Q. What is the typical range of Radio systems?
A. Diversity systems have a greater range and better reception stability than single channel systems. This can be affected by walls, pillars and even human bodies, so for best results make sure you have 'line of sight' between transmitter and receiver. Generally these days manufacturers quote anything from 30 to 100m range, but this is different in real world situaltions. For large or problematic setups we can advise on remote antenna systems to boost your signal.

Q. How do I know if my old radio mics are legal?
A. If you buy them from DM Music, all our systems conform to MPT 1345, which are license exempt. The current rules (2009) allow use of up to 4 radio systems simultaneously, each running on individual frequencies within the deregulated (license exempt) bandwidths. For more systems, or to run on other frequencies (when deregulated options are in conflict with other users) you will need to contact JFMG - the UK radio licencing body. They can advise on and supply licences for alternative frequencies for fixed locations in the UK - this is usually only a few tens of pounds per licence. please see www.jfmg.co.uk for more information.

Q. Do I need a single or diversity system?
A. It depends on how near the transmitter is to the receiver and if there is lots of metal in the building. Diversity systems are more stable as they actually have two receivers in the unit, each scanning for the strongest signal. there are 'Space (Synthesised) diversity' and True diversity systems available - the True systems have two receivers bbut the Space systems actually only have one, but the two aerials each scan for signal to send to the one receiver.

Q. How do I know a good make from a bad one?
A. DM Music have sold more radio mic systems to churches than anyone else in the UK. We know the good from the bad ones and therefore we offer a money back guarantee. We would recommend you select a system with more than one frequency (eg 8 selectable frequencies) and, if budget allows, choose a True Diversity system for maximum reliability.

Q. Should I use rechargeable batteries?
A. Rechargeable batteries need to be discharged completely before recharging. If this discipline is not followed the battery’s life is shortened. Unlike normal alkaline batteries, rechargeables don’t fade, but rather shut down instantaneously. This could be a problem in the middle of a sermon! We recommend Nickel Metal Hydride (NiMH) rechargeable batteries for radio systems.

1. Try to keep your antennas at right angles to each other. This allows for 'polarised' signals which may not be recieved by aerials on a certain angle.

2. Keep the transmitter as close as possible to the microphone, preferably in the ‘line of sight’.

3. Adjust the squelch control on the receiver to reject signals other than the one it is supposed to receive.

4. Systems can use rechargable batteries. However they discharge typically only 7.6volts rather than full 9 volts which is not sufficient to operate transmitters properly. We recommend Nickel Metal Hydride (NiMH) rechargeable batteries.

5. Place lavalier microphone as close to the mouth as possible to avoid feedback - generally a hand span distance from the mouth is a good bet.

6. Do not cover lavalier microphone with items of clothing - wear on the outside of the clothing to avoid feedback and interference.

7. If the minister in your church insists on walking in front of the speakers you may be advised to purchase a graphic equaliser or feedback eliminator.


8. Human bodies absorb a lot of radio signal so position your radio mic transmitter nearest to the receiver, eg. don't wear a belt pack in back pocket if you have signal problems - postion it in a front pocket or on your belt poitning to the radio receiver postion

9. Keep radio mic receivers away from metal objects if possible as these absorb and refect radio waves.

10. Try moving receivers away from walls as these can reflect radio waves

11. Do not tune several radio systems to closely - keep each frequency comfortably clear of any others you use. Also radio frequecies tuned to mathematical factors of other frequencies (eg. 2 x the first frequency) can cause 'intermodulation' which may result in dropout or interference.

Many cheap radio microphone systems have only one antenna which means they are prone to ‘dropping out’ in mid-performance if a reflected radio signal happens to interfere with the direct radio signal.

True diversity systems essentially give you two receivers in one box, and reduce the risk of ‘drop outs’. DM Music recommends True Diversity systems wherever possible.

Even 'Space' or 'Synthesized' diversity systems which use a second antenna are still prone to problems because they still have one receiver circuit.