More on
beverage
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Basics
General info on the Beverage
How to
Get a perfect Beverage
Wires
How thick, what material?
Feed
From radio
to antenna
Ground
Ground and terminate
— here's how
Remote
Remote control of the Beverage
Views
Love letters about life with
a Beverage |
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Headline
A Bowen, N4OO
Top Band mailing list, May 24, 2000
Installing a Beverage is not a trivial undertaking. I have 4 of
my own and have helped others with theirs. The following procedure
has evolved.
I use a "sighting" type compass (Suunto, look up on internet) to
establish the direction.
I then lay out the line using 500-600 ft of small diameter white,
nylon line. Unless you do this, maintaining a straight line through
woods and underbrush will be difficult.
An axe and loppers have been most helpful with clearing a path,
particularly in our north Florida "jungle".
For a height gauge, I make up a 9 ft length of aluminum tubing,
which helps to establish a consistent height above ground.
I use only the ceramic insulators that are sold for electric fences.
The plastic ones, being a soft material, tend to pop off as the
tree grows. I anchor the insulators with long, drywall type screws.
I have found screws to be more reliable than the nails.
Be sure to use the plastic washers that come with the insulators.
Depending on your rain fall and climate, the tree will probably
grow arond the insulator in about 4 years.
For anchor points that fall between trees that are on line,
I stretch a piece of nylon line between 2 trees to support the wire.
The maximum distance between supports generally should be 40 ft
or less. I try to keep the deviation from the sighting line to less
than a couple of degrees.
Alternatively, you could install a post of your own making.
In this area, landscape timbers (8 ft, $2.50), with a 4 ft extension
of pressure treated 1 X 4" board works well. So does a steel fence
post with a 10 ft length of 1 1/2" PVC pipe over the top. The timbers
are cheaper.
I use #17 galvanized steel fence wire for the main conductor.
This stuff runs about 3 ohms per 100 ft and is perfectly satisfactory.
I have also used #18 copper clad steel and #18 insulated wire. I
have never been able to tell that one is better than the other.
Steel is a lot tougher.
Fence wire and insulators are sold here at most rural hardware stores
and lumber yards.
The other wires were usually purchased at flea markets or scrounged
from a number of sources.
The start point anchor for my Beverages is a power pole "stub"
(cutoff). I obtained it from the local power company, by signing
a form at their office.
If you cannot obtain one of these, which are generally 8-12 ft long,
use 2 landscape timbers, bolted together.
I use a guy wire type insulator and a large turnbuckle which is
used to tighten the wire when you are finished.
Go easy with tension if you are not using the steel wire.
For tie wires at the insulators, I use 6" length of #18,
single strand, insulated wire.
Be aware that smaller diameter trees move a lot in the wind.
Be prepared to do maintenance after every wind storm. These generally
occur just before a contest.
Fallen branches are also a problem and generally occur during a
contest or when a rare one is active.
At the far end, I mount a 500 or 470 ohm, 2 watt resistor
in a plastic pill bottle. This goes in series with the wire, to
ground.
I have one Beverage which uses the "slanted to ground" ending and
the others simply bend at the last insulator and go straidght down
to ground.
I have never been able to tell that there is any degradation with
the wire going vertically for 9 ft or so.
For a ground rod, I use 1/2 of a 10 ft length of 1/2", M, rigid
copper tubing. These have been on sale at the large hardware stores
for less than $4/length.
The ground at the start/central point should be 2 or more of these
same rods, or maybe multiple 10 footers. I think that 2 short ones
are generally better. I use 2 short ones and about 12 square feet
of 1/2" hardware cloth, which happened to be on hand.
I make my own 10/1 transformers using .500" OD cores of #43
material.
This core will hold about 10 turns of #24 insulated wire taken from
multi conductor telephone wire cable.
Wind a 3 turn primary between the ends of the larger winding.
Put a 470 ohm resistor across the large winding and measure the
impedance on the small winding with your MFJ or Autek Analyst. You
should measure around 50 ohms. If not correct, adjust the turns
on the large winding.
You can also construct the transformers as shown in ON4UN's book,
Low Band DXing.
I have made them both ways and my ear cannot detect any significant
difference. The instruments I have show that the impedance ratio
is maintained over a wider frequency range with the trifilar winding.
I do not have equipment for measuring the efficiency.
You can mount the transformer and connector in a plastic
utility box. I use the small blue ones that are handled by the large
hardware/lumber places. Use 2 machine screws for antenna and ground.
Hook the small winding to the coax connector. All my coax cables
run to a 4 position relay box, remotely switched from the shack.
I use a separate transformer for each antenna.
For leed-in cable, I use RG6. This has been available at
local ham flea markets for very reasonable prices, such as .04 per
foot. Losses are very low with this cable and at these frequencies.
I am not concerned with the small mismatch between the cable and
the output Z of the transformer. Anything under 3:1 is OK with me
at these frequencies.
Summer is not a great time to construct Beverage antennas in the
southern latitudes.
For installation in the woods, I use a 6 ft aluminum step ladder,
the height reference and a pail containing the insulators, screws,
battery drill motor, tie wires and other tools. Don't forget the
extra nylon line.
It is not exactly an "all you gotta do is..." project.
Incidently, my Beverages are also very effective on 80/40/30M. |
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