Amateur Radio is a fascinating hobby with many facets that can be practised by all amateurs alike. All the different things that make up this hobby culminate in contacting other persons with the same basic interest and, above all, the contacts made will contribute towards friendship and goodwill to each other. In these times of stress and strife, we all need to make friends more than ever before, and we can only promote goodwill by being on our best behaviour whenever we pick up the microphone, the Morse key or use a computer in Amateur Radio. Politeness is the key to good operating. In the same way that we have Traffic rules for road usage, and the Law of the Land for the good of the community, so there are Regulations and Operating Procedures governing our hobby, designed for us to obey, in order to make it easier to live with our fellow man. Both are designed to make our hobby such a pleasure.
Although the double-tuned circuit is popular with Amateur Radio experimenters, its response can sometimes be misleading. Here's how to evaluate and adjust double-tuned circuits for maximum performance. The double-tuned circuit, among the most common filters found in radio equipment, consists of two tuned circuits, or resonators, that are coupled together, allowing energy in one to be shared with the other. Designing a double-tuned circuit for use at HF and below is not difficult,' yet builders commonly encoun ter practical difficulties in building and adjusting the double-tuned circuit, especially at VHF and above. The result may be a circuit that does not meet the filtering goal. Although HF double-tuned circuits differ greatly in physical appearance from those built for microwave frequencies, all double-tuned circuits share many similarities. This tutorial emphasizes their universal properties.
All of them use the DPLL and a digital output which produces a square wave. However, a square wave would not meet the FCC regulations on spurious emissions because of the odd harmonics that turn the fundamental sine wave into a square wave. A sharp filter is necessary to reduce the unwanted harmonics that make up a square wave. Paragraph That requirement jumps to 60 dB below the fundamental emission for frequencies between 30 and MHz.
A ham radio has usually zillions of buttons and knobs and dials on its front panel. To the neophyte, those just look very confusing and unhelpful. This script aims to clarify some of this jargon for you. Controls the amount of pre-amplification in the RX before the first if stage is reached. In some radios, if this is zero, almost no signal will reach the speakers and you will not able to hear anything.