So What's Changed Recently?
Terrestrial TV here in the UK has now fully switched over to digital and some of the TV frequencies radio/wireless microphone users shared in the UK have been changed and it is quite likely (particularly if you use more than four microphones together as we do in schools and theatres etc more often than not) that you will need to change these systems now as they are now illegal to use and you could be fined thousands of pounds and have your equipment confiscated...
The good news is that we at 'Sound Hire' are offering you a part exchange/trade in for your old radio/wireless microphone systems against new systems of your choice on the new frequencies...
Each manufacturer of these microphone systems uses different codes such as Band A, B, C, D, E, K, and U etc which is confusing to say the least. Nearly all these systems will have the frequency range shown on a label either on the back or underneath the receiver and on the back or inside the battery compartment on the transmitter. If you can't find this information please feel free to email us and we will look it up for you 'free of charge' if you give us the make and model of the systems you have along with as much information such as 'Band C' etc as you can provide. You could take a picture of the label and email it to us if that helps?
What Choice Do You Have?
There are still free to use frequencies for these microphone systems here in the UK such as 2.4GHz (also used by Bluetooth and WiFi and Wireless DMX devices all of which can cause interference). 2.4GHz systems usually offer a range of up to 30mtrs and between 4 - 8 usable frequencies. There is though a real possibility of interference on this frequency band due to the amount of devices using it in todays world.
There is also a 1.8GHz frequency band appearing on the market which is free to use in some European countries and now legal to use here in the UK as part of the PMSE Channel 38 Shared License. Unlike 2.4GHz this part of the frequency spectrum is clear of devices such as Bluetooth, WiFi Routers and Wireless DMX etc.
UHF TV Ch 70 - 863-865 MHz
Next you have Channel 70 (UHF 863 - 865MHz) also used by devices such as wireless comms, wireless headphones along with other devices and although this remains free to use throughout the UK and many countries in Europe several manufacturers of high end systems are not recommending the use of these frequencies any more as they are so close to the new mobile phone frequencies there is potential for interference looming. As of now there isn't any hard proof one way or the other regarding possible interference on this frequency band and there won't be any proof until the mobile phone companies begin fully utilising our old TV frequencies around the 792 - 822 MHz and 833 - 862 MHz frequency band.
UHF TV Ch 65 - 823-832 MHz
Channel 65 (UHF 823 - 832 MHz) is the latest released set of frequencies for radio/wireless microphone here in the UK. It was released in March 2015 as part of a wider EU agreement intended to harmonise the increasing demand for available frequencies for radio/wireless microphone use. These frequencies are included as part of the PMSE Channel 38 Shared License.
UHF TV Ch 38 - 606-614 MHz
Channel 38 (UHF 606 - 614MHz) is the safest of the lot if you are a serious user of radio/wireless microphones here in the UK. It is the new dedicated frequency band allocated for their use throughout the UK. You will need an annual license to use it just like the old Channel 69 (UHF 854 - 862MHz) but this will give you up to twelve usable analogue microphone systems within this frequency band depending on the manufacturer you use. More recent digital microphone systems can offer more usable microphones however there is a cost to these systems which can easily top a thousand pounds each so it depends on your budget. In addition to Channel 38 Ofcom/PMSE have now released Channel 65 (823 - 832MHz) for radio/wireless microphone use for those who have a Channel 38 license.
The higher the frequency band the more line of sight and shorter range the equipment will be. For example 2.4GHz and 1.8GHz offers the shortest range and any obstacles between transmitter and receiver can cause severe disruption of the RF signal. You will do well to get 30mtrs reliable operating distance between transmitter and receiver even in perfect near conditions. The UHF frequency band such as Channel 70 (863 - 865MHz) usually offers distances of more than double the above in near perfect operating conditions and is less affected by obstacles between transmitter and receiver. Channel 70 does have a restricted power output though. The new professional user UHF frequency bands Channel 65 (823 - 832MHz) and Channel 38 (606 - 614MHz) offers higher power output (up to five times that of Channel 70 systems) and is quoted as offering 100 - 200mtrs range line of sight by some manufacturers.
You should be aware the distances quoted are maximum distances the manufacturer recommends and that in a real world theatre venue with the transmitter packs being positioned under costumes you are looking at reducing these distances typically by anything between 60% - 80% depending on the costume and the venue as well as other possible factors.
At the end of the day radio/wireless microphone systems are low powered devices designed to use several together at a time. To avoid interference between several systems just some of the requirements include low power output and very good filtering and much more and this is why these systems cost what they cost. At around £100 each or less for a complete system cross your fingers and hope for the best and don't expect more than one or two to operate together. At around £500 each for a complete system you can get up to twelve microphones operating together. At around £1500 each and upwards for a complete system you could get sixty to one hundred microphones operating together but you are getting into many TV channel spaces and special short term licensing requirements. These costs are just a ball park indication and no more than that of what you could expect to get for your money.
Our Advice & Recommendations
Please note the above information is given in good faith as a general recommendation based on our many years of experience with such systems. Please be aware there are many things that can affect the performance of any radio/wireless microphone system from any manufacturer whatever the cost. Generally the more you pay the better you get in terms of both audio quality and interference resistance.