Tuesday, February 7, 2017

Getting 160 meters on a budget. Post #1036.

Getting on 160 meters on a budget
Accessed on 07 February 2017, 20:05 hrs, UTC.
Author:  NO6L.
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As solar activity wanes and propagation gets more difficult on the higher HF bands (20 through 10 meters), radio amateurs are finding plenty of dx and local contacts on 160, 80, and 40 meters.  Forty meters is becoming a "workhorse" band for regional nets, local rag chews, and fairly good DX after the sun sets.

Eighty and 160 meters also offers some excellent propagation at sunset and sunrise, as well as reliable communications during the day.  The one major drawback to antennas on 80 and 160 meters is the sheer size of dipole or vertical antenna for these bands.  According to NO6L, all is not lost if you want to explore the benefits of the 160 meter or "gentlemen's band."  If you can find enough space for even a compromised inverted L antenna, you can get on 160 meters and find plenty of local and regional contacts to fill your log. One hundred sixty meters also shines during the evening hours, when DX is possible.

In this article, NO6L shows us how to build a simple inverted L antenna that will cover the 160 meter band as well as 80 and 40 meters with a few minor changes. NO6L says you must be aware of several compromises that will affect the performance of the inverted L for 160 meter:

"You may be saying, “If you think you can fit an “L” in a city lot, you must be high”. I can assure you, I am quite sober. In order to accomplish this feat you will have to accept compromises. But I can also assure you, they will have very limited impact on performance. Especially when it comes to comparing it to a mobile antenna adapted to fixed station use and a puny multiband vertical that's only about 30 or 40 feet tall that you get the pleasure to spend hundreds of dollars on. So, what are the compromises?
The first is height, the higher the vertical portion of the antenna, the better. If you can only go up 20 feet, it will work. I know, mines at 24 feet and works well. The “L” works good because a quarter wave antenna only radiates from the bottom 20%, the rest is only there for “loading” purposes, so as long as it's there, somewhere, it'll work fine. So, that means the “L” should begin to function as a Marconi with a height as little as 25 feet, with some skewing to the pattern. But, like I said, the higher the better.
The other compromise is the counterpoise. This is where “The rubber meets the road”, almost quite literally. But what happens when you're renting, the lot is only the 100x60 feet I mentioned above or you just don`t want to lay out 64 .2 wave ground radials, that's over 6000 feet of wire, that`s a lot of money. The trick is, grab anything that is already available to use. Here's some examples; Put a couple of 8 foot ground rods in at the base of the antenna first. Run a wire from there to the RV in the side yard and attach with an alligator clip. Run a couple of wires to the chainlink fence. Run a wire to the faucet coming out of the ground. Position the base of the support near a grassy area that is always damp. Run a loop of thin wire around the shack, and/or house and/or the garage and bond them to the ground rod/s. Any thing that has an actual or “virtual” large area is a potential counterpoise. If a neighbor will let you, use some items in their yard. And if they're also radio amateurs, join forces and combine counterpoises in both yards. No, it's still not the ideal counterpoise, but it's not only better than nothing, it's better than what you could buy for several hundred bucks, with exception of a High Tower (TM), maybe, and even they need a counterpoise."

If you can deal with these limitations, then you'll find 160 meters a good place to hang out with your friends.

Be sure to check the replies those who responded to the original article. Some alternative 160 meter antennas worth trying include the 3/8 wave length inverted L, a "long" random length wire, and a 3/8 wavelength loop.

For more information on 160/80 meter backyard antennas, check out antenna articles from the late L.B. Cebik (W4RNL) or the "W6SAI HF Antenna Book" by William Orr (W6SAI).  The book is still in print and can be ordered from CQ Communications.
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http://hawaiisciencedigest.com (science and technology news for radio amateurs).
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