Home » 2022 » 02
Skip to content

Monthly archives: February, 2022

Rothammels Antenna Book – Translated and revised from the 13th German edition

Rothammels Antenna Book For many years, radio amateurs have been using this reference book, which has acquired a firm place in amateur-radio literature as an “antenna cookbook.” Dating back to the fifties, it has developed into a comprehensive reference book for practical use, which has been published in numerous German-language editions. In the interest of …

Ten Minute QRP Transmitter

Ten Minute QRP Transmitter The design apparently originated in 1996 in an amateur radio club QRP publication.  The name originates since the original author claimed he built this transmitter and make a QSO with it in just 10 minutes time. There are no coils to wind  it tunes a wide range of crystal frequencies, and it outputs an …

Circuits – Sovina2 40M Class E Transmitter

Adaptation of Class E amplifier for amateur radio application is very rare due to inherent difficulties in filter design associated with it till release of usdx transceivers. The above compact transmitter uses class E amplification with three BS170 mosfets, a popular approach in usdx final. What’s new is the oscillator…any similarity with the NS40 is …

VK4FUQ Optimized sloper antenna for 3.5Mhz

VK4FUQ’s optimised sloper antenna for 3.5MHz. Radiator and counterpoise radial are both one-quarter-wave in length (length in metres = 71.37/(frequency in MHz) or in feet 234/MHz). The radial should be at least 5ft (preferably about 8ft) above ground and immediately underneath the radiator. Good quality insulators are need at the top of the preferably non-conductive …