Multifeed per tre o quattro satelliti (Astra,Hotbird,Atlantic Bird..)

Questo testo in realtà è un post usenet del 2006, me ne sono ricordato scrivendo in un altro newsgroup, lo riporto anche qui, forse sarà utile a qualcuno...

L'idea, confortata dalla presenza di altri esempi trovati cercando su Internet e Usenet, è quella di aggiungere al mio classico dual feed HB/Astra altri due LNB, uno puntato su Atlantic Bird 3 per prendere i canali francesi in FTA, l'altra sui 28.2E per prendere non Astra 2D che alle mie latitudini (Firenze) con una parabola da 85cm è una causa persa, ma gli altri canali FTA (di interesse molto scarso in verità) trasmessi da Eurobird e gli altri Astra. E' essenziale avere un supporto multifeed che consenta di regolare anche in altezza gli LNB. I fuochi secondari infatti
si trovano più in alto rispetto a quello centrale, non sono sul medesimo piano orizzontale, anche se con i soliti dual feed da 3-6 gradi la differenza è trascurabile: con 18 gradi di differenza invece bisogna alzare l'LNB secondario di circa 2.5 cm rispetto a quello posto sul fuoco
principale (l'installazione è avvenuta a Firenze)

Sui negozi online italiani non ho trovato niente del genere: in Germania invece sono relativamente diffusi, a quanto pare vengono montati da immigrati dell'Est per prendere Astra, HB, Sirius e Amos. Da uno dei pochi rivenditori tedeschi che spedisce anche in Italia ho trovato questo "multifeed 4-fach halter" della "mactep creative electronics".

Circa 10 euro più s.s. Il supporto ha rivelato queste particolarità:

+ attacco più o meno standard con due fori distanziati di 25 mm per due bulloni con testa da 10 mm - entra nel braccio della mia Sateco del 1994 perfettamente - nel foglietto di istruzioni si menziona la Gibertini da 85 cm

+ molto leggero

- impressione di solidità/qualità non eccezionale, forse anche per la leggerezza dei materiali usati però.

-- come si vede dalla foto non consente di mettere l'LNB centrale proprio nel fuoco centrale della parabola :-( Per certe configurazioni può andare bene: io invece voglio tenere sul fuoco centrale HB perchè alcuni TP risultano al limite. Uso discreti LNB da 0,2 db ma ho anche una calata di
circa 60 mt fino al Dreambox posto esattamente nel punto più distante di casa dalla parabola.

-- Almeno con la mia parabola non c'è abbastanza spazio per realizzare l'obiettivo iniziale (5w-13e-19.2e-28.2e). Almeno per ora ho dovuto rinunciare ai 28.2We.

Per montare il tutto ho cercato diverse soluzioni, ma l'unica che mi assicurasse la piena ricezione di HB sul fuoco centrale è stata attaccare la barra curva del nuovo supporto al vecchio già presente, usando fascette di plastica e stringitubo. Il tutto sembra reggere anche se non so se a
lungo andare se il puntamento non si perderà. Ecco alcune immagini dell'ambaradan:

Ho effettuato il puntamento di Atlantic Bird con un decoder analogico sintonizzato su uno dei canali SECAM di AB3 - si è rivelato di gran lunga il metodo più comodo. Come si vede dalle foto è essenziale avere la possibilità di posizionare l'LNB in altezza e anche in inclinazione rispetto al palo della parabola. Purtroppo la mia parabola è stata posizionata in alto e in sporgenza rispetto al terrazzo e questo rende molto difficoltoso regolare di fino la posizione dell'illuminatore - senza
rischiare di cadere dal terrazzo intendo...), ad ogni modo riesco a ricevere senza alcun problema il tp 11591V di France TV con i canali FTA in DVB-S, anche sul Dreambox a 60 mt di cavo di distanza (AGC del satfind al 70%). L'LNB usato è un B.E.S.T. Germany apparentemente da 0,1 db anche se a quanto ho visto un pochino peggio dei Clarke Tech da 0,2 db nominali che
uso per Astra e HB.

Probabilmente dovrò trovare una soluzione migliore per il supporto, specie volendo raggiungere l'obiettivo originario - comunque anche non essendo posizionati nella parte più favorevole del footprint dei satelliti cercati è possibile senza grandi sforzi realizzare la configurazione multifeed.

