Wednesday, July 2, 2014


July, 2014

By Tomas Hood, NW7US

HF Propagation

Solar activity is roughly the same this year as last year.  This results in maximum usable frequencies staying consistent with the same period, last year.  We expect good openings into most areas of the world through out the day on 22, 19, and 16 meters.  Through the summer, expect a lot of propagation between north and south regions during the daylight hours.  Nineteen and 16 meters will be the strong daytime bands, with 19 remaining a popular band throughout the year.  Reception of stations located in tropical or equatorial areas may be possible well into the hours of darkness.  For distances between 800 to several thousand miles, expect exceptionally strong signals.  Multi-hop signals will be prevalent.  Late afternoon and early evening broadcasts will likely congest the band. 

Twenty-five and 22 meters will remain open from just before sunrise to a few hours past sunset.  From late afternoon to well into darkness, expect these bands to offer worldwide coverage. 

Thirty-one meters is a year-round power band with outstanding domestic and international paths, around the clock.  During periods of low geomagnetic activity this summer, this band may offer long distance DX all through the night.

Forty-one and 49 meters offer domestic propagation during daylight hours and somewhat during the night.  Geomagnetic storms will wipe it out, however.  The tropical bands (60, 75, 90, and 120 meters) are not noticeably affected by the solar flux, but are degraded during geomagnetic storminess.  Through the summer, expect these bands to be more challenging.

Overall, daytime bands will open just before sunlight, and last a few hours after dark.  Look higher in frequency during the day, as these frequencies will be less affected by any solar storms occurring, and more broadcasters have transmissions in these upper bands.

VHF Conditions

July is one of the noticeably more active months of the year for VHF propagation between stations from about 500 to about 3000 miles apart.  Strong signals appear on the lower VHF spectrum, and then quickly fade away.  Experienced VHF DXers know this season as the Sporadic-E season, and July is in the very peak of the yearly season that begins in May, and ends by September.

Sporadic E propagation (abbreviated as Es or Es) affects the highest frequencies of the shortwave spectrum, as well as the lower to (sometimes) the mid-VHF spectrum.  It occurs most frequently during late spring and early summer.  Sporadic E propagation does not typically last very long, but the openings can be quite strong. 

The summertime Sporadic-E (Es) season for the Northern Hemisphere should still be active through July.  Usually these Es openings are single-hop events with paths up to 1000 miles, but July's Es events, like June's, can be double-hop.  Look for HF openings on the higher frequencies, as well as on low-VHF, throughout the day but especially in the afternoon.

Of course, with the increased geomagnetic storminess, there is a chance of Aurora and the related Aurora-mode propagation.  Check out the latest conditions at my propagation page, < >.

I'd like to hear from you

I welcome your thoughts, questions, and experiences regarding this fascinating science of propagation.  You may e-mail me, write me a letter, or catch me on the HF Amateur bands.  On Twitter, please follow @NW7US (and if you wish to have an hourly automated update on space weather conditions and other radio propagation-related updates, follow @hfradiospacewx).  I invite you to visit my online propagation resource at < >, where you can get the latest space data, forecasts, and more, all in an organized manner.  If you are on, check out < > and < >. 

Until next month,

73, Tomas, NW7US
PO Box 27654
Omaha, NE 68127

Web site:
Twitter: @NW7US ( )
Twitter: @hfradiospacewx ( )

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