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| I am a newbee in satellite, I am somewhat confused in pointing the satellite dish at Hot Bird. When you say 13degrees E of south, was it S13^E? Does it mean make 13deg from the south toward the east? sorry for this dumb question.
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| Thanks Martin, I used the Satellite finder this morning and it was like magic. After 5 hours frustration last Saturday it literally took 10 minutes today and I am back in communication with the English speaking world. Ciao Joe Thanks for writing, Joe. However, I have to explain that Joe knew what he was doing and had read all the available information on both my satellite web sites and in my free book. If you are an absolute beginner, please don't open your parcel, pull out the new meter and rush out into the rain to align your dish. In fact I recommend you don't work in the rain at all unless you are very experienced! Rainwater down your collar is at best unpleasant and doesn't help you to concentrate. Rainwater down your cable is a disaster and you shouldn't take the risk. Dear Martin, I would like to take this opportunity to express my satisfaction with your Digital + Analogue sat finder meter. It certainly lived up to all your descriptions of it and made us wonder if we would ever have found the satellite properly without it. Eric Thanks, Eric. I should point out that the satfinder won't actually "find" the satellite for you. You have to align the dish as best you can with the aid of a compass, home-made sextant and anything else you have. The meter will assist you with the final, accurate alignment that is so essential to guarantee continued viewing in bad weather. |
H28-8235d Digital/Analogue meter This meter has a built-in 22kHz tone generator which you can switch on or off. As you know, a "Universal" LNB has two internal oscillators - a 10.6GHz oscillator for "high frequency band" and a 9.75GHz oscillator for "low frequency band". It selects "high band" when it receives a 22kHz tone from the coaxial cable. In addition, it responds to the input voltage for polarisation selection (13 volts selects vertical and 17 volts selects horizontal polarisation. The changeover point is around 14.5 to 15.5 volts so the supply voltage must be above or below that range for reliable switching of polarisation). The 22kHz tone is a 0.5 volt "ripple" which is superimposed on the 13v or 17v supply voltage. That's the technical stuff. You don't need to understand what it means, provided that you understand that: 13v = vertically polarised signals are received I might as well mention that some receivers can pulse the 22kHz on and off very rapidly (like Morse code). This is called DisEQc signalling and can be used to tell some LNB switching boxes or dish motors what to do. This is not relevant to the discussion but people keep asking me! Sky Digital is broadcast from a cluster of satellites positioned above the equator at 28.2 degrees east of south. Magnetic variation occurs and must be added to - or subtracted from - the actual compass reading to give the true azimuth. So, for example, if I used a compass here in Cheshire, England, I would have to position the dish east of south by 28.2 + 5 = 33.2 degrees, according to the compass. Sky Digital is a little unusual because, at the time of writing ( November 9, 2000 ) there is no transmission on low band from 28.2E. (January 2001 there is now some signal as these transponders are in use). This makes it easy to locate the satellite cluster with the SatCure meter. Position the dish as accurately as possible using a compass and protractor with plumb line (if you have nothing better - read my FREE book) then connect the meter with a receiver or suitable power supply (12 volts dc will do for now) to provide power. Switch tone ON and align the dish for highest reading. Switch the tone OFF. There should now be hardly any signal because there is only a few transponders in use on 28.2E in the low frequency band. In contrast, if you try this with, say, "Hot Bird" at 13'E then the signal indication will remain high because low band carries lots of transmissions from this satellite. Once you have aligned the dish as accurately as you can, then use the meter to get the strongest signal by pulling the dish up/down, left/right a fraction. Lock it in this position, then move the LNB backwards and forwards in its clamp to find the best focal point. Finally, twist the LNB to get the highest signal reading. This is normally achieved with the LNB body almost vertical with the cable hanging downwards so be sceptical if it isn't! Remember that the parabolic dish is really a mirror which is concentrating the satellite signal at one point near the end of the arm. The LNB must be exactly at this point. OK, you should now be able to receive a picture on at least a few channels but allow the receiver a minute from power-on to translate the digital information from the satellite ("searching for listings"). Finally, feed 17v or 18v into the meter so that the LNB switches to horizontal polarisation. If you are using the Digibox to power the LNB, press:- SERVICES .. 4 .. 0 .. 1 .. SELECT .. 2 and you will see the DEFAULT TRANSPONDER MENU that looks like this:-
Use the Down Arrow button to move the cursor to "Polarisation" and press the Right Arrow button to change the setting from V to H. Press the Down Arrow button three times to highlight "Save New Settings" and press SELECT. The LNB voltage will now be 17 volts instead of 13 volts. BE SURE TO SET THIS BACK TO "V" WHEN YOU HAVE FINISHED. Note that it may NOT be necessary to carry out any adjustment with horizontal polarisation and it should NOT be done until you have a picture in any case. If you have a good picture and a reasonable "Quality" indication in the on-screen menu then there's no need to make any further adjustment. If the quality reading is low, then further adjustment is needed, otherwise you could lose the picture and sound in bad weather. The rotational position of the LNB determines whether it receives horizontally or vertically polarised signals. If it is incorrectly positioned then it can receive BOTH at the same time. This will cause many problems with pictures "breaking up" so rotate the LNB in its clamp to get the best QUALITY reading for horizontal (17v) then repeat it for vertical (13v) until you have reached the best compromise. IMPORTANT: The meter will reduce the signal to the receiver quite drastically! This may be helpful in aligning with an analogue receiver (adjust for minimum sparklies) but a digital receiver may give NO picture with the meter in-line.
>Martin, Oh, jeez. I've never done an installation and I failed Geography "Oh" level (Oh)! Standing behind the dish you are looking South East and East is to your left. The dish is pointing at (28 + 19)/2 = 23.5'E of S. Bear in mind this is *true* south so take the magnetic variation into account. Don't just look at the compass. As the dish acts as a *mirror*, the 28' LNB will be on your right and the 19' LNB on your left, still standing behind the dish. Yes, I think we agree. Now, get the LNBs fitted and the dish aligned as accurately as possible. Don't forget to add the "magnetic variation" for your location, to the compass reading. This means that 28' translates to something like 33' on the actual compass. Check the elevation for your location. It's about 26' above the horizon, here in Cheshire, England, but that angle increases as you get nearer to the equator. Remember that the elevation gives you the position of the satellite above the horizon and *not* the angle of the dish arm (unless it's a "prime focus" dish). For an offset focus dish, the elevation angle markings are sometimes stamped into the bracket. If not, then you'll have to guess. |
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