The virile way to the Macintosh…

This spring I was almost psychologically ready to buy myself a Mac mini. Then Steve Jobs announced the switch to the Intel processor. Can’t spend 500 EUR for a soon to be obsolete PPC machine, no can’t do. In August the new 10.4.1 Intel/PCC developer kit OSX was leaked, patches were produced to run the OS on some specialized PC hardware and/or virtualizers like Vmware or more generic PC systems. It is now possible to run 10.4.1 OSX on a PC with practically all the features of the Apple Developer kit with.. 1) a SSE3 Celeron/P4 processor (with a Prescott Core), 2) an Intel 915 chipset motherboard (now sadly discontinued, but mobo still available, the best seems to be the Intel GUXL with a 775 socket) 3) generic hd/dvd/dvd-rw/case/psu Even a SSE2 CPU (but not lower) and a non 915 chipset mobo will do, but with lower performance, especially in the graphics department. For the details on how to do it a very good starting point is www.osx86project.org and www.win2osx.net. I built myself a good “hackintosh”/”macintel” system with: a 60 EUR Asrock P4 Dual 915-GL a 70 EUR socket 478 2.8 GHz Celeron D CPU, two 35 EUR 512 mb DDR DIMMs, a 30 EUR stylish but cheap iTek case  and an ‘old’ 60 gb IDE HD and DVD reader. I’ve also tried a Sparklan WL-660GS  wireless nic as an almost plug-in Airport replacement (it uses the same broadcom chipset)  with good enough results. I chose the 478 socket over the newer 775 socket because I’ve mostly 478 machines at home and at work I can eventually cannibalize something from – the Asrock mobo has a strange PCIX-AGP combo slot in addition.

 

I can use (a bit slowly) most PPC OSX apps with the Rosetta emulation – Office, Macromedia Studio, the Adobe suite all run. All the HW (sound, ports, networking, and usb) works. The newer universal binaries run very fast, the lowly Celeron clearly outperforms the Mac mini. I’ve doubts about the longevity of the whole hack – the 915 chipset, being discontinued, won’t appear in retail Intel Macs, and possibly won’t be supported by the new, final Intel OSX, newer builds of OSX for Intel have added protections against running on standard Intel hw (tough rapidly developing work is being done at least for the latest 10.4.3 build), but it’s a great way to test and play with the Macintosh system anyway. If the ‘hackintosh’ won’t be able to run OSX in the future, it will always be useful as a second or third PC, and newer and better Mac minis (hopefully minis you don’t need a special tool just to open them) will be on the market. Here are some photos. The wireless keyboard/mouse is an el cheapo Nortek system (the mouse eats battery power like a McDonald punter, the keyboard is still running on the included batteries), the screen is 15’’ LG LCD monitor.

 

Spenglerian pessimism

The always interesting Steve Jobs gave recently this interview to MacWorld. Besides the joke (or was it ?) about pirates 'burning in Hell' this passage struck me as  interesting:

“Apple does that better than any other company in the world. What makes us different? Most of our competitors don’t have engineers anymore. Everyone else designs in the Far East.”

They don't have engineers anymore. Of course they haven't been actually manufacturing anything for more than a decade, now. And to-day they're not even designing anything. They just live on marketing the stuff, apparently - support has been outsourced to India, of course.

Local 'remote' Mathematica Kernel on Mac OS

Say, you run Mathematica 5.x locally on a system (Mac OSX 10.4.1 for intel with Rosetta, for instance) where communication between the frontend and MathKernel has problems. You can work around the problem running remotely the local kernel. Here's how:

- create a /sbin/math.sh file with this one line of text

/[path to Mathematica /directory/Mathematica 5.2.app/Contents/MacOS/MathKernel $@

- chmod +x /sbin/math.sh

of course. Of course you have to know how to use the Terminal and some basic unix knowledge.

- ssh-keygen -t rsa

you have to be logged on as the user you use normally (not root)

- Enable remote login in System Preferences - Sharing - this enables sshd

- Start the fronted, go to Kernel, Kernel options, add a new remote kernel using /sbin/math.sh 2&>/dev/null as remote command, localhost as remote host. Define the defaults at your will. Upon launching the kernel you should be asked for the user password, but at last the frontend should communicate normally with the kernel.

Half-homemade wi-fi antenna with built-in extension...

I'm currently in München  for a few weeks. Among others, I enjoy my lodger's Wi-Fi Internet connection. I live in a dépendance and the signal strength is always low, weather-dependant (that pesky, ever changing german weather), and subject to interference from other WLANs in the neighbouhood (those pesky, überrich Germans). I have to think of something if I want to waste time on the net even in Germany. The simplest thing would be putting the PC on the window...



Mmmm, nee, nee. Perhaps the lodger won't be too happy. At the local Saturn I've found a very handy coaxial extension for Wi-Fi antennas, for only 19.99 € (those pesky, ultracheap German prices). It's a D-Link product, whose packaging is this:




The only problem: while the card-side connector fits perfectly, the antenna side screwable connector doesn't fit my detachable antenna, and no other Wi-Fi antenna I've seen. So what do you do ? You cut the connector, split the cable in order to expose the inner copper core, for a length which must be the same as the normal Wi-Fi antenna. You get a perfectly working, even if quite fragile, wi-fi extension with a built in antenna. Of course one can build himself the whole cable without buying the D-Link extension, with the right connector and coaxial cable, and make a more solid antenna, but I'm here with only a screwdriver, a cutter, and little time. For now, this hack workssss....

