[ARCHIVED THREAD] - NVIS

Posted: 8/8/2007 8:15:28 AM EDT

There is NVIS info spread through a couple threads so I thought I would try to bring the entire NVIS thing into this thread. I believe NVIS is a highly important part of survival communications. NVIS allows you to reach stations 0-300 miles away that would otherwise be missed in the skip using other methods. In my opinion you are better off being able to communicate with close communities who are able to respond quickly.

What is NVIS (Near Vertical Incidence Skywave)?
(From TacticalLink.com)

NVIS , short for Near Vertical Incidence Skywave, utilizes high-angle skywave paths between stations instead of ground-wave or surface-wave in order to communicate via HF radio. NVIS was originally evaluated by U.S. Army Forces in Thailand during the Vietnam conflict in the mid-1960's It was found that Mobile stations, using whip antennas bent parallel to the ground, could communicate more reliably with their base-stations. Signal strengths would be weaker using high-angle skywave but communications would be more reliable, less subject to fading, and consistent between stations. This was because the intervening terrain was less of an absorber of signals. Terrain obstructions between stations, such as hills, mountainous areas, jungle growth, built-up areas with tall buildings, no longer become path obstructions with stations when NVIS techniques are employed.

NVIS Links

NVIS Propagation Conditions
hflink.com/propagation/

ARRL Power Point Presentation on NVIS (Great place to start looking for information)
www.arrl.org/FandES/ead/materials/NVIS.ppt

ARRL Doc File on NVIS Operation
arrl-sc.org/Tech%20Presentations/Near%20Vertical%20Incidence%20Sky%20Wave.doc

Hi-Q NVIS Antennas
www.hiqantennas.com/

Field Deployment of NVIS (Actual setups and tests in the field)
www.tactical-link.com/field_deployed_nvis.htm

Elpa Antennas (No longer sold new but can be found from surplus resellers. Specifically made for NVIS)
www.hflink.com/antenna/elpa/

I'll add more as I find it.

Posted: 8/8/2007 3:11:35 PM EDT

[#1]

www.athensarc.org/nvis.asp

I posted this last night in another thread, a huge amount of NVIS info there as well as many additional links at the bottom of the page.

Posted: 8/8/2007 6:05:10 PM EDT

[#2]

some NVIS antenna info here as well:
archive.ar15.com/forums/topic.html?b=1&f=123&t=440825

ar-jedi

Posted: 8/9/2007 11:17:15 AM EDT

[#3]

I finally figured out why none of the NVIS tests were working properly. The flippin IC-718 that I picked up used isn't working properly. I'm waiting to hear from Icom about where I can send it etc.

--Scott

Posted: 8/19/2007 4:53:21 PM EDT

[#4]

I have an IC-7000 with an HI-Q 5/80 vertical on my truck. The antenna has a 102" whip on top. I tie the top of the whip down to my trailer hitch so it doesn't hit stuff and behold.....it works GREAT as an NVIS antenna.

If I want to DX...I just untie the bottom of the tether and allow the whip to stand straight up. Just talked to a guy in Jamaica from Ft Worth yesterday. Not bad for a mobile, given the solar cycle.

NVIS from Army MARS:

NVIS in Depth

Quick & Easy NVIS

Warning

Confirm Action

[ARCHIVED THREAD] - NVIS

[ARCHIVED THREAD] - NVIS