Data & Text Mode digital Radio

Data & Text mode Digital Radio Communication Data and Text mode digital radio communication has matured over the decades and now forms an important aspect not only of professional and commercial radio but is also an integral part of amateur radio. Radio amateurs have been in the forefront of the process of experimentation, development, and validation of workability and reliability of many of the digital communication modes that are in vogue today. The earliest text mode digital radio communication protocol that was used for effective long-distance radio communication of text messages was Radio-Teletype (RTTY). This was a straightforward and very basic mode that used binary FSK over a narrow baseband and was essentially an extension of cable teletype. However, even though there has been rapid evolution that brought in scores of new, more reliable, efficient, and robust protocols, RTTY still remains firmly entrenched to date. Whereas, with the advent of advanced technologies and computer algorithms and with the passage of time, several digital modes that came into being at one time often fell by the side only to be replaced... Click Here to Read Full Article […]

How to get started on ISS Cross band Repeater?

Getting started on ISS Cross band Repeater The new version of the ISS Cross Band Repeater had been activated on 2nd September 2020 at 01:02 UTC. Since it is still in the testing and deployment phase at the time of writing (October 2020) of this article, its service might currently be available on an intermittent basis. Nevertheless, this should be great news for millions of radio amateurs around the world as it is indicative of was is in store for us in the coming days. The ARISS program (Amateur Radio on International Space Station) has been active for many years. Under ARISS, a variety of amateur radio communication activities have been conducted at specified times as per declared schedules. Amateur radio operators around the world have made numerous FM radio voice contacts with astronauts onboard the ISS as well as received SSTV picture transmissions from the ISS. However, the above activities in the past required adherence to ISS activity schedules. Radio amateurs could make radio contacts with the astronauts but only when they were free to operate amateur band radios…... Click Here to Read Full Article […]

VHF/UHF & Free Space propagation

VHF/UHF & Free Space Propagation – A primer Radio wave propagation across the entire spectrum including VHF, UHF, and microwave primarily depends on the principles of Free Space propagation. As the radio waves propagate, they are subsequently acted upon by several other physical phenomena like reflection, refraction, diffraction, absorption, etc to modify their net behavior. It is therefore important to get a fair insight into the basic aspects of Free Space propagation. To brush up the above concepts, please check out our article on Fundamentals of Radio Propagation. In the case of VHF/UHF communication that is nowadays commonly trending amongst radio amateurs, quite often most of these modifier effects rarely come into play. The reason being that over the last 30 years or so, a large section of radio amateurs conduct VHF/UHF communication either on short-distance local point-to-point circuits or use repeaters which are at times trunked using hybrid methods like the internet based Echolink or similar platforms. Moreover, the general trend is to use FM radios. This makes propagation on these bands rather mundane and elementary and one is... Click Here to Read Full Article […]

World Order

World Order – The evolving economic trends The World Order is determined by sets of collectively agreed rules of engagement amongst nations that determine orderly trade transactions, allowing a smooth flow of goods and commodities. However, these rules evolve. Historically, we have witnessed a constant evolution of this world order over centuries. Needless to say, the more powerful nations typically use their clout to influence the rules of world order to their advantage. Very often we consider the military strengths of nations and their geopolitical clout to be the other notable influencers of world order. It may well be so… However, the most important core factor is the economic strength of each nation. Military strength as well as geopolitical influence cannot exist in a vacuum. They can only be built on top of a strong economy. Hence, economic strength is the lynchpin that holds the other dominoes of world order in place. If the economy of a nation strengthens, its military and geopolitical strengths also increase, and vice-versa. Therefore, let us take a journey through the evolution of global economic... Click Here to Read Full Article […]

Antenna Fundamentals

Introduction to Antenna fundamentals In this section, we will examine some of the fundamentals of radio communication antennas. Acquiring a sound knowledge of antenna fundamentals is very important. In a radio communication environment, for any station to function optimally it is very important to pay great attention to the antenna installation. Although every radio station hardware including the transmitter and the receiver are important but eventually when it comes to overall performance, it is the quality of the antenna that plays the most important role. As the saying goes… “A radio station is as good or as bad as the antenna it has”. Hence we will lay special emphasis to the principles of antenna fundamentals and without going into much mathematics, we will try to keep our discourse as intuitive and simple as possible. most types of antennas that we encounter in the real world are typically some kind of a standing-wave antenna. They are usually dipoles or some derivative or combination of a set of dipoles. One might ask at this stage that what about complex antennas like a... Click Here to Read Full Article […]

