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Monday, April 30, 2012

How To Watch FTA Channels Through C-Band Dish: Part 1




Many DTH users are not happy to have many FTA Channels on their respective DTHs such as Dish TV. Reliance BIG TV, Airtel Digital TV, Sun Direct, Tatasky and DD Direct+ but we have our own solution to watch many FTA Channels in one time setup through C-Band and today we will gives you Do It Yourself guide to watch FTA Channels Through C-band dish. Here is guide to watch FTA Channels through C-band.

C Band Dishes:

C Band requires the use of a large dish, usually 6′ feet across. C Band dishes vary between 3′ and 16′ normally, depending upon signal strength of the satellite and location in which they are used.
C Band dishes are much larger than Ku Band dishes used for DTH services, some folks refer to them as BUD (Big Ugly Dish). C Band is the original frequency allocation for communications satellites. C-Band uses 3.7-4.2GHz for downlink and 5.925-6.425Ghz for uplink. The lower frequencies used by C Band perform better under adverse weather conditions than the Ku band or Ka band frequencies. However they are affected by terrestrial interference like Wimax, High tension lines etc.

Types of Dishes:

The most important consideration in case you wanted your own c-band FTA setup is the Dish itself, There are mainly two types of dishes (note:- This is applicable for any band), The first one is the parabolic dish antennae with a prime focus and the other one is the offset antennae, A prime focus antennae is a parabolic dish which concentrates the reflected signals to it’s exact focus, Here the feed horn is mounted at the focus of the parabola, (or generally we say the lnb is in the centre of the dish, an offset dish can be roughly described as a section of a larger parabolic dish so the focus falls outside the dish and the feed horn appears to be mounted outside the dish,

Here is a prime focus dish:

Prime Focus Dish

Prime Focus Dish

and an offset dish :

offset dish

offset dish

Both have their own advantages and disadvantages, However if you want to use an offset dish with c-band , You will need a conical scalar ring and matching feed horn, Moreover prime focus dishes are simpler to construct and usually less complicated than offset dishes.

Another difference between dishes is that some are made of solid panels and others use a mesh to reflect signals, Even though solid dishes have higher gain , Mesh dishes are preferred if the size of the dish is large, as using mesh as reflective surface can actually reduce the weight of the dish and also helps in easy draining of water in rainy areas, They also help to some extend in reducing wind loads, if the mesh holes are larger in size , But if anything falls on the dish, the mesh gets damaged much more easily than the solid panel dish, See the image of a mesh dish below:-

mesh dish

mesh dish

The main consideration in choosing a dish are

1. How much space you have to install the dish :-

Dishes do need space to install, if you live in a town or city, the chances are that you do not have a large spare space over your roof or garden, Always keep this requirement first before buying a satellite dish.

2. How strong is the satellite footprint over your location :-

If the satellite you intent to catch has a strong footprint over your location , you need only a smaller Dish, If the satellite footprint strength is lower you need a larger dish.

3. What is your budget :-

The cost of a satellite Dish increases tremendously with it’s size, A larger Dish needs more metal for its reflector and supports, Also they require more costly to maintain are more prone to damage from Rust, winds etc, (Also larger dishes are a mess to align, read turning them to various satellites etc.)

Also there are various types of mountings for the dish , A ground mount dish is comes with a base so that it can be easily placed on the ground, Just a few weights will keep it on the ground, see pic-1 above, other types require you to provide different methods of installation, see pics-2 &3 above. For a DIY C-band setup My recommendation is to go for a 6′ or 8′ prime focus dish as in pic-1 above, This really is a good point to start with and is pretty easy to handle, However please find some level ground to place the base of the dish, An inclined ground simply will cause a lot of troubles when you start tuning it.

The Lnb or Lnbf

The dish is only a reflector, It reflects the weak signals to it’s focus, The real antennae is the lnb (Low noise block), The feedhorn placed at the focus of the dish acts as a waveguide and directs the concentrated signals to the probes inside, these probes are connected to an electronic circuit inside and the signals are mixed to get resulting Intermediate frequencies (IF), these intermediate frequencies are send through the cable to a receiver which decodes the signal into channels.

There are different types of lnbs , The standard Lnb has to be mated with a feedhorn, There are lnbs integrated with a feedhorn, These are popular and known as lnbf, here are some pictures:-

1.Standard lnb, Usually single polarity,(Either H or V)

Standard lnb

Standard lnb

2.Standard lnb with feedhorn attached

Standard lnb with feedhorn attached

Standard lnb with feedhorn attached

3.A Dual Polarity lnbf looks like this from the feedmouth:

Dual Polarity lnbf

Dual Polarity lnbf

4.A twin output Dual Polarity lnbf (you can attach two receivers to this one):

Twin Output Dual Polarity lnbf

Twin Output Dual Polarity lnbf

5. A C/KU combo lnbf, You can use this for a satellite with C-band and Ku-band, like Insat-4B, where you have DD-Direct+, alongside FTA C-band.

