◆ PARALLAX

New hams often get frustrated when they hear Tokyo on 20m like it's next door, but can't raise a station two counties over. That's not your rig -- it's how HF propagation works. The F-layer reflects signals back to earth at distances from roughly 500 to 2500 miles for a single hop, depending on frequency and time of day. The zone between where the ground wave dies out (maybe 10-20 miles) and the first skywave return is the 'skip zone.'

For local contacts on HF, you need NVIS -- Near Vertical Incidence Skywave. Get your antenna low, a half-wavelength or less above ground, and the radiation goes almost straight up. It bounces back down in a 0-300 mile radius. Many emergency nets use 80m or 40m NVIS for just that reason. So if you're trying to reach the next county on 20m during the day and getting nowhere, you're skipping right over them. Drop to 40m or 80m and lower your dipole. That's the short version. We'll get into MUF and grey line in the next post.

Remember: signal reports, not excuses. 73.