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The QM7 antenna is a simple 7 elements Yagi with 3.70 m boom length for the lower 144 MHz SSB/MGM band, used it mainly for Sporadic-E and MS contacts. It exhibits a forward gain of 11.35 dBd; i.e. 13.5 dB forward gain over the isotropic radiator, while the F/R is about 12.5 dB

For radio amateurs engaged in propagation studies and DXing on the 6-meter band, understanding the distribution of active beacons is crucial for assessing band openings and signal paths. This resource presents a static map compiled by _Carl-Axel Lindberg, SM6NZV_, illustrating the geographical placement of European beacons operating on the 50 MHz band, which is vital for monitoring sporadic-E, F2-layer, and other propagation modes. The map, last updated in April 2002, serves as a historical reference for beacon locations, allowing operators to correlate observed signal reports with known beacon positions. While not real-time, it provides foundational data for analyzing past propagation events and understanding typical beacon coverage areas across the European continent. Operators can use this information to identify potential receive stations or transmit points for future _DX contacts_ on the _Magic Band_.

Presents the mechanical and electrical specifications for a 5-element Yagi beam antenna designed for the 6-meter band. The resource details element lengths, spacing, and boom dimensions, specifically utilizing _EMT conduit_ for construction. It includes a diagram illustrating the element layout, a coaxial balun connection, and a reported SWR curve, providing a practical blueprint for hams to replicate the design. The design achieves a reported SWR of **1.1:1** at 50.125 MHz, indicating efficient impedance matching across the primary 6-meter DX window. The boom length is specified at 2.44 meters (8 feet), with element lengths ranging from 2.87 meters for the reflector to 2.59 meters for the director 3. This configuration suggests a gain figure typical for a 5-element Yagi, likely in the range of **9-10 dBi**, making it suitable for local and sporadic-E DX contacts.

Sporadic-E clouds location and estimated MUF real time map by DXMAPS

Two modes of propagation at 50MHz E-layer & Sporadic-E by Ken G4IGO

Approximately 24 minutes of recorded audio from Flame Christian Community Radio on 1521 kHz was logged on January 4, 2014, demonstrating the pursuit of distant broadcast stations. This resource focuses on the hobby of DXing, primarily targeting the Mediumwave (AM) band and the 2-6 MHz shortwave Tropical Bands, along with VHF FM. It details how factors like solar activity, time of day, and seasonal weather patterns significantly influence radio propagation, enabling reception of signals from hundreds or even thousands of miles away. The site includes a collection of DX logs, such as _Sporadic E_ reception of FM stations from Algeria, Spain, and Portugal in May 2020, and _Radio New Zealand_ on 15720 kHz. It also features comprehensive UK RDS listings, information on _MW Carrier Monitoring_ of European and trans-Atlantic AM carriers, and reviews of equipment like the _Sangean ATS909_ portable radio. Historical news entries document significant events like the closure of CBC's 50 kW CBA transmitter on 1070 kHz and RTE's 567 kHz MW channel.

Dedicated to 50MHz and 144MHz. Online 2m and 6m logs. Real Audio sound clips of Tropo, Aurora, Sporadic E, Meteor Scatter, TEP and F2 Propagation.

Sporadic-E clouds location and estimated MUF real time map

Concentrating on VHF DX, Aurora, Meteorscatter, TEP, Sporadic E, EME, VHF DXpeditions. Daily updates.

The Buddipole Deluxe, a portable HF/VHF antenna system, receives a practical assessment from IW5EDI after a month of field use. The author, constrained by antenna restrictions, highlights the system's crucial role in enabling portable operations, even managing sporadic digital activity from a balcony. Direct comparisons to a fixed 3-band dipole reveal surprisingly comparable signal reports on 15, 17, and 20 meters, underscoring the Buddipole's effectiveness in real-world scenarios. Tuning the Buddipole proves straightforward on bands down to 20 meters, though the review notes significant challenges with SWR on lower bands like 40 meters, where achieving better than 3:1 SWR was problematic. Observations also include SWR variations with dipole rotation and mast height, suggesting environmental factors play a role. The overall manufacturing quality of the antenna and its accessories, including the tripod and carry bag, is deemed good, despite a minor issue with a pole connector. Looking ahead, the author plans to construct a homemade Buddipole version, possibly optimized for the 30-meter band, specifically for PSK31 operations from an apartment. This personal project reflects a common amateur radio practice of adapting commercial designs for specific needs, further extending the utility of portable antenna concepts.