C/KU combo lnbf

C/KU combo lnbf

Check out the two pins for c-band and Ku-band on a combo lnbf, The one on top is the ku-band and the one on side is for C-band

two pins for c-band and Ku-band on a combo lnbf

two pins for c-band and Ku-band on a combo lnbf

Cable:

The usual consumer grade cable for connecting the lnb to the receiver is the RG-6, The costlier the cable , the better, is the norm here, As costlier cables are usually well built,

DISEQC switch :

A DISEQC (Digital satellite equipment control) switch is used for getting signals from more than one dish/lnb to one receiver, Please note that Diseqc 1.0 specification supports a maximum of Four lnbs, But to use a Diseqc switch you need a receiver supporting the protocol of the Diseqc you want to use, But these protocols are usually backward compatible, A Diseqc 1.2 receiver, will usually support a DiseqC 1.0 switch. Here’s a Diseqc switch

Diseqc switch

Diseqc switch

Receiver:

This is the most difficult choice in a FTA setup, A lot of receiver models are available in the market, The essential considerations in choosing a receiver is the ability to tune and decode the transmission type and encoding used by the channels of your choice, That necessarily means some preparation for the future, In this case future is only three to five years long, Technology does change fast, There are receivers capable of recording (PVR) and there are receivers capable of HD outputs etc. The main consideration in choosing a receiver for FTA as I see it now are
1.Ability to autoscan, If a receiver cannot do an autoscan (ie scan and add all frequencies of a satellite without the need for you to add TP frequencies manually is the most important feature required by a FTA enthusiast.

2.Ability to decode mpeg-4 and DVB-s2 formats.

3.If you have the latest HD -tv or planning to go for an HD capable TV , then an HD capable receiver is required.

4.A signal level indicator is most desirable as this will save a lot of time and money by helping you to tune the satellites.

So choose one fitting your budget and requirement, Always make sure the signal meter and autoscan feature.

Other tools:

You do not need anything more than a couple of spanners, A Philips head screwdriver, Pliers , a good sharp knife, a magnetic compass and a few F-connectors for connecting cables to start your FTA setup. The most important addition is a portable TV , Well nothing helps you more if you intend to actually catch every bird on your skies. Without this you will need to do some weightlifting if you do a lot satellite scanning (BY lifting your TV to the dish and back), Always make sure this little toy is available.

Getting it all together:

For my setup, I have a six feet C-band dish, It came in parts , to be assembled by the user, The box had an assembly manual inside, also a kit of nuts&bolts and a two headed spanner is included in the box, The first thing to do after opening it, is to sort the similar items together, Nuts&bolts of similar size should be kept together, SO are the various brackets and arms. The petals need careful handling, bending anything will make you repent later, Do not use excessive force, Choose a flat surface, It is better if you place a small table in the centre and use it to arrange the petals in the inverted shape, Use the nuts and bolts to assemble the dish surface from the petals. Leave it here and assemble the base , Read the manual carefully, the assembly details are usually shown in it with diagrams, Place the assembled dish on the base, The whole process takes about a hour or two depending on your experience level, If you have a friend who has done it before, IT will be great help. In any case it is always better to have some helping hands to hold the parts while you do this, Once the assembled dish is placed on the base and secured, fix the scalar ring on it , using the three or four arms provided, Now measure the distance from the scalar ring to the edge of the dish in at least three four positions all around, they should be equal or within say one cm difference. Here are some images:

Petals joined to form the dish

petals joined to from Dish

petals joined to from Dish

Dish with Base fixed:-

Dish with Base fixed

Dish with Base fixed

Scalar ring:-

Scalar ring

Scalar ring

Some weights on the base holds the Dish well , You can use concrete to fix it as well, Some dishes comes with mounting brackets too

some-weights-on-base

some-weights-on-base

Finally the assembled dish looks something like this:

Assembled Dish

Assembled Dish

This dish here is four years old, and has my own artwork to prevent rusting, Your new dish will look clean and shiny, Take a look through the Center Hole of the scalar ring

Center Hole of the scalar ring

Center Hole of the scalar ring

, IT must be centered on the dish

Here’s a size comparison of c-band dish and DTH dish,

Dish Size Comparison

Dish Size Comparison

Installing the lnbf:

The lnbf is to be installed into the scalar ring, On the top portion of the scalar ring is the skew markings, Insert the lnbf so that the skew marking ’0′ is pointed to the 12′o-clock position to start with, we will adjust it after getting the signal, similarly there are f/d markings on the side of the lnbf, The f/d ratio of your dish is mentioned either on the cover of the dish or in the manual, Choose the value accordingly, For a 6′ dish it should be somewhere between 0.34 and 0.36 , In my case I choose 0.35 to start.

skew

skew

fd-marking

fd-marking

Do not tighten the lnbf now, Just tighten a few turns so the lnbf is held firmly, we need to adjust it more. It is time to adjust the Azimuth and Elevation now. Elevation means the angle between the dish pointing direction towards the satellite and the local horizontal plane. It is the up-down angle. Azimuth means the rotation of the whole antenna around a vertical axis. It is the side to side angle. You rotate the whole dish all the way around in a 360 deg circle to get the elevation.

