- 15 -
Providing a Good RF Ground
This active vertical antenna works well with just a single copper ground rod used as the
mounting rod.
You can test ground quality by listening to a steady local signal. Attach 15 feet of wire laid
in a straight line away from the coaxial feedline. If you observe a change in signal or noise
level, you need to improve the ground. A second rod spaced a few feet away from, and
connected to the first one may correct the problem. If a good ground cannot be established,
use a
DXE-RFCC-1
Feedline Current Choke that will further decouple the feedline from
the antenna and reduce common mode current and associated noise from the feedline.
If you locate your ground mounted antenna where ground rods cannot be used effectively,
you must use a radial system. A suitable radial system consists of four to twelve equally
spaced radials, with each radial being at least 15 feet long, but not longer than 20 feet.
Only if the antenna is located over rock, on a roof, or otherwise installed where conductive
soil conditions do not exist, you must use a ground screen. Welded-wire galvanized screens
are okay for this receive antenna only and are not recommended for transmit antennas.
Screen radius must at least equal the element height and be placed around the antenna as
symmetrically as possible, but should not exceed a radius of 20 feet. The active receive
vertical radial system should never be connected to any metal structure to assure low noise
operation.
Do not use elevated radials or grossly asymmetrical radial configurations. The ground
system is an integral part of this receiving system, and if it is asymmetrical or exhibits
pronounced resonances, the antenna system may not function properly.
Connections
For single antenna installations, the
DXE-FVI-1
- Feedline Voltage
Injector is installed near the operating position. When using the Active
Receive Antenna, the
FVI-1
powers the
AVA-2
active antenna through
its
ANT+
feedline connection. See
Figure 12
.
If possible, bury the feed line for some distance from the antenna. This
helps to decouple the feedline from unwanted noise. A
DXE-RFCC-1
Receive Feedline Choke will also ensure feedline decoupling.
Connect a suitable 75 Ω feedline to the type F connector
OUTPUT
.
Leave a small loop in the feedline to relieve stress on the
AVA-2
connection and securely attach the feedline to the mast below the
mounting plate.
Figure 12 - Connections to the
ARAV4 system using the FVI-1