Presents the VHFDX.EU web cluster, a specialized resource for VHF, UHF, and microwave DX spotting. It details the cluster's functionality, including real-time spot aggregation and a DXCluster Map interface for visualizing activity. The resource highlights its integration with the MMMonVHF backbone, ensuring a robust data flow for monitoring band openings and propagation events across higher frequencies. It also references reviews of the ON4KST and N0UK chat systems, which are frequently used in conjunction with VHF DX operations. The platform offers a mobile-optimized view for on-the-go access to DX spots, catering to portable and mobile operators. It further provides daily ES (Sporadic E) spot summaries, a critical feature for VHF operators tracking this specific propagation mode. The cluster serves as a central point for operators to share and receive information on rare grid squares, contest activity, and general band conditions above 50 MHz.

Personal home pages of John g4xgt Ten FM,DRM,sporadic "E" and Ham links

About Sporadic E propagation at wikipedia

Over 150 pages of content are dedicated to maximizing activity on the 6-meter band, often referred to as the _Magic Band_. The resource details various propagation modes, including sporadic E, F2, and tropospheric ducting, providing insights into their characteristics and how to leverage them for DX contacts. It also covers essential equipment considerations, from transceivers and transverters to specific antenna designs optimized for 50 MHz operation, such as Yagis and Moxon antennas. The eBook presents strategies for participating in 6-meter contests and pursuing awards like _VUCC_, offering practical advice on logging software and operating techniques. It includes discussions on software tools useful for predicting propagation and managing contacts, alongside guidance on finding and utilizing DX maps to identify openings. The author, K5ND, shares his extensive experience to help operators achieve successful 6-meter DXing. Specific sections address the code of practice for 50 MHz operations and provide assistance in locating rare DX opportunities. The content is structured to guide both new and experienced operators through the nuances of the band, from initial setup to advanced operating strategies.

Sound clips and notes on sporadic E on four meter band

The map display allows you to select by locator, or clicking on the map, where you want to calculate the probability of Sporadic-E by building a combination EPI, Es Probability Index, based on factors using many of the known parameters which can effect Es. T

Students amateur radio club SPORADIC of Kursk's state technical university . In entire lifetime the radio station worked under the main calls: UA3KUO, UK3WAF, UZ3WWW, RW3WWW, and also used more than 60 calls in radio-expeditions(RC3W, R6SE, RP3W, RI1OP, RI1SI, R6SC). The chief of radio station since 1977 is Pikkiev Valery RW3WW.

Recent researches seem to support the hypothesis that Sporadic E propagation could be connected to presence of thunderstorms.

Sporadic E is a form of propagation that can arise with little warning, and enable radio frequencies of 150 MHz and more to travel over distances of a thousand kilometres and more.

This review of progress and future Prospects provides a practical guide for effective use of VHF sporadic-E propagation.

Documents the design and construction of a **four-band Moxon beam** antenna, covering 20, 15, 10, and 6 meters. Author W7JMP shares his journey from initial research and computer modeling using 4NEC2 to the final on-air testing and optimization. The project aimed for gain over a dipole on 20 meters, with a budget under $500, including the antenna rotor. The design incorporates fiberglass spreaders and a single feedpoint, avoiding complex relay switching. The article details the selection of materials, assembly techniques, and the critical tuning process. W7JMP describes fabricating the hub, mounting spreaders, and attaching elements made from stripped THTN wire. A notable innovation is the use of a half-wave tuning stub with a loading coil for in-situ adjustment of the 20-meter reflector, optimized via remote S-meter readings using a webcam and smartphone. This method allowed for fine-tuning the **front-to-back ratio** without lowering the antenna. Initial testing revealed a dipole-like pattern, which was significantly improved after tuning, resulting in reported 2 to 4 S-unit front-to-back ratios and enhanced signal strength for DX contacts on multiple bands, including sporadic E on 10 and 6 meters.

