AN/GRA-4
Antenna System
and uses
Well first of all, it
comes as part of several other Military Antenna systems so before you
say to yourself, why would I want one of these here are some uses and pictures.
An Off Center-Fed Long-Wire.
A Center-fed with Coax Dipole.
Usage of the wire reels, and the center
"Cobra Head" coax Assembly.
For that 160 meter Dipole.
The laying out of the support systems.
Preparation to raising the Supports.
Two people can put this antenna system together
in about 1 hour, for the three support system.
The method of raising the support.
What is in that Bag?
What comes inside the above system
to make the vertical mast.
The whip elements used to bring the total
height of a vertical to 47 feet.
it comes with a center device for making a dipole
and reels for the legs.
The connector is an "N" type and there is an attachment
to convert it to an Inverted Vee antenna.
say to yourself, why would I want one of these here are some uses and pictures.
An End Fed Long-wire.
An Off Center-Fed Long-Wire.
A Center-fed with Coax Dipole.
Usage of the wire reels, and the center
"Cobra Head" coax Assembly.
For that 160 meter Dipole.
The laying out of the support systems.
Preparation to raising the Supports.
Two people can put this antenna system together
in about 1 hour, for the three support system.
The method of raising the support.
What is in that Bag?
What comes inside the above system
to make the vertical mast.
The whip elements used to bring the total
height of a vertical to 47 feet.
This item opens up and spouts forth
with
equipment to make a 47 foot vertical, with base insulator
guy stakes, guy ropes, a mast adapter for MS-*** antenna elements, a 5 pound sledge hammer and
a ground plate.
Sometimes you may want to just run 100 watts or so in which case you will need the equipment
bag with the low power antenna equipment in it.
guy stakes, guy ropes, a mast adapter for MS-*** antenna elements, a 5 pound sledge hammer and
a ground plate.
Sometimes you may want to just run 100 watts or so in which case you will need the equipment
bag with the low power antenna equipment in it.
it comes with a center device for making a dipole
and reels for the legs.
The connector is an "N" type and there is an attachment
to convert it to an Inverted Vee antenna.
I have used various
tuners to handle the vertical portion and get it on the ham bands, here
are a few
that I use around the shack.
The Collins 180L
Making the controller and cable for this took
some time, schematic is Here.
The BC-939A
I sit this unit in a plastic Tote with a
single high voltage feed thru
Insulator on it.
HERE ARE A FEW OF THE MANUALS.
They describe usage, and implementation.
TM 11-5820-251-14P
TM 11-5985-229-12P
TM 11-5985-231-24P
TM 11-2651
TM 11-5985-249-24P
TM 11-5820-467-15
I fabricated an adapter for the top section.
This lets me add a Capacitive Hat to the top
of the 40 foot vertical sections.
It attaches and is secured with 4 8-32 screws which
also provide connections for 4 40 foot wires,
which make up the top-hat portion.
If you want a mobile whip the MS-115, 116, 117
Elements are needed along with a mounting bracket
and the insulated base to screw them into.
Get "Hardened Brass" Hardware to attach the
base to the mount, don't forget to use the rubber ring
between the base and the mount!
Oh yeah and the tie down, remember the clearance on the High-Way is 13.5 Ft.
The Bulbous thing is for the tip of the antenna, so folks don't get hurt.
that I use around the shack.
The Collins 180L
Making the controller and cable for this took
some time, schematic is Here.
The BC-939A
I sit this unit in a plastic Tote with a
single high voltage feed thru
Insulator on it.
HERE ARE A FEW OF THE MANUALS.
They describe usage, and implementation.
TM 11-5820-251-14P
TM 11-5985-229-12P
TM 11-5985-231-24P
TM 11-2651
TM 11-5985-249-24P
TM 11-5820-467-15
I fabricated an adapter for the top section.
This lets me add a Capacitive Hat to the top
of the 40 foot vertical sections.
It attaches and is secured with 4 8-32 screws which
also provide connections for 4 40 foot wires,
which make up the top-hat portion.
If you want a mobile whip the MS-115, 116, 117
Elements are needed along with a mounting bracket
and the insulated base to screw them into.
Get "Hardened Brass" Hardware to attach the
base to the mount, don't forget to use the rubber ring
between the base and the mount!
Oh yeah and the tie down, remember the clearance on the High-Way is 13.5 Ft.
The Bulbous thing is for the tip of the antenna, so folks don't get hurt.