WCF SECTION PRESS RELEASE #20-13

NEXT NVIS TEST SCHEDULED FOR SATURDAY 3/07/20

On Saturday March 7, 2020 at 0900 a Near Vertical Incident Skywave (NVIS) test is being conducted on 75 Meters.  Larry Gispert KR4X, an ARRL Official Emergency Station and Fred Seely AA4ME, who is with Highlands County ARES, will be overseeing these tests.  The test will take place on a frequency of 3913 KHz on Lower Sideband (LSB).  Depending upon the Maximum Useable Frequency, test may also be conducted on 60 Meters at 5370 Khz USB (CH-3), and on 40 Meters at 7282 KHz. Note: 60 meters is USB in order to keep emissions within the F.C.C. mandated channel limits. Also the Maximum Useable Frequency (often called the FoF2) info will be used to determine which frequency to use. NVIS theory suggests using the amateur band that is closest but below the projected FoF2 frequency.

Gispert stated the following concerning the NVIS test, “The current data does indicate that any Horizontal HF antenna mounted at a height of less than a quarter wave length above ground does exhibit some NVIS tendencies. We realize that most hams have their 80/75 meter antennas mounted at a height of less than 60 feet and those antennas do exhibit some NVIS radiation. We adopted the height of less than 15 feet to insure maximum NVIS radiation… We were interested in proving the viability of this form of transmission for covering distances between 100 to 300 miles of separation by using High Frequency (HF). The thought was that during times of emergency the normal internet, telephone and VHF/UHF repeaters might be over crowded or disabled and two or more HF stations could provide the necessary communications links between identified emergency locations.”

At 0900 Gispert and Seely will meet on 3.913 kHz LSB running NVIS antennas (horizontal dipoles mounted at a height of 15 feet or less).  KR4X, will be setup at Picnic Island Park at the southern tip of the Interbay Peninsula in South Tampa and AA4ME will be setup in Highlands County (a distance of at least 100 miles apart). We will start at power levels of 100 watts and decrease incrementally to determine the viability of the communications path.  All stations are welcome to listen in or participate with their NVIS antenna.  GIspert and Seely have previously conducted these test in the 2009 and 2010 time frame and on a few occasions since then.

END OF PRESS RELEASE