Shortwave Listening (SWL) "Receive-Only" Antennas - Away Is Better - Then Up ! - Or Is It ?
- From: "RHF" <rhf-newsgroups@xxxxxxxxxxx>
- Date: 26 Jun 2006 19:52:03 -0700
Steve,
Shortwave Listening {Receive Only} Antennas
- Away is better then Up ! Or Is It ?
Where you are better off {usually} with a longer
Antenna + Ground + Feed-in-Line System and
Local Noise is :
Very High Signal & Very High Noise Antenna Design :
A 10 Foot Coax Cable feed-in-line up the side of
the House to the Peak of the Roof that is coupled
to a 100 Foot Horizontal Antenna Element and
using the Radio Shack's Ground.
- Why - The First 50 Feet of the Antenna is close
to the House and Noise and the other 50 Feet
is relatively Noise Free.
Very High Signal & High Noise Antenna Design :
A 25 Foot Coax Cable feed-in-line going out away
from the House 15 Feet that is coupled via a
Matching Transformer to a 15V/85H Foot Inverted
"L" Antenna Element and using the Radio Shack's
Ground.
- Why - The First 50 Feet of the Antenna is close
to the House and Noise and the other 50 Feet
is relatively Noise Free.
Moderate Signal & Less Noise Antenna Design :
A 50 Foot Coax Cable feed-in-line going out away
from the House 40 Feet that is coupled via a
Matching Transformer to a 15V/60H Foot Inverted
"L" Antenna Element and using a Matching
Transformer and a remotely located Ground Rod
at the base of the Antenna.
- Why - The First 25 Feet of the Antenna is close
to the House and Noise and the other 50 Feet
is relatively Noise Free.
Moderate Signal & Very Low Noise Antenna Design :
A 110 Foot Coax Cable feed-in-line going out away
from the House with 100 Feet Buried that is coupled
to an a Far-End-Fed 15V/50H Foot Inverted "L" Antenna
Element and using a Matching Transformer and a
remotely located Ground Rod at the base of the Antenna.
- Why - The Entire 65 Feet of the Antenna is away
from the House by 50 Feet and is relatively Noise Free.
The-Bottom-Line - Use the Available Space to position
the Wire Antenna Element away from Sources of Noise
and let the Signal Levels take care of themselves when
the Length of the Wire Antenna Element is beyond
35 Feet.
at least that is the way i see it - iane ~ RHF
.
Shortwave Listener Antennas => http://tinyurl.com/ogvcf
http://groups.yahoo.com/group/Shortwave-SWL-Antenna/
SWL Antenna Group => http://tinyurl.com/ogvcf
.
The Shortwave Listener's Blessing :
SWL BLESSING => http://tinyurl.com/s2bjm
May You Never Tire of Listening to the Radio and Always
have Strong Signals and Noise Free Reception ~ RHF {ibid}
http://groups.yahoo.com/group/Shortwave-SWL-Antenna/message/9233
.
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Steve wrote:
Ron Hardin wrote:
It's true of random wires as well. Noise that's propagating is picked up
in proportion to Signal that's propagating, so the ratio is the same regardless
how much of it you gather.
What varies is the energy of that relative to the internal noise of the
receiver.
Once you're above the receiver's internal noise, more gathering doesn't help.
Thus better receivers fail to benefit where worse receivers do, from larger
antennas.
--
Ron Hardin
rhhardin@xxxxxxxxxxxxxx
On the internet, nobody knows you're a jerk.
What you're saying makes sense, and in another thread people have been
talking about the PA0RDT Mini-Whip, which, assuming it does what
everyone says, seems to demonstrate that small antennas can be just as
effective as much larger ones. Still, I have the sense that something
important is being left out. If I'm listening to AFN on 7811 with a
modest 20 ft wire and then switch over to a 100 ft wire, it does not
seem as though the 100 ft wire allows me to hear exactly what I was
hearing on the 20 ft wire, only at higher volume.
I always figured that, because most of the noise that plagues us is
local, a longer wire would have a greater "reach"---i.e., it would be
able to gather a greater proportion of signal in addition to all of the
local noise that you'd hear on a wire of *any* length. Another way to
put it: I'd have thought that what you can hear via antennas of
different sizes is analogous to what you can see through telescopes of
different sizes. Because of atmospheric distortion, there's a limit to
what you can resolve using an earthbound telescope, no matter what it's
size (that's why we put telescopes into orbit). There's a ratio of
light to atmospheric distortion that just can't be overcome...building
bigger telescopes won't help. However, this is consistent with the fact
that the big reflector on Mt. Palomar can make out much more detail on
the moon's surface than the telescope in my backyard. And the only
explanation for this is the fact that the big reflector is taking in
more light from the moon.
But enough of my armchair speculation. I'll leave it to you experts out
there to decide (assuming you're still awake)!
Steve
.
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