Near Vertical Incident Skywave NVIS Antenna

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Near Vertical Incident Skywave (NVIS) Antenna

• Carlton Wells, AG4UT
• 01-08-04

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What Sparked My Interest?

• New 60m band
• FCC Report Order in ET Docket 02-98, FCC
  03-105A1
• QST, June 2002
• QST, August 2003
• The 5 MHz channels also might provide the best
  propagation in the event of a disaster when 75
  (3 MHz) and 40m (7 MHz) bands are not favorable.
• Read FCC quote in QST, August 2003

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What Led Me to NVIS?

• An article on a military discovery when stowing
  its whip antenna.

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How Did I Decide on a NVIS Ant. Design?

• Internet search
• Discussion with fellow hams (AG4UU K4TB)
• Current and future operating habits (mobile base
  and ant. jump kits)

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Objectives of Using a NVIS Antenna

• Minimize low takeoff angles (grd. waves and DX)
• Maximize very high takeoff angles (near
  vertical)
• Thwart long-distance electrical
  disturbances (thunderstorms)
• Get signals out of valleys (not applicable in
  Florida hah!)

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Compliments of Albert Pion, KK7XOQST article,
June 2002
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Compliments of Albert Pion, KK7XOQST article,
June 2002
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Compliments of Albert Pion, KK7XOQST article,
June 2002
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Compliments of Albert Pion, KK7XOQST article,
June 2002
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http//www.eham.net/articles/5747
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Parts List

• 3 10 PVC, 1.5 pipe
• 5 1/5 PVC cap
• 4 1/5 PVC coupler
• 2 1/5 PVC cross tee
• 1- 1/5 PVC tee
• 6 double-prong coat hooks
• 300 - 14 str Cu, red insulation

• 4 RG-58A/U
• 1 PL-259
• 1 UG175
• Misc. dacron polyester rope
• 6 tent stake
• 3 eyebolt, ss

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Parts List (cont.)

• Misc. PVC primer and cement
• 6 connector, solderless crimp
• 2 solder tab
• 6 insulator
• 1 36 duffle bag

• Balun
• Misc. steel wool
• 2 plastic discs
• Misc. silicon sealant, non-corrosive

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NVIS Dimensions and Tuning
/- 75 kHz on 75m /- 100kHz on 60m /- 140kHz on
40m
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Other NVIS Antennas

• http//www.ci.san-jose.ca.us/oes/races/hfradio.htm
  
• 100 horizontal wire 6 AGL
• 15 military whip antenna 7 AGL, oriented
  horizontal off vehicle
• Dipole antenna 10.5 AGL
• http//www.eham.net/articles/4141
• 3367 40/75m antenna 3-5 AGL
• Spring-mounted, CB whip tied down for mobile oper.

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Suggested Applications

• Jump Kit for Hams providing a public service
• N. Florida ARES Net and others
• Field Day to eek out points within the skip zone

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Thats My NVIS!Thank You!

• ag4ut_at_arrl.net