40m butterfly

A Feasible Full Sized 40 Meter Beam - This project started as a result of renewed interest in 40 meters coupled with the desire for an antenna system that would be more effective than the simple dipole.

G5RV Beam  ^pop - G5RV 40m Beam Antenna

40M Fullwave Loop Antenna - KA6WKE full wave antenna for the 40m amateur radio band

A Vertically Polarized Delta Loop for 40m  ^pop - Practical contruction and designing notes of a delta loop for the 40 meters band

G5RV on 75m and 40m - Why the G5RV is a good antenna on 75m and 40m

W6NL 40m Moxon Yagi - Designed and built by W6NL looks like a loaded yagi this 2 element moxon antenna offer 6dbi

OptiBeam - OB2-40M - High efficient, extremely compact yagi by the use of the ‚Moxon Rectangle Technique

Center-Loaded Off-Center-Fed Dipole - 6 band - Multiband Center-Loaded Off-Center-Fed Dipole (CL-OCFD) antenna that work on 80m 40m 30m 20m 15m 10m by ON4AA

80 & 40 Meters vertical antenna  ^pop - May work on 160 meters too, by EI7BA

GAP Titan DX performance test - GAP Titan DX Evaluation, antenna for 10m 15m 20m 40m 80m

40m Short Antenna  ^pop - GM4JMU shortened dipole for 40 meters band

UN DX Contest 2010 - The Kazakhstan Federation of Radio sport and Radio amateur (KFRR) and Ministry of Tourism and Sport of the Republic of Kazakhstan are announcing the First UN DX CONTEST All world-wide radio amateurs having the amateur radio licence are invited to participation. Contest period: 12.00 UTC 22 May – 12.00 UTC 23 May 2010 Bands: 160m, 80m, 40m, 20m, 15m, 10m. Modes: CW and SSB

1SL1A Sealand DXpedition - 9-10 December 2000, Bands to be concentrated on will be 10m,15m,20m,40m,80m. WARC bands and 160 are being considered

Omiss - OM International sideband society incorporated nets 75M, 40M, and 20M Nets begin one hour earlier during Daylight Savings Time

IC-PCR 1000 in Germany on-line receiver - Icom PCR 1000 HF/VHF/UHF Antenna VHF/UHF Diamond X 50N HF W3D22 80m/40m 34m (111,54 feet) long based in Germany Hamburg JO43XO.

Contest audio file - MP3 file recording a QSOs with SP5CKA and SN7N (SP7PS) in SP DX Contest 2001 on 40m (recorded by SP7PS)

Chameleon HF Multiband Antenna - The Chameleon V1 HF Multiband Antenna is a mobile antenna that can also be used as portable. Lightweight antenna system with 10 BANDS capability 6m, 10m, 12m, 15m, 17m, 20m, 30m, 40m, 60m & 80m.

The Ventenna - Rugged, disguised 2m, 220MHz, 440MHz, and 2m/440 dual band antennas, HF portable antennas, portable dipoles.

W3FF Antennas Buddipole - The Buddipole is a hi-tech, take-apart dipole designed for HF portable operations. The antenna uses a multi-band adjustable coil for all bands 40m - 2m.

The Sunspot Cycle - Sunspot Numbers, The Butterfly Diagram, the Greenwich sunspot data and sunspot realted infos.

40MHz Frequency Counter Module - Design for a very low cost 6-digit frequency counter module using of the shelf components

40 meter 100 watt Transmitter - 40 meter transmitter by K9GDT

A 80/40m DDS controlled QRP CW transmitter - JUMA-TX1 is a 5W CW transmitter for the 80/40m bands. Juha (OH2NLT) and Matti (OH7SV) have had high quality CW keying and a compact size as design goals for this project. No coils need to be wound to construct this transmitter!

40 meter CW/SSB Receiver - The K9GDT 40m receiver

A 80/40m Direct Conversion HF Receiver with DDS VFO - Juha (OH2NLT) and Matti (OH7SV) have designed JUMA-RX1, an award winning 80/40m direct conversion HF receiver with highly accurate direct digital synthesis VFO. The receiver is very compact, because it constructed using surface mount components. No coils need to be wound to construct this receiver!