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Author Topic: Top-Loading the HF-2V  (Read 536 times)
NI0C
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Posts: 2391




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« on: March 03, 2006, 01:00:58 PM »

About a week ago, I added some top-loading to my HF-2V.  Using three very droopy wires each about 15 ft. long, I was able to short out 60% of the 40m coil and about 25% of the 80m coil.  My bandwidth on 160m went from 9 KHz to about 20 KHz, and on 80m it went from 40 KHz to 50 KHz.  I'm afraid the wires aren't going to last very long though (due to wind stress), and I'd hate to have a wire break in the midst of a dx chasing session.  So I'm looking for a more permanent top loading scheme.  

I have plans from DX Engineering for a modification to the HF-2V, adapting their "Hot Rodz" capacity hat (uses horizontal steel rods), and am gathering up the materials.  I'm curious about the results of others who have added top-loading to this antenna.

73,
Chuck  NI0C
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VE3IOS
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Posts: 79




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« Reply #1 on: March 04, 2006, 06:33:47 AM »

Chuck; Bencher(Butternut) has an add on top loading kit for the HF-2v
http://www.bencher.com/antaccessory.html

jeff
VA3XQ
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NI0C
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Posts: 2391




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« Reply #2 on: March 04, 2006, 11:15:28 AM »

Hi, Jeff.
 
Bencher's top loading kit consists of four wires with terminals, plus a slightly longer bolt for attaching the wires to the junction of sections "K" and "L."

It's like their GRK, ground radial kit-- just wires with ring terminals.

73,
Chuck  NI0C
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KB9CRY
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« Reply #3 on: March 04, 2006, 06:50:27 PM »

I top load the HF2V antennas used in my 80M 4 square.  They consist of three, 25 ft. long 14 Ga hard drawn stranded wire terminated in small plastic insulators and small UV resistant dacron rope.  They attach just below the 2 & 3rd section.  I terminate them to the antenna with a ring terminal which is attached at the screw that holds the section together.  Since there is a lot of potential load that bears on the solder joint of the ring terminal, I then folded the wire under the screw and down against the antenna section and then secured them to the section with a small SS hose clamp.  I've had mine up for 5 years now and have only had one fail by abrasion of the wire on the edge of the hose clamp.  The wirea are loosely guyed and also help stabalize the antenna so that it doesn't whip too much in gustly winds.  Hope this helps.  Phil
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NI0C
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« Reply #4 on: March 05, 2006, 02:44:38 AM »

Phil,
Many thanks for providing details of your top-loading arrangement and how you addressed the problem of strain relief on the wire connections.  That's exactly the kind of info I was looking for.

A 4 square of HF-2V's, eh?  That tells me you like the antenna.  So do I.  I tried the MA8040V earlier this season, but sold it and put the HF-2V back up.  There are three reasons:  The HF-2V hears better in my location; the HF-2V can do 160m (or 30M); The HF-2V can be tuned from the ground.

I've now got all the parts I need for the DX Engineering top loading mod and will be trying it out in another week or so as time permits.  The basic idea is to use DXE's hub assembly designed for screwdriver antennas, attaching stainless steel rods for top loading.  Since the rods will be horizontal, they will have approximately a 40% advantage in length over wires drooped at a 45 degree angle.  I'll be able to install up to six rods, each with a length up to six feet.  I'm anticipating I'll have to add some light guying to the antenna with this extra weight near the top.  

73 & thanks again,
Chuck  NI0C
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KB9CRY
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« Reply #5 on: March 06, 2006, 07:13:59 AM »

Chuck, where are you going to install this DXE top hat?  The top two or three sections of a HF2V are very tiny and can barely hold up their own weight.  Adding any kind of weight on the tippy top will surely cause the antenna to fail, especially with 6 ft long rods?

And guying the antenna on the top two sections will also not be wise.  My HF2Vs are guyed at the intersection of the third and fourth section, about 2/3 up.  Gd luck.  Phil
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NI0C
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« Reply #6 on: March 06, 2006, 08:17:20 AM »

Phil,

The plan is to install the DXE hub at the junction of the 5/8" and 1/2" tubes (same place that Bencher recommends for attaching top-loading wires).  The hub will thread onto a piece of 3/8" rod that will extend into the 5/8 inch tube (shimmed with a short length of 1/2 inch tube inside it) and into the 1/2" tube above the hub.  I'll cut slots in the tubes and clamp them to the rod with stainless steel clamps.  

I may well opt for for 4 foot rods instead of the 6 ft. for stability reasons.

73,
Chuck  NI0C
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