--By Thomas Witherspoon If you’re following the new Xiegu X6200 closely, you might recall that I took a prototype version of the radio out two weeks ago for a POTA activation. Propagation was so challenging–as in, a complete radio blackout in North America due to an X-Class flare–it took about 90 minutes of calling CQ POTA to snag the ten needed for a valid park activation. I had planned to post the activation video on YouTube, but learned shortly after the activation that this particular unit was a proper prototype instead of an early production run radio. This is a detail I misunderstood prior to the unit shipping. I only shared the 2+ hour video to Patreon supporters, but not on my YouTube channel for this reason. Production This past weekend, I received a second Xiegu X6200: this time, a production run unit! POTA Time! Two days ago–Tuesday, June 11, 2024–I took the new X6200 out for a POTA activation on the Blue Ridge Parkway (US-3378). I had a couple of hours that morning to fit in the activation, including a round trip from the QTH. The best site for a quick activation was the Folk Art Center picnic area. Thanks to the early hour, there was no competition for picnic tables. I decided to pair my PackTenna 9:1 End-Fed Random Wire with the X6200. This provided a chance to test the ATU with a readily matchable antenna (in the future, I’ll make it sweat a bit more by using a transformerless random wire antenna). This production run X6200 has the same firmware (version 1.0) as the prototype, but the hardware has received noticeable updates. I spotted two changes–one cosmetic and one that had a positive impact on performance–almost immediately. In the activation video below, you’ll see that I spent a few minutes doing an overview of the X6200. One of the first things I did was set up the X6200 for CW Message memory operation. I demonstrated (after a bit of head-scratching) how to input the CW message using the X6200’s built-in on-screen keyboard. (If the CW Message Memories confuse you, check out the short primer in my previous post). Gear: X6200 via RadioddityPacktenna 9:1 UNUN Random Wire Antenna ABR Industries 25’ RG-316 cable assembly with three in-line ferritesKey cable: Cable Matters 2-Pack Gold-Plated Retractable Aux Cable – 2.5 Feet Begali Traveler GoRuck GR1 USA Weaver arborist throw line/weight and storage bag GraphGear 0.9mm 1000 Automatic Drafting Pencil Rite In The Rain Top Spiral Notebook Camera: DJI OSMO 4 action camera with Joby Telepod Sport Tripod DJI Wireless Microphones On The Air The last time I hopped on the air with the X6200, it was proper work making any contacts. It was a struggle and it wasn’t the X6200’s fault. It was our local star! I decided to start on 40 meters since it was still mid-morning. After calling “QRL?” and hearing no reply, I pressed the second CW message memory button where I loaded “CQ POTA DE K4SWL” and the radio started transmitting. After only a few calls, I started receiving replies–woo hoo! I ended up working my first ten contacts in nine minutes. Excellent! I then logged seven more stations for a total of 17, then QSY’d to the 30 meter band. Turns out, 30 meters was also pretty healthy. I worked a total of ten more stations. Success! This brought my total to 27 contacts in 39 minutes (noting that eight minutes of that was me chatting with the camera between band changes). Overall, excellent results! I had hoped to have enough time to give SSB a go, but I simply didn’t. Still, CW was the mode I was most interested in testing. QSO Map Here’s what this five-watt activation looked like when plotted out on a QSO Map: Here’s a close-up since these contacts were clustered together: Activation Video Here’s my real-time, real-life video of the entire activation. As with all of my videos, I don’t edit out any parts of the on-air activation time. In addition, I have monetization turned off on YouTube, although that doesn’t stop them from inserting ads before and after my videos. Note that Patreon supporters can watch and even download this video 100% ad-free through Vimeo on my Patreon page: Click here to view on YouTube. First Impressions The X6200 definitely held its own during this activation. While I didn’t have pileups, per se, there were times when there were competing stations on frequency. The internal speaker’s audio quality isn’t exactly exceptional (I think it’s a bit weak) but then again few QRP field radios have exceptional speaker audio fidelity–the Icom IC-705, Yaesu FT-818, and Penntek TR-45 being three notable exceptions. As I expected, the