Dish setup info please

[rowlejohn]

Hi folks,
I am setting up a motorised 80cm dish, pole mounted with a Tecnomate box. I already have a Sky minidish & digibox which I will keep as "Free to view".
The motor is a Alsat, Dark Motor and I will e using a Thomson quad LNB.
I am baffled by all the angle settings and what they represent. I live in Ireland and the Satlex website tells me my location is Lat.53.343 North and long. -7.055 West. the other figures given are LNB Slew -23.25 deg and elevation 21.13 deg. for my location.
The bracket on the motor, on to which the dish is mounted is graduated on one side as "Elevation" and the other as "Latitude"-do I set the Latitude on this bracket at around 53 deg.? Additionally, and more confusing is that the bracket which is on the dish and is clamped to the motor bracket is also adjustable and has a scale in degrees, so if I set the motor bracket at say 53 deg., what angle do I have to set the dish bracket to?
Then in the motor setup instructions there is mention of "Declination"-what is this?
Finally the Satlex site informs me that the LNB "Slew angle" is given as -23.25 deg. for my location-is this anti clockwise from vertical looking directly at the dish from the front??
All these angles etc. are overwhelming from a novices point of view. I can read a compass and know where 28 deg.E. of South is but all the terminoligy is over my head.
Can someone please explain in idiots language how I set the dish up.

[robbo71]

Hi,

You set the motor elevation to correspond with your latitude.

Some motors are marked latitude on one side and elevation on the other.
So yes, set the latitude side to your latitude.

Elevation is simply 90-latitude and vice versa.

The dish elevation (called declination for motorised systems) can be set by looking up tables etc , or by adjustment. I find the adjustment method far easier.

All you have to do for this is to adjust the dish elevation for best signal when the motor has sent the dish to your closest to due south satellite, which in your case is 8W.

There is an excellent guide to setting up a motorised dish in the FAQS section by BGonaSTICK, have a read of that, and if you get problems, come back and ask.

For a motorised dish, you don't have to worry about skew, just set it to zero. When you change the motor position, the whole dish gets skewed instead.

Robbo

[rowlejohn]

Thanks Robbo- I can rebuild machines and car engines but all of this seems way over my head-I will look on the link.
Cheers and happy Paddy's Day!!!!!!!!!!!

[robbo71]

If you can rebuild engines then there is no problem. This is far simpler. It is just a matter of getting your head round it.

Put in simple terms, the dish rotates on an axis that is aligned to the earths polar axis ( that is why the pole coming out of the motor is not vertical). The dish also has to tilt down from that axis, so that it is pointing to where the satellites are approx 22000 miles above the equator.

When the dish rotates round it appears to follow an arc in the sky. The vertical position if the arc is governed by the motor elevation, and the steepness of it by the dish declination. The pupose of the exercise is to get your arc matching up to the arc that the satellites appear to be in.

[kerrywez]

Hi rowlejohn,
When you get the latitude set on the motor, put your latitude and longitude into your box and using usuals send the dish to Atlantic Bird 2 @ 8 degrees West, that should have your dish pointing just about due South for your location. Now select the frequency for Al Jazeera 10972 V 27500 3/4. Then just turn the motor a wee bit to get the signal peaked better, after you have got the signal the best you can, thighten the motor bolts.

Now slacken the nut that holds the dish to the elevation scale, this will be right behind the dish, do not slacken it too much, just enough to allow movement. You need to either raise or lower the dish till you get the very best reception that you can get.

I hope this helps you a bit, it is not very technical, a wee bit of an Irish way of explaining. Good luck and have a very happy Paddy's Day.

Very best regards Wez

[rowlejohn]

Well,disappointing day today. Fitted the pole and dish-solid as a rock, ran the cable-a job I hate with all that fibreglass in the loft and connected it all up.
Started to set it up with the Technomate instruction book and the motor would not run. Up on the roof I went and tried manually to move the motor using the L & R buttons and all the motor would do is kick slightly, the LED's on the buttons were lighting up when they were pressed. Tried slackening off the backlash adjustment screw a little and the motor started to run albeit "Jerky"-wasn't smooth at all. Came back down and got the signal meter, removed the cable to the motor from the Technomate, leaving the cable to the LNB from the motor connected and connected the meter to the motor and feed cable. Adjusted the motor fixing to the pole until the meter peaked and then tilted the dish until it also peaked. Didn't touch the LNB slew (It's vertical) as it's in mid air and not accesible from the roof.
Connected the feed back into the motor and dead as a dodo-no lights-zilch.
The motor is an Alsat Dark Motor-brand new from Egay.
Anyone have any ideas???????

[robbo71]

It's either a dodgy connection or the motor is faulty.

There is a guide on here somewhere on how to fit F-connectors.

Or there is this one:-

How to fit F Connectors to coaxial cable

Make sure there is enough of the central core sticking out.

Did you switch the receiver OFF when disconnecting the cables?

Oh, by the way, its a good idea to check the motor out indoors on a short length of cable before going to the hassle of installing it.

[rowlejohn]

No I didn't switch off to remove or fit the cables. It started to get dark when I packed up but I will check the length of the centre core tomorrow-weather permitting but I think that I left it around 10mm past the nut on the "F" connector. I made sure that the plugs were secure and checked the ends with a miltimeterto ensure that the braiding was isolated from the core.Also gave them a coat of Silicone grease before they were assembled. If the weather is okay tomorrow, I will take the motor off and check it on the bench with the Technomate..
Thanks for coming back to me Robbo so quickly.

[robbo71]

10mm seems a bit long, it should be about 3mm. I don't know if this would have an adverse effect or not though. I suppose its possible it could short something out inside the motor, I dunno.

I would try a bought lead with the motor indoors, if it doesn't work send it back for a replacement.

Also it is unwise to disconnect while switched on, there is a possibilty of causing damage.

[kerrywez]

Hi rowlejohn,
It is never a good idea to connect any cable to any equipment without having the power switched of, that was one of the first things I learned when I started out working with CB radios.

I any case do as robbo says and try the motor with a factory made lead, if you have one, if not then make sure that you have the F connectors on as they should and try the motor in the house. If the motor is not working then it must be the fault is with it. Remember to have the box unplugged when you are disconnecting or connecting anything. Good luck with it and I am sure you wil get it sorted.

Before you do anything make sure that you have set up the box as per the instructions in the manual. I know that you might well be thinking this guy thinks I am stupid, but nothing could be further from the truth, just trying to cover all the possibilities.

Very best regards Wez