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Which North?

witchy

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#1
I'm trying to realign my motorised sat dish, I've reset the motor back to 0 and now I want to point the dish at 1 deg west (closest possible sat to south).

To find south, I need to know where north is, so which north do i need, true or magnetic??
 

X-Wolf

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#2
You will need to know where true North is,
and count the difference in degrees to mag North (+/-)
From that you can use mag readings +/- the difference, to spot on sat location.

Some good reading here and a great locator here

Hope that helps.
 

nohidingplace

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#3
get a compass and a map align the compass on mag north,adjust map so compass and mag north line up and follow this up with looking for the opposite direction of true north i.e. true south, as far as I can remember from my boy scout days.
 

witchy

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#4
According to Google Earth, my house faces south, perfectly!

Absolutely bang on south :)

So do i just need to point the dish directly straight out infront to get south or is there a catch?
 
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#5
Not sure it is going to matter

I think the difference between Magnetic and True north (in UK) is only about 2 degrees. You will be doing well if your compass system can distinguish betwenn the two norths.

I suspect you will find the satellite signal by approximate bearing and then dish adjustment.
 

witchy

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#6
Thanks guys.

Now for my next problem, lol.........

My motor is a few years old (very old), I bought it second hand in 1993, so it may even date back to the 80's!

Elevation is set by adjusting a nut on a long threaded screw bolt, there are no markings on to indicate any angles, is there an easy way to tell what angle my dish is at?
 

nohidingplace

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#7
According to Google Earth, my house faces south, perfectly!

Absolutely bang on south :)

So do i just need to point the dish directly straight out infront to get south or is there a catch?

there's a catch alright make sure the dish is aligned properly and that the pole it is connected to is square.
 

witchy

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#8
Yes mate the pole is square, it's cemented into the garden and has been in use for 8 years, it has however, for the past 2 years been getting used as a climbing frame by my kids - Curse them!, lol

I'll double check it tomorrow but I'll be amazed if it has moved, it really is well dug in with plenty of bricks and cement to hold it in place.
 
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#9
Dish elevation

Hi again,
I'll make a couple of assumptions about your system. If these are wrong, the suggestions will likely be wrong as well.

I am assuming that:
a) The dish mount is a modified polar mount (since your [elevation] angle is set by a long screw .....nothing better

b) your dish is driven by an actuator motor (telescopic motor tube thing)

c) Your dish is an offset dish (the LNB sits below the centre axis of the dish

First step would be to confrim that your support pole/tube is truly vertical. Getting this wrong will make all other settings very very difficult.

Secondly, if the elevation screw is undisturbed, it should not need to be touched. This setting (declination) controls the shape of the elevation curve that the antenna traces when being driven in East-west direction. If this is changed (or incorrectly set in the first place) it will cause the dish to miss easterly or westerly satellites (or both). ie if this screw is set incorrectly you can't track the Clark belt properly. And the bigger the dish, the more critical this setting becomes

Assuming you don't/haven't moved this:
try driving the dish east/west until you find 1 deg west satellite and confirm you have correct satellite by tuning to one of its channels.
Then reset the drive to zero.

You should now be able to track all satellite that you have line of sight to.

You ask about the dish angle. Assuming its an offset dish, the offset angle is commonly 22-25 degrees. So if the dish edges were vertical, the true elevation angle would be 22-25 degrees.

If you looked at Sky (28.2 East) from southern UK, the elevation angle would be about 25 degrees ie the (offset) dish would look to be pointing approx horizontally.
If the dish is prime focus (ie centre-fed), the dish elevation angle would appear to be about 25 degrees.

Hope that helps
 

witchy

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#10
I am assuming that:
a) The dish mount is a modified polar mount (since your [elevation] angle is set by a long screw .....nothing better
Correct.

b) your dish is driven by an actuator motor (telescopic motor tube thing)
No.
I don't know what it's called but it doesnt have any sort of tube/piston/pipe pushing the dish.

c) Your dish is an offset dish (the LNB sits below the centre axis of the dish
Correct.

First step would be to confrim that your support pole/tube is truly vertical. Getting this wrong will make all other settings very very difficult.
I just checked it with a spirit level and a plumb line. The fooking thing has shifted :( , it is leaning slightly forward (towards south). :(

Secondly, if the elevation screw is undisturbed, it should not need to be touched.
I fiddled with the elevation screw yesterday :(
I put it back to it's 'original position' as best i could using the rust markings on the thread, but it's most likely knocked off.

I could have this sorted in no time if i still had my old Pace MSS300 receiver, the way i used to realign it was to tune into a weak Analogue signal @ 1west then fine tune everything, reset the motor to 0 and then everything just fell into place, not very professional but it worked a treat :)

2 months ago the wife was having a clearout and she binned my old analogue machine AND my signal strength meter, i even gave her permission to do it as i thought i'd never use them again.

