Finding channels


Say what?

By 'finding channels', I mean sitting down and taking a little look-see at what channels are available by using the brute-force method of, erm, 'finding' them.



To pass the time, mainly. You could cheat and use a satellite channel list, but how up to date is it?
This process is akin to taking a metal detector onto the beach - only you won't get wet shoes and you won't get rained on and you won't have to put up with screaming kids/dogs/other metal detector fans (delete as applicable).
You will, however, have to put up with finding numerous ring pulls.


What's the catch?

Ah... Well... How do I put this politely? If you look on frequency 12345 for a channel with a symbol rate of 27500 and the FEC 2/3 - the Digibox will tell you that there is no such channel if it happens that the FEC is 3/4 and not 2/3. Bloody stupid, I know. Luckily the older Astra satellites only use two of the available options.

I made up that frequency, in case it wasn't obvious. The closest is 12342 H 27500 3/4 which offers some RTLs and BBC Prime. Sadly BBC Prime is scrambled for some sort of satellite operator...


Channel syntax

The channel tunings are given in the following format:
   <frequency> <polarisation> <symbol rate> <FEC>
for example:
   BBC World - 12285 V 27500 3/4

The frequency is specified as five digits with no decimal point, your Digibox will place a decimal point between digits two and three, such as 12.285.
The symbol rate, also, is given as five digits with no decimal point. The possible rates are 22000 and 27500 while the Digibox says 22 and 27.5. The Digibox measures in Megasymbols/sec while I use kilosymbols/sec. Same thing though...


The frequencies

If you enter an invalid frequency, the Digibox will inform you that the available range is 10700 to 12750.
Actually, if we take two adjacent channels, they are 19 apart, so we can work back to discover the first channel is 10713 V and the last channel is 12746 V. They alternate between horizontal and vertical polarisation. This gives us a frequency range of 2033 which divides by 19 to become 107 possible channels.

This is not actually strictly true. Some channels have an offset larger than 19, I suspect these offsets are between satellites. It helps to have my list handy so if you spot that the channel you calculate (with your handy calculator) is a few digits off, you can correct it.


Manual Tuning

The best way I've found to add channels is to go into the hidden installer menu (press 'Services', '4', '0', '1', 'Select' in that order and ignore the screen display until the end) and use the Manual Tuning option.
This is mostly identical to the normal Add Channels system, except while it is looking for channels you will see the Signal Test display. This is helpful for judging if anything is 'there' (some channels are analogue) especially if you have forgotten the polarisation!

The process is a bit weird. Here goes. You'll see a reasonable signal quality and lock will say 'OK'. This is because, when you aren't doing anything else, the Digibox returns to the default transponder (perhaps this is where it gets the menu music from?).
Upon finding digital channels, the Network ID and Transport Stream will both become 0000 for a moment, to be updated by the new values. Press 'Select' and you can pick from the channels shown.


What Symbol Rate and FEC?

Well, if 22000 5/6 does not work, try 27500 3/4!

As a rule of thumb, the frequency range is 10700 to 12750. The channels in the middle (say, 11500 to 12500-ish) use 27500 3/4 while the remaining channels (on the 'outsides' of the frequency range) use 22000 5/6.

Note that the Digibox supports a number of FECs, but it only supports the two symbol rates already discussed. If you have a little broadcaster that uses, for example, 11000 or the like, you will not be able to receive it with a Digibox. The majority of other digital receivers support 1000 to 45000 (give or take a little - the 100 euro box goes up to 30000kS/sec, and amusingly the 1,300 euro box only goes up to 32000kS/sec!).


Won't it take forever?

To check around a hundred stations in two possible Rate/FECs including working out if you've lost sync with the actual channels or if you have mixed up the polarisation sequence...?
It will waste away the time on a rainy Sunday.


What can I expect to find?

For watching? Probably nothing unless you can speak German. As I find interesting things, I modify my channels list to save you the trouble of doing it yourself.


Any interesting stuff?

If you are more of a nerd, you might enjoy:
"Infocast mail Astra"      11511 V  22000 5/6
"Test_R"                   11834 H  27500 3/4
"Astra Satmode" (many)     12245 V  27500 3/4

Also, keep an eye on the following combinations. They appear to be valid digital transmissions but report 'No channels found' (not even test channels).

11473 V  22000 5/6
11872 H  27500 3/4
11910 H  27500 3/4
11967 V  27500 3/4
12435 V  27500 3/4
12727 H  22000 5/6

If you are 'into' signal extractions (you know what I mean), then you may like to take a look at "BBC Prime" which is an evening-only channel broadcasting the 'best' of BBC things. Whether or not it is 'the best' will depend a lot on your tastes. You can find this at 12340 H 27500 3/4 and again at 12378 H 27500 3/4.
You will also find a large number of themed radio stations (i.e. Traditional Country, New Country, UK Hits, Italian Contemporary, '80s Hits) at 12043 V 27500 3/4. If you find out how to receive these, please let me know! An '80s only radio station sounds right up my street.


Encrypted channels

Quite a number of channels are encrypted. I don't think you can receive them with a Digibox, though it may be possible with a plug-in module - it isn't something I've known anyone to have done.
When you choose an encrypted channel in the Other Channels list, the screen will clear to blue with the channel bar showing. It may update with the now/next programmes, however the main part of the screen will remain blue.
You will not be asked to insert a viewing card!
A useful little shortcut is that pressing back up at this point will take you straight back to the Other Channels list - nifty, huh? Once a picture has been received you can no longer use this shortcut.
To see this in action, if you program in MTV Central, pop in any of the other MTV channels on that boutique, like MTV F - they're all encrypted.

To remove a channel from the Other Channels list, highlight the channel and press yellow but WARNING: You aren't asked to confirm, it happens immediately.
When you next select a valid channel there will be a pause of a second or so as the channel list inside the Digibox is updated.
Note also that the cursor moves up the list as you delete, so if deleting more than one channel at a time, be careful that you don't nuke channels you want. This has caught me out a few times...


And finally...

Find anything interesting? Have you any interesting screen grabs, test cards, etc? Email me ( heyrick at-symbol merseymail with-a-dot com ).

You'll find a simple colour-bars testcard at 11568 V 22000 5/6.


Have fun!
And Happy Hunting!


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Copyright © 2004 Richard Murray