Simple HF Baluns for 50/75 ohm coax
- Show diagrams, winding methods and tables of some 1:1 and 4:1 baluns for 1.8 - 30 MHz suitable for use up to 200W (400W peak) on systems using 50 or 75 ohm coaxial cable input where SWR should not exceed 1.6:1.
About Digital Smart Technologies
- A general guide to D-STAR.
The purpose of D-STAR is to allow HAM Radio operators to speak further and clearer using digital voice while sending data from 1200 BPS on up at the same time.
Low Frequency Transmission Modes
- Article by W1TAG on operating modes used on low-banding.
The 2200 meter band (135.7 - 137.8 kHz) is only 2.1 kHz wide, so voice work on SSB or AM is out. Find out the best modes on LF
SPLAT! for Windows
- This free software is useful for visualizing terrain and performing Longley-Rice path loss and coverage prediction using the Irregular Terrain Model.
A Windows port of the Linux-based SPLAT by John Magliacane.
Interdigital bandpass filter designer
- Fill out the form to design a bandpass filter as described in the January 1985 issue of Ham Radio Magazine. These filters are generally limited to frequencies above 200 MHZ because their size is slightly longer than 1/4 wavelength