All I've got to find satellites now is a Dreambox running the Satfind 3 plugin, as far as i can tell it's utter garbage, even with the dish unplugged it reports 60% signal strength with 75% AGC and a BER of billions!, lol
 

witchy

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#11
I've taken a few pictures of the motor, hopefully someone can fully ID it for me, all i was told was that it was a heavy duty polar mount - that was 14 years ago, lol

:)
 

nohidingplace

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#12
looks like an H2H ( horizon to horizon) positioner poss old jaeger or something along that line.If it is then in it's day was top notch as on my old Prime Focus had to use an 18" arm,not nearly as good as an H2H
 

witchy

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#13
I'm thinking of ditching it as it's not Diseqc and it's pretty noisy.

I visited SyxX last week and his new diseqc setup was totally silent, i want one! :)

Can someone recommend a cheap diseqc wallmount and motor, i see motors on eBay for about £35, are these ok?

Also, how would i connect that dish to one of the new mounts, the connectors look entirely different, would i need a new dish?
 
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#14
Decisions, Decisions....

Hi,
Yes it does look like a really solid H-H motor drive.

It's a shame the pole is no longer vertical. This is more important the larger the dish size and the greater the Azimuth range of satellites you want to access. If you want an 80cm dish and only to view 28E/19E/13E then a south leaning pole, whilst not ideal, can be accommodated.

If I were in your shoes (?) and assuming a new dish size of no more than 1 metre, I would scrap/Ebay(?) what you have and buy:

a) Technomate TM 2100A Diseqc (Highly recommended. I think this is the best quality Diseqc around)
b) Something like the Triax 88 (90 cm) dish
c) Wall mounts are very variable qualities. SatelliteSuperStore sell the best ones I know of but they are very very expensive in my opinion!!!

I would not put a Diseqc motor on a dish larger than 1 metre. I would go for a 36volt Jaeger motor (a Diseqc staellite receiver would need to drive a VBox to convert to the more powerful 36 volt motor drive system.

I would advise taking a look at the SSS website. It's full of good/useful information even if you buy elsewhere:

h**p://www.satellitesuperstore.com/dishes-motors.htm

I would want to go to some effort to make the pole truly vertical if I was to reuse it instead of going for a wall mount though.

Good luck
 

witchy

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#15
Thanks for the advice mate :)

I'll ditch that pole as it has a massive concrete base and will be murder to try and work on. I'm looking to buy a smallish dish, definately no larger than 1meter, so I'll go the Diseqc route - also i really don't want yet another powered box (Vbox) sitting in my livingroom, lol.

I've been offered a Metronic Diseqc motor for £25, it's brand new in the box, do you reckon this is a reasonable buy?

My new wall mount, whats the minimum distance from the wall that I'll need for a 1meter dish?
 
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#16
Diseqc

Hi,

I don't know anything about the Metronic drive (though I have used a Metronic transparent 80cm dish without any problems). All of these Diseqc units LOOK to be much of a muchness.

The reason I recommended the Technomate 2100 is that its pole points down rather than up. Most other Diseqc units seem to be designed for the pole to point down. I am pretty sure the downward pointing pole is more stable/effective.

On the downside, the 2100 will probably cost nearly twice as much as the Metronic.

Don't expect too much of a Diseqc motor. It will be slower than a 36v motor and also a little less stable in the wind since they are higher geared and it is the gearing that resists the wind load. The more exposed (to the wind) your dish will be, the more I would favour the Technomate.

Yer pays yer money and takes yer choice.

Re the wall mouting, and assuming a south-facing wall, the Diseqc H-H will give something like 70 East to 70 West so the standoff from a plain wall probably needs to be 40-50cm or more so that the dish edges don't foul the wall at +-70 degrees.

Cheers
 

ekko star

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#17
If your pole is not TRUE vertical, forget even trying to reset it as you will gte nothing but possibly only a few satellites.

You will unlikely need to set Azimuth and Declination as you have a H2H mount. Simply set this to 0 i.e the highest point in the arc of the motor and poi t roughly to where SOUTH is on compass. Do this during the daytime when 1W has a strong signal and you will likely find the bird quite quickly.

Unfortunately H2H motors have a habit of developing 'play' with anything over 1m dish size. Nothing is as robust as an actuator arm.

However, you must get vertical right to begin with !!!!
 

fezzy

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#18
You could use the original pole !
Bolt another to it, sticking up a few feet , and pack the bolts with
washers to get it straight. A short scaffold pole would be ideal.