Propagation to 3B7C

You will find via the buttons above and below, the  forecasted mean signal strengths between 3b7 and the 40 cq zones. Dean Straw n6bv developed the underlying forecast data with support of the American Radio Relay League. The 3b7c dxpedition management team thanks Dean and arrl for their support in making this data available to the dx community.

Parameters and adjustments

Dean n6bv chose these parameters as appropriate for forecasts for 2007 September’s 3b7c dxpedition dates:

·    Mid-September.

·    Very low smoothed sunspot number of about 10, equivalent to a solar flux around 72.

I made the following adjustments to the raw data provided by n6bv:

·    On each band, I adjusted signal strengths to accommodate the antennas to be employed by 3b7c. Each band’s table of forecasts includes details on this adjustment.

·    For the 30, 17 and 12 meter bands, I interpolated signal strengths between those provided by Dean for the adjacent bands. I marked the possibility of a long path opening if either of the adjacent bands’ forecasts indicated a long path opening.

Using the tables

Each table entry (use the buttons below to access the tables) shows the highest predicted signal strength, in s-units, from the locations within the cq zone for which forecasts were calculated. “9” corresponds to 50 µV, with each s-unit corresponding to a 4 dB change.

You must make two further changes to the calculations:

·    An adjustment to account for your station’s antenna system.

·    An adjustment to account for your station’s transmitter power.

Each band’s table lists the details for these adjustments.

Special reminder!

The forecasts represent mean signal strength during the hour under undisturbed ionospheric conditions. On half the days of the month, signals could be stronger, and on other days signals could be weaker than forecasted. Furthermore, minute-by-minute variations in the ionosphere will enhance and degrade signal strengths.

As a result, even if the forecast suggests your station will have little success in hearing or working 3b7c, you should not give up! If you are on the air:

·     during a day with better-than-average conditions, or

·     during the minutes when ionospheric variations favor your location, or

·     during a time when stations from other parts of the world with large populations of dxers are not very loud at 3b7c,

you may make a successful contact with 3b7c even though the forecast data says “unlikely”.

Information from the dxpedition:

During the 3b7c on-air operation and if we can get a reliable link back to the Internet, the team hopes to post a daily propagation and planning statement to the website. This statement will:

·    Highlight qso statistics to date.

·    Discuss propagation experienced during the previous 24 hours, especially any openings that varied significantly from forecasts.

·    Summarize plans for the next 24–48 hours, including special emphasis on particular bands to certain parts of the world or on certain modes.

This daily statement, together with these forecasts, should help you plan your chase of 3b7c.

We hope to work you on every band and mode. Good luck!

— Eric Scace k3na

  Click the button below for the propagation predictions for the band