CW Radiotelegraphy – A Robust mode

CW Radiotelegraphy – A disaster surviveable mode CW Radiotelegraphy is the oldest mode of radio communication and yet perhaps the most robust mode available to mankind to date. CW Radiotelegraphy is an adaptation of the cable telegraphy based on the Morse code signalling method for text communication devised by Samuel Morse way back in the year 1837. After some refinements, Morse code could be used to communicate through uppercase alphabets, numerals, and several punctuation marks. The structure of the code has been intelligently designed to provide high efficiency by assigning shorter code sequences to the alphabets that were more frequently used in the formation of English language words and sentences. Marconi used the Morse code to conduct the historic maiden radio contact. The transmission of Morse code over the radio waves thereafter became the standard method of radio communication. All other modulation modes like radiotelephony etc came into existence much later. With the advancement in technology, many different modes of information modulation over the radio were developed over the centuries. However, Morse code transmission over the radio, despite its early... Click Here to Read Full Article […]

Radio Signal Modulation Principles

Introduction to Radio Signal Modulation For serving the purpose as a practical communication medium, the radio wave has to undergo a process of radio signal modulation. There are several ways of achieving the objective. For instance, we are all familiar with medium-wave and shortwave AM radio broadcast, or the FM radio that not only sounds better than typical AM broadcast radio but is also capable of stereophonic transmission. Then again, we have television broadcast transmissions that allow us to see motion pictures along with the synchronized sound. Other than these, messages are transmitted from one place to another for commercial use, military, maritime-mobile, aviation, space communication, telemetry, etc. The applications of radio communication are endless. We as radio amateurs have had the radio as a medium for almost a century in various forms and experimented with various aspects. We are all perhaps familiar with some of the fundamental aspects of the process of radio signal modulation. For instance, we are conversant with the terms Amplitude modulation (AM), Frequency modulation (FM), single-sideband modulation (SSB), etc. With the dawn of the digital... Click Here to Read Full Article […]

Radio Communication Microphones

Radio Communication Microphones – The Untold Story How to optimally set up and use a microphone in a radio communication environment? This is perhaps one of those questions that rarely tickle in the minds of radio amateurs. Their minds are usually preoccupied with, what they believe to be more pressing matters like selecting a latest-model of a jazzy transceiver, or a fancy accessory, etc… So, many people don’t even bother to think twice about a small thing like a microphone. Although the microphone might appear to be trivial, it actually, goes a long way in shaping the overall on-air performance and quality of the radio station. In this article, I will walk you through some of the important factors related not only to the selection of a microphone but also to its optimal placement in a ham-shack environment. Fortunately, most commercial manufacturers of radio transceivers include a suitable microphone as a standard accessory. Typically, these are handheld microphones with a PTT switch. While transmitting, a radio operator would hold the microphone close to his mouth and press the PTT to... Click Here to Read Full Article […]

Amateur Satellite Communications

Amateur Satellite Communications – An Introduction Amateur radio satellite communications present unique opportunities as well as challenges that are different from what we experience with terrestrial HF, or VHF/UHF. Let us examine the important aspects and get started. Although commercial and military satellite communications and other space applications involve several intricate technologies, we will focus on satellite communications systems related to amateur radio use. We have already touched upon some important aspects in our articles related to Space Radio Propagation and Earth Satellite Orbits. You are welcome to peruse these articles to familiarize yourself with some of these important aspects to get a holistic view of the underlying principles. Amateur space satellite communications began way back in the 1960s with AMSAT OSCAR series. The initial satellites only used analog linear transponders and telemetry beacons in Low Earth Orbits (LEO) that were nearly circular. However, with the passage of time, amateur radio satellites have expanded in variety by including digital modes, FM repeaters, DATV, etc. Although by and large most of the amateur satellites are still placed in LEO we also... Click Here to Read Full Article […]

EME Moonbounce communication

EME Moonbounce Communication – Getting Started Earth-Moon-Earth EME Moonbounce communication is a very fascinating aspect of amateur radio. This is the earliest application of earth satellite communication ever attempted by radio amateurs. Well before the first artificial earth-orbiting satellite was placed around our planet, the moon was used to bounce radio signals off its surface for establishing communication between radio stations on earth. Unlike the man-made artificial satellites that orbit the earth at relatively lower altitudes, the moon is a natural earth satellite that has the highest known altitude. Moreover, the man-made satellites are active and carry transponders and repeaters while the moon can only perform as a passive reflector thus adding far greater challenges. Successful attempts at bouncing radio signals off the lunar surface were done in 1953, however, the first successful two-way communication was established in the early 1960s. Ever since then, radio amateurs from around the world have been using the lunar surface to establish Earth-Moon-Earth (EME) Moonbounce communication. The earlier contacts were made using slow-speed CW and large antenna arrays were driven by transmitter output of... Click Here to Read Full Article […]