TravelMate's wireless networking not working ?

after swearing and tireless trying,
the damn thing still gives you but nothing ?

You've checked the WEP, you've changed the speed,
and lo! your centrino is still in dire need,
don't despair old friend, that's what you shall heed:

The Beginning of Petrophobia!

Notes on The End of Suburbia by Greg Greene 

I’ve stumbled more or less by chance on this documentary shot in 2004. I’ve seen it several months ago, and I highly recommend it – I don’t think it’s available in languages other than English, but the DVD is region free, it plays everywhere.

The 78’ film is about the so-called ‘Peak Oil’ phenomenon. If you don’t know exactly what ‘Peak oil’ is, then browse these sites: www.peakoil.net, or look it up in the Wikipedia, whose relevant English article is in my view a good starting point to delve deep into the matter.   Google’s first pick ( http://www.lifeaftertheoilcrash.net/ ) is the website of an attorney-turned-peak oil-activist a little bit too derivative and too alarmist for my tastes. In a few words, Peak Oil refers to the theory that the global oil production will be reaching its maximum output in a few years, or even sooner, and then decline inexorably. The implications of this phenomenon for the western and especially the American way of life are potentially enormous. The documentary was evidently created on the wave produced by the 2003 USA and Canada blackouts, and the rise in oil price of the following months. It is even more relevant today, with oil prices hovering on the whereabouts of sixty dollars per barrel. The American Way of Life always struck me as a caricature of western civilization, overblown cities, overblown riches, overblown industries, overblown houses, overblown people, both physically and mentally. The introduction of ‘The End…’  with the history of the creation of the suburban sprawl where allegedly 50% of the American population currently resides is another confirmation of my idea. The development of public transportation, streetcars, buses, metros, even railways where systematically hampered, because of a few developers and big government fellows who saw an opportunity in driving middle class citizens out of the cities in newly constructed country houses, reachable only by car on newly constructed highways, which also lead to newly constructed malls. Public transportation is not viable in areas with a very low population density like the suburbs. The result: in 60 years after the end of WWII Americans consumes double the amount of resources of their European counterparts just to drive to work, to buy groceries and to heat their homes. Inner cities have been spoiled; larger and larger rural areas have been converted into soulless housings. The problem: all of this depends heavily on the availability of cheap fossil fuels, which are allegedly becoming scarcer and scarcer. Enter the experts: the juiciest part of the documentary is a series of interviews with several personalities who have written books on the subject. The documentary is in a nutshell a primer on peak oil. The interviewees are, with some possible exception, reputable personalities in their field. It doesn’t seem we’re dealing with plain quackery or conspiracy theorists here, that’s why I recommend the movie and got interested in the subject. James Howard Kunstler is a journalist turned writer – he speaks vehemently on the decline of American values and on the threats to globalised commerce posed by the impending energy crisis. Matthew Simmons is a renowned investment banker specialising in the energy industry – he has been warning the international community about the scarcity of fossil resources for a while. Colin Campbell is a retired American geologist living in Ireland who a few years ago has published an article in Scientific American about the real size of world oil reserves, finding that the generally accepted opinion that a peak is to be expected only a little before the middle of this century is probably wrong. Kenneth Deffeyes and Ali Samsam Bakhtiari are two other geologists who have come to the same conclusions. The latter works for the Iranian government, the former teaches at Princeton and has recently published a book on the perspective of energy production after peak oil.

Richard Heinberg could describe himself as a ‘cultural ecologist’, teaches at the not too terribly renowned http://www.newcollege.edu/ but has written a number of very interesting books with some compelling views. He’s rather pessimistic about the chances of solving future energy problems, advocating even ‘some way of reducing world’s population’ [before it will violently reduce itself in Malthusian ways] The only real dubious character is Michael Ruppert, an ex cop turned journalist after a hiatus of many years. He links the current energy problems to the Bush-Cheney-Neocon policies and wars in the Middle East. So do all the others experts, but especially after having browsed ‘Crossing the Rubicon’, his book I think that his opinions should be taken with a grain of salt. What about hydrogen, bio diesel, nuclear power, solar energy and all the other tricks that according to the general media should save the world in the improbable case oil would run out? According to the experts there are serious limitations to every of these solutions. Changing our (especially theirs, that is, the Americans’) lifestyle would be much better, and some potentially very hard troubles lie ahead anyway. The limit of this documentary honesty lie in the fact that no opposite point of view (which of course exist, not everybody thinks doom is impending) is shown. Nevertheless, this a very, very good documentary, much better and less manipulatory than Michael Moore’s for instance. It’s not as fun as the other 2004 gem – Super Size Me – but probably even more nutritious food for thought.