Motorised satellite setup problem?

[js2k]

Hi, a few questions before I go into my setup problem pls?

1. With H-H motor, does the elevation angle of the dish changes as it moves horizontally, for different satellites position?

2. 1m vs 80cm dish, from UK is there major differences in term of how many satellites can be received?

3. With 0.6db LNB (universal type) vs 0.2/0.1db - does this really shows the quality on TV or is the dB rating are for reception in term of weak signal area?

4. With TM5400/5200, I really like the sensitive LNB input tuner - does anyone knows why it improves the viewing signal more noticebly than ie, sky digibox? Is there any shop that sell just an adapter that can do just that pls? (I've seen the LNB amplifier adapter but that's like a carrier of signal over distanced cable, I don't think it is the same?)


PROBLEM with motorised setup:
1. Fit the wall mount and it is 95-100% vertical.
2. Fit motor/dish onto mount.
3. Line of sight problem, because my house is a terraced house, the only south facing wall is the back of the house, where I have put the mount, seem ok to me but it doesn't have a 100% clear line of sight. Nextdoor chimney & roof is approx atleast 5m away from my dish with approx 2-3m higher than my dish.
4. Connect all cables etc... to Positoner & Receiver, managed to track 1W and able to view BBC World (Signal Quality ~ 70%).
5. When I try to move to 28.2E, I got absolutely nothing, I even try manual tracking by hand. When I try to move the motor from 90E to 90W, I think I only tracked two satellites (1W & some other), do you guys think it is Line of Sight problem?
6. Regarding my motor, I couldn't find motor cable to use so I use 2 x 2 core flex cables, I can rotate the motor using the MOVE MOTOR function on either the receiver/vbox, but not when I want to move via different satellite positions, could anyone confirm whether it is cable problem pls?

PHEW that's all. Any help would be much appreciated.

 

[Robbo]

Hi,

1. Yes.The motor spindle rotates on an axis aligned to the earth's polar axis.
AS viewed from the ground the dish is looking higher in the sky at '0' position than it is at any other position. It scribes out an arc, to match the satellite positions.

2. Not a major difference, but there are a small number of satellites and beams that you can get on a 1m that you can't on a 80cm, also depends on location. 7W, some 23.5E, some 26E and 16E are examples.

3. The dB rating of LNBs is their noise figure. The lower the better theoretically. It is calculated as the ratio of signal to noise in to signal to noise out, expresed in decibels.

Yes you may have a line of site problem, the figures you provide, give an angle to the top of the chimney as approx 30 degrees.

As the dish moves round the arc, you have to make sure any obstacles are below the elevation angle required for any particular satellite. dispointer.com, will provide you with all the figures.

Robbo

 

[js2k]

Hi Robbo, could you pls advise what angle of line of site is best required for the motorised dish to be mounted.

Am I correct to think that the zero position of the motor is the lowest elevation angle of the arc? Hence if 1W sat can be tracked, then all sat can also be tracked (providing the line of site problem is sorted)?

 

[Robbo]

Hi,

I don't understand the first part of your question.

You need to try and get good line of site for all satellites that you want that are receivable on the arc.

The initial setup must be done on the satellite closest to you due south, eg Thor (0.8W) or 5W for others.

I suggest you read one of the Diseqc motor setup guide stickies, although you have a 36V motor, the procedure is similar, except that you won't be able to use USALS.

When the motor is at zero, it is at the TOP of the arc, i.e the HIGHEST post. Have a look at this http://www.satellites.co.uk/satelli...t-motorised-systems/117335-satellite-arc.html

 

[js2k]

You said 30 angle was my line of sight to the obstruct object, what angle should be best situated for the dish for obstruct object for the line of sight to be clear?

 

[Robbo]

If the object is 3m above your dish and is 5m away this equates to approx 30º.

If your dish points towards the obstruction, and the required elevation angle is below 30º you won't see the satellite.

For any satellites you want, the angle up to any obstructions must be less than the elevation angle for the those sats.

Eg, for Thor say, where I am the elevation angle is 32º, if I had an obstruction 5m away and 3m (30º) up, my dish would see over it. However if I was after 28E, whose elevation is approx 25º for my location, and the same obstruction was in that direction instead, my dish would not see the satellite.

I always measure the angle to the obstruction from the bottom of the dish (assuming that the top of the dish is clear), but for stronger satellites like 28E, you can get away with the dish being partially obstructed.

 

[angusc]

You said 30 angle was my line of sight to the obstruct object, what angle should be best situated for the dish for obstruct object for the line of sight to be clear?

JS2K,

Try this site for Dish alignment, it allows you to enter in obsticals and there height and distance from the dish. _hxxp://www.dishpointer.com
Also this GAAPS site might also be helpfull to allow you to align your motor on alternative position other than true SOUTH: hxxp://www.satellitewiz.com/DiSEqC_Motor_Calculator.html

I have just fitted an H-H mount and the way i did it was to first ensure that the pole is 100% vertical as this is THE MOST important first step to ensuring that your motore tracks the satellite arc. Then i powered the mount to a satellite that i knew has strong signal and then adjusted the H-H mount on the pole to get the strongest signal. That seems to work for me and now when i rotate to another satellites they seem to be strong signal.

 

[js2k]

Hi again, ok had a good night sleep.

Thanks Robbo for the Line of sight angle explanation, I now need to do some research on the satellites on the arc and its elevation angle required, then build a new mount so it's high enough to track the arc.

As my profile stated, I got a Geotrack 99 motor, the manual booklet show I need to mount the dish on the motor as pictured show below, but my dish is an Orbital and the elevation swing is back and forth, so mounting the dish as manual suggested will NOT give me the full elevation angle swing on my dish?! (Because it will touch the motor, see picture). I was wondering whether this is normal?

 

[Robbo]

I don't think you will have a problem, the dish face I don't think will need to point so low that it will hit the motor. You will find out when you come to install.