There is little to no documentation available to explain the proper use of wireless microphones in South Africa, as Nicholas de Kock of Romanza Films recently found out.
Says De Kock: “I’ve had a problem trying to find frequency numbers for the legal operation of UHF radio mics in South Africa. Most sales people can’t even tell me the frequency range for the equipment they are selling, or otherwise no-one seems to be selling equipment in the legal range. With online sales taking over as well a lot of the equipment is coming from the US – it’s like a wireless orgy.’
After spending some time researching on the web, De Kock came across guidelines from the Independent Communications Authority of South Africa (ICASA) for the 2010 FIFA World Cup. But as this was a once-off event it did not help his dilemma.
The official view
ICASA is governed by the Independent Communications Authority of South Africa Act and the Electronic Communications Act (ECA). Its mandate, among others, is to regulate electronic communications to ensure efficient use of the radio frequency (RF) spectrum.
On the subject of radio microphone operation in South Africa, ICASA’s Gert Visser says: “If you operate in the 486 to 838 UHF range you should be OK. On the UHF waveband, 470 MHz and 862 MHz are now mainly used for broadcasting TV programmes. So frequencies between these should be clear.’
The technical advantage to UHF is a frequency range that has relatively low levels of interference from technical equipment. Propagation conditions are also good, achieving high ranges and effectively penetrating buildings.
De Kock adds: “I have been getting an increased amount of interference operating in heavily populated areas which has been affecting my production.’
Visser is aware of the situation. “The problem does exist where a local church will order mics online, but this will only be discovered when they operate them. These illegal operators will be dealt with by our inspectors.’ (ICASA may seal or seize the equipment.)
Visser continues: “This is strictly enforced otherwise interference would be rampant. Suppliers and sales companies are constantly applying for licences for new products, so the fault doesn’t lie there. This applies particularly in the broadcast and film industries.’
Radio microphones use very little power – from 10 to 50mW (a mobile phone uses up to 2W) and can achieve ranges of around 100m while retaining excellent audio quality, which is sufficient for reporting purposes, sports and cultural applications.
Local and foreign entities involved in the provisioning of electronic communications may apply for exemption from standard equipment type approval during the hosting of special events.
On stage, these low power levels can still penetrate scenery, be picked up backstage and also maintain links with receivers without loss of quality when artists go out into the audience, as in the recent U2 concert.
For these types of events ICASA issues temporary licences that are valid for a month. “ICASA will accept test reports of the relevant European standards, provided the testing has been performed at an accredited test facility. Control of this is difficult as illegal transactions do take place,’ notes Visser.
Analogue to digital transmission switchover
De Kock says he would like to upgrade to the new Sennheiser G3 or Sony UWP-V1 lapel mics. “However South Africa’s digital switchover is also a concern even if it is a few years off as I would like my equipment to be future proof. The digital crossover in the US had a big impact on the wireless mic industry.’
At present analogue technology requires a TV channel with a width (frequency requirement) of 8MHz to transmit TV programmes. 7MHz is needed for broadcasting the TV programme, leaving a gap of 1MHz used primarily by reporters with wireless microphones. In digital transmission, there will be four TV programmes in one frequency range replacing one analogue programme. In theory the digital frequency requirement for transmitting TV programmes is reduced to a quarter of that of analogue.
This “saving’ will see 3/4 of the band theoretically freed up. These frequencies can be given to other services.
One of the threats is mobile TV services broadcast on the DVB-T2-H standard, such as DStv Drifta for example. These programmes are transmitted in the UHF range, which is why many programme suppliers who until now could only be received on cable or satellite are pushing for the UHF range.
Primary services like TV programmes have priority in the frequency range they are allocated. In the main, wireless microphones are a secondary service and are therefore of lesser importance when frequencies are handed out.
Another factor is that in the near future the technical quality of TV is going to be improved from SD (Standard Definition) to HDTV (High Definition) which requires more spectrum.