You can to use a calculator like the online calculator at http://www.dishpointer.com, Just find out your latitude and longitude, (easily done if you have Google earth or even a map will do for the purpose), Use your compass to find the Azimuth angle, and turn your dish towards the direction, The Elevation can be adjusted using an inclinometer (if you have one, or else simply do the rough elevation pointing), You can make your own simple inclinometer if you follow instructions on this page http://www.satsig.net/pointing/how-to-make-inclinometer.htm , After trying this for a few times you won’t need any of these as you will be able to simply tell which satellite is where, Things do change with experience

If you trying to catch the Apstar 7 satellites at 76.5E by which all bangladeshi channels broadcast their service go to the dishpointer website and find the position of dish putting your location.

Dish Pointer

Dish Pointer

So the next step is to setup something to tune the satellite and adjust it, This is where your signal strength meter in your receiver will help you, and this is where the small B&W tv, we mentioned in tools comes to use, See the simple setup

Tuning Receiver and Small TV

Tuning Receiver and Small TV

Now Connect the cable to the lnbf and receiver, start the receiver and feed in some known TP from 76.5E(Use http://www.lyngsat.com/Apstar-7.html to get TP frequencies), Suppose Maasranga TV at 3799 H tp,symbole rate 4330, It has the strongest Tp in 76.5E and therefore makes it easier to tune, It is nearly 87%, so good dish pointing here.

Initial tuning

Initial tuning

Now we will try adjusting the lnbf skew a little, To do that keep the channel tuned and loosen the lnbf a little, slowly rotate it to either side and lock it where the signal quality is best, After doing this my signal quality is above 90%

After skew

After skew

Now we know we have successfully tuned the 76.5E satellites, Do an autoscan to see if we are getting all channels to acceptable levels

FTA Channel List on Insat 83E

FTA Channel List on Insat 83E

The channels broadcasting in Mpeg-4 format are shown as radio as this old receiver is only Mpeg-2. To make sure everything is fixed we will check out some random channels ,Once we are satisfied that everything is coming clear , Tighten the lnbf, Hold the lnbf while doing this, Otherwise as the screw tightens there is a chance of the lnbf rotating and resulting in bad signal quality, Always wear rubber chappals while doing all these, As all electronic equipments can give you a rude electric shock, if something gets short or malfunctions.

So after some hours of hard work , We finally have our own basic C-band setup, You can connect the cable to your living room, take the receiver there and enjoy Free To Air television, for a long time now

In the next part , you will find how to add more satellites to this setup.

13 comments:

  1. Pls guide as to use a readymade dish from market (about 2' or 60 cms in size) to catch Free TV channels from air

    The dish described by you (6' to 8') is too large to be able to instal in flat systems in multi-storey building

    Thank you
    AK Agarwal
    akagarwaal@gmail.com

    ReplyDelete
    Replies
    1. There are minimal size requirements. For C-band the minimum dish diameter for a decent signal reception is 6', for most Ku-band satellites you need a 3'-4' diameter dish.

      Delete
  2. Dammit! "Antennae" is PLURAL, not singular. Also please learn the difference between "its" and "it's" -- it's obvious you don't know its differences.

    ReplyDelete
  3. Thanks a lot for your post, this was an inspiration for me to install a FTA dish by myself.

    Thanks a lot for the detailed explanation.

    ReplyDelete
  4. for c band suntech LNBF i got 80% quality.but no strength for apstar 7 in saudi arabia. Receiver model starsat SR-X 1500 ultra. i put transponder 3799-H-4330-3/4.LNB frequncy- universal.0/12 v off.
    Is some thing going wrong? My data input ok or not?
    Can you please help me.

    ReplyDelete
    Replies
    1. I beg to differ with you. You NEVER get Quality without Signal Strength. In other words you always get signal strength, even if the antenna is looking to the ground, but you can only get quality if your dish is looking at the proper satellite. The other important thing is, I don't think your LO frequency is Universal, it's more then likely 5150

      Delete
  5. This is Excellent blog article. so Impressed your blog article. said for this sharing site.
    Thanks.
    diseqc switch

    ReplyDelete
  6. Good work. Please keep it up Brother.

    ReplyDelete
  7. nice guideline for receiving downlink of tv channel.


    Thank
    Md. Habibe Azam
    Broadcast Engineer
    habibeazam@gmail.com

    ReplyDelete
  8. how to istal c band 6 feet mesh dish receiver analog old , setellite tv channel free air so pls help

    ReplyDelete
  9. how to istal s band 6 feet mesh dish receiver analog old , setellite tv channel free air so pls help

    ReplyDelete
  10. please tell me how many Chanel will i get in big c band dish

    ReplyDelete
  11. According to selected satellite you can get around 200-300 channels.........

    ReplyDelete