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A basic installation for a directional antenna includes:

Tower or Mast Pole

Mounting Bracket (Eave, etc.)

Antenna Rotor

Short pipe-section(s) to mount antenna

Coaxial Cable

Rotor Cable

Rotary beam antennas provide an important advantage in that signals are focused in a favored direction and likewise received to enhance station performance.  Signals to and from other directions are attenuated (reduced) to minimize interference and maximize effective power.

An operator using a rotatable beam up forty feet will probably not be the first to break through pileups of signals calling faraway locations, but such an installation usually provides very satisfactory performance.

Obviously, fifty feet of antenna height is better than forty....sixty is better than fifty, etc.  But expense, installation and maintenance are greatly simplified if a lower height is chosen. 

MOUNTS:  These attach a tower to a supporting structure such as a home or other building.  Eave-mounted towers are the most common.  The mounting bracket attaches to a high point along the edge of a home's roof and may avoid a need for guy wires when overall height doesn't exceed forty feet and the antenna is relatively modest.

For most UHF and VHF antennas, and even some smaller HF beams, telescoping masts (single-pole supports) may be suitable.  Eave mounting is recommended.

Rooftop mounts are also available.  Mast height for roof-mounted antennas may be limited.

GUY WIRES:  Generally, a set of three guy wires should be used at thirty-foot intervals on a tower.  If the tower is attached to an eave that is ten feet above ground, the first set of guys may not be needed unless overall height exceeds forty feet. 

Flexible wire rope is recommended for guy cables.  For small antennas at lower heights, #10 solid wire or heavy-duty nylon rope may suffice.

ROTORS:  The surface area specification of a beam antenna determines the size of rotor required. Also the antenna net weight may be a factor.  Make sure that rotor ratings are equal to or greater than antenna specifications.

Heavy-duty TV antenna rotors like the Hy-Gain AR-40 will suffice for most VHF/UHF beams and even some small HF trap beams.

For most small and medium-sized HF beam antennas, heavier duty rotors such as the Hy-Gain Ham IV are recommended. 

Other manufacturers provide rotors with equivalent specifications, so shop around.

If tower dimensions allow, rotors can be mounted inside the tower near the top.  This is preferable to installing a rotor between the top of the tower and the antenna.

New rotor price range: $300 to $800

TOWER SECTIONS: Rohn 25G is by far the most common tower used by hams.  It comes in ten-foot sections that bolt together.  Used Rohn tower sections are available.  Remove any rust or corrosion before using.  If rust is widespread or bracing is loose, AVOID. Typical price for a new ten-foot 25G section is $100 plus shipping. An enclosed top-section costs about $150.

SELF-SUPPORTING TOWERS:  Generally more expensive and larger than guyed towers, self-supporting towers are stabilized by tapering sections and/or by strengthening key points.  Rohn 25G add-ons allow self-supporting use (without guys or mounts) up to 40 feet. Rohn 65G can be made self-supporting up to 80 feet. Prices for new 40-foot self-supporting towers start around $1,000.  The 80-foot 65G costs around $8,000 new.

CRANK-UP TOWERS:  These are expensive compared to Rohn 25G but offer added convenience in antenna installation and maintenance.  They crank down to roof level which is handy when storms approach or if one is away for extended periods of time.

Aluma Towers offers light-weight crank-up towers that hams have used for decades.  The forty-foot model is a good choice.

E-Z Way is another manufacturer. 

Cranking can be automatic using a small motor or accomplished by manually turning a handle attached to the crank mechanism.  An internet search on "crank-up towers" should yield helpful links.

New 40-foot crank-up tower prices start around $1,500.

FOLDOVER TOWERS:  Self-supporting towers can be modified to fold down to the ground and commercially-made foldover towers are available.  These are usually somewhat less complex and cheaper than crank-up towers.  Fold-over conversion hardware prices start around $500.

HAZERS: Working like a simple elevator designed to easily raise and lower your antenna and rotor, these simplify antenna installation and maintenance on stationary towers   A hazer wraps around the tower and uses a pulley to move the antenna up and down the tower. Similar to raising a flag up a pole. Eliminates climbing to service antennas.  Hazers and associated hardware start around $500.

MAST POLES:  For smaller antennas, a single pole may be sufficient.   Several sections can be joined together.  Ten-foot, top rail pipe sections used for chain-link fencing are an option.  Typical cost is $10-$20 per section at local home improvement outlets.

Or you can buy a telescoping mast.

These masts come in 20, 30, 40 and 50 foot maximum extended heights.  Plan on overlapping the sections for greater stability.....a 50-foot telescoping mast overlapped to provide 40 feet of antenna height, etc.  Typical price for a well-designed 50-foot telescoping mast is $200.

Guy wires for mast poles should be used at 20-foot height intervals.

CEMENT BASE:  Very tall towers should have their base anchored in concrete.  Pour the concrete around and under a metal base plate.  Let the concrete set for a week or two before attaching the tower.

For towers under fifty feet or so, driving the bottom foot or two of the tower or mast into the ground may be sufficient.

GROUNDING: Especially if your antenna is the tallest point on your lot or prone to lightning strikes, make sure the base of the tower or mast is connected to a nearby long rod driven into the ground.  Several ground rods in parallel are even better.

No lightning protection works every time.  Disconnect coaxes from your equipment when you aren't using it.

TOWER INSTALLATION:  For Rohn 25G and similar sectional towers, install the first ten-foot section into the base or ground.  An erection fixture a.k.a. gin pole is recommended to hoist additional sections for installation. Gin poles cost $250-$500.

For smaller lightweight towers, it may be possible to assemble several sections first and "walk" the completed tower up to a perpendicular position.

INSTALLING YOUR TOWER: Start by carefully planning your installation and procuring items needed.  Recruit others to assist.  You'll need a "ground person" and a climber.  For masts, two people may suffice.  For tall towers, you may need three or four people.  Recruit friends and those you communicate with on the air.

Due to liability insurance limitations, NOFARS and many other clubs do not participate in recruiting tower workers or providing club-owned equipment.  But you can arrange on an ad-hoc basis.

Otherwise, some tree services can install towers though you may need to direct them.  Having a crane available makes tall tower installation go much easier.  Home handyman services are another possibility.

Two-way communications companies may agree to install Amateur Radio towers and there are independent experienced climbers who install towers for a fee.  Some travel from other areas of Florida and nearby states to do antenna jobs.  Internet searches are the best method to find an experienced independent tower climber.

SAFETY:  Ground crew members should wear hard hats to protect against falling hardware.  Even a bolt or a bracket can cause serious injury if it hits someone's head.

Climbers need approved safety harnesses.  Inspect thoroughly before using.  Some harnesses are subject to dryrot.

When climbing or  disassembling towers, inspect for rust and ensure that the tower base is in good shape.  Many injuries have been caused by a rusty lower section or base breaking loose while a climber worked above.

JaxRadio.net

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