The article "Simplex Channel Confusion on 2 Meters" from AmateurRadio.com discusses challenges in selecting suitable simplex frequencies on the 2-meter (144 to 148 MHz) band. The main issue is the variation in channel spacing, with some areas using 15-kHz and others 20-kHz spacing. This discrepancy can cause confusion and interference problems. The article advises checking local VHF band plans for guidance on simplex frequencies and notes the importance of frequency coordination in amateur radio. It also mentions the National Simplex Calling Frequency (146.52 MHz) as a universally recognized channel. For more detailed information, you can read the full article.