ATU easily handled the PackTenna 9:1 UNUN EFRW. Of course, the 9:1 is easy to match even with mediocre ATUs. This Tufteln random wire antenna has no transformer, thus will be a great test for the Xerox 6200’s ATU. Soon, I will test the ATU with more challenging wire antennas, but I suspect it’ll match them. Xiegu is known for having exceptional, wide matching-range ATUs. As noted, there is still a bit of a keyer timing issue, but Xiegu is working on that and, as I say in the video, I know they’ll sort that out since they did on their previous radio models. Also, only minutes prior to publishing this report, I heard that Xiegu will make it possible to change the default filter widths of the three filter options in the next firmware update. Good news indeed. The X6200 battery also seemed to hold up well for the full activation. If I recall correctly, it still had roughly ⅔ of the battery capacity (7.9V) at the end of the activation. I plan to take this loaner X6200 on various field excursions over the next few of weeks or until Radioddity asks for it to be returned. I’ll do my best to handle it with care, but I fully intend to put it through its paces with some POTA and even SOTA activations in CW, SSB, and possibly (if you can believe it) in FT8. I’d really love to see how it handles SOTA DX pileups. As I mention in the video, I’ll give a full, detailed review of the X6200 likely in an upcoming issue of The Spectrum Monitor magazine. Xiegu tends to roll out a lot of updates early in the product life cycle, so I expect numerous firmware updates ahead. I’ll always mention in the field report what firmware version I’m running. Thank you… Thank you for joining me during this POTA activation with the X6200! I hope you enjoyed this field report and my activation video as much as I enjoyed creating them! Thanks for spending part of your day with me! Cheers & 73, Thomas (K4SWL)

In the evolving world of radio communication, RF (Radio Frequency) technology remains at the core, facilitating seamless data transmission across long distances. Among the various innovations, RF Direct Sampling has emerged as a pivotal shift in radio receiver design, offering a fresh perspective on signal processing. This blog gives an overview of RF Direct Sampling—exploring its essence, operational principles, pros and cons, and its application in Icom models. Additionally, we unveil the new Xiegu X6200, a groundbreaking product that leverages this new technology. What is RF Direct Sampling? RF Direct Sampling is an advanced technique used in radio communication systems. Traditional RF systems rely on heterodyne or superheterodyne architectures where the received RF signal is first mixed with a local oscillator signal to convert it to a lower intermediate frequency (IF). This IF signal is then sampled and processed. However, RF Direct Sampling simplifies this process by directly digitizing the RF signal, bypassing the need for frequency conversion to IF. The Simple Principle Behind It The principle behind RF Direct Sampling is simple yet revolutionary. Its components include a low-noise amplifier (LNA), specific filters, and a high-speed analog-to-digital converter (ADC). By using a high-speed analog-to-digital converter (ADC), RF signals can be directly sampled at their operating frequency. From there, digital signal processing (DSP) techniques are applied in a Field-Programmable Gate Array (FPGA) or similar processing unit to extract the desired information. This method eliminates the need for various mixers, filters, and amplifiers typically found in traditional receivers. Advantages of RF Direct Sampling The RF Direct Sampling approach offers several benefits: -Improved Signal Integrity and Quality: Direct sampling reduces the number of conversion stages, minimizing noise and distortion. This results in a cleaner, high-fidelity signal closer to the original RF wave, enhancing the user's listening experience. -Reduced Complexity: By eliminating multiple mixer and local oscillator stages required in superheterodyne designs, RF Direct Sampling simplifies the receiver's architecture. This can increase reliability, reduce points of failure, and lower production costs. -Wide Frequency Coverage: Instantaneous wide band reception allows for receiving a broad spectrum of frequencies simultaneously, beneficial for software-defined radios (SDRs) processing multiple frequencies at once. -Enhanced Dynamic Range: High-resolution ADCs used in direct sampling offer a greater dynamic range, enabling the receiver to handle strong and weak signals