VHF Propagation Path Profiler – Web App

Terrestrial VHF Propagation Path Profiler The VHF Propagation Path Profiler presented here is a comprehensive application that allows us to graphically render and mathematically compute various relevant VHF/UHF propagation metrics including VHF propagation path losses, over the realistic terrain profile between any two point-to-point locations on the surface of the earth. The true terrain topological profile including hills, valleys, terrain undulations, etc accounted for. The VHF/UHF signal diffraction over various features of the terrain profile is included in the computation. Moreover, the nature of the TX and RX sites in terms of the built-up area resulting in structural clutter is also taken into account. For graphical signal path rendering and numerical computations over the terrain profile, not only the terrain topology but also the terrain bulge due to the curvature of the earth is factored into the computations. Various input variables like the antenna height over ground, their gain, etc can be set. The frequency band and the TX power levels are also settable. This signal path rendition is not an over-simplified straight line that some people often assume but... Click Here to Read Full Article […]

Elements of Amateur Radio Station

Amateur Radio Station (Ham Shack) A thoughtfully set up amateur radio station (Ham Shack) goes a long way to provide a pleasant and fulfilling experience for years at the end, in the world of amateur radio. Not only does a meticulously planned and well-configured station allow a person to enjoy the hobby to the fullest, but it also ensures adequate flexibility and scalability so that one may continue to upgrade his station without having to make drastic alterations to keep pace with the advancement in technology. This is notwithstanding the fact that a lot of amateur radio activity is also conducted using portable, field, or mobile equipment. A typical amateur radio station comprises two sets of hardware. They are a set of outdoor hardware comprising of the antenna and related stuff and a set of indoor hardware that comprises the transceivers and associated peripherals. The outdoor and the indoor hardware are interconnected through a transmission line that forms a very vital part of the overall radio station setup, however, unfortunately, it is often taken for granted and treated as trivial.... Click Here to Read Full Article […]

Solar Activity and Ionosphere

Solar activity and its influence on Ionosphere The most exciting and intriguing aspect of radio propagation is Solar activity leading to the creation of the Ionosphere on earth. The entire universe including our Solar system presents us with countless gigantic physical phenomena that continually occur on a real-time basis. In our planetary system, the Sun is the focal point that influences almost all aspects of our life on earth. In this article, we will briefly focus on some of the mysteries of mother nature that make HF radio communication possible. Without these effects that determine how the upper atmospheric structure of the earth is shaped, not only would the HF radio have been non-existent but perhaps there would have been no life on earth. Our sun is a very large celestial body acting as the central pivot of our solar planetary system. It is a continuous source of energy that reaches all planets. The energy released by the sun is multi-faceted and wide-spectrum. This includes electromagnetic radiation across RF, heat, light, X-rays, etc and also sub-atomic particles including electrons, protons,... Click Here to Read Full Article […]

100W on a Wire Antenna – How far would it reach?

100W on a Wire Antenna – Is it good enough for DX? 100W on a Wire antenna! … How far could it possibly reach? This is perhaps one of the most hotly debated rookie topics in the world of amateur radio. It has always been like this and it would always be the same. A radio amateur who has been newly initiated into this field takes a while to come to terms with reality. Intuitively, it becomes very difficult for a rookie operator to even imagine that 100W on a Wire might be more than adequate to communicate around the entire world. At times, a station with a plain-Jane dipole antenna and running as low as 5-20W may comfortably work the world. When I say this, I do not mean working via weak-signal digital modes like FT8, FT4, etc. The operating situation cited above refers to radiotelephony SSB QSO. However, for all this to be viable on a reasonably regular basis, there are a few fundamental prerequisites. First of all, the station operator would need to acquire a fair understanding... Click Here to Read Full Article […]

Ground Wave Propagation

Is it Ground Wave or surface Wave propagation? Both the terms ground wave propagation, as well as surface wave propagation, are relevant. However, we often tend to use them interchangeably and loosely, which is technically incorrect. There is a difference between the two. When most radio amateurs use the term groundwave, it is actually the surface wave that they usually refer to. So, what is the difference between the two terms? Technically, the ground wave is a term used to represent a combination of several subtly different propagation modes. These include the Direct wave mode (LOS mode), surface reflected mode and also the true surface wave. In other words, the Surface wave is only a sub-set of the multi-faceted propagation mode that we collectively call the Ground wave. In this article, we will examine various modes comprising of the Ground wave with special emphasis on the Surface Wave which is quite unique and special with a propagation method that is so different from the others. The properties of the surface waves make them very useful for establishing robust, reliable and... Click Here to Read Full Article […]

