Are HF Bands Really Dead during Low SSN at Solar Cycle Minima?

Low SSN Solar Cycle minima – HF bands dead? Too often we hear amateur radio operators complain about HF bands being dead during the low ebb of a solar cycle that causes low SSN. Really? Who says the bands are dead? Think again… Let us do a reality check. At the time of writing this post, it is November 28th 2019. We are passing through the cusp between solar cycle #24 and #25. The solar activity is at its rock bottom. The ionization density of the ionosphere is at a dismal low. Does it make HF radio propagation a challenge? Yes, it does… But it does not mean that the bands are dead?… Not Really. What really happens during the low SSN conditions is that HF band propagation openings that used to happen frequently are now less frequent. The duration of these openings to a particular DX destination becomes shorter. The strength of band openings becomes shallower. However, none of these means that the bands are dead or there is no propagation. All it means is that now HF DXing... Click Here to Read Full Article […]

Need We Fuss About Exact Antenna Bearing for HF DX?

Do we need to set eaxct antenna bearing for HF DX? While working distant stations on HF bands do we need to be fussy about the exact beam headings and antenna bearing for HF DX? The short answer is NO… Yet, with the availability of various software utilities available to us both as standalone applications or online services, we often tend to get carried away. Several amateur radio operators, unfortunately, believe that unless their directional antennas like the Yagi are pointing precisely at the DX location they would not receive optimum signals. This is far from the truth. Let us quickly examine why. Of course, what we are discussing here is notwithstanding the fact that for VHF/UHF terrestrial radio contacts across several tens of kilometers one would need to beam quite accurately. Not only because the beam flare-out is narrow at short distances but also because much higher antenna gains on VHF and beyond produce far narrower beams… However, right now, we concern ourselves only with HF antennas for DX contacts. People at times ask me, What is your Grid-square?... Click Here to Read Full Article […]

Is FT8 popularity growing at the cost of SSB Phone and CW?

Is FT8 growing at the cost of SSB Phone and CW? This is a million-dollar question. The debate on whether FT8 popularity is growing at the cost of SSB Phone and CW modes is raging across various social media platforms as well as other forums. Amateur radio operators with diverse individual preferences often have quite different and conflicting views on the matter. Some people tend to predict a doomsday scenario for traditional modulation modes while others justify it as a natural evolutionary process. On social media forums dedicated to ham radio, we constantly read about FT8 contacts being made in hundreds while very little is mentioned about the regular SSB radiotelephony, CW, or other traditional modes… It leaves an impression that by-and-large, the ham radio community might have embraced FT8 and consequently moved away from SSB phone and CW… At least, that’s the impression we get from what we read these days. Is the above assumption true? … Perhaps NOT! … Perhaps the majority of FT8 QSOs are done by radio amateurs who are relatively newer licensees, belong to the... Click Here to Read Full Article […]

Wire Antennas

HF Wire Antennas – A Primer When we speak about wire antennas, the first and foremost thought that comes to mind is the 1/2λ Dipole antenna. This is indeed a classic antenna that is not only used extensively by HF amateur radio operators but also by the shortwave broadcasters and various HF commercial radio communication stations around the world. Of course, there are a variety of other types of wire antennas not only mono-banders but multi-banders too. Most of these antennas are low cost while being easy to fabricate and deploy. The performance of wire antennas for HF terrestrial radio communication is also rather good and cannot be dismissed as trivial antennas. Most wire antennas are horizontally polarized due to their physical orientation. Although the surface wave (ground wave) range of these antennas is lower than the vertically polarized ones on account of horizontal linear polarization, the fact of the matter is that they leverage the properties of the ground (earth’s surface) underneath to provide excellent performance characteristics which are suitable for sky-wave ionospheric skip mode long distance (DX) propagation... Click Here to Read Full Article […]

Radio Transceiver S-Meter – Pitfalls to avoid

Radio Transceiver S-Meter – Lesser known facts An S-meter of an HF radio transceiver is a very important instrument on the rig and is used extensively for signal reporting by amateur radio operators while in QSO. However, unfortunately, its calibration accuracy appears to be on the lowest rung of priority for the commercial manufacturers of amateur HF radio equipment. The calibration of the S-meter of most HF transceivers (including several well-acclaimed rigs) is absolutely appalling, to say the least. However, on a brighter note, let us also acknowledge that some of the newer, and modern high-end transceivers that are becoming available these days rely heavily on SDR techniques and often extensively employ DSP to replace various receiver functions that were traditionally done using analog circuits. DSP functions bring to fore several advantages including a far more accurate implementation of S-Meter characteristic response. In this article we will unravel the mysteries, lies, and truth behind typical S-Meter behavior and also dwell into some of the common confusions that are sometimes created. From the perspective of HF amateur radio operators, the ramifications... Click Here to Read Full Article […]