without distortion or overload. -Flexibility and Future-Proofing: Digital signal processing (DSP) flexibility enables updates and improvements via software, extending the equipment's lifespan and enabling new features without hardware changes. Disadvantages of RF Direct Sampling Despite its benefits, RF Direct Sampling does come with its own set of challenges: -Higher Initial Cost: Implementing RF Direct Sampling requires advanced hardware such as high-speed analog-to-digital converters, which can be expensive initially. -Complex Filtering and Processing: Robust digital filtering is necessary to avoid aliasing when directly sampling the RF spectrum, requiring substantial processing power and potentially increasing device costs and power consumption. -Thermal Considerations: High-speed ADCs and subsequent digital signal processing units generate heat, necessitating effective thermal management to maintain performance and prevent damage, potentially complicating device design. Icom's Pioneering Models Icom, a premier name in radio technology, embraced the power of RF Direct Sampling early on, integrating it into their renowned models. One such model is the IC-7300, a trailblazer that has redefined the standards for HF rigs. Its high-performance RF Direct Sampling system offers superior RMDR (Reciprocal Mixing Dynamic Range), perfectly balancing simplicity and cutting-edge performance. With its real-time spectrum scope and a large touch screen color TFT LCD, it offers an intuitive, immersive experience for users. Then there's the IC-9700, a true embodiment of versatility. Designed explicitly for VHF/UHF enthusiasts, it's the first transceiver in its class to employ RF Direct Sampling. The IC-9700 provides a host of advanced features, including dual watch operation and satellite mode, bringing a new level of excitement and convenience to VHF/UHF operating. Introducing the Xiegu X6200 In the ever-changing landscape of radio technology, the Xiegu X6200 emerges as a beacon of innovation. This cutting-edge shortwave transceiver harnesses the power of RF Direct Sampling to deliver unparalleled clarity and versatility in communication. Designed for amateur hobbyists and seasoned professionals, the X6200 combines a sleek, compact form with a suite of advanced features that promise to elevate the radio experience to new heights. A Revolution in Connectivity At the heart of the X6200 lies a commitment to excellence. Direct digitization allows for a cleaner, more precise signal, offering users a level of performance previously unattainable in traditional setups. This, coupled with its broad frequency coverage, ensures that the X6200 is not just a tool for communication but a gateway to a world of exploration. Compact Powerhouse Despite its modest size, the X6200 packs a formidable punch. Its design reflects a meticulous attention to detail, integrating state-of-the-art technology in a portable package. This transceiver is not just about making connections; it's about breaking barriers, offering flexibility and power in scenarios ranging from remote field operations to the comfort of your own home station. Your Companion into the Future The Xiegu X6200 stands as more than a piece of equipment; it represents a forward leap in the journey of RF communication. With its blend of innovation and practicality, it not only meets the current demands of the RF community but anticipates the needs of tomorrow. Whether you're engaging in complex digital modes or simply enjoying the purity of SSB operation, the X6200 is your steadfast companion, ready to explore the vast and dynamic world of radio waves.   Conclusion RF Direct Sampling represents a monumental leap forward in radio communication technology. Despite its inherent challenges, the undeniable advantages of streamlined design, enhanced performance, and expanded frequency coverage underscore its transformative potential. By revolutionizing the landscape of RF signal processing, RF Direct Sampling seamlessly blends simplicity, performance, and cost-effectiveness. With the unveiling of the Xiegu X6200, we eagerly anticipate our role in advancing RF communication and providing enthusiasts with cutting-edge solutions. Are you ready to embrace the dawn of RF technology's future? Dive into RF Direct Sampling and witness its transformative impact on your communication systems. With its numerous benefits and widespread adoption, RF Direct Sampling isn't just a fleeting trend – it signifies the evolution of RF processing, inviting you to explore its boundless possibilities.