Multiband End-fed Half-wave EFHW Antenna

Multiband End-Fed Half-Wave EFHW Antenna The End Fed Half Wave antenna or the popularly known EFHW antenna has been around almost ever since the inception of HF radio. Nevertheless, the EFHW antenna had in the past, been rather sparingly used by amateur radio operators due to various reasons. Although it is simple to build and is a multiband antenna, it has several attributes that make its overall performance far less than optimum for any serious HF DX operator’s liking. However, in the present day and age, thanks to many commercially manufactured EFHW antenna available in the market, more and more radio amateurs, especially the newcomers to HF communication are opting for this antenna despite its numerous shortcomings that can only be partially mitigated to acceptable levels by careful adjustments and tweaks that could be done by a knowledgeable and seasoned operator. A rookie operator, on the other hand, might most probably not even be aware of these shortcomings, let alone knowing ways and means of addressing them. Despite this many people take a plunge into amateur HF radio, armed with... Click Here to Read Full Article […]

Fundamentals of Radio Propagation

An Introductory Primer on Radio Propagation A good understanding of various radio propagation phenomena is vital to leverage propagation conditions to one’s advantage in establishing radio communication. Radio wave propagation is perhaps as important as the clarity on antenna performance and behavior. On our website, we have several in-depth articles that dwell on most of the important propagation phenomena. However, in this introductory article, we will introduce the readers to some of the fundamental building blocks that would be helpful in following the narrative in our other articles related to radio wave propagation. Over here, we will touch upon several concepts related to not only HF radio but also VHF and UHF. In any form of communication scenario over geographic space, the transmission of a signal from one point to another is the fundamental objective. Radio communication systems achieve this objective by exploiting the transmission and propagation behavior of their primary propagation medium which is the free space. The radio waves or the electromagnetic (EM) waves travel through the atmosphere above the earth from one point to another across the... Click Here to Read Full Article […]

Does Coaxial Cable Choke at Antenna cut RF Noise?

Coaxial cable choke and RF common-mode noise Is it really true that a section of coiled coaxial cable choke at antenna feed-point would effectively cut down the radio RF noise substantially? Will the perceived reduction be enough to make operating especially on the lower frequency HF bands a pleasure? These are some of the questions that come to mind. Well, there are a multitude of opinions with many people suggesting that it is indeed worthwhile. Let us impassionately and realistically examine the effects of such coiled coaxial cable chokes that are often used near the antenna feed-point and figure out with rational scientific logic if they are truly as effective as one might be made to believe… At this point, some readers may feel impatient and say, stop beating about the bush, give us the bottom line… OK, the bottom line is NO! they don’t work well enough to feel jubilant or elated. Especially, on the lower HF bands like the 80m, or 40m. Even on the other higher frequency HF bands, they don’t perform as well as one might... Click Here to Read Full Article […]

5 Stages of Grief – Collapsing Hegemony

5 Stages of Grief – Collapsing Hegemony The 5 Stages of Grief that seems to be setting in with the gradual collapsing hegemony of the west are akin to the famously described 5 stages of grief by the renowned psychologist Elisabeth Kubler Ross in her 1969 book “On Death and Dying”. Of course, the psychological state of mind that she described was in the context of the death of a person or impending death due to a terminal illness. Nevertheless, her postulates appear to be quite applicable to the current ongoing global phenomenon of the gradual death of the unipolar system and collapsing hegemony. According to Elisabeth Kubler Ross, persistent, traumatic grief can cause us to cycle (sometimes quickly) through the 5 stages of grief: Denial, Anger, Bargaining, Depression, and Acceptance. These stages are a part of our coping mechanism and our attempts to process change and psychologically protect ourselves while we adapt to a new reality. The 5 stages of grief define the 5 distinctive phases where they start in a Denial mode whereby refusing to acknowledge the hard... Click Here to Read Full Article […]

Miscellaneous Antennas

Classic miscellaneous antennas for communication Under our section on Miscellaneous Antennas, we will cover a variety of well-known antennas that do not typically fall under the genres like Yagi, Quad, LPDA, Wire Antennas, etc. These antennas are good and efficient antennas often used by radio amateurs as well as for various commercial and military applications. Some of these miscellaneous antennas are Cardioid pattern antennas, Four Square, Lazy-H, W8JK, ZL special, Moxon, Cobweb, Hex-beam, Bruce array, Bobtail curtain, etc to name a few. Many of them are multi-band antennas while others are mono-banders. Some of these antennas have quite unique characteristics with great performance. This is only an introductory article. However, under this section, we will from time to time expand upon them through in-depth articles and dwell into greater depths discussing their design principles, characteristics, and practical designs. Another antenna that is designed by yours truly, called the ‘VU2NSB OmniDX” antenna will also be presented. BTW, the list of antennas cited here is by no means exhaustive. These are only a selection of popular antennas in the miscellaneous category. Other... Click Here to Read Full Article […]