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Author Topic: Stealth insulator for end fed antenna  (Read 558 times)

KF7ZFC

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Stealth insulator for end fed antenna
« on: September 30, 2020, 03:06:13 PM »

I will be buying a UltiMax 100 end fed antenna. The insulator is large and probably looks like an "insulator" to even those in the HOA who are not hams.

What are my alternatives that will be "stealthy"? Max power 100 watts. 80-10m

Thanks
Steve

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KF4HR

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Re: Stealth insulator for end fed antenna
« Reply #1 on: September 30, 2020, 03:37:09 PM »

Most any EFHW (End Fed Half Wave) antenna will allow you to install the transformer at ground level so your coax can be hidden underground if necessary.  If you want to do away with the transformer just run a random length of wire (thin = stealthy) and use an Antenna Tuner in your shack.

As for a stealthy end insulator I recommend a small rectangular piece of clear plexiglass.  Just drill a hole in each end for the antenna wire and support rope, string, or perhaps clear fishing line.   
« Last Edit: September 30, 2020, 03:52:06 PM by KF4HR »
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W6QW

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Re: Stealth insulator for end fed antenna
« Reply #2 on: September 30, 2020, 03:51:41 PM »

Easy solution - use Kevlar fishing line.  Available in a large range of break strengths. I have used this for for years as stealth insulation and it easily handles full legal limit.  My favorite color is camo green.
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WB6BYU

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Re: Stealth insulator for end fed antenna
« Reply #3 on: September 30, 2020, 04:45:25 PM »

When I already have 20+ feet of plastic rope tying off the end of
a wire antenna, what additional benefit is a couple more inches
of plastic going to make? 

So I just tie the rope to the end of the wire.  Never had a problem
at 100W.

That assumes, of course, that your rope is an insulator, but there
are so many options these days in nylon, polyester, Dyneema,
Kevlar, etc., that that shouldn't be an issue.  Some of the braided
fishing lines are excellent, and at the moment my doublet is strung
up with black "tactical micro cord", which is almost impossible to
see from a distance.  (The wire is about #26 with a brown/green
stripe, and is difficult to see unless you get the sun on it just right.
Or when you get frost on it...)

K6AER

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Re: Stealth insulator for end fed antenna
« Reply #4 on: September 30, 2020, 06:12:49 PM »

Lay the counter poise on the ground around the house. Put the rest of the assembly under a plastic rock.
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AK5B

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Re: Stealth insulator for end fed antenna
« Reply #5 on: September 30, 2020, 09:26:51 PM »

Flat automotive primer (battleship/Dish Network grey) is your best and easiest way to make anything against the sky stealthy.
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N8NK

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    • N8NK QRP
Re: Stealth insulator for end fed antenna
« Reply #6 on: September 30, 2020, 11:46:34 PM »

For evey one of my antennas- two inverted vees in the trees, and for elevated radials on verticals, I use black zip ties, the 8" variety. They are increddibly strong and long lasting. I even use them to for the center 'insulator' of the vees. I've not had one fail in the 3 years the dipoles have been up. Also, for nice insulators, bags of 25 or more can be bought that are meant for electric fences. They're similar to ceramic egg insulators, only plastic. Not good for HOA use unless painted: they're bright yellow.  73 and good luck   :)
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W9WQA

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Re: Stealth insulator for end fed antenna
« Reply #7 on: October 01, 2020, 11:33:01 AM »

weedwhacker cord is cheap, unbreakable, waterproof, hard to see,lasts forever,great insulator...mine is up for 16 years now.
did i say hard to see and cheep,? !

oh, that makes it the only all in one antenna hanger..
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KH6AQ

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Re: Stealth insulator for end fed antenna
« Reply #8 on: October 07, 2020, 07:00:44 AM »

To make fairly stealthy antennas I use bare stranded copper wire tied off with clear 50 lb test fishing line. The UltiMax 100 end fed antenna uses insulated #14 wire. Bare wire may require some lengthening to achieve the same resonant points. Sunlight does deteriorate clear fishing line. I replace mine every year before it breaks.
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W9WQA

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Re: Stealth insulator for end fed antenna
« Reply #9 on: October 07, 2020, 07:03:47 AM »

To make fairly stealthy antennas I use bare stranded copper wire tied off with clear 50 lb test fishing line. The UltiMax 100 end fed antenna uses insulated #14 wire. Bare wire may require some lengthening to achieve the same resonant points. Sunlight does deteriorate clear fishing line. I replace mine every year before it breaks.

weedwhacker cord is cheap, unbreakable, waterproof, hard to see,lasts forever,great insulator...mine is up for 16 years now.
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WB6BYU

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    • Practical Antennas
Re: Stealth insulator for end fed antenna
« Reply #10 on: October 07, 2020, 08:56:22 AM »

One factor to consider is that voltages are higher at the ends of
shortened antennas (assuming the same radiated power).  I have
heard of folks setting their antenna insulators on fire running the
legal limit into a commercial coil-loaded dipole, so one does need
to be cautious above barefoot power levels.


The UltiMax 100 is one of the "matching transformer plus wire"
variants, so, depending on the wire length chosen, it may be
a "short antenna" on some bands.  However, the voltage at
the end will be reduced by losses, and due to the current
distribution along the coax cable back to the radio (and from
there into the AC power wiring, etc.) if it isn't used with an
effective ground system (in spite of the manufacturer's claim
that radials or a ground connection are "not required").

My guess is that with such an antenna, the voltage withstand
of the end insulator is going to be the least of your problems.
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