Imagine this: you're at home with your Radioddity HF radio, and suddenly, you're chatting with someone across the globe! HF radio has this incredible power to connect us over vast distances, transcending geographical boundaries. But here's the catch: HF radio relies on the Earth's atmosphere for signal propagation, specifically a layer called the ionosphere. This means our beloved hobby is intimately intertwined with the whims of the weather. Understanding this connection is key to unlocking the full potential of HF radio, especially for Radioddity enthusiasts who seek those long-distance connections. Credit: Homa Pilot In 2024, solar activity has been particularly noteworthy, influencing HF radio communication in significant ways. Increased solar flares, sunspots, and other solar events have led to a more dynamic and sometimes unpredictable ionosphere. For instance, several solar flares and coronal mass ejections (CMEs) have caused temporary disruptions and enhancements in HF propagation. Additionally, geomagnetic storms triggered by these solar events have led to both stunning auroras and challenging communication conditions, particularly in polar regions. Staying informed about these solar activities and their impacts on the ionosphere is more crucial than ever for HF radio operators. Let's embark on a journey to uncover the dynamic relationship between nature's elements and radio waves, paving the way for optimized connections through popular transceiver models like the X6200, X6100, G90, and G106. HF Radio and the Atmosphere: A Quick Explanation Think of the ionosphere as a giant, invisible mirror in the sky. When you transmit on HF frequencies, your signal bounces off this "mirror" and returns to Earth, potentially reaching receivers thousands of miles away However, this atmospheric mirror is anything but static. Its reflectivity constantly changes due to several factors: · Solar Activity: Increased solar flares and sunspots mean a denser, more reflective ionosphere, leading to better HF propagation. · Time of Day: The ionosphere weakens at night without the sun's energy, affecting signal strength and range. Nighttime often means shorter-range communication. · Seasonal Changes: Just as our weather has seasons, so does the ionosphere. These variations influence HF conditions throughout the year. Credit: Carlos Molina Now, let's add the dramatic effects of meteorological events into this mix! Meteorological Events: HF Radio's Unseen Players Thunderstorms: More Than Just a Light Show We all know the power of thunderstorms—the crackle of lightning and thunder's roar. But for HF radio operators, these storms bring their own set of challenges: · Lightning Interference: Those spectacular lightning discharges are bursts of radio noise. This noise can drown out weak HF signals, leading to static interference and making communication difficult. · Disrupting the Mirror: The immense energy released during thunderstorms can cause fluctuations in the ionosphere. These disturbances affect signal reflection, leading to fading and making it hard to maintain stable communication. Sporadic E: Summertime Surprise As days grow longer and temperatures rise, a peculiar phenomenon called Sporadic E appears in the ionosphere. · Patches of Reflection: Think of Sporadic E as temporary, dense patches of ionization forming in the lower ionosphere. These patches can reflect signals at higher frequencies than usual. · Double-Edged Sword: While this can temporarily extend your HF communication range to unexpected locations, it also increases the likelihood of interference from stations operating on different frequencies. Sporadic E can be both a blessing and a curse! Solar Storms: A Force From Above Though not a traditional meteorological event, solar storms deserve mention due to their profound impact on HF radio. · The Sun's Energy Boost: Solar flares, bursts of energy from the sun, can supercharge the ionosphere. This can lead to unusually long-distance propagation, making HF connections exceptionally good. · The Downside of Energy: However, this increased energy also brings higher levels of solar noise and can cause temporary HF communication blackouts. Credit: theweek.in Geomagnetic Storms: Auroras and Blackouts Triggered by intense solar activity, geomagnetic storms are disturbances in Earth's magnetic field and often adversely affect HF radio. · The Dazzling Side-Effect: While visually stunning, the beautiful auroras seen during geomagnetic storms are indicators of significant ionospheric disturbances. · Radio Silence: These disturbances can lead to significant HF radio blackouts, particularly in polar regions. During intense geomagnetic storms, HF communication in affected areas may become impossible. Solar Eclipses: A Unique Phenomenon Though rare, solar eclipses also have unique effects on HF radio propagation. · Temporary Night: During a solar eclipse, the moon blocks