This page offers radio amateurs (experienced and beginners) a useful overview and tutorials on HF propagation conditions. Here you will find basic and advanced explanations, as well as practical methods, charts, maps, models, real-time measurements, assessments, comparisons, references, and an index.
If RF noise threatens to take your hobby away, this could be probably a good solution to reduce or even eliminate RF Noise.
This is a small collection of K9YC info and my experiences. Problems by feed lines of 1/2 lambda length. CMCs in transmitting and receiving systems. Antenna unbalance, Maximal allowed power, Choke winding tips.
This page is a project for a small loop antenna for reception of short wave broadcasting. It is in Portuguese and contains pictures and schematics to build your own antenna
This article describes the construction of a 9,50 m long dipole for the 30 m band (10.1 MHz to 10.15 MHz). It was designed to be mounted ca. 6 m above ground inside an attic. The calculations were performed by OE1MEW
If your FT-817 has stopped powering up from the internal battery but works from external power, then maybe the internal battery fuse has blown. There is a small PCB mounted fuse to protect the battery and radio. This fuse can blow, if it does your radio will not work from battery power. This page will describe how to test the fuse and describe how to make a repair.
The estimated international sunspot number (EISN) is a daily value obtained by a simple average over available sunspot counts from prompt stations in the SILSO network.