NVIS Page 8

Copyright © 2002-2072 by Harold Melton, KV5R. All Rights Reserved. Feel Free to Link to This Page.

Links to More NVIS Study

(August 2021: Removed several dead links)

Shop for ready-made Dipole Antennas here.

A great introductory article:

Field Manual 24-18 Appendix M — Lots of info and graphics (now on this site!)

Search Usenet groups for NVIS (hundreds of postings by NVIS experimenters):

The HF Portable Group:

Technical background:

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5 thoughts on “NVIS Page 8
  1. Thank you KV5R for a great micro-summary to NVIS.
    I’m a newbie, got my general ticket last august as a birthday present to myself.

    I’m thinking out loud here, bet wouldn’t a legnth of chain link fence serve the purpose of a ‘decent’ ground if run under the dipole in cases of crappy dirt?

    Some folks might be able to use that….

    I.E, if one had the wherewithal to to do it.
    Of course this won’t work with mobile, cvcc

    • Never tried it, but I don’t think chain-link would work very well, due to all the millions of potentially corroding joints (poor lengthwise continuity).
      However, welded-wire fencing might do the trick, tho I don’t have any idea how wide it would need to be to effectively reflect RF and reduce ground losses.
      The best (and cheapest) solution to the poor earth problem would be to raise the dipole higher and put an elevated wire reflector element (5% longer) under (~ .2 to .25-wave) under the dipole. In effect, creating a 2-element yagi pointed straight up. However, how effective that might be on non-resonant freqs is questionable.
      One thing is certain, putting a dipole over a large pond or wet/salty/acidic marsh works very well — so the trick (without such pond/marsh) would be to duplicate the conductivity and large area. Since an acre of welded-wire fencing would cost $thousands, I’d prefer the elevated reflector wire — but then, it requires higher supports for the dipole. That’s getting away from the “NVIS” idea, where a simple dipole is strung up pretty low (fast and easy), typically in an EMCOMM scenario, not an optimized permanent installation.
      Hope that makes sense!
      73, –kv5r

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