865 El Camino Drive, Xenia, OH 45385-1115, USA. tel +1 937 825 5032 Amateur Radio G8IFF W8IFF (was KC8NHF), e-mail ni...@ngunn.net www http://www.ngunn.net Member of ARRL, GQRP #11396, QRPARCI #11644, SOC #548, Flying Pigs QRP Club International #385, Dayton ARA #2128, AMSAT-NA LM-1691, AMSAT-UK 0182, MKARS, ALC, GCARES, XWARN. _______________________________________________ Sent via amsat...@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
