Background

Since 1996 the Institute of Local Television has been looking for a terrestrial television transmission system to help support low-cost small-scale TV broadcasting. Field trials of an inexpensive 2.4GHz TV transmission and relay system were run from September 2002-October 2003 in Aberfeldy .

Experimental Television

Following the success of the Field Trials, '2.4 TV' is being introduced to support small-scale community and educational TV services. This television transmission role for 2.4GHz in the UK at least is new although the technology involved is in use for video senders and CCTV. The 2.4GHz band was set aside internationally for use by licence-exempt services. The core elements of the 2.4TV equipment are widely available. In 2.4TV the 2.4GHz frequencies are restricted to a maximum output of 10 milliwatts.

2.4GHz is also the same band used digitally in wi-fi applications for providing wireless computer connections and for internet use in 'hot-spots' such as cafes, stations and airports. Therefore, 2.4TV applications need to take into account other users of the 2.4GHz band in the immediate area.

In the Aberfeldy Field Trial a pilot community TV service - e-tv - was transmitted from the Locus Building to The Palace Hotel (500mtrs) and to the Glassie Bunkhouse (2000mtrs). Also a domestic video-sender receiver was also installed in The Fountain bar across the town square from the transmitter (70mtrs) for reception of community TV programmes being shown during a local festival.

Typical applications identified for 2.4TV

• educational television - linking a student-run TV station into halls of residence and for providing distance learning or video conferencing for schools in remote locations;

• neighbourhood television - for a service transmitted between tower blocks. Utilising the UHF system in each tower or group of houses to convey the signal to each home on a spare frequency;

• hospital TV - running with sound and picture from (eg) the hospital's radio studios (utilising the UHF system in each ward/block) or for providing health advice remotely to village communities in areas with poorly developed communications;

2.4TV - Aberfeldy Field Trial 2002-2003

The Field Trial consisted of three 2.4TV reception points and relays. The service ran on a video server with teletext inserter. This was located in a room beneath the transmitter at the Locus Building in Aberfeldy town square from where:-

• reception at The Palace Hotel was by an external yagi aerial. The signal was converted through an RF modulator and distributed via the hotel's UHF network to its 21 bedrooms. The signal was re-transmitted on a second frequency from the hotel roof for indoor set-top reception up to 100 metres away;

• reception at the Glassie Bunkhouse was via an external parabolic aerial at 2000mtrs distance from the Locus Building. The signal was piped to the bunkhouse TV via a SCART connector and relayed for further reception within 100mtrs. For two weeks at the start of the trials the Glassie Bunkhouse system was powered by solar panels - testing the idea of remote intermediate relays being used for bouncing the signal over hilly terrain.

• reception could be bpicked up by households on domestic set-top receivers where the signal can be received up to 100mtrs unobstructed. This was tested on a set-top receiver at The Fountain Bar (70mtrs) during a local festival;

 

Self-sufficient system

Fitted with solar panels or a wind generator charging a 12 volt battery sources of renewable energy free relays to be set-up at remote sites providing 'hops' to reach population centres over hills or difficult terrain.

Server based TV services

The Institute of Local Television has helped design and develop an inexpensive video server to work with 2.4TV. The '2.4 video-jukebox’ handles several hours of MPEG2 encoded programming on its swoppable hard discs, providing 24/7 broadcasting and requiring no staff contact over extended periods. The schedule can be updated via phone line or ethernet connection while programming can either be uploaded via ethernet or by swopping-out the hard discs.

The schedule on the '2.4 video-jukebox' can also be changed by the viewer with requests for programmes made by following recorded instructions on the phone and entering a four digit code on phone's keypad.

The '2.4 video-jukebox' provides potential revenue from premium rate phone requests.

Who is involved?

A Scottish charity, the Television Trust for Scotland has managed Aberfeldy's 'e-tv' service on the 2.4TV Field Trial since July 2002. The charity's educational objective is to provide training in television for access to broadcasting. E-tv - was on-air between September 2002 and October 2003 screening video programmes, TV graphics, local commercials. The service ran with stereo audio and teletext and was updated periodically throughout while the Institute trialed its 2.4TV equipment.

The Institute of Local Television is a not-for-profit company established in the 1990s to lobby for and develop small-scale public-service oriented television.

Following the Aberfeldy Field Trial, the Institute has begun rolling-out '2.4TV' in the form of a social franchise. The Institute will plan and support the introduction of a simple 2.4TV system which the local community takes over to expand, develop and manage as required. The essence of the social franchise is that locally accountable and managed TV services become established with the help of training and courses. These courses can be provided in conjunction with local community agencies or NGOs which we hope will include training in site surveying, 2.4TV engineering, TV production, TV text & graphics, copyright and licencing issues and so on.

For further enquiries contact local.tv@virgin.net or:-

Institute of Local Television
13 Bellevue Place
Edinburgh
EH7 4BS
44 (0) 131-466 3021

© Institute of Local Television, 2003

 

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