Using spectrum analyzer.
You should now have a perfectly peaked dish and you can check this using a
spectrum analyzer. A spectrum analyzer displays frequency vs. amplitude of all carriers, per polarization, per satellite. If you used Ku-band satellites for
peaking, it will be as good as it can be. If you used C-band satellites, you will
want to repeat the fine tuning steps using Ku satellites. As you go from satellite to satellite in the tuning process, note the weakest channels on each satellite and see what effect your adjustment process has on them. If at the end of the adjustment process and there are still weak channels then check the eirp footprints (eirp for Eastern Hemisphere satellites, for Western Hemisphere satellites) for that satellite and channel (transponder) to see if they are aimed into your region and, if possible, use a spectrum analyzer to look at the weak channels (transponders) and see how weak they really are in comparison with the stronger channels on other satellites with similar eirp patterns to see if ground effects are playing a role in reception and/or if your tuning is that much off. Also compare weak channels to strong ones on the same satellite to see if the weak channels might belong to a broadcaster that is simply not uplinking a strong signal or is uplinking a half transponder signal. All these actions will give you peace of mind that you have done the best job possible and will tell you if what you need is a bigger dish to receive the weaker channels. On older satellites it is a fact that some transponders age quicker than others and thereby are inherently weaker. A spectrum analyzer allows more quantative understanding of the variations in transponder reception per satellite than does monitoring each channel with a TV. In regards to final tracking of the dish, in general, it is said that Ku reception is three times more sensitive to tracking errors than is C-band and tracking Ku satellites is really where a spectrum analyzer comes in handy. The last thing to do after satisfying yourself that your installation is its best, apply VNR (video noise reduction) and/or bandpass filters, as built into
your receiver, to any channels which still show a few sparkles. A satellite
receiver with a good set of internal filters (especially Chapparal brands) will
increase video quality by a 'grade', i.e. make a 'B' grade image to an 'A' grade. If you are using a frequency tunable receiver (again, Chaparral), then try adjusting the center frequency and frequency range of any channel that is giving you a problem especially if you think they might be half transponder transmissions or transmissions on non standard transponder bandwidths, i.e. a downlink on a 54MHz transponder.
Thread: Setting up a Big Dish
Results 11 to 20 of 21
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If you have a spectrum analyzer (I don't) ;) – 06-21-2011,08:05 PM
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Post Thanks / Like - 1 Thanks, 0 Likes, 0 Kiss My AssJERRY_BAQ thanked for this post
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In Closing..... – 06-21-2011,08:09 PM
SUMMARY:
Find top satellite first then satellite at lowest arc position then program
satellites in the middle between these two then program your way down to the lowest satellite at the other end of the arc. Always adjust north-south axis before making elevation/declination adjustments. Always adjust elevation before making any declination adjustments. To determine whether to make elevation or declination adjustment, program as many satellites as possible into satellite receiver then use this chart to analytically see which adjustment is appropriate.(The best manner to understand this is to understand that the satellite arc makes a half circle and that the tracking movement of mount of dish makes another half circle and when these two half circles are aligned then dish is properly tracked.)If at any time a satellite signal quality can be improved by manually lifting or lowering the dish then your adjustments are not complete. A perfectly tracked C-band arc can appear to be 'all over the place' when you go to program the Ku satellites - do not be shocked. So repeat fine tuning steps on the Ku arc but stay away from further north/south adjustments in Ku fine tuning unless you are really convinced it will be beneficial or you can really get 'mucked up'!! Be sure, on Ku, that you are not chasing weak or half transponder channels and that your dish size relative to site location relative to transmitted footprint is conducive for high quality reception from the questionable weak signal, i.e. check the footprint of that transponder to see if it is being transmitted to your region. Ku signal strength can vary greatly from transponder to transponder within a satellite - especially on hybrid C/Ku satellites. On Ku, national news feeds are
usually strong throughout the coverage region; regional feeds may be on a spot beam; local news feeds may be uplinked weakly and dependent on a very large dish at the home station to bring in a quality picture; private educational classes are often half transponder transmissions and depend on a very large dish at the receive site to bring in a quality picture. For dedicated Ku satellites the energy level of the transponders is more even and your major problems will be one of spot beams - you may be under a strong regional coverage yet be marginal in a spot coverage.If you really want to 'play' with your system further (and your wife does not mind), position and leave the dish on the satellite with weak channels and experiment with moving the focal point (the feed) in and out slightly then with moving the setting of the F/D ratio slightly. Remember that warped dishes (antenna
symmetry), missing panels, hail damaged panels and loose bolts in the mount (especially check the bolt that connects the pivot axis tube to the mount cap) will deter top performance from your system - and Ku reception is the most sensitive to incorrect focal length and F/D settings.When you are satisfied with your efforts, recheck that all bolts are completely tight and definitely tighten the mount cap to axis tube bolt. Also, make a definitive mark on the pole/mount cap for the correct alignment just in case extremely high winds should cause the dish to rotate slightly on the pole. In high winds, position the dish at the top of the arc at which point is the least resistance to wind forces; aiming the dish into the wind will put the most strain on your installation.Last edited by stone1150; 06-24-2011 at 09:04 AM. Reason: added chart then swapped for better chart
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06-21-2011,08:13 PM
I know it seems like alot yo do. But it's not as bad as one thinks once you get going. If anyone has any questions, just ask and I will do my best to clarify for you. Have a great day!
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06-21-2011,08:38 PM
There is a lot of good information here!!! I appreciate you taking the time to put all of this together!!! EB
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Meine Dreambox One ist ein Stück Scheiße!.
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06-22-2011,12:14 AM
Excellent information and appreciated.
Thread stuck..
click click b00m
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Guest Guest06-22-2011,12:08 PM
I thought I knew all the ins and outs, obviously I was wrong. I have a long weekend coming up, starting on Friday-think I'll see if I can max out my bud.
Thanks for the info Stone.
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Angle Finder – 06-24-2011,08:56 AM
This is what I use when I work on my dish..... I also added a chart to the "summery" post at the top of this page. Have a great day!
Last edited by stone1150; 06-24-2011 at 09:05 AM.
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Polar Mount Angle Readings – 06-24-2011,12:42 PM
Here is a pic of a polar mount. This will hopefully give enough info on where to take angle readings when you align your dish. Have a great day!
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Focal distance calculations.. – 06-24-2011,12:46 PM
Here is a diagram that shows the focal distance calculations for the feed in relation to the dish. You can use this formula to figure the focal point if you do not know what it is or it wasn't listed in that list I posted earlier. Have a great day!
Note: a better diagram uploaded... one that can be read! Sorry for any confusion the previous diagrams caused...Last edited by stone1150; 06-29-2011 at 01:26 PM. Reason: Added note about bad diagram.....
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Magnetic Deviation – 06-29-2011,01:44 PM
Here is another chart I found buried from the past. It explains finding true north. To track the arc correctly, you need to locate true north. For example..... where I live I need to add 3 degrees to my compass reading to locate true north. The map is not the greatest quality however should do the job. Each line on the map is 1 degree. Weather you add to or subtract from your compass reading, depends on if you live east or west of the Mississippi river. Have a great day!