40 metre traps

Magnetic loop for 80-40 meters - Evolution of a project of a magnetic loop resonating from 80 to 40 meters

Bazooka antenna for 40 meters - A bazooka antenna project for the 7 Mhz by PD7MAA

W3DZZ for 40 and 80 meter - Home made w3dzz antenna for 40 and 80 meters band

40 meter 4-square antenna - A permanent working 40 meter system based on a 4-square antenna

PY6CJ 80/40 meters dipole - A center feed trapped dipole for 80 and 40 meter band in spanish

NVI 40 Meter Antenna Modeling - The idea of using a low mount dipole, enhanced with reflector wires directly beneath the dipole, on the ground, appears to be a very good approach to creating an NVI specific antenna for local HF operation.

The Hudson antenna - A vertical antenna for 80 and 40 meters project with lots of assembling pictures and plan by LU9DPD in spanish

40M 3 element beam - History project and dimensions of a 3 element yagi beam for 40 meters band

TLV40m antenna - Top Loaded vertical antenna for 40m Band with elevated radials

Top loaded vertical - Vertical Antenna for 40m Band with elevated Radials Top Load is a Mesh 2 x 1 meter (Netz 2x1m) enamelled wire 0.5 mm diameter (CuL 0,5mm)

Portable dipole for 40 Meters band - Pictures and swr reports for a portable dipole antenna for 40 meters band in german

Collinear Microstrip Patch Antenna - Design of a 869 Mhz Collinear antenna

Indoor multiband dipole - This indoor dipole is available in two version for 20-10 meters and 40-10 meters. EZNEC data files available by HB9MTN

Build a hanging dipole for 2 metres - Described here is a simple omni-directional, vertically-polarized dipole for two meters. Made from coaxial cable, it can be rolled up and stored in a small container

40m broadband vertical antenna - A loopy loop loaded vertical antenna operating range 7.0 to 7.3 MHz by S. C. Chuck Smith, WA7RAI

AO-40 70cm Uplink Antenna - homebrew satellite antenna

1200Mhz 40elements YAGI - A table with element size and spacing for a 40 Elements yagi antenna for 1200 Mhz

Windom for 80-40-20-10 m - A windom multiband antenna for 80 40 20 and 10 meters band. Include picture for a 1:6 Balun. In french

Contest University - After a year of preparation, 150 students and 11 professors participated in 10 hours of intense Contesting instruction covering some 22 topics, with over 400 pages of text

IZ3DVW/B - 40meter band beacon on 7,039.6 MHz

Free Web Receivers from UK - Up to 3 free to tune receivers based in Bedfordshire England, Ten Tec RX320D, Yaesu FT-840 and Icom PCR-100

Troubleshooting Traps - This article refers mainly to the old Cushcraft 1/4 wavelength AV series of antennas (12AVQ, 14AVQ etc) hence the references to radials. The R series (R5, R7 etc) are 1/2 wavelength antennas, and the radials are NOT 1/4 wavelength resonant.

Codec 2 - Codec2 is an open source low bit rate speech codec designed for communications quality speech at around 2400 bit/s. Applications include low bandwidth HF/VHF digital radio.

A low cost 600 watt ultra-linear amplifier  ^pop - This compact little amplifier is the brain-child of Pat Murdoch, ZL1AXB, in Auckland, New Zealand. It is only 11" wide, 4" high, and 9" deep. Operates for 40, 20, 17, 15, 12, and 10m

40 meter QRP Transceiver - This semi-homebrew QRP (low power) CW transceiver is based on the ARK-40 transceiver kit, by S&S Engineering. With its built-in CW keyer and 5 watts of power, the basic ARK-40 transceiver is an outstanding 40 meter CW performer