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Portable NVIS Antenna

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The Thought

• I want an antenna easy to:

• Transport

• Set up

• Use

• No Coils or Traps (1/2 wave length Dipole antenna)

• Easy to build

• No Tuner Required

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Time for a trip to Lowes

• Four 10’ lengths of 1 1/2” PVC schedule 40 pipe

• Four 1 1/2” End caps

• Three 1 1/2” T Fittings

• Five 1 1/2” Coupling joints

• One 1 1/2’-1 1/4” Reducer

• One 3/4” PVC junction

• Two 1/2” plugs

• 3/32” ferrules and stops (rope section)

• Spool of 14 AWG (500’)/ more than I needed

• PVC Primer and Cement (comes in a kit packet) Small is plenty

• Coat Hooks

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Stuff I had on hand

• Reciprocating Saw (hand saw works, it is just PVC) I take the easy way sometimes

• Power Drill and Bits

• Crimping Tools

• Rivet Gun

• Can of Orange Spray Paint (your choice and tastes may vary)

• Soldering equipment

• SO-239 Chassis Mount

• Screws/ Washers/ Nuts/ rivets

• RTV

• Rope

• Tent Stakes

• 1/2’ Pex (insulators)

• Zip Ties

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Getting Started

• Cut the straight end of the reducer (about 1/4”) as it is too long

• Drill a 1/8” hole in each of the 1/2” caps

• Drill a hole for the SO-239 in the center of the Junction box

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Assemble the Box

Cement the

Reducer to the Box

Cement one of the 1 1/2”

Couplers to the

Reducer

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The Ferrule & Stop

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A Bit of Electrical WorkI goofed and missed putting the wire an ferrules through the end caps before the end eyes were attached. The wire would have been longer as well. I suggest about 10” to make attaching the element easier.

Should not have attached these yet.

Stop should be here

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More of the Box

• The hole for the SO-239

• Screw holes drilled

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More of the Box

A bit of RTV and screw it in place with the Ground Side Jumper

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More of the Box

• The End caps should have been in place for the previous step

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Getting Started

• Cut 9 section of 1 1/2’ pipe to 34”/ Clean up the cut ends

• Cement one end cap on the end of 4 of the cut pieces

• Cement the remaining 4 couplers at one end of other 4 sections of pipe

•

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The Top Section

• I put two sets of Coat hooks to store the Elements of the Dipole

• No coupler on this piece

• The hole is to run the Coax inside

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The Base

• You will need to cut Two pieces of scrap about 2” to act as a coupler

• Cement the three 1 1/2” Tee pieces to look like this

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Paint the Mast

• I taped the ends with the famous Blue Masking tape keeping the last 2 1/2” from getting paint on them

• I painted everything except the Junction Box with my Orange Spray Paint

• I should have covered the couplers to keep paint out (I still need to sand them clean)

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The Mast Top

• The Duffle bag is 36” long

• One of the mast pieces should have been cut to 30” to fit into the bag because the Junction box makes it too tall

• I missed drilling a hole in one of the other mast sections to allow the Coax to exit

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The Elements

• I cut two lengths for each Band with extra for fold back

• Put a crimp eye to attach to the Junction box jumper

• 60M 44’ + 2’

• 40M 33.5’ + 2’

• 20M 17’ + 2’

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Insulators

• I cut Six insulators from some extra Pex I had on hand

• Drill a hole in each end big enough for the line and element wire

• These were painted when I painted the mast

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Here it is waiting to assemble

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The assistant

• Chores first

• Grandpa can not mow after we have the antenna in the yard

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Here it is

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Need to add an exit hole here

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Tuning

• We set up the elements to be staked at about 40’ from the mast

• Only the 40M and 20M were set and tuned

• It took about 1 hour to assemble and tune two bands

• Two weeks later on another visit I set the antenna up in 10 minutes no helper

• The helper on another visit added time, about 30 minutes

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Results From Altus OK.

• Contacts in one Day (really just two hours)

• New Orleans

• Miami

• Portland

• Seattle

• Mexico City

• Vancouver

• The weird one

• Blackpool (England) 4/8 Report

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Questions??

The assistantsChristopher

& Jack

At the Fireman Challenge