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iDirect 3000 and 1.2m hughes

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Aug 23rd, 2008 at 9:47am  
Hi : I'm using iDirect3000 with hughes 1.2 dish with isite 7.1.1 I'am start losing the signal so I check the dish and I found that screws that tie the polarization is loose so I adjust it and I measure the signal but it give me 1.5 maximum so I know that I had to point the dish properly so I log into the router to see the lock angle calculator
and I find a lot of numbers and this my first time I found some difficulties to know what this numbers means. I found some manual but it sucks and I need some help from the experts here. below you can find some information here
elevation:true 38.25
offset: 17
and also notice  
elevation acutal:21.25
azmiuth true: 102
polarization: -72.80
so iam confused between this number what to use in my antenna aligment.and should i adjust the elevation first or what.  
so please in need some help.
and can some body tell how to use isite pointing software what cable i need to connect when measuring the signal and how swing the dish during searching for the signal (right to left or up to down
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« Last Edit: Aug 23rd, 2008 at 11:25am by Admin1 »  
 
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Reply #1 - Aug 23rd, 2008 at 11:12am  
You say the polarisation clamp was loose.  It is unlikely that the LNB/BUC/feed assembly would rotate on its own by many degrees so this may have been loose all of the time and is not the cause of the outage.  You can check the polarisation angle by looking at the feed assembly from above and behind the dish.  Does it look as though it has been adjusted 73 deg anti-clockwise from any of the possible quadrant 0, 90, 180, 270 starting positions.  Altering or adjusting the polarisation will not affect the beam pointing.

If you had a working system and are losing the signal due to the antenna pointing being loose, then it is likely that you are only slightly mispointed.  To peak up, make a record of the signal level.  Adjust azimuth or elevation by 1 turn.   Record the measurement again.  If worse, you have gone the wrong way.  If better, continue in same direction.

If the dish mount is tight however, your problem may be moisture/corrosion in the cables.

Best regards, Eric.
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Reply #2 - Aug 23rd, 2008 at 2:56pm  
hi Eric:
i check the polarization and i adjusted to -73 but the problem i dont know what coordinate i use . iknow how to adjust the elevation but what number should i use ( actual or true ). is any body have an idea of that.
also i will give some information about my location( latitude 12.05 Deg N-  logtitude 24.8833333) and the spacecraft locatation is (68.5 Deg E) bear in mind that iam using 1.2 m dish what is the setting that i should use.
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Reply #3 - Aug 23rd, 2008 at 3:36pm  
If you have completely lost the satellite due to dish movement the following will help find it again:

Lat 12.05N  Long 24.88E  Sat 68.5E

Dish:  Polarisation -72.8
Elevation 38.3
Azimuth 101.7 magentic compass

First set polarisation to nominal.

    If you are told to receive Vertical start with the broad faces of the LNB rectangular waveguide on top and underneath.  If the LNB is on an arm it is probably sticking out at one side or the other.

   If you are told to receive Horizontal then start with the broad faces of the LNB waveguide to either side. If the LNB is on an arm, the LNB is probably at the top or underneath.

Second, apply the polarisation adjustment.  Turn the feed 72.8 deg anticlockwise, while facing towards the satellite.

Set the true up/down beam elevation using the elevation scale, if there is one.  The other 'actual' elevation angle is the slope of the front of the dish.  If the front of the dish is exactly vertical the true beam elevation angle will be upwards at 17 deg, but this depends on the dish design. The beam direction is normally, approximately, a line from under the lower edge of the dish to just above the feed window aperture.

Azimuth 101.7 is generally eastwards, somewhat to the right of where the sun rises.  Sweep boldly either way to find the satellite.

This page lat long finder may help as it will show your house and the beam angle relative to the walls of your property.
Type in nyala sudan and you will go right there, press +++ to see your house.

If you have lost receiving a signal from the satellite and the dish has not been moved consider an LNB cable problem.

Best regards, Eric
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Reply #4 - Aug 24th, 2008 at 11:36am  
Dear Eric :
i follow your instruction and i double check the cables but i cannot got any signal larger than 3.2 and that after three hours struggle. but iam notice there some palm trees 20 meter in front of the dish may be it block the signal but iam not sure .may be it LNB problem .and since i found new LNB should i replace the old one.and test the signal with that. and what the sign of damaged LNB.
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Reply #5 - Aug 24th, 2008 at 2:31pm  
Your initial message said:
"I'am start losing the signal so I check the dish "

Does this mean that you have been operating a good service for a long time and that is it now intermittently failing ?

Have the trees grown and are they now blocking the beam ?.  Put your eye behind and just below the lower dish edge.  Sight over the top rim of the of the circular feed horn window.  The lower edge of the cylindrical beam is that line.  Do the trees obstruct the beam?.