Principles of Radiation

How does antenna radiation occur? The basic question before us is how does an antenna work? Why does antenna radiation occur? Why does a wire carrying RF current radiates to produce EM waves which travel through free space or the propagation medium across long distances? How does antenna radiation actually occur? There are many such related questions pertaining to the fundamental principles of the functioning of antennas. We will try to keep the discourse simple as we try to unravel the mysteries of antenna radiation. Does it mean that any wire carrying alternating current behaves like an antenna? The answer is both yes and no. Theoretically, when alternating current flows through a conductor (wire, pipe, rod, etc.) will potentially convert some of the electrical energy into electromagnetic (EM) wave radiation. How small or how large is the quantum of EM energy radiated from the conductor will depend on several factors which include the geometrical layout of the wire, length of the wire in relation to the wavelength (λ) or frequency (1/λ) of the AC excitation source, its proximity to another... Click Here to Read Full Article […]

Omnidirectional Antennas

Introduction to Omnidirectional Antennas In the literal sense, an Omnidirectional antenna is an antenna that radiates uniformly in all directions. However, in reality, the term Omnidirectional needs to be taken in the context of the communication application scenario. For instance, for an antenna in free-space like an antenna onboard an LEO satellite, one might expect it to radiate uniformly in all directions in 3D space, whereas, for terrestrial HF station it would be expected to radiate uniformly in all directions (360°) around the azimuth (horizontal plane). In yet another scenario of a ground station antenna for LEO satellite use, one would expect an omnidirectional antenna to not only cover 360° in azimuth but also at all elevation angles above the surface of the ground thus producing a hemispherical dome-shaped radiation pattern above the earth. Omnidirectional antenna classification is not based on any specific antenna design structure but is classified on the basis of the radiation pattern it creates. Based on the above introduction, one might expect the magnitude of gain in the desired directions would be perfectly uniform but that... Click Here to Read Full Article […]

Low SSN – Why do most Hams find HF Radio so difficult?

HF Radio communication so difficulties during Low SSN It is true that most ham radio operators around the world in their quest for DX on HF radio find it exceedingly difficult during low SSN conditions at Solat Cycle minimas. Currently, as I write, we are negotiating low SSN conditions as we are making a transition from Solar Cycle #24 to #25. I agree that the difficulties are much greater during this phase in comparison to the high SSN phase. However, the question that is often asked is, are the HF bands practically dead? … The short answer is NO! Can we still continue to make adequate radiotelephony SSB and CW DX contacts on HF during low SSN? YES! … Do we need to fall back on ultra-weak signal modulation modes like FT8 to survive? … NO! … Those of us who give up on SSB phone or CW and find ourselves limited to FT8 are certainly doing something horrendously wrong. Most probably, the ham radio station setup is unsatisfactory… Hold on! I hear some readers saying, what nonsense are you... Click Here to Read Full Article […]

Urban Antenna Height above ground – Facts & Myths

Urban antenna height above ground – The truth The antenna height above ground, especially in urban areas on the HF bands, poses a set of unforeseen issues that an average radio amateur is often blissfully ignorant about. An experienced operator knows all this too well but a large section of our community is often unaware of several kinds of radiation lobe pattern distortions and reduction in overall antenna efficiency that occur due to the presence of various natural geographical artifacts and man-made entities like buildings, sheds, bridges, overhead cables, water-pipes, etc that cause havoc. Despite a seemingly good antenna height, the most common problems that usually plague a typical urban antenna installation are considerable distortion in the radiation pattern. The textbook lobe patterns and gain figures of antennas may not hold true anymore. The second casualty is the overall efficiency of the antenna as a radiator. The nearby building structures and objects within the near-field zone of the antenna often absorb a certain amount of transmitter energy and may also alter the resonance and spoil the attainable SWR. I have... Click Here to Read Full Article […]

SSN, SFI, Solar Data for HF Propagation

SSN, SFI, Solar Data for HF Radio Propagation Here are some of the important Solar activity parametric data that are responsible for influencing the behavior of the Ionosphere on earth. These, in turn, are instrumental in determining HF radio propagation conditions on various bands. The information presented here is automatically updated on a regular basis. The data-set is presented in two formats below. They are the graph format and a tabular metrics format. The graph which displays the history of measured SSN and SFI derived SSN – SSNf(10.7) that prevailed over the last 60 days is updated once a day, while the Solar terrestrial data metrics table is updated on an hourly basis. This page also explains each and every Solar Data Parameter that we have covered here so that amateur radio operators irrespective of their technical understanding could get a reasonable insight into how HF radio propagation on Earth is influenced by the Sun’s activity. This way, one can watch for changes in various critical parameters and make an informed decision related to HF radio band opening prospects. Why... Click Here to Read Full Article […]