Microphones Radio mic frequencies- a question for users

[Jules]

A question for anyone using Radio mics, from one of our suppliers. As you may know there are two different sets of frequencies used by stage radio mics- band 70 (a free for all band) and 38 (a licence series of channels). Most players seem to be opting for the easy and cheap option of channel 70, for obvious reasons. The question- would anyone here who uses kit like this be interested in using a paid for frequency band? The advantages being that doing should ensures a clean, uncluttered frequency- unlike 70 where there’s a chance of ‘treading on other mic users’ toes’, bandwidth wise- its a more ‘future proofed’ system in this respect .

Any thoughts welcome

 

[TimboSax]

I've used in ear monitors for a while on channel 70, and recently started using a radio mic for the sax also on channel 70. I occasionally use wireless for the guitar, but that's a Line6 digital system, so uses a different frequency altogether. No-one else in the band uses wireless, so that means there's only two frequencies used in channel 70, and I've never had a problem with interference or crosstalk.

However, if I was in a band which had more users, then I'd seriously consider channel 38, to ensure there was little chance of interference, as the bandwidth is wider. Last time I looked (a couple of years I think), it was about £75 per year for a license?

 

[Young Col]

Jules
I'm not a user but I can give you some thoughts/points as an ex-radio spectrum regulator.
The licence free channels are available on what is called the "non-protected/non interference" principle. That is users must accept interference from other authorised users (ie users of proper licence free equipment) but at the same time they must not cause interference to other authorised users. In theory there is protection from unauthorised sources, such as electrical equipment or the harmonics or intermodulation products of other radio users on different frequencies, or of completely unauthorised use. However, for a one off gig, if you do get interference from something that shouldn't be there, the chances of getting Ofcom to do anything are virtually nil. Licence free use is well down their list of priorities (things like interference to safety of life services comes first) and they have something like a 60% reduced staff from my day 10 years ago.

Permanent sites, professional users, theatre musical productions and broadcasters will use licensed channels. A West End musical may well have 20 or so channels plus some spares. There is more certainty about non interference from other mic users as the frequency use is planned (using protection ratios based on signal strength). There is still the risk of interference from unauthorised use (I recall a few instances where the studio feed to pirate broadcasters' transmitters caused problems) or something faulty (again, I recall a taxi firm's faulty transmitter interfering with a West End show) and even though the licenced use should get response from the regulator, in practice it still won't be immediate, which is why a few spare channels are kept.

You need to judge the risk yourself, but for one off use at gigs unless you are in very close proximity to other venues, you will probably get away with licence free kit. I believe most have a couple of switcheable channels so you have a work round built in. My son was a professional sound engineer for some years and when did many quite large on-off gigs and things like after show parties. He said they rarely needed anything other than the licence free channels.
Hope that's helpful.
YC

 

[Colin the Bear]

The battery amp I use for busking and solo gigs came with a radio mic. I've always been worried I may pick up something through it but nothing to date. I'm not looking for anything else at the moment. Paying for a different channel isn't on the cards.