To test an LNB point it at cold sky, by aiming the dish away from any satellites.  The noise reading on the meter should be low.

Then point the LNB at something warm, like your hand or foliage / ground.  The noise level should increase.

Then point the LNB at a satellite.  The noise reading on the meter should increase significantly.

The above tests are not conclusive, as the local oscillator in the LNB may have drifted off frequency.  Cheap DRO LNBs have a wide frequency stability, up to +/- 3 MHz in some cases.  This makes it difficult for the receiver to find narrow carriers like 2 Msps.  Cheap DRO LNBs are more suitable for wide satellite TV type carriers with 27.5 Msps.

If yours is a new site and has never worked then I would get back to your service provider and ask what polarisation you are supposed to be receiving and transmitting, and what options file you need to set the modem tuning and other parameters.  Your LNB must have the correct local oscillator frequency to match the calculation: Satellite downlink frequency - LNB local oscillator frequency = modem options file L band tuning frequenvy.

Best regards, Eric.
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Reply #6 - Aug 24th, 2008 at 3:18pm  
thank you dear Eric for valuable contribuation my pain begins like that before three month the satellite work fine then it start to work strangly . it take long time for rx to go green (during that rx and net is flashing amber) and when the rx turn green then the tx and net becomes also green bear in mind that for rx to turn green it takes long time (2hours and day by day  the time requried is increasing ( 1 week ago it takes 5 hours to connect ) and the internet connection becomes too slow and some time you lose the connection (tx and net is flashing amber)but it will come back in minutes but now days it no longer working at all (rx and net flashing amber) .for the trees it not completly block the beam but when you look behind the horn you will see some portion of the trees. for the LNB test as you know iam fairy new to this field so i dont know how make this test .but my friend had new LNB i will use it tomorow for testing
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Reply #7 - Aug 24th, 2008 at 3:29pm  
for the trees it not completly block the beam but when you look behind the horn you will see some portion of the trees.

If your eye is behind and just under the lower edge of the dish, sight over the top edge rim of the round feed aperture.  The tree must be completely below that line, preferably 2m below that line.

A corroded cable due to moisture is quite likely.  If you strip back the outdoor end you may find that the braid has turned to powder and the inner wire is burned and blackened at the pin.

Alternatively the dish pointing may just be just off the satellite due to dish movement on the mount.

Best regards, Eric.
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Reply #8 - Aug 26th, 2008 at 3:14pm  
i think the trees is not the problem.so i determinte the to solve the issue just to know what is happening. so i buy digital multemeter and grab my konig sat finder and read some manual . and here what is happening.first i disconnect every thing from the BUC and and wait until all the light in back of router is on(LNB power and BUC power) and i meaasured the voltage on other end of the wire.and i found it was ok (LNB 18v .BUC 24 v) but when i double restart the router and and test again there no voltage so bring other cable and test again and the confusing thing is this stuff working randomly.so i attach the konig sat finder between the rx and LNB and fire up isite and start pointing the dish and i get the same reading (2.2-3.1 ) but if i pickup the sat finder from the roof (metal roof) i had stronger signal (8v)and if i move the dish away the signal is still there .so i suspect is the roof making some noise. so help me please. by the way i got new LNB nut iam not able to use it because it can be installed on both way
any how here the information about the LNB
P/N 1024572
Sn 00064459
NJR2754hh
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Reply #9 - Aug 26th, 2008 at 5:31pm  
Hi,

First i must confess i didnt read all the thread, just the last post.

What is the elevation of the dish?
Metal roof can cause lot of problems indeed, either because of thermal noise or reflection of signal to the dish.

One possible solution would be to reverse the installation, meaning install the dish upside down, that the feed support tube will be above the reflector and not below it.

Other possible solution will be to use a wall mount if the dish is small, and install the dish on the wall of the building, away from the roof.
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Reply #10 - Aug 26th, 2008 at 5:56pm  
You were measuring the voltage at the end of the LNB cable and it was 18 volts.

You did a double restart of the modem and there was then no voltage.

Possible hardware fault:

I suggest you remove the LNB cable and test with a length  of centre pin wire poked into the Modem LNB RX in socket.  Does +18 volts reliably appear there following multiple reboots.   If so the fault is likely to be to do with the cable.  Is there an intermittent break along the cable somewhere ?    Check the cable on its own with ohms range on your meter ?  You need two people.   Does the resistance change if you pull on the plugs, does waggling the cable cause changes.  Are either of the centre pin wires too short ?  Does the test centre pin wire feel as if it gets caught by springs and makes good contact inside the modem socket ?

