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Constructing an HF End-Fed Half-Wave (EFHW) vertical antenna, the resource details the winding of a monoband matching unit, inspired by _AA5TB_, designed to provide a 50 Ohm impedance match without a ground plane or antenna tuner. It specifies the use of a _T200-2_ ferrite core for the transformer, outlining the 13-turn secondary and 2-turn primary winding process with enamelled copper wire. The document also describes the integration of a coax capacitor, whose length is critical for tuning and varies by band, with specific starting lengths provided for 20m, 17m, 15m, 12m, and 10m operation. The practical application section guides the builder through tuning the antenna using an antenna analyzer, emphasizing the iterative process of spacing secondary windings and trimming the coax capacitor to achieve resonance at the desired band frequency. It highlights the antenna's low angle of radiation, beneficial for DX, and claims up to 2 S-points improvement over a _G5RV_ or similar doublet when used as an omnidirectional vertical. A comprehensive shopping list, including specific part numbers from _Rapid Electronics_, is provided, along with advice on selecting fiberglass fishing poles for support and suitable antenna wire.

Constructing a Lindenblad antenna for 137MHz NOAA satellite reception involves specific design considerations for optimal performance. The resource details the use of 4mm galvanised steel fencing wire, 300-ohm television ribbon cable, and wood/plastic components for the antenna structure. Key dimensions for a 137.58MHz-resonant antenna are provided, derived from the ARRL Satellite Handbook, specifying s, l, w, and d as 42, 926, 893, and 654mm respectively. The antenna is designed for Right Hand Circularly Polarised (RHCP) signals, requiring the four folded dipole elements to be tilted clockwise by 30 degrees. A significant aspect covered is impedance matching between the antenna's 75-ohm impedance and a typical 50-ohm receiver input. A twelfth-wave matching transformer, constructed from 117mm sections of 50-ohm RG-58 and 75-ohm RG-59 coax with a 0.66 velocity factor, is described. The article also addresses coaxial cable and connector selection, recommending 75-ohm Type-N connectors for RG-6 cable in professional setups and F56/F59 connectors for general use, while strongly advising against PL-259/SO-259 connectors for VHF. Strategies for mitigating Radio Frequency Interference (RFI) are discussed, including antenna placement to shield from local TV transmitters and the use of commercial or DIY band-pass filters, such as cavity resonators or helical notch filters, along with ferrite chokes on coaxial cables. Antenna orientation is explored, noting the Lindenblad's 'cone of silence' directly overhead and its maximized sensitivity towards the horizon. An experimental vertical tilt of 90 degrees is presented as a method to improve overhead reception and reduce interference from strong horizontal signals, particularly relevant in high RFI environments like the Siding Spring Observatory site.

Documents the OC1I and OC6I IOTA DXpeditions to Peru, specifically highlighting operations from SA-098 (Isla La Leona) and SA-076 (Isla Lobos de Afuera). The OC1I team logged over **8000 QSOs** from SA-076, while OC6I made 1400 QSOs from SA-098, despite challenging propagation conditions. The resource details the equipment used, including an _IC-7000_, an IC-706mkIIG, and a TS-440SAT, along with various antennas such as a 160m dipole, FD4, G5RV, and a multi-band vertical for 17m, 20m, 30m, and 40m. The DXpedition dates are specified: OC6I operated from SA-098 between December 28 and December 30, while OC1I was active from SA-076 from January 2 to January 7. Both operations are confirmed as valid for IOTA credit. The page also includes a video link for the OC6I operation and a photo gallery from the DXpedition. Feedback is welcomed, and the webmaster is identified as Bodo Fritsche, DL3OCH.

Operating as FY/F5UII, Christian F5UII conducted a DXpedition to French Guiana (FY) from January 13 to 30, 2013. The primary operation utilized the FY5KE radio club station in Kourou, with activity focused on voice modes during specific weekday hours. The resource details the operator's intent to transmit before 12:00z and after 22:00z, or as availability permitted, from the mainland. A significant aspect of this operation involved a dedicated weekend activation of the Salut Islands, specifically **IOTA SA-020**, from January 19-20, 2013. This segment of the DXpedition was conducted from Royal Island (Ile Royale), part of a group including Devil's Island (Ile du Diable) and St. Joseph Island (Ile Saint Joseph), located 14 km offshore from Kourou. The station setup for the IOTA activation included 100 Watts of power, a GPA-030 vertical antenna for 10m, 15m, and 20m, and dipole antennas for 17m and 40m, with antenna deployment contingent on site conditions and propagation. The operator anticipated strong interest for the SA-020 entity.

The reason for making this antenna was the desire for a vertical (hence DX-ish) antenna that would cover at least 20m that would fit on my 5m fishing pole. This antenna can work on 20m 17m 15m bands and it is suitable for SOTA operations

WB8LZR details the construction and initial field results of a multi-band vertical wire antenna, designed to complement his existing horizontal loop for improved DX on 80 meters. The antenna utilizes a 67-foot vertical wire, configured as a quarter-wave radiator on 80m, and employs a 1:1 current balun for RF isolation on 80m, 30m, and 17m. For bands like 40m, 20m, and 10m, where the wire acts as a half-wave or full-wave radiator, an additional impedance transforming _unun_ is integrated to manage the significantly higher feedpoint impedance and voltage. The author notes the vertical's performance as a receiving antenna, observing reduced noise compared to his main horizontal loop, particularly on 80m, and even hearing some long-path signals the loop missed. Initial QRP contacts, including a **1-watt** QSO with a _VP2 station_ on 30m, demonstrate its transmit capability. While the radial system is currently rudimentary, the project outlines practical considerations for multi-band vertical deployment and impedance matching.

The 1/4 wavelength vertical antenna project, initially designed for 20 meters, has evolved into a versatile portable solution covering 10 through 60 meters. K0BXB details its construction, emphasizing a bottom-loaded design with a tapped loading coil and four 10-foot counterpoise wires. The author shares personal experiences and field results, including **18 QSOs** during a park activation on 17m and 30m with 10 watts, and a **2,435-mile** contact with a contest station in Bonaire on 20m using 5 watts. Comparisons are drawn to commercial offerings like the _Wolf River Coils TIA_ and _QRPGuys Triband Vertical_, highlighting the DIY antenna's small footprint, light weight, and ease of tuning for POTA activations. The resource includes insights into using test equipment such as the _NanoVNA_ for SWR optimization and discusses various radiator lengths, from 17-foot wire to a 102-inch whip, demonstrating adaptability for different portable setups. Construction tips cover coil winding, tap placement, and connecting feedlines and radials using common components.