[mythtvnz] Aligning a Sky dish for Freeview

[Nick Rout]

I just found this page

http://www.lyngsat.com/tracker/optusd1.html

which shows azimuth and elevation for Optus D1. You need to click on the
map to set where you are - quite difficult as the scale is small, but it
does confim that for the middle of the south island you want the elevatio=
n
about 38 deg and azimuth 341 deg (ie about 19 deg west of north).
Presumably that is true north, not magnetic.

Interestingly if you click near the top of NZ the elevation is nearer 44
deg, so there is quite a variation from the top of the country to the
bottom - don't use Barry's figure of 35-37 deg if you live in Kaitaia. Th=
e
azimuth varies considerably too.

As I say its pretty inaccurate given the scale. There may be better
trackers available, one where you could accurately put in your lat/long
would be good. No doubt the math is pretty simple for a computer to work
out (or an ancient mariner with a set of log tables). However as you are
going to do the fine placement with a meter, the accuracy is probably
sufficient. It sounds like the signal is pretty easy to pick out from the
dross.


On Tue, August 7, 2007 10:56 pm, Barry Clearwater wrote:
> Ok, I'm slow at replying but this hasn't yet been said so...
>
> Possibly to add to the very good pdf at freetv.co.nz, under the free
> satellite DIY guide these specifics for the Optus D1 satellite:
>
> There is a cheap $20-$30 version of the beeper/meter you can buy at Dic=
k
> Smiths or online, or maybe even borrow one which helps you pan through
> the signals from the satellite. As said in the guide it gets connected
> in between the dish and the receiver or sat card, using power from the
> card to operate once its all connected up.
> Depending on your mount, the dish may have an angle of tilt indicator,
> you are looking for 35=C2=B0-37=C2=B0 tilt above the horizon as your st=
arting
> point.
> Optus D1 is certainly strong, and it peaks the meter a lot stronger tha=
n
> the nearest satellite to it. The trick is to sweep s-l-o-w-l-y from jus=
t
> before NNW towards N and watch the meter and listen to the beep for the
> strongest tone/signal. There may be 3 or 4 small peaks but the advise
> from an installer to me was it was the second signal but by far the
> strongest. You can repeat this manoeuvre a couple of times taking note
> of where the signal peaks are. Once settled on your direction  160=C2=B0=
, you
> may need to fine adjust the vertical tilt for max signal.
> To tune the LNB to the right polarisation (ie rotating it) there should
> be a null signal at 90=C2=B0 off of the correct Horizontal Polarisation=
 where
> the meter drops off. You should then come back 90=C2=B0 for best signal=
. You
> will probably need a signal level meter off the actual receiver or from
> the mythtv channel tuning helper, or use one of the scripts that take a
> feed directly from the card.  The one I used talked/spoke out the signa=
l
> levels from the sound card speakers! 56 55 53 50 40  etc etc.
> This was my experience and I got a pretty good result with very little
> mucking around.
>
> On Mon, 2007-08-06 at 15:11 +1200, Jonathan Guthrie wrote:
>> A while ago we had Sky via satellite, then we got it cheaper and
>> easier via TelstraClear cable... however the dish stayed on the roof
>> until we replaced the roof last year.
>>
>> However I'd like to put it back on the roof and set it up so I can
>> get Freeview on MythTV :)
>>
>> Is there any resource out there that may save me time/hassle working
>> out how to align it etc?
>>
>> ta.
>>
>> Jono
>>
>> // ---------------------------------------------------------
>> /*
>>      Jonathan Guthrie
>>      xServe Ltd, Wellington NZ
>>      jono@xserve.co.nz   |   http://xserve.co.nz
>>      DDI +64 4 978 7388   |   Mob +64 21 678890
>>
>> */
>> // ---------------------------------------------------------
>>
>>
>>
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>
> --
> Barry Clearwater <barryc@bcsystems.co.nz>
>
>
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--=20
Nick Rout