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Installation Hints for Antennas

Installation Hints For
Antennas, cables and surge arrestors
 
- Mount the antenna on the mast or tower and, if a directional type, aim it with a compass towards the master site. Make a good connection with the clamp to the metal of the support structure. Ensure the clamp is tight without damaging it.
 
- Run the heavy gage LMR-400 coaxial cable up to the antenna, tying it in place with black (NOT white!!) tie wraps every couple of feet. Some people put a couple of turns of electrical tape over the tie wraps too for added protection from the sun.
 
- Connect the cable's N male connector to the antenna's N female connector. Ensure they mate properly then tighten them up by hand. (don't use a wrench, it’s not necessary and may damage the connector!) 
 
- Ensure you run the cable DOWN away from the antenna so water can't follow the cable down into the antenna itself. Also make sure that you don't put tension on the connection.
 
- As shown in the Sealing RF Connectors document, seal the connection with rubber splicing tape (vulcanizing tape) and form it by squeezing with your hand, then add a layer of electrical tape over top. The point is to keep water out.
 
NOTE: If desired you can connect the cable to the antenna and do the sealing on the ground, before going up the tower or to the top of the mast. But ensure you do not put too much pressure (eg by dangling the cable down from the antenna) on the connector.
 
- Connect the long LMR-400 cable's N male connector at the bottom to the lightning arrestor's N female connector. Again tighten firmly by hand only.
 
- Include a drip loop so water following the cable falls off the cable before reaching the arrestor.
 
- Seal the connection from the cable to the arrestor with overlapping layers of rubber splicing (vulcanizing) tape and cover that with an overlapping layer of electrical tape.
 
- Connect the short jumper RF cable from the lightning arrestor (N male of the cable to N female of the arrestor) to the radio. Run this cable carefully in the equipment cabinet to keep it out of harm's way.
 

 
NOTE: A radio may use any of several connector types eg N, TNC or SMA. Ensure you have the correct jumper cable for your radio type.
 
- The lightning arrestor and the bottom of the mast or tower must be grounded. This typically requires a 10 foot ground rod or a good ground plate buried several feet deep. (A very tall tower may require more rods eg three evenly spaced around the tower) The cable must be a heavy gage (green) ground cable. The cable must be routed as short and straight as possible from the arrestor or mast/tower to the ground rod. Any bends not needed must be avoided. Definitely do NOT coil up any extra ground cable as this (and bends) causes impedance to the high energy discharges from lightning.
 
 
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