Is there an intermittent power supply fault in the modem ? Loose fuse, loose connector, hairline crack in F connector PCB soldering ?

Possible software fault:

There is an options file for iDirect modems and in the file there are lines like:
odu_rx_dc_power = 1
odu_rx_10_MHz = 0
I expect yours says dc_power ON, like this.

Is there any way the modem can reboot with dc_power set to off ?    Can the active dc_power status be observed ?  Mike can probably say.

Best regards, Eric.
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Reply #11 - Aug 27th, 2008 at 3:14pm  
iam really start to hate i direct and as i reading the posts in this forum it seem to me that every body had problem with pointing every thing attached to this piece of ***** called idirect 3000 and this piece of **** called isite. because this things must work smoothly
so idecide to start from scratch so unpluged  the cables from the antenna and take the router home  and test it hundred times
and i measure the LNB power at the router end and it give me 18.7v every timei also test the BUC power and it gives me 24vso ithink my router is ok and iam sure tha ihad the right option file because it work for me before . and also make extensive test for the cable and imeasure the voltage at the other side of the wire(which will be bluged at the BUC and i give the desired voltage 18.7 v&24v. so iam now sure that the cables and the router is ok.so does iam right? some body tell me please.
so tomorrow i will start the pointing again and ihad onther new LNB just in case.and i would do it the right way this time so iam thinking about using any thing other than isite antenna pointing (i read something about using telnet session to do this)i also had konig satellite finder and iam thinkg of using it at same time with isite pointing software because the satellite finder cannot measure the signal exactlty and it use relative escale .so ineed some advice about the LNB because i suspect that it really cause of my suffering and iam thinking of using the new LNB which is compatible with my hardware as purchased as replacement the new LNB is larger and can be connected on two direction and you can find some information about it if you look for previous post.so i thank every body for thier effort and i decided it will be the last time i try to point this *****dish
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Reply #12 - Aug 27th, 2008 at 4:01pm  
You say the new LNB is larger and can be connected two ways.  The NJR2754HH 12.25-12.75GHz LO=11.3GHz +/- 900kHz, has a square flange.  When you attach the new LNB make sure that the two rectangular waveguide holes match up with one another.  The LNB is attached on the end of the filter sidearm.  The central, on axis, waveguide is the transmit waveguide and connects to the large transmit BUC module.

You say your service was good until three months ago, when it started to deteriorate, with long outages, and became progressively worse.

Now you have checked the LNB power supply and the cable, I hope changing the LNB and repeaking the pointing will solve your problem.

One small note:  You presumably still have your feed polarisation set to approx what it was 3 months ago.  You have never said what nominal polarisation your ISP told you to set for receive - so we can't help other than to say that you should be -72.8 deg anticlockwise (as viewed towards the satellite) from two of the four quadrant positions 0, 90, 180, 270.  We don't know (as you have not told us) if your start position is 0,180 or 90,270 deg.  If your feed polarisation is now the same as it was 3 months ago, leave it unchanged.

Check with your service provider that you are using the latest tuning information.  They may have upgraded or changed their outlink carrier during the long outage.

Best regards, Eric.
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Reply #13 - Aug 28th, 2008 at 7:49am  
Hi Eric:
Thank man for your valuable input iam in touch with my service provider so i think there no change in the carrier signal. for the polarization it should be -72.8 as you say. but i dont understand the nominal polarization and the starting postion as i can see there scale there so i set the polarization to -72. and i think that you are talking about set the polarization not from the zero i think . so i search my office and i found some document holding some parameter done by the man who make the installation and there some thing about LNB polarization horizental and tansmetion polarization also horizental so please tell me how to adjust this polarization thing before i start  the pointing may be that will help me and i thank you very much for your help .
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Reply #14 - Aug 28th, 2008 at 8:26am  
Polarisation adjustment refers to the rotation of the Feed/LNB/BUC assembly in its yokes.  When correct you will get 100% of the wanted signal. When 90 deg away from that you will get 100% of the wrong signal.  There is a very broad maximum, but what is more important is minimising interference from the wrong signal.  The cross-pol null is very narrow so accuracy is important.  If you had the polarisation wrong by 45 deg you would receive two equal level signals, both at 50% power. The two signals would be superimposed and very seriously interfere with each other.  So, lots of power but no lock on the demodulator.  

First.  If you are to receive nominal horizontal polarisation then the polarisation starting position is with the LNB side arm at the top (or the bottom).
...  The broad faces of the LNB rectangular waveguide input will be on either side. Regarding the internal pin, it does not matter which side it sticks out.  The pin is horizontal, which is what matters.

