channel()

channel( <channel / tuning> )

Description

This instructs the teletext receiver to switch to the specified channel.

Specifics

RISC OS uses 'channel presets' where the channel settings are made in the !Teletext configuration, and then you choose the channel as a number from 1 to 9. It is not possible to select a specific UHF channel; and values outside of the permitted range will be faulted.

Windows does not offer 'channel presets', so you should specify an absolute UHF channel in the range 21 to 69; and other values will be faulted.

Undocumented...

The television broadcasting frequencies are split into three 'bands'. The first of these is BAND I which is 47-68MHz (nominally channels 2 to 4). The second of these is BAND III which is 174-230MHz (nominally channels 5 to 12). The latter, and the only frequencies available in the UK is BAND IV-V which is 470-862MHz (channels 21 to 69).

It is with apologies to European viewers that WinTTX does not specifically support frequencies outside of the 21-69 range. To be honest, I am not certain if the tuner is physically capable of receiving such frequencies.

If you are Belgian and you are willing to give this a try, WinTTX (v1.50) will accept three special channels as follows:

75	175.25MHz	Corresponds to La Une in Dinant / Houffalize / Malmedy
89	189.25MHz	Corresponds to La Une in Bruxelles
96	196.25MHz	Corresponds to La Une in Wavre

Please note that this is acheived purely by synthesising the data to instruct the tuner to tune to those frequencies. I will not be held liable for damage incurred as a result of trying this; however if you do try this, please let me know how you get on.

Why Belgium? Because RTBF Sat teletext listed the frequencies.

Why is there no sound in Europe?
If you connect a lead to the Aux port (audio/video output), you will not hear any sound in Europe using a Ground Control/Octopus receiver (and probably not with others, either). This is because the UK uses PAL I where the sound carrier is +6MHz from the tuned channel; however Europe uses PAL B/G where the sound carrier is only +5.5MHz. A good television engineer may be able to rectify this by altering something inside your tuner.

channelid()
set() for "status(channel)"

La une: 5 175.25 Dinant / Houffalize / Malmedy 7 189.25 Bruxelles 8 196.25 Wavre