Trouble with 8Ft dish, notfinding any bird.

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nyfrench

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Dec 13, 2011
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I setup a dish in my backyard, an 8 Ft parabolic from Sadoun with a DMX741 LNBF C/Ku. The receiver I have is a Junuo DVB-2500. There is only one problem, it does not hit anybird, none. Signal intensity is above 80s, however, the signal quality fluctuate between 0 and 1. The dish is rightly aligned. The satellites that came with the receiver are: Hotbird 13E, Nilesat 7E, Arabsat2B 33E, Badr 26E, Telstar 15E, Amos 4W, Sirius 4E8, Eutelsat W3A, Eutelsat W6, Turksat 1C, AsiaSat3S C 105.

Also, there is no ability to add a satellite with polarity below 5150.
 

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FaT Air

HOA Free Zone
Feb 27, 2010
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97W 48N
:welcome to the forum, We're all her to help.
Your latitude and longitude must be known before tuning a BUD on a polar mount. Along with active transponders on the satellite closest to your longitude
The receiver must have active transponder frequency and SR programmed for the satellites you're going to use to aim and align the BUD. This may help - http://www.satelliteguys.us/c-band-satellite-discussion/222234-bud-manual.html
Don't know anything about that model. If you're in N.A., hopefully you can change the satellite names, positions, and transponder info. TheList is a good resource for transponder info.
 

Robz

SatelliteGuys Family
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I setup a dish in my backyard, an 8 Ft parabolic from Sadoun with a DMX741 LNBF C/Ku. The receiver I have is a Junuo DVB-2500. There is only one problem, it does not hit anybird, none. Signal intensity is above 80s, however, the signal quality fluctuate between 0 and 1. The dish is rightly aligned. The satellites that came with the receiver are: Hotbird 13E, Nilesat 7E, Arabsat2B 33E, Badr 26E, Telstar 15E, Amos 4W, Sirius 4E8, Eutelsat W3A, Eutelsat W6, Turksat 1C, AsiaSat3S C 105.

Also, there is no ability to add a satellite with polarity below 5150.

I have six foot polar mount dish from Sadoun and three DMX741's. Check that your f/D (focal length/Dish diameter) is set correctly. The f/D ratio for the eight foot dish is .385. Mine is .38. From the picture, the LNB seems too far away from the dish. The LNB has an f/D scale, with numbers 2,4,6,8,0,2. they represent f/D ratios of .2, .4, .6, .8, 1.0, 1.2. Set the LNB into the scalar ring so that the top edge of the scalar ring is aligned to .385. Your scalar ring may be different than mine. Check where the alignment reference is relative with the LNB.

Easy to say; but, there are two problems.

1. The spacing between .2 and .4 is only about 7/32 inch. You have to guesstimate .385. You might do better with calipers or micrometer
and pre mark the setting.
2. The set screw alignment is extremely crude. No chance for precision alignment. It really sucks.:rolleyes:

However, If you are lucky you can get reasonable alignment.

As I mentioned before I have three DMX741's. I thought they were all bad. I could not get any to work until found a way to preset the LNB's position.
It would be very simple to use a spiral f/D pattern instead if the linear method. The numbers would be spaced further apart. Also mark the polarization angle scale around the middle part of the LNB rather than the impossible tic marks at the top.
 

chaskuchar

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Apr 16, 2010
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saint charles, missouri
robz,thanks for that info on the dmx741. i got mine adjusted about where you said, mine is at 4.2, but i had to fabricate my legs to attach the scalar ring to. charlie
 

guacharaca

SatelliteGuys Pro
Jun 5, 2010
270
1
Vernon, BC
Where are you located? Isn't elevation a little high?

I agree. A wood frame building with a peaked roof, a picket fence, and a winterized new aparment building in the background puts you north of 40 degrees latitude in North America. But your dish pitch puts you south of 40. Something does not fit Watson.
 

nyfrench

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Dec 13, 2011
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Hello guys, thank you everyone for your prompt responses. I did not expect this much replies on such short notice, much appreciated. My longitude and latitude is 40.835524,-73.929757. I live in the Bronx, NY.

Robz, I will dissect your info and readjust the LNB and take closer pictures for you guys to help me better. For receiver, I don't know how to go about that.
 

patmos

SatelliteGuys Family
Aug 9, 2005
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After following the wise counsels above, Please cover the centre hole. The dish does come with that cover. To my great surprise I found that it makes a great difference with the center cover on. My reasoning cannot explain that...may be someone here
 

chaskuchar

SatelliteGuys Pro
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Apr 16, 2010
807
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saint charles, missouri
i have a 6' sadoun dish. i first tuned it up without the center hole covered because i couldn't figure out the circular plate and put it between the dish and the mount. then figured out it should have been a nice dish and moved it in front to cover the hole where the dish plates come together. well, nothing worked for reception so went through the tuning process again. it's working fine now and it works better with the plate installed correctly. charlie
 

SatelliteAV

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Sep 3, 2004
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Roseville, CA
If inserting the center hole cover improved the Signal Quailty readings, it is most likely that the LNB feedhorn is not properly centered and aimed at the center of the dish. Very suspect!

The LNB assembly probably is off center and the dish aiming is compensating for this error by an increase or decrease in elevation and/or an azimuth adjustment.
 

nyfrench

Thread Starter
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Dec 13, 2011
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I inserted few pictures of the LNB tuning. The first pic shows the dielectric plate. The last one shows the circular position at .385, roughly. The two in between show the LNB. I guess it's ready to be put back up again, with the 0 degree inscription placed in the middle, or place the sticker looking up. I'm lost here.
 

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Jim S.

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What satellites are you trying to receive that you're using the dielectric plate? There are only a few that require it.
 

FaT Air

HOA Free Zone
Feb 27, 2010
6,668
914
97W 48N
The dielectric plate needs to be removed for all satellites over North America. Only needed on a few out over the Atlantic Ocean. Those that need it, the polarity will be labeled R or L. Those that don't need it , the polarity is labeled H or V. North & South America - LyngSat
Does your dish pivot with an actuator? How about some pictures of the backside of the dish, the mount (polar or Az-El), as that will determine how to aim it and the proper "skew" of the feed(741)
Since it's a little known, or none, receiver you have, a few pics of the menu screens may help also.
I think I remember the 741 requires the "0" to be placed along the vertical axis of the dish when used on a polar mount. see above about "Skew". This is not the case if the dish is Az-El, unless you're only aiming at your zenith.
 
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