Second. Apply the -72.8 deg anticlockwise adjustment, while facing towards the satellite.  The LNB side arm will now be at approx 10 o'clock position, as viewed towards the satellite.  The tiny polarisation scale may be marked with numbers that go backwards or have wrong way +/- etc, so make the -72.8 deg anticlockwise adjustment using common sense and only use the scale markings to determine the amount of movement.  If the scale is inadequate wrap a strip of paper round the feed throat and mark the circumference C.  Remove and measure C mm.  Required movement amount is C x 72.8 / 360 mm.  Reattach the paper strip and turn the feed assembly using your paper marks.

Best regards, Eric.    
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Reply #15 - Sep 6th, 2008 at 6:59pm  
Hi Eric
i glad to tell you that my dish is now working perfectly and it was LNB problem .and as soon i replace the LNBadjust the polarization i was able to lock was very helpful to me to solve this issue and i really thank you very much dear Eric and thank for every one in this truly very helpful website
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Reply #16 - Sep 11th, 2008 at 1:22pm  
thanks Eric after reading your reply iam now able to lock the signal and it reading about 15v .but my service provider say it should be about (16-17).anyhow there internet connection now but it very slow .so i think i need to repoint the dish properly becuase i did it so fast because to get the 15v was achievment to me and you know how much i struggle to do that. so i begin to work on the pointing again .thereis no problem with adjustment of the azmiuth but my problem is with the elevation. there some point ineed to know :
1 - there is two elevation scale A and B and i notice that the elevation A dont match with B (about 10 degree)and that strange because i thought that it should be the same take in mind that i use elevation B to adjust he elevation last time.
2- i think i had some trouble with four bolts (this dish is there for about three years)because if i loosen all of them the dish is not moved smoothly and that true if i tie them also so i think i had to but some oil on them. and what about the big bolt behind the dish should it be loosened or tied during the elevation adjument and what the role of this  bolt exactly .
  so i think iwould be very helpful if you provide me with some information about elevation adjustment and if there some picture that will be helpfull too.
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Reply #17 - Sep 11th, 2008 at 2:30pm  
If you are now accessing the internet you are eventually pointed at the correct satellite.

You now need to spend a  long time peaking up and gradually tightening the mount until polarisation, azimuth and elevation are all rock solid tight and don't move when you push on the dish.  The signal volts should be at the maximum.

Since you have now found the wanted satellite you can ignore discrepances in the elevation scale but a considerable amount of gradual fine adjustment and tigntening is now needed.   I don't understand any of your 4 bolts or single bolt as antenna mounts differ cosiderably.  If you have a Channelmaster mount with 4 bolts, 2 on each side, and one elevation adjustment bolt on top then slightly loosen the 4 side bolts before adjusting the top elevation adjuster, which should be done gently with someone taking the weight of the feed, otherwise you will strip the thread.  Grease on the hidden elevation screw thread helps.  Adjust in 1/6th turn increments.   You need to spend at least 30 minutes peaking up.

Regarding polarisation adjustment call your hub and get them to help while you reach up under the feed arm and turn the feed 1 deg each way while they measure your cross-pol alignment (1 minute per measurement).

Best regards, Eric.
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« Last Edit: Sep 11th, 2008 at 5:25pm by Eric Johnston »  
 
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Reply #18 - Sep 11th, 2008 at 10:10pm  
thanks Eric for your quick response i clearyunserstand what you talking about but iam already change the elevation during me attempt to adjust the dish .and yes there  are the 4 bolts 2 in each side and there one in the back. but i need more information about the polarization and cross polariztion adjustment because this completly new term to me (cross polarization) so i need more information about that
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Reply #19 - Sep 11th, 2008 at 10:20pm  
Lat 12.05N  Long 24.88E  Sat 68.5E

Dish:  Polarisation -72.8
Elevation 38.3
Azimuth 101.7 magentic compass

First set your receive polarisation to nominal.

If you are told to receive Vertical start with the broad faces of the LNB rectangular waveguide on top and underneath.  If the LNB is on an arm it is probably sticking out at one side or the other.

If you are told to receive Horizontal then start with the broad faces of the LNB waveguide to either side. If the LNB is on an arm, the LNB is probably at the top or underneath.
 
Second, apply the polarisation adjustment.  Turn the feed -72.8 deg (anticlockwise), while facing towards the satellite.

Once your system is in communications with the hub talk to them and get them to measure your cross-polarisation signal.  You may need to adjust your polarisation a few degrees either way to get into the exact null.  The polarisation accurccy need to be about +/- 1 deg to avoid interference to other services.

Note that even after you have found the satellite the azimuth and elevation need peaking up really accurately.  It will take at least 30 minutes of adjusting and gradual tightening of all the bolts.

Best regards, Eric.  
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