ARES / RACES and the
NVIS Antenna


There are many times when an ARES or RACES group will need to provide communications for a served agency over terrain that is not inducive to those communications. Such as many of the areas in Colorado where our most known feature, mountains, heavily restrict VHF/UHF communications. As such we, as an organization, have taken to using the Near Vertical Incident Skywave (NVIS) antenna on 40M and 75M (60M works very well but few have the equipment).

Construction and Testing

An overview of the NVIS antenna and its construction are on the separate page.

Since there are many different opinions on what constitutes an NVIS and what configuration of NVIS will work for ARES/RACES, we have started testing various configurations in the hope of finding the most cost effective and easiest to construct configuration that will adequately handle our communication needs. This testing will be conducted any time we have three or more people that have time to work on their antennas and/or help with the testing.

The testing itself will optimally be a comparison between two (or more) antennas from the same site and, within a few minutes time, to minimize the effects of changes in band conditions. If you do not currently have an NVIS antenna, then it is obvious you will be testing the initial antenna only and simply looking for something that works. After that, you will be able to help compare antennas.

Distance between Antennas

At least one of the stations working a test will of necessity not be within ground wave distance of other stations in the test. We want to evaluate NVIS performance and two stations, say at Byers and in Lakewood, would hear each other on the ground wave and not know how effective either antenna was for NVIS operation.

Reporting Results

PLEASE report the results you get from all of your tests! These will be extremely valuable to those that do not currently have a license that allows them to participate in the tests. Why, you say? Very simple, they will be able to review the results (yes, you can have your call/name omitted from any "aw-S[bleep]" results, if you ask) and learn from the collective wisdom of our group.

Other NVIS Information