Hello Jay,
We have noticed your posting on Topband, so we will offer some additional
information.
The single Active Receive Vertical Antenna is designed as a no-gain antenna
with a flat response across several octaves of the HF
spectrum. This allows the Active Vertical to receive low angle signals and
noise at a lower total level, thereby improving the
signal to noise ratio (s/n). This approach works well in relatively low noise
environments, which is a general requirement for any
receive antenna system, be it an Active, a Beverage or another type. The
Active, or any receive antenna, cannot be located near
metal containing structures, or buildings with noise producing devices, such as
typical home. Fences, metal sided or metal
containing buildings, towers and transmit antennas will all receive large
amounts of noise from a variety of sources and re-radiate
it. A nearby receive antenna will not function properly in this environment.
Receive antennas must be located in the clear.
I have used a single Active Receive Vertical in a rural environment with an
average winter low noise level of S1 to S4. The results
using the single Active Receive antenna were Good to Excellent improvement in
signal intelligibility on 160 through 15 meters, as
compared to reception with different types of transmit antennas, is an
indication of improved s/n. However, it is not a gain
antenna, nor can it be compared to a directional antenna, such as a loop or
Beverage.
If a single high level noise source is well away from your location by several
wavelengths or more, this may be a case where a
phased array may offer s/n improvement. The use of two or four Active Verticals
in a phased array can reduce the received noise
coming from a certain direction, if you are able to point the null of the array
toward the noise. This is beneficial only if the
phased antenna array can offer reception of the desired signal, while
simultaneously nulling the noise. If the noise source and the
desired signal are in the same direction, a phased array cannot assist.
If a very modest noise level is coming from all directions, then the phased
array may help reduce total received noise enough for a
s/n improvement.
If the high noise source is nearby, then all antennas would be adversely
affected. If a high noise level is received from many or
all directions, then a receive antenna cannot assist weak signal DX operations
on 160 or 80 meters.
After adding radials to the Active Receive Vertical, which normally does not
require them, you did not see any change in signal or
noise levels. That indicates that your ground connection is sufficient for the
antenna to function normally. It may also indicate
that your latent noise level may be too high to benefit from a receive antenna
system.
Without a description of the trouble you are having, it is difficult to be
specific. Therefore we believe this general information
regarding the DX Engineering Actives, and the nature of receiving antenna
systems, might be helpful.
Please write to us if you need additional assistance.
73,
Rod Ehrhart - WN8R
DX Engineering Customer Support
dxengineering@dxengineering.com
www.dxengineering.com
Comtek Systems Customer Support
info@comteksystems.com
www.comteksystems.com
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