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Author Topic: 160 antennas  (Read 442 times)
K4FLH
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Posts: 9




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« on: February 04, 2010, 09:29:22 AM »

I imagine that this has been discussed more times than Carter has pills. I am looking for opinions on what is the best antenna for 160 meters on a piece of property that is not only small but irregularly shaped.

Here's what I have to work with.
The lot is pie shaped, 130ft. at the widest point across the front, 190ft. deep and only 10ft. across the back line.
Half of the lot is level. The other half is a steep hill which is heavily forested. From the back of the house to where the incline starts is 20ft. and the width at the start of the slope is 75ft. Wierd shaped but not a lot of grass to mow! LOL

I can put up anything I want(no covenants)but I'm on a tight budget(who isn't?) and would prefer not to have to erect a tower.I have two 30ft. push up poles on the house already and a ground mounted 10ft. tripod with 10ft. of mast coming out of it with a Gap DX Titan on it right at the edge of the slope.
Any advise would be appreciated.
73
Bill/k4flh
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KAISERSOUSE
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Posts: 327


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« Reply #1 on: February 04, 2010, 09:32:37 AM »

You could fit a dipole length-wise in that space
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KAISERSOUSE
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« Reply #2 on: February 04, 2010, 09:34:11 AM »

Actually no,...it would only fit if i wasn't a total dumbass and had used the right freq to calculate.

I'll move along....
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KB9CRY
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« Reply #3 on: February 04, 2010, 09:40:00 AM »

Depends on what you want to work;;;domestic or DX.

Domestic, low dipoles and loops work well.

DX, for transmit, either an Inverted L or shunt loaded tower work well.  For receive, you'll need something else, like a Beverage, pennant, flag or EWE.

Homework time.
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W8NF
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Posts: 53




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« Reply #4 on: February 04, 2010, 09:57:10 AM »

When I lived in California, I had a notably smaller lot.  I'll assume your goal is DX...if not, then you've got plenty of land to put up a loaded dipole, which is easy.

In my case, I used, for receive, an offset-fed 60 foot horizontal wire which I nominally called a "40 meter offset fed dipole".  Lowering it to only 10 feet high reduced the low-angle pickup enough to attenuate the noise received from my neighbors' electronics.

But what to do for TX in an antenna field that's only 20 X 40 feet?  Aha!  A 50 foot telescoping TV mast was placed upon a varnished stack of 2X4s for insulation.  Four top hat wires, 20 feet long each, were added to the guy rope system.  Resonance was about 2.8MHz, and I made a fixed-frequency tuner using soft-drawn 1/4" tubing from Home Depot.

For radials, I went gull-wing style, connecting them to a copper wire ring at the base, raising them up nearly parallel to the mast, to about 10 feet high.  Some went over the top of the house toward the street, terminating in Sycamore trees, others went toward the back lot line.  Some terminated on the wood fence.  Of these wires, none were more than 30 feet long.  But I had a "secret weapon".  That wood fence along the back line was connected to neighboring fences, none of which had gates.  I was able to run one radial wire, elevated four feet, along the wood fence to the south, nearly 150 feet, and another to the north about the same distance.

At the time, my only rig was a Drake B-line, which was capable of making no more than 20 watts on 160.  That was enough for a dozen countries in the 160DX 'test in 2001.

My conclusion:  DX transmitting is the easy part.  Receiving is where you'll put your effort.

Dave W8NF
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WA3SKN
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Posts: 5559




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« Reply #5 on: February 04, 2010, 12:22:32 PM »

Just string up a loop, the larger and higher the better, and feed with ladder line and a tuner. It does not have to be cut to frequency.  Operate on any frequency that you can load with the tuner.
Oh, and keep it away from any power lines!
73s.

-Mike.
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WX7G
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Posts: 6328




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« Reply #6 on: February 04, 2010, 06:49:08 PM »

You have room for a vertical or an inverted-L.

The simple way to get going is to configure 126' of wire as an inverted-L. Run it from ground to the top of one of the 30' masts then to the hill. A dozen 50' radials is a good start. Direct feed with coax and  the VSWR should be under 2:1 at resonance.

Verticals works well too and can range from very short to very tall. I use a 12' top loaded vertical on 160 meters. The Hustler 5BTV vertical can be top loaded with a DX Engineering top hat. The top hat and a Hustler RM80 resonator can be placed on a mast from 12' to 60' to make a top loaded vertical. Beware the bandwidth is but 20 kHz.

Another homebrew antenna which I have built a few of consists of a mast with a top hat and a homebrew inductor at the top. I put 1/10 of the inductance at the base so it can be tuned from the ground.

If you choose the top loaded vertical post the dimensions of the top hat and I'll give you directions for building the inductor. Close wound #14 THHN (house wire) on a PVC pipe makes a fine inductor having a Q of 300.
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K0ZN
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Posts: 1563




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« Reply #7 on: February 04, 2010, 07:08:19 PM »

There is no quick, easy answer to this. What you need to do is spend some time with the ARRL Antenna book and get a handle on 160 M antennas and their feeding and care. Most ham's QTH's are unique and you have to figure out what combination of supports and antenna type mesh to be best at your QTH.

The above said, from what I have seen over the years, probably the best, most efficient (in most average ham situations) and effective antenna for the buck is the inverted L. They have been around a long time and are a proven decent performer. Properly done they are a good antenna and not a huge amount of wire is needed (1/4 wave minimum) and you can bend the horizontal portion some to fit as necessary. The downside, is that an Inverted L is not a "plug and play" antenna. You have to have a matching network or UNUN and/or understand what is necessary to get a decent match.
Close doesn't count in this case.

The reality is that on 160 Meters, MOST ham antennas are far less than optimum, but will still work out amazingly well.

The key to your success is KNOWLEDGE about what you are doing....and that comes from some book study.

73,  K0ZN
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