Radio transmitters are used for communication by Citizens' Band enthusiasts, radio amateurs, radio taxis and many other licensed and authorised services. Strong radio transmissions from any of these sources could affect your set.

In many cases there is no fault with the radio transmitter and the radio operator is not to blame. The problem occurs because the TV set is not designed well enough to resist signals which it should not receive. In such cases the TV set is said to be lacking in immunity

This is how a strong radio transmission from CB. amateur radio, radio taxi or other service could affect your set. The pattern on the screen may vary slightly depending on the type of transmission. The TV sound is often affected and you may even hear the voice of the operator.

Possible Remedies

1. You can cure many cases by fitting a simple plug-in high-pass fflter between the plug on the end of the aerial lead and the aerial socket on the back of the TV set. A variety of suitable filters are available and your dealer will advise you which ones to try. See Fig. 5 and Appendix 6.
2. If the filter does not work, the TV set will require an internal modification to improve its immunity to interference, In which case:
   • a.If the set is still under guarantee, return it to where it was bought, explain that A lacks immunity to radio interference and ask for it to be put right.
   • b.If it is no longer under guarantee, take it to your dealer, explain the problem and show him Part 2 of this booklet.
   • C. It the dealer is unable to carry out the internal modification, write to the manufacturer of the set and explain the problem.

How to fit a filter

Most problems of radio transmitter interference to TV can be resolved, or diminished, by simply fitting a filter between the aerial lead and the TV set.

When you have decided, by looking at the pictures in this booklet and carrying out the checks, that the problem is a radio transmitter.