sunlight, causing a temporary night-like condition in the region of totality. This sudden change impacts the ionosphere in notable ways: · Ionospheric Cooling: Without the sun's radiation, the ionosphere cools and ionization levels decrease, making it similar to nighttime conditions. This can cause HF signals to weaken or fade, leading to unstable communication paths. · Experimental Opportunities: Solar eclipses present a unique opportunity for radio enthusiasts to study ionospheric behavior under these transient conditions. Observing how HF propagation changes during an eclipse can provide valuable insights into the ionosphere dynamics. Sunspots: Solar Activity and HF Communication Sunspots, regions of intense magnetic activity on the sun's surface, have a profound impact on HF radio communication. Band-Specific Effects: Sunspots and HF Bands · Higher Bands (15m, 10m): These bands benefit significantly from increased sunspot activity. Enhanced ionization improves signal reflection, allowing for more reliable and longer-distance communication. · Lower Bands (80m, 40m): While these bands are less affected by sunspot activity, they can still experience improved propagation during periods of high solar activity. However, they are more susceptible to noise and interference. Solar Cycle 25: A New Era of HF Communication We are currently in Solar Cycle 25, which began after the solar minimum in December 2019. This cycle is expected to peak in 2025, offering exciting opportunities for HF communication, especially on higher bands like 10m. · Current Cycle: Solar Cycle 24, which ended in 2019, was the weakest cycle in 100 years, with a peak sunspot number of 114 in April 2014. Solar Cycle 25 is anticipated to bring increased sunspot activity, enhancing HF propagation conditions. · Historical Context: Solar Cycle 24 had an unusual progression, with the Northern Hemisphere peaking two years ahead of the Southern Hemisphere, resulting in fewer sunspots during the maximum phase. Introducing the QT Series If you want to follow Solar Cycle 25 and experience the joys of HF communications while taking advantage of the benefits of solar activity, here are two of Radioddity's 10-meter radios. QT40: Classic Design, Modern Performance The Radioddity QT40 is a powerful 10-meter radio, ideal for long-distance communication. · 40W Transmission Power: Delivers crystal-clear communication over long distances. · Noise Reduction: Ensures clear audio in noisy environments. · Weather Channel: Stay updated with weather bands and NOAA alerts. · Customizable Features: Includes CTCSS/DCS, PC programming, ASQ, SQ, RF gain, VOX, and HI-CUT. QT60: Versatility for Enhanced Communication The Radioddity QT60 is a high-power 10-meter radio, perfect for those needing robust performance and versatility. · 60W High Power: Enhances your communication experience. · Diverse Modes: Includes FM, AM, SSB (LSB & USB), and PA modes. · User-Friendly LCD Screen: Easy access to menu choices and crucial information. · Customizable Noise Reduction: Five levels of TX & RX noise reduction. · ASQ Function: Filters out background noise for clear communication. Understanding RF Propagation: The Science Behind the Magic HF radio communication is deeply intertwined with the principles of RF propagation. Understanding these principles can help operators better predict and adapt to changing conditions. Ground Wave Propagation: Close to Home · Hugging the Earth: Ground wave propagation involves HF signals traveling along the Earth's surface. This mode is particularly effective at lower frequencies and over short to medium distances. · Terrain and Obstacles: The effectiveness of ground wave propagation can be influenced by terrain, vegetation, and man-made structures. Smooth, conductive surfaces like seawater enhance ground wave propagation, while rough, obstructive terrain can weaken the signal. Sky Wave Propagation: Reaching for the Sky · Ionospheric Reflection: Sky wave propagation relies on the ionosphere to reflect HF signals to Earth, enabling long-distance communication. The ionosphere's various layers (D, E, and F) play crucial roles in this process. · Variable Conditions: The state of the ionosphere is affected by factors such as solar activity, time of day, and season. Operators must be aware of these variables to optimize communication paths. Line-of-Sight Propagation: Beyond HF ·Higher Frequencies: While more relevant to VHF and higher frequencies, line-of-sight propagation is a straightforward concept where signals travel directly between antennas without relying on reflection. ·Obstacles and Range: The range of line-of-sight communication is limited by the curvature of the Earth and obstacles like buildings and mountains. However, it provides reliable, interference-free communication within its range. Line-of-Sight Propagation: Beyond HF The interplay between HF radio waves and the ionosphere makes HF