NVIS Antennas
Dependable HF Coverage Within 400 km
For mobile use the choice seems to be a 16 ft whip, which is pulled
down near the end, so it is parallel with the roof of the vehicle, making
the signal go vertical. There are variations of this for permanent mobile
antennas. It is recommended that the antenna be fully horizontal when not
moving, if possible for best operation.
Fixed stations seem to have two options;
- Dipole antenna for 40m and 80m with a 15 ft insulated mast in the centre.
Design Guide: http://www.vcars.org/tech/NVIS.html
Same design, but more details on the mast:
http://webpages.charter.net/w9wis/NVIS1_nn4.html
Buddipole N-Vee Antenna (more good ideas)
http://www.w0ipl.com/ECom/NVIS/cbp-nvis.htm
- Tri-band dipoles for 40m, 60m, 80m
http://www.eham.net/articles/5747?ehamsid=7515fe781d0225269955278b2269f9f0
Similar design, but tri-band 40m, 60m, 80m
http://www.commacademy.org/2004/handouts.php
(This is a large PowerPoint presentation)
- Wire antennas located very close to the ground, either
fed from the vehicle antenna mount or from a portable radio
Examples with user results:
http://www.tactical-link.com/field_deployed_nvis.htm