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The tri-band trapped delta loop antenna design operates on 80 meters (3.5–4 MHz), 40 meters (7–7.3 MHz), and 30 meters (10.1–10.15 MHz) using a single triangular wire loop. This configuration eliminates the need for an external antenna tuner or band-switching relays. The antenna's physical perimeter, approximately 270 feet, establishes 80M as the fundamental band, with specific trap placements enabling resonance on 40M and 30M. Trap design and placement are critical, with 30M traps positioned inboard of 40M traps within the horizontal element. Each slant leg measures approximately 80 feet. The resource references foundational information from the _ARRL Antenna Handbook_ and _ON4UN’s Low Band DXing_ regarding full-wave loop behavior and feedpoint impedances. The project aims to provide multi-band HF operation from a single, fixed antenna structure.

Chavdar Levkov, LZ1AQ, presents an experimental comparison of small wideband magnetic loops, building on his previous work on wideband active small magnetic loop antennas. His research focuses on increasing loop sensitivity by maximizing the short-circuit current, which is directly tied to the "loop factor" M = A/L, where A is the equivalent loop area and L is its inductance. Levkov's methodology involves reducing inductance and increasing area through parallel or coplanar crossed (CC) configurations, comparing these designs against a reference single quad loop of 1 m2 area. Experimental verification included testing three distinct loop types: a simple quad loop, two coplanar crossed (CC) loops, and eight parallel loops, all designed to have a total geometric area of 1 m2. Measurements were conducted at 1.8, 3.5, 7, and 10 MHz using a small transmitter 270 meters away, with a Perseus direct sampling receiver for precise signal level assessment. The results consistently showed that CC loops, particularly Loop 5 (two CC circular loops with 1.44 m2 total area), yielded significantly higher currents, up to 9.1 dB over the reference loop at 3.5 MHz, validating M as a reliable predictor of loop sensitivity. Numerical simulations using MMANA further corroborated the experimental findings, demonstrating an almost perfect correlation between the calculated M factor and the induced loop current for 15 different loop models. Levkov concludes that CC loops offer superior sensitivity for a given loop area, while parallel loops are advantageous for minimizing physical volume. Practical recommendations suggest using loops with an M factor greater than 0.5 uA/pT for quiet rural environments, and he provides a spreadsheet tool, WLoop_calc.xls, to aid in optimizing loop configurations for specific operational needs.

FT-240 toroids measurements. The data was measured using well-calibrated HP instrumentation. All plots have been adjusted to a frequency range of 1-100 MHz on the horizontal axis and a resistance/impedance range of 10-1,000 ohms on the vertical axis. This adjustment facilitates comparison among different materials and aids in determining their suitability for use on the HF ham bands.

An FT-817 ceased transmission on the VHF 2m band, despite the other HF, UHF, and 50 MHz bands operating correctly. Suspecting an excess of input signal during FT-8 mode transmission, they conducted measurements with an oscilloscope, revealing a burnt-out PIN diode, identified as D3003, type HSU277, on the PA unit board. Following the replacement of this surface-mounted diode, their FT-817 resumed operation on the 144 MHz band.

This article describes the implementation and testing of a low-power GPS tracker using LoRa technology in the 433MHz amateur band. The system, built with AIThinker RA-02 modules and Arduino controllers, demonstrated successful communication over non-line-of-sight distances up to 5km. Operating with a 125kHz bandwidth and spreading factor of 11, the tracker achieves a data rate of 500 bits/sec. Powered by a LiPo cell with power-saving features, the final compact design operates for approximately 1.5 weeks between charges with 3-minute reporting intervals, consuming just over 1mA in idle mode.

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.

Examines the Sangean ATS-505 portable receiver, a unit introduced in March 2000, providing an in-depth analysis of its capabilities. The review details critical specifications such as its 6 Volt DC power requirement, utilizing 4 AA batteries, and its physical dimensions of 128 x 214 x 39 mm, weighing 840 g without power cells. Frequency coverage spans **LW** from 153-279 kHz, **MW** from 520-1710 kHz, **SW** from 1711-29999 kHz, and FM from 87.5-108 MHz, making it a versatile listener for various broadcast types. Key features highlighted include a backlit display for low-light operation, 45 memory presets for quick access to favorite stations, and the inclusion of Single Sideband (SSB) mode, which is crucial for serious shortwave listening and utility monitoring. The review also draws technical comparisons with other Sangean models, specifically the ATS-404 and ATS-909, pointing out differences in band coverage and operational features. This independent assessment offers practical insights into the ATS-505's performance, helping enthusiasts understand its place within the portable receiver market.

Presents the NED International DX Group, a **CB radio** organization established in the Netherlands on August 23, 2026, by 19NED000 and 19NED001 Henricus. The group primarily operates on the **11-meter band**, utilizing various modes including FM, AM, LSB, USB, CW, FT8, FT4, FT2 Ross, and JS8, with all digital modes permitted. Membership is free and open to active operators and SWLs. Key operating frequencies include 27.405 LSB, 27.265 USB for FT8, and 27.245 USB for JS8. The group also maintains activity on PMR Channel 10 at 446.11875 MHz FM. The organization is actively seeking volunteers for roles such as webmaster (proficient in PHP, MySQL, and security), digital eQSL and paper QSL card management, logo and banner design, and country/province directors.