WWV and WWVH

The standard time stations WWV (Ft Collins, Colorado) and WWVH (Kauai, Hawaii), which transmit on 2.5, 5, 10, 15 and 20 MHz, are also popular for propagation monitoring. They transmit 24 hours a day. Daily monitoring of these stations for signal strength and quality can quickly provide a good basic indication of propagation conditions. In addition, each hour they broadcast the geomagnetic A and K indices, the 2800-MHz

Table 21.5

Shortwave Broadcasting Bands

Frequency (MHz) Band (m)

2.300-2.495 120

3.200-3.400 90

3.900-4.000 75

4.750-5.060 60

5.959-6.200 49

7.100-7.300 41

9.500-9.900 31

11.650-12.050 25

13.600-13.800 22

15.100-15.600 19

17.550-17.900 16

21.450-21.850 13

25.600-26.100 11

(10.7-cm) solar flux, and a short forecast of conditions for the next day. These are heard on WWV at 18 minutes past each hour and on WWVH at 45 minutes after the hour. The same information is also available by telephoning the recorded message at 303-497-3235. The K index is updated every three hours, while the A index and solar flux are updated after 2100 UTC. These data are useful for making predictions on home computers, especially when averaged over several days of solar flux observations.