irishpaddyroar

As caretaker in a school I was asked to set up microphones for an event in our school hall.It involved extending the microphones which plugged into sockets on the stage down to the centre of the hall.I used a length of coaxial TV cable to extend the microphone cable to where it was needed.I had used this cable previously at another venue to extend the microphone points successfully.This time however I picked up a radio station loud and clear.I checked the microphone plugged into it's original point and it worked perfectly.Plugged it back into extension cable radio worked loud and clear.After about an hour I found that by using a different length cable to connect into original plug socket point the system worked without any radio station breakin.Plug back in first cable radio loud and clear.Conclusion I had matched the radio frequency length perfectly with the total length of the microphone cable used so that when I altered the length of the cable it did not match any radio frequency and so the amp setup worked perfectly.Remember a radio reciever is an amp which has a tuner which changes the length of the ariel to match the station being recieved.The old valve radios long ago (Ireland 40ft of wire ) used an exact length of wire set between two insulators to pick up the radio station. There was only a fine tune adjustment to improve the reception.So anyone picking up radio reception on any form of amp needs only to change the length of wire between mics or guitars to stop the radio signal length being matched.This worked for me when using a microphone.If signal length is 103.4 all you need to pick up this signal is a length of wire 10.34meters or 103.4 meters or 1.034meters.hope this helps