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Author Topic: New house; need some antenna advice  (Read 1462 times)
WK5H
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Posts: 111




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« on: October 28, 2012, 12:11:52 AM »

We've just moved to a new (well, new to us) house, and I have a lot more room to play with antennas.  Although, not a HUGE amount, but far more and different options than my last QTH.

I will be setting up my office/ham shack on the 2nd story.  Right next to the office, is a door leading to small deck that overlooks the back yard.

One of my main questions is, does radio height above ground affect the performance of an antenna?  The reason I ask, is because I may be able to put up a vertical in the backyard with a good radial system, but, the radio being on the 2nd story, will be at least halfway up over ground as a vertical antenna would be.

My other option would be to put a dipole over the tree tops in the backyard, but, the coax would be coming off horizontally to the dipole as opposed to going vertical to the ground first. what characteristics would this antenna have?

I have also thought about putting a vertical on the deck railing, which would put the radio elevation-wise at the same height as the feed point.  But, I wouldn't have an option for a radial field.  How well would a counterpoise work, going down to the ground from the feed point, essentially creating a vertical dipole?
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N3WAK
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« Reply #1 on: October 28, 2012, 06:01:32 AM »

First of all, I congratulate you on wanting to construct your own wire antenna.  That's the way to go. 

1.  Go ahead and put your radio on stilts if you want--it won't matter. 

2.  In my experience (more than 35 years of experimentation, with a lot of duds along the way), a vertically-polarized antenna will be noisier than a horizontally-polarized antenna, although, depending on height above ground, a lower vertical will be better for DX than a lower horizontally-polarized dipole should it matter to you.  I'm a casual operator, so I prefer a horizontally-polarized antenna; most of mine are inverted vees, which are simple mechanically to erect and maintain. 

3.  As I understand it, your coax should depart from you dipole at a right angle, ideally.  Of course, any angle is better than no antenna.  Straight down has an advantage because gravity wants to pull your coax feedline to the ground.  If your feedline goes out to the side--which is fine, since it's still a right angle--you have to contend with gravity and support the horizontal run of coax.  Either should work, but I've never chosen to fight gravity--straight down to the ground has always worked best for me. 

4.  A 1/2 wave vertical dipole might work great for you.  Ideally, the bottom of the lower leg should be a 1/2 wave above ground, but it doesn't sound like that will be the case at your house.  I think I'd just try it regardless.  If it doesn't work great, try a horizontal dipole over the trees--if you feed it with ladderline and use an external tuner, you'll likely have a very effective, multiband antenna. 

5.  If you go the 1/2 wave vertical route, make sure a passer-by doesn't get close to or touch the lower leg of the antenna when you're transmitting.  They'll get RF exposure and maybe an RF burn.  So, be cognizant of safety if there are little kids around. 

73, Tony
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KB5UBI
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Posts: 97




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« Reply #2 on: October 28, 2012, 05:45:48 PM »

The OP didn't say what bands he was interested in or how much he has to spend. I'll presume 80-10 and the typical limited budget. Question: What is the deck railing made of and how long is it?. Metal railing and a few additional radials could make an elevated Vertical work well, except the close proximity to the shack could cause problems. The OP mentioned he had space. He could put up a vertical and maybe one or two different wire doublets.

The reason I asked about the railing: I sometimes have 20 meter evening QSOs with an operator in Hawaii who puts out a very strong signal using nothing more than a screwdriver mounted on his patio railing.

I'm happy with my antenna options for HF, with 125 foot and 90 foot doublets at 35 feet, both fed with ladder line, a ground mounted 80-10 meter vertical over 16 radials, a vertically polarized 17 meter Delta Loop hung under an Oak tree and my 25 foot wire noise antenna. With the exception of the Butternut vertical, I doubt I have over a 100 dollars combined in the wire antennas.

I am sometimes hampered by an intermittent power line noise problem and have been working with the utility to resolve the problem. I have not found the verticals to be more sensitive to noise than the doublets in my particular situation, probably because all my antennas are near or at power line height. When I do experience the noise, I use the 25 foot noise antenna and null out the noise by phasing.

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WK5H
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« Reply #3 on: October 28, 2012, 09:20:10 PM »

Sorry; yes, for most practical purposes, I'm interested in 80m-10m.

The deck is wood, and the house is rock face.

I do have an ATAS-120a, which for "now" purposes, I could mount on the deck, and have a counterpoise going down the deck supports towards the ground.  I do have a dog in the back yard, but, I'd make sure to keep it out of nose range.

The house was built in 1935, and even though it's been updated quite a bit, it still needs some work.  Enough that it's probably going to take away from most of my wire antenna building time.  I'm not against building my own, and I do enjoy building my own things.  But, for now, if it's anything more than a simple dipole, it's going to have to be put on hold.

Would the ATAS work with the vertical counterpoise?  Well, for as good as an ATAS can work? Smiley
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K5LXP
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« Reply #4 on: October 29, 2012, 07:29:09 AM »

Would the ATAS work with the vertical counterpoise?  Well, for as good as an ATAS can work? Smiley

A "vertical counterpoise" would in fact be a reactive element, and thus may give you some trouble tuning on some bands.  If it was cut to resonance on a particular band (example, 16ft/20M) then the ATAS should tune and work fine on 20M.  I've used my ATAS "portable" directly on the ground with a 16-radial field.  Works about the same that way as it does mounted on a car.  You have nothing to lose.  Set it up and try it out.


Mark K5LXP
Albuquerque, NM
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W0BTU
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« Reply #5 on: October 29, 2012, 02:23:34 PM »

What are the dimensions of your new property, and if there are trees, how high are they? Knowing that would help us help you better.
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WB2WIK
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Posts: 20666




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« Reply #6 on: October 29, 2012, 02:33:36 PM »

Sorry; yes, for most practical purposes, I'm interested in 80m-10m.

The deck is wood, and the house is rock face.

I do have an ATAS-120a, which for "now" purposes, I could mount on the deck, and have a counterpoise going down the deck supports towards the ground.  I do have a dog in the back yard, but, I'd make sure to keep it out of nose range.

The house was built in 1935, and even though it's been updated quite a bit, it still needs some work.  Enough that it's probably going to take away from most of my wire antenna building time.  I'm not against building my own, and I do enjoy building my own things.  But, for now, if it's anything more than a simple dipole, it's going to have to be put on hold.

Would the ATAS work with the vertical counterpoise?  Well, for as good as an ATAS can work? Smiley

The ATAS is a heavily loaded vertical whip that normally depends on a car or truck (or better still, van or SUV) roof for its counterpoise, and any of those work a lot better than a wire.  With the system you describe, probably "most" of your "counterpoise" system is really the outer conductor of your coax, and that's not a good thing.

You talk of the yard and the deck, but isn't the peak of the roof higher? Wink 

Taking advantage of "what's already there" is usually the first thing I consider when moving to a new house (or an old house).  If the peak of the roof is the highest thing around, I start there and go up from there.  Better location, likely higher and more open than the deck, and the roof provides a great place to lay out real radial wires that will work.
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