Tremolo (NF-Signal-Sinus modulieren, 2x 741)

Many motorised car aerials are not fully automatic in operation but are provided with a manual dashboard switch. Thls has a biased centre off position, and to raise the aerial it is necessary to hold the switch over to one side until the aerial is fully extended. To lower the aerial the switch is held over to the other side until the aerial is fully retrac- ted. It is quite easy to forget to lower the aerial when leaving the car, thus losing the vandal-resistant advantage of a motorised aerial.