Saturday, 10 March 2012

Satellite TV on your boat.

Satellite TV on your boat does not require a huge amount of money or technical knowledge. Mounting a dish on the boat can be done. However, if the boat moves around the picture can be a bit hit and miss as the dish moves in and out of the signal beam. A dish does not have to be mounted up in the air like a normal TV antenna. All that is needed is a clear view of the satellite. A dish that is mounted on the ground will be much more stable than one mounted on the boat. Mount the dish on the towpath using a simple tripod. Even a small photographic tripod can be adapted for use.

Satellites are earth-synchronous or geo-stationary. This means they circle the earth in a specified orbit, at the same speed as the earth itself. As a result, they appear to stand still. All geo-stationary satellites revolve around the earth at a height of 36,000 km, precisely over the equator.

The next problem to be solved is pointing the dish in the right direction. Watch this video, it’s very surreal. This is the next generation satellite finder: Point your iPhone anywhere towards the sky and see all the satellites lined up, on the live video screen! At a glance, you’ll see where the satellite is and whether any trees or buildings are blocking the line of sight. Setting up a dish is going to be a piece of cake with this app. This is a truly useful app for the professional and do-it-yourself enthusiast alike.

You can also get visual help on the Internet. Have a look at Dish Pointer and enter your location and then choose a satellite from the list. The program will draw a line to the satellite on to the image of your location. This will give a good idea of the direction to point the dish in. Because there are different designs of dishes available its difficult to place the dish at the correct angle upwards. Modern dishes intended for home television use are generally 43 cm (18 in) to 80 cm (31 in) in diameter, and are fixed in one position, for Ku-band reception from one orbital satellite.

Three of the most popular satellites in the UK are:
On 28.2E - ASTRA 1N, 2A, 2B, 2D
On 19.2E - ASTRA 1H, 1KR, 1L, 1M, 2C

For rough tuning you can use  a compass. The compass is for approximate dish setting, using earth's magnetic field as a guide to the location of that little metal box floating twenty three thousand miles above your head in space. But as there's a satellite positioned approximately every three degrees along the circle above the equator - some giving strong signals in the UK, some weak. So an error of a couple of degrees East or West will select you the wrong satellite.

An inexpensive "Satfinder" gadget  that measures signal strength can be purchased on ebay for £5. A more professional unit can go up to £100 or more.

The next problem is knowing what channel is available on what satellite.

A list is available on Wikipedia of all of the free-to-air channels that are currently available via Astra satellites (2A/2B/2D/1N) and Eutelsat's 28A satellite located at 28.2 °E. These are the same group of satellites used for the Sky pay-TV platform and the Freesat free-to-air platform, therefore existing installations for these platforms would not require a realignment of the satellite dish or the purchase of any additional equipment. New capacity has been added so new channels can launch free-to-air via Astra 1N. There are plenty of similar sources of satellite information available on the Internet.

A TV program listing for each satellite and its associated channels is also available on the Internet. Some services are by subscription (SKY for instance) other services are free.  Here is a PDF download listing of the Free Satellite Broadcasts


No comments:

Post a Comment

Please put your name to your comment. Comments without a name may automatically be treated as spam and might not be included.

If you do not wish your comment to be published say so in your comment. If you have a tip or sensitive information you’d prefer to share anonymously, you may do so. I will delete the comment after reading.