communication a dynamic and sometimes unpredictable endeavor. By understanding the impact of meteorological events and the principles of RF propagation, operators can better navigate the challenges and opportunities presented by the ever-changing environment. Radioddity Users: Tips for Weather-Resilient HF So, how do we, as Radioddity users who love HF, adapt to these ever-changing conditions? ·Stay Informed: Knowledge is power! Regularly check space weather forecasts (NOAA's Space Weather Prediction Center is an excellent resource) and real-time propagation reports to anticipate potential disruptions. ·Embrace the Change: Be ready to adjust your approach: - Frequency Agility: Don't be afraid to switch frequencies if you encounter interference. Experimenting is part of the fun! - Digital Modes: Explore the resilience of digital modes like FT8. These modes are designed to cut through noise and fading, offering more reliable communication during challenging conditions. ·Patience, Patience, Patience: Most importantly, remember that HF conditions are always in flux. What doesn't work now might be perfect in a few hours. Embrace the dynamic nature of HF radio, and you'll be rewarded with incredible experiences. Conclusion HF radio communication is a captivating blend of technology and nature's forces. By grasping how weather, the ionosphere, and radio waves interact, we become more than just operators - we become HF explorers! At Radioddity, we want to empower you to venture confidently into the world of HF. We encourage you to embrace the adaptability HF requires, stay curious, and never stop exploring the magic of connecting with the world through the airwaves.

　 What is HF radio? Known as the decameter band or decameter wave, high frequency (HF) is the ITU designation[1] for the range of radio frequency electromagnetic waves (radio waves) between 3 and 30 megahertz (MHz). The HF band is a major part of the shortwave band of frequencies, so communication at these frequencies is often called shortwave radio. Because radio waves in this band can be reflected back to Earth by the ionosphere layer in the atmosphere – a method known as "skip" or "skywave" propagation – these frequencies are suitable for long-distance communication across intercontinental distances. The band is used by international shortwave broadcasting stations (2.310 - 25.820 MHz), aviation communication, government time stations, weather stations, amateur radio and citizens band services, among other uses. Different from VHF (Very High Frequency - 30MHz-300MHz) and UHF (Ultra High Frequency - 300MHz-3GHz) radios, HF radios cover far greater distances thanks to ionospheric refraction – but the HF radio signals are prone to distortion by atmospheric conditions such as geomagnetic storms or solar flares that radio users cannot control. HF communications are best suited for long distance communication between ground operators and base stations. Some HF radios normally cover HF band only, like the Xiegu G106, Xiegu G90, Xiegu X6100. 　 What about VHF/UHF radios? VHF radio waves operate in a band between 30-300 megahertz, while UHF radio signals are propagated within 300 megahertz and 3 gigahertz. These radio waves travel over line of sight, making them ideal for local communications over a few kilometres. Indeed, VHF radio waves normally travel within line of sight along the Earth’s surface. Common uses for VHF are FM radio broadcasting, television broadcasting, two way land mobile radio systems (emergency, business, private use and military), long range data communication up to several tens of kilometres with radio modems, amateur radio, and marine communications. Air traffic control communications and air navigation systems (e.g. VOR, DME & ILS) work at distances of 100 kilometres or more to aircraft at cruising altitude. VHF was used for analog television stations in the US, and continues to be used for digital television. UHF radio waves propagate mainly by line of sight; they are blocked by hills and large buildings although the transmission through building walls is strong enough for indoor reception. One of the biggest pros of UHF radios is that they do a much better job of penetrating barriers in urban locations, like concrete, steel, and wood. So this kind of radio is best suited for use indoors, including buildings with multiple floors, in industries such as manufacturing, distribution, education, retail, hospitality, and healthcare. They also work well for businesses that function in both indoor and outdoor settings, where there are a lot of surrounding buildings. Nowadays, some radios are capable of transmitting on both VHF & UHF bands, like Radioddity GS-5B, making it meet more outdoor and indoor activities requirements. There are also some dual-band radios featuring 10W high power like Radioddity GA-510, supporting a longer range of communication. 　 US Amateur Radio Bands Reference - SOUCE