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Author Topic: Multiband HF antenna and ladderline into tuner  (Read 3799 times)
ZS5BG
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Posts: 7




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« on: April 18, 2010, 09:10:39 AM »

Hi

I am in need of some expertise regarding the placing of a wire antenna at my QTH.

I have a James Millens 92210 transmatch and am busy making the ladder line .

I have very tall gum tress either side of my house and they are approximately 90 m (300 feet)apart.

The antenna I am wanting to place up is something I can use for 80m-10m .My main operation is on 40+80m but at times would like to try 160m.

So my question is what antenna type would suite my needs .

My study which is my inside shack is equi-distant from both trees so the ladderline can hang straight down and enter .

With this I have a choice to run a 160m doublet or other extended zepp's and the feeder into the matching unit .

There are many different choices and the only way forward is to get some sound advise.

Thanks

BradZS5BG
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WX7G
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Posts: 5917




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« Reply #1 on: April 18, 2010, 03:25:27 PM »

You can certainly build an 80 meter long dipole fed with open line and use it on all bands. 160 meters should be getting good at your QTH in a month.
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AB4D
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« Reply #2 on: April 20, 2010, 10:34:07 AM »

You didn't say how far away from the back of the structure the trees are standing.  If they are some distance away you could put up a delta loop (triangle shaped loop),using a single peice of wire fed with ladder line.

Whereas, you would have one leg run from the structure to the first tree, the second leg would run across the 300 feet between the trees, the third leg would return back to the structure, attach one lead of the ladder line, and the other side to the other.

Use a dogbone insulator to support and seperate the ladderline/antenna ends.

73
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ZS5BG
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Posts: 7




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« Reply #3 on: April 20, 2010, 01:50:45 PM »

Good idea ,a Delta loop could work well regarding the setup I have .
One of the questions was - originally do I place up a large loop or zepp type antenna ,I will have to find out how the Delta loop id compared to the original thought of a dipole feed with 600 Ohm ladder line.

I have since got the porceline spreaders which will give approx 600 Ohm with the wire I have (hard drawn steel SWG 14(2mm).Plus porceline EGGs for the ends.

Can the Delta do 80-10m ? Anyone have  experience with these antennas? I assume they will also be quieter antennas compared to dipoles.
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WX7G
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« Reply #4 on: April 20, 2010, 02:26:07 PM »

Why use a delta loop? I can run a simulation of each for you on every band and you can decide which antenna you prefer.
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ZS5BG
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Posts: 7




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« Reply #5 on: April 21, 2010, 10:28:32 AM »

Some RF patterns would be very useful.

My setup is :

Shack in the middle and in line with the two tallest trees either side of the shack .This means that nothing will be skewed, the 600 Ohm ladder line will come straight down into the tuner.The trees are approx 100m apart.

The trees , if I get a professional tree climber can have the pullies at approximately 50 meters up from the ground.

I did look at some Delta loops on the net but very few mention the multiband operation .

If you could do some plots on the extended doublet Zepp for the main bands 80/40/20/15/10 that would be great .

Thanks in advance.

Brad
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AD6KA
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Posts: 2232




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« Reply #6 on: April 26, 2010, 01:37:21 PM »

"The trees , if I get a professional tree climber can have the pullies at approximately 50 meters up from the ground."

FIFTY Meters up? Those are some serious trees
for a backyard. (Maybe I've lived in the suburbs too long) Smiley

I'd go with the 80m ladderline doublet, with a really
strong center connector.

Also I'd use high end marine quality pulleys (from
a boating shop) and stainless steal hardware everywhere
you can outdoors. Oh, and UV resistant Dacron or such for the
ropes & lanyards, also available at the boating shop.)
Not cheap, but if you're paying professional tree climbers
to go up there and set this up, you don't want the hardware to corrode
and/or fall apart after a few seasons and have to pay them to go up again.

Boy, I'd love to see photos of those guys climbing the trees.
Maybe you should build a webpage about how you put up
your antenna!
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AD6KA
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Posts: 2232




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« Reply #7 on: April 26, 2010, 01:39:03 PM »

Sorry, I meant "stainless Steel" not stainless *steal*
Please do NOT shoplift the hardware,haha!
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ZS5BG
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Posts: 7




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« Reply #8 on: April 28, 2010, 05:31:13 AM »

Here is the link to my page with a small picture of the trees above the wooden shack.

I will be making a new page for this antenna project .Currently I cant access my web server so it may take a few days.

http://zs5bg.repeater-builder.com/index.html
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ZS5BG
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Posts: 7




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« Reply #9 on: April 29, 2010, 09:38:33 AM »

Here is the ladderline so far.
http://zs5bg.repeater-builder.com/IC-703photos.html
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AB4D
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« Reply #10 on: April 30, 2010, 04:04:35 AM »

The Delta Loop can do multiband operation when fed with ladder line.  I like the full wave loops, they tend to be quieter than dipoles and work well on the low bands, when the antenna is cut for the lowest band of operation.

I've used ones that are resonant for 80 meters on every band through 10 meters without any issues.
« Last Edit: April 30, 2010, 04:07:49 AM by J. Jones » Logged
ZS5BG
Member

Posts: 7




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« Reply #11 on: May 02, 2010, 06:48:26 AM »

Hi AB4N

I was looking at the Delta loop in an upside down triangle config being feed via 600 ohm at the bottom .

I did look around on the web but found very little on the multiband usage of this type of antenna , also polarisation may be an issue .

So far my better half has agreed to the monster antenna , with provision I take the ugly one down in the front of the house-this was the plan all along .
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