Sometimes the best direction to send your signal is straight up!
Near vertical incidence skywave, or NVIS, is a skywave radio-wave propagation path that provides usable signals in the range between groundwave and conventional skywave distances—usually 30–400 miles (50–650 km). It is used for military and paramilitary communications, broadcasting, especially in the tropics, and by radio amateurs. The radio waves travel near-vertically upwards into the ionosphere, where they are refracted back down and can be received within a circular region up to 650 km from the transmitter. If the frequency is too high (that is, above the critical frequency of the ionospheric F layer), refraction fails to occur and if it is too low, absorption in the ionospheric D layer may reduce the signal strength.
There is no fundamental difference between NVIS and conventional skywave propagation; the practical distinction arises solely from different desirable radiation patterns of the antennas (near vertical for NVIS, near horizontal for conventional long-range skywave propagation).
EFHW-8010-1K ™ Multi-Band End Fed Half Wave Antenna This is an End-Fed Half-Wave (EFHW*) antenna for 80/40/30/20/17/15/12 and 10m bands. Unlike many... Read more
100MHz to 750MHz Log Periodic Array Description InnovAntennas design and build Log Periodic Arrays for any bandwidth and for any purpose. Our LPDA... Read more
OCF HF Vertical Dipole Higher performance, HF Multiband DX Flagpole Antenna covering 3.5 to 50MHz with NO radials sound like relief for your CC&R... Read more
Compatible digital radio protocols and networks DMR (BrandMeister, DMRplus, DMR-MARC, Phoenix, XLX, TGIF) D-STAR® (DCS, REF/DPlus, XRF/DExtra, XLX) Sy... Read more
In this video I show you how I setup an audio mixer for my ham radio station. I am using this mixer to monitor the audio outputs from my Elecraft K3,... Read more
“An amazing new mode for quickly communicating around the world with low power and simple antennas. In this video Jim uses exterior holiday or C... Read more