From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mx1.redhat.com ([209.132.183.28]:47074 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750815AbZLARPd (ORCPT ); Tue, 1 Dec 2009 12:15:33 -0500 Message-ID: <4B154F26.6070607@redhat.com> Date: Tue, 01 Dec 2009 15:15:18 -0200 From: Mauro Carvalho Chehab MIME-Version: 1.0 To: "OrazioPirataDelloSpazio (Lorenzo)" CC: no To-header on input <"unlisted-recipients:; "@bombadil.infradead.org>, linux-media@vger.kernel.org Subject: Re: DIY Satellite Web Radio References: <4B14195D.6000205@autistici.org> <4B142E2C.1020108@redhat.com> <4B143E29.4090307@autistici.org> In-Reply-To: <4B143E29.4090307@autistici.org> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-media-owner@vger.kernel.org List-ID: OrazioPirataDelloSpazio (Lorenzo) wrote: > Mauro Carvalho Chehab ha scritto: >> Receiving sat signals without dishes? From some trials we had on a telco >> I used to work, You would need to use a network of low-orbit satellites, >> carefully choosing the better frequencies and it will provide you >> low bandwidth. > I also believed this, but their use geostationary orbit [1] and > terrestrial devices handly and without dishes [2] [3]. > I belive they should rely on some very robust modulation e channel > coding, but unfortunately I didn't find any specification. >>From what I remember from the tests, the worse problem were related to the transmission. If you're just receiving data, it is possible to receive without a dish, depending on the transmission frequency and modulation schema. It works better with some spread spectrum modulation, since you'll have some gain due to frequency diversity. You may also use a dual antenna to gain a few more dB's. However, if you need to transmit data to the satellite (to have something close to Internet via Amateur Radio), I doubt you'll be able to do it without a highly directional antenna. > > Lorenzo > > > [1]http://en.wikipedia.org/wiki/XM_Satellite_Radio > [2]http://shop.xmradio.com/xm/ctl10600/cp49770/si4025808/cl1/xmp3_portable_radio_with_home_kit > [3]http://shop.xmradio.com/xm/ctl10600/cp56879/si4343009/cl1/xm_direct_2 >