Detect 10m, 11m, 12m band openings
Detecting band openings in the 10m, 11m, and 12m radio bands can be done by listening to popular frequencies in these bands. The 10m and 12m bands are licensed amateur radio bands capable of global communications when ionospheric conditions are favorable. The 11m band is license-free and typically has more users such that an amateur radio operator may listen to 11m to determine if 12m and/or 10m are also experiencing enhanced skywave propagation.
A good 10m frequency to listen to is in the vicinity of 28.074 MHz and 28.078 MHz, which are the FT8 and JS8call suppressed carrier frequency as tuned in upper-sideband (USB) mode. This can be tuned by a converted CB radio in AM mode on 28.075 MHz. An AM mode radio tuned to 28.075 MHz will hear a seemingly random series of tones with a 15 second interval. The tones heard in an AM receiver come from multiple FT8 or JS8Call signals heterodyning.
For 12m, listen to FT8 / JS8Call USB 24.915 MHz or USB 24.922 MHz. If only having a converted AM CB radio, tune 24.915 MHz or 24.925 MHz.
11m DX frequencies to monitor include:
- AM 27.025 MHz (CB channel 6, high powered calling frequency)
- AM 27.185 MHz (CB channel 19, road calling channel)
- AM 27.065 MHz (CB channel 9, Spanish language calling frequency in Central and South America)
- FM 26.805 MHz (FM 11m DX calling frequency)
- USB 27.245 MHz (CB channel 25, JS8Call frequency)