40 meter

419 links - and 8 categories

Magnetic Monster Loop Antenna for 160m - A monster magnetic loop antenna for 160 meters band. This Magnetic loop is optimized for 1840 Khz + 50 Khz. PDF Article published on La Radiospecola 10.22
[ Hits: 849 | Votes: 2 | Rating: 10 ]

SAFARI 40-30m vertical Antenna - Roach pole vertical antenna for 40 and 30 meters band featuring good performance on short skips contacts compared to wire dipole
[ Hits: 310 | Votes: 0 | Rating: 0 ]

Spiral Dipole Antenna for 40m - This antenna is an off-center fed spiral dipole for 40 meters. The spiral dipole is very compact, making it well-suited for limited space (like an apartment patio), while the off-center feed gives the antenna some multiband capability.
[ Hits: 295 | Votes: 3 | Rating: 7 ]
Low Bands Battle Creek Antenna - This antenna is designed for 40, 80 and 160 meters to complement a tri-band beam normally taken on DX peditions for 10, 15 and 20 meters, so six bands can be worked with only two antennas.
[ Hits: 137 | Votes: 0 | Rating: 0 ]
40 meters band beverage antenna - The author describes his experience building and using a Beverage antenna for the 40-meter band. Despite encountering some challenges, the antenna offered some improvements in receiving stations compared to a 3-element inverted Vee antenna. The Beverage antenna showed a significant daytime signal-to-noise ratio improvement and received signals better than the Vee antenna. However, the front-to-back ratio was not ideal, and the transmit power seemed to affect the Beverage antenna. Overall, the author concludes that the Beverage antenna might be more suitable for locations with higher noise levels. The total cost of the antenna was around 30 Euros.
[ Hits: 34 | Votes: 0 | Rating: 0 ]

Shortened 40 meter Vertical for POTA SOTA - Build A Shortened 40 Meter Vertical antenna For POTA / SOTA Activations. A project for a portable wire antenna for 40 meters band suitable for POTA or SOTA operations.
[ Hits: 125 | Votes: 1 | Rating: 10 ]
Vertical bazooka antenna for the 40m - A quarter wave vertical omni-directional antenna for 7 MHz. Formulas for dimensions in feet and meters are provided. Ideal radial angle is between 35° and 45°. Velocity factor (Vf) varies based on coax type.
[ Hits: 135 | Votes: 7 | Rating: 6.85 ]

Capacitive Antenna by DL7JV - Experimenting with capacitive antennas for 40 and 80 meters band. A very space-saving antenna with good receivings caracteristics
[ Hits: 166 | Votes: 1 | Rating: 9 ]
Microvert Antenna for 40m by ON7IR - A mircovert antenna assembled for the 40m version of the DL7PE antenna. A one meter long aluminum tube with 24mm diameter is used for the base (element 1) and a 50cm aluminum tube with 20mm diameter for element 2 (the extention). A pvc pipe, 34cm long and with a diameter of 38mm, is used to wind the coil on (1mm enamelled copper wire).
[ Hits: 152 | Votes: 0 | Rating: 0 ]

160m Inverted Delta Loop - This 160 meter Delta Loop antenna is made of Hard drawn copper wire AWG 10, the two upper side are 148.5 foot each base wire is 240.9 foot, the feed point at 30.69 foot to one corner, feed with 450 Homs balanced line to an antenna tuner on the ground, then with 50 homs coax to the shack.
[ Hits: 114 | Votes: 0 | Rating: 0 ]

Make your own 40/80 Dipole - Make your own dipole for 40 and 80 meters band, assembling standard product parts like 40 meter traps, the 1:1 balun and insulators
[ Hits: 125 | Votes: 0 | Rating: 0 ]

Multiband portable wire antennas - Vertical end fed antenna used for portable operations. The antenna will work on 80 with acceptable results, it will work fine on 40m, and it will be a good deal better than a normal 1/4 wave GP on 20, 17, 15 meters.
[ Hits: 187 | Votes: 0 | Rating: 0 ]
8010 Enfed Antenna - With this antenna the coverage is 80,40,20,15 and 10 meter band without any antenna tuner and the average SWR is below 1.2 on phone bands. The total antenna lenght is about 23 meters , with one 20.4 meters long segment from the 1:49 transformer to the 110uh coil and about 2.2 meters long segment from the coil to the insulator.
[ Hits: 142 | Votes: 0 | Rating: 0 ]

K1FM Mini Magnetic Loop - Original HF magnetic loop antenna designed by the author to work in conjunction with QRP transceivers like the FT-817 in portable operations. In this configuration the loop can operate from 30 to 10 meters. Using a two spires radiator of the same diameter it also covers 40 meters.
[ Hits: 118 | Votes: 1 | Rating: 8 ]

Reversible 40 Meter Moxon ^updated - The author wants a compact, switchable antenna for 40-meter ham radio. They compare 3 designs: rectangle, short-tipped W6NL, and T-hat. All work well electrically, but mechanics matter for a large antenna. The rectangle needs strong support, while the T-hat is sturdier with slightly longer elements. The T-hat design wins for now, but the author will focus on its mechanical details next.
[ Hits: 74 | Votes: 2 | Rating: 5.5 ]

RX Loop antenna - This loop antenna is intended to be connected as an antenna for receivers that do not have a built-in antenna such as an HF set or an old tube radio. This square barrel is wound on a wooden frame. It consists of two windings that are galvanically isolated from each other, a main and a coupling winding. The diameter is about 40 cm.
[ Hits: 60 | Votes: 0 | Rating: 0 ]

Modified Ground Plane Antenna Adds Second Band - This article explains the trick of how to shorten and lengthen pairs of radials to make a 2-band ground plane antenna. Included is a "Table of Multi-Band Possibilities" covering the range of 6 to 40 meters.
[ Hits: 53 | Votes: 0 | Rating: 0 ]

Arduino QRP Transceiver: DIY Success on HF Bands - This article introduces an Arduino-based QRP CW Transceiver designed for lower HF bands. The journey begins with the Wotduino, evolving from a keyer to a multi-mode beacon. The development includes a QRP transmitter and culminates in a receiver inspired by Roy Lewallen design. The transceiver, controlled through a control bus features a signal path, modulation, filtering, and adjustable frequency settings. Despite initial testing intentions, successful QSOs on 80 and 40 meters showcase its functional capabilities.
[ Hits: 111 | Votes: 1 | Rating: 1 ]