Radio aids – optimising listening opportunities: Guide

Frequencies and transmission

Sometimes there can be interference or a break in the transmission when using radio aids.

• A clear line of sight between the transmitter and receiver(s) will give best results.
• Hiding the transmitter (if not body worn) behind books, tins etc will decrease coverage dramatically irrespective of frequency of transmission.  
• Be aware when using the system outdoors, that obstructions can get in the way of the signal from transmitter to receiver.
• Within a room, blind spots will occur if a metal structure or other obstructions are between the transmitter and receiver.

Below are some frequently asked questions - and answers - about radio aids and transmission of signals.

1. The  building has a mobile phone mast on top.   a)  will it cause a health hazard?         No  b) will it interfere with the radio aid?        No
2. Will the radio aid present a health hazard?      No
3. Will the WiFi interfere with the radio aid?      Extremely unlikely but the radio aid system may cause the WiFi reception to reduce.  In which case move the WiFi.
4. Can I run radio aid systems in adjacent rooms/classrooms: YES but discuss with your supplier as minor technical adjustments may be required.
5. Are all manufacturers systems compatible? Not in every case. Also some accessories may not be compatible with all ALDs made by the same manufacturer: always check.
6. I have completed all the checks but I still cannot hear through the system.  Check you are not shielded from the transmitter aerial location.
7. Does the signal drop as batteries decline?   No - the radio aid has a battery limiter which shuts off the system when the battery level drops below a certain point (normally there is a bleep to warn that the battery is fading).
8. Does the signal normally fade away at a distance, cause distortion of ‘voice’ or just drop off?  A Digital transmission has a cliff edge drop off when it goes out of range.  An FM signal fades gracefully.
9. Why do by batteries run down so quickly?   Radio aids and ALDs mainly use small single cell batteries with a limited capacity.  If the ALD is used only as a hearing aid, the batteries last a reasonable time but the battery life is shortened when streaming music or phone conversations as these require extra power from the battery.

Click here to read a full description and explanation of analogue v digital, frequency spectrums, regulations and physics used in radio aid and ALD technology by Brian Copsey.