- 4 -
Mounting Tube (A) Installation
When the bottom tube with insulator (A) is ground mounted, it should be protected against
corrosion if placed in concrete, damp acidic or alkaline soil. Asphalt roofing compound,
polyurethane varnish or other sealant that protects against moisture may be used. Concrete may be
used in areas of high winds for greater strength, in which case the post may be twisted slightly
during setting for easy removal later. Ensure it is not mounted at an angle. You want the antenna to
be vertical when fully installed. To help maintain the antenna base, place a larger diameter metal
tube, such as the
BUT-MPS
Mounting Post Sleeve in the ground, then you can slip tube w/insulator
(A) in and it will be protected from direct contact with the concrete.
Tube with insulator (A) must be installed in a hole approximately 21 inches
deep so that the upper end of the fiberglass insulator is approximately 7 inches
above ground level. Pack earth tightly around tube w/insulator (A) so that it
remains vertical. When installed, you want the top of
tube
A at 2-3 inches
or
less
above ground level to keep the feedpoint below 5” above ground level.
NOTE: HAMMERING TUBE W/INSULATOR (A) INTO THE EARTH
MAY CAUSE THE INSULATOR TO SPLINTER. If the post must be hammered into the earth,
protect the end of the insulator with a block of wood
NOTE: DO NOT USE U-BOLTS TO ATTACH TUBE W/INSULATOR (A) TO A MAST,
TOWER ETC. WITHOUT ADDED PROTECTION. U-BOLTS WILL EVENTUALLY CUT
INTO THE TUBING AND WEAKEN THE INSTALLATION. If U-bolts are used, place a larger
diameter metal tube, such as the
BUT-MPS
Mounting Post Sleeve over tube w/insulator (A).
Similar precautions should be observed when using TV style towers with locking bolts.
The
BUT-RMK-II
Roof Mounting Kit includes the
BUT-MPS
as well as the
BUT-STR-II
Stub
Tuned Radial Kit.
Radial System
The use of a radial system is a key requirement for any high performance quarter wave vertical
antenna system.
With any vertical antenna system, the radials are the second half of the
antenna. The radials contribute to the radiation efficiency of the entire vertical antenna
system.
The exact number of radials required for low SWR and reasonably efficient operation will depend
in large measure on local earth conductivity, and this may vary considerably from one place to the
next and from one frequency band to the next. For most installations the soil conditions will be
poor to very poor when it comes to conductivity.
The best procedure is to assume that most earth is a poor conductor over the HF range and that
some radial wires will be needed. Radials may be placed on the surface of the earth or buried
slightly below the surface to get them out of the way, and their length is largely a matter of