Examines the long-standing debate among radio amateurs and scientists regarding the correlation between thunderstorm activity and _sporadic E_ propagation on VHF bands, particularly 144 MHz. The authors, including DF5AI, initially approached the subject with skepticism, believing that the significant vertical separation between thunderstorms and the E-layer made a direct link improbable. Their project, initiated in 2004, involved comparing 144 MHz DX reports from hams with meteorological sferic observations, aiming to definitively disprove the theory. While their initial data analysis for the 2004 sporadic E season did not yield clear evidence for thunderstorm-triggered events, the team found compelling reasons to reconsider a "maybe" stance. They cite scientific discussions on thunderstorm effects on the ionosphere, impressive statistical correlations from the _GPS/MET radio occultation experiment_ linking convection to E-region irregularities, and OH nightglow measurements showing severe thunderstorm impact at 85 km altitude. These findings suggest that current data analysis methods might be insufficient, prompting a call for further investigation. The paper delves into the geophysical background, explaining neutral, ion, and electron interactions in the ionosphere, the wind shear theory for sporadic E formation, and various atmospheric wave phenomena, including convectively generated gravity waves. It proposes a model where gravity waves, originating from intense convection, propagate upwards to create wind shears that contribute to sporadic E layers, documenting their current understanding and encouraging fellow amateurs to conduct their own studies.

Fifty-one MHz operation, often called the "magic band," benefits significantly from a well-designed antenna, and this resource details the construction of a rigid 6-meter _Moxon antenna_ using common DIY store materials. The author, 4L/G8BAG, shares his experience with the 6m band, highlighting its potential for long-distance contacts, with single-hop sporadic E propagation enabling QSOs up to **2,500 km** and multi-hop contacts reaching **10,000 km**. The project emphasizes cost-effectiveness and durability, utilizing yellow gas pipe with an internal stainless steel lining for the antenna elements. The article provides specific dimensions for the Moxon rectangle, derived from the 12mm internal diameter of the gas pipe's steel core, rather than the outer plastic. It also details the use of white PVC water pipe for insulators and mounting, ensuring a tight fit with the yellow gas pipe. Initial testing with an MFJ antenna analyzer showed an excellent 1:1 SWR across the 50-52 MHz range, even when using 75 Ohm satellite cable as a feeder. The construction process is straightforward, involving cutting and bending the gas pipe, fitting insulators, and connecting the feedline. The author's successful on-air results, including a 1000 km contact with a temporary vertical, underscore the effectiveness of the 6m band and the Moxon design. The resource concludes with a note on exploring heavier gauge gas pipe for future 10m antenna projects.

A Case For Thunderstorms Causing Sporadic E on 6 Meters. In Propagation and Radio Science, Eric Nichols explains one possible mechanism is thunderstorms that are strong enough to break electrons free forming a cloud of free electrons.

Live MUF is a DXC (cluster) telnet client which attempts to resolve propagation modes from spots and also attempts to calculate sporadic e possibilities purely based on incoming data from the cluster. It has great circle mapping (GCM) built in to the app for live mapping of spots. Live MUF also can be used as a world wide converse telnet client, ON4KST telnet client and DXC at the same time. Live MUF also has basic logging capabilities in case you need an emergency logger at any time.

The paper examines the potential effects of thunderstorms on ionospheric _sporadic E_ propagation at **144 MHz**. It addresses community skepticism by considering scientific investigations into travelling ionospheric disturbances and spread-F irregularities, suggesting that thunderstorm effects on the ionosphere cannot be generally excluded. A model is presented where thunderstorm-triggered gravity waves travel from the troposphere and stratosphere into the ionosphere, potentially causing wind shears at E region level, which are considered a cause of mid-latitude sporadic E layers. The _GPS/MET radio occultation experiment_ and OH nightglow measurements support this model by showing a correlation between convectively generated gravity waves and electron density irregularities in the E region. A ham radio project analyzed the spatiotemporal correlation between 144 MHz sporadic E long-distance communication and VLF radio emissions from lightnings (sferics). The June 27, 2004 event showed a correlation between sferic and sporadic E scatterer positions, motivating further analysis. The paper proposes a data analysis method for amateur radio propagation studies, contingent on scientific observatories providing raw data.

Facilitates real-time coordination of scheduled contacts (skeds) for weak-signal modes on VHF, UHF, and microwave bands, including meteor scatter, tropo, sporadic-E, and EME. The platform features dedicated band rooms for 50 MHz, 70 MHz, 144 MHz, 432 MHz, 1.2 GHz, 2.3 GHz & up, and 28 MHz & below, displaying online users with their locator, distance (QRB), and beam heading (QTF). Users can propose skeds specifying frequency, mode, and UTC time, receiving a countdown and antenna pointing instructions. It integrates propagation alerts, including solar data and Sporadic-E MUF from ionosondes, indicating potential band openings for 6m, 4m, or 2m. DX spots from clusters and users are sorted into band rooms, offering a "Sked" button for online stations. A station map displays users with Maidenhead grid squares and great-circle paths. Verified callsigns through QRZ.com enhance trust among operators. The service is free, non-commercial, and operates without advertising or tracking.