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Noise Cancelling Antenna!
- Thread starter psycho
- Start date
The only noise canceling antenna I know might exist is one with a feed line with heavy losses. This can happen if water gets in the coax and has time to work on the shield. The SWR may act bad when wet, but after it dries and has done some damage the SWR may show better than ever. IMO, this is due to attenuation, the same thing that makes the ears good as a result of the loss.
It has been my experience that such a line will still talk and have very good ears, so this condition might not always be bad, unless you just have to show everybody a big signal. A sure way to check this is to place an inline meter and a dummy load at the antenna end and check how the watts look compared to the watts in. In my experience with lines <:> less a 100' feet the present of output should be in the 90% range of the input.
It has been my experience that such a line will still talk and have very good ears, so this condition might not always be bad, unless you just have to show everybody a big signal. A sure way to check this is to place an inline meter and a dummy load at the antenna end and check how the watts look compared to the watts in. In my experience with lines <:> less a 100' feet the present of output should be in the 90% range of the input.
So basically what you are saying is that it is not the size or length of your antenna or coax that matters, but the quality of the signal injected?
I'll have to remember that.
Hello Guys,
Please do not think the only way to reduce noise is by adding length to a coax cable.
Escpecially not when we are talking beam antennas:
(it is however very efficient ...adding length hihi)
Noise..... whatever is "picked-up" by the antenna.
Now, we can do a couple things.
1- Decrease the beamwidth. (more gain)
We can do this in the azimuth as well as the elevation plane.
(The last one is often forgotten by many many manufacturers and antenna enthousiast
But of vital importance. There can be a dramatical drop of several S-units when it comes down to it.)
2- Make a closed loop configuration e.g. quad/deltaloop/F-yagi/FMR yagi etc.
This will reduce the so called p-static, please google p-statice for futher information.
3- The antenna its impedance. By lowering the impedance the antenna becomes more critical for rain/snow/ etc...a high impedance antenna (50 ohms for example) will have less issues. The additional bennefit is that the a higher impedance antenna becomes less "irritated" by near by obstacles.
Of course there is more, The point im trying to make...there are more ways to reduce noise.
And thats just about the most important thing there is...(with a DXing point of view):
It is not the forward gain from a antenna on 11 meters which makes the difference...
It is the abbility to put the signal under the rigth angle and illuminate those who you do not want to hear that makes a qso.
Kind regards,
Henry 19sd348
HPSD Antenna systems
All about antennas
Please do not think the only way to reduce noise is by adding length to a coax cable.
Escpecially not when we are talking beam antennas:
(it is however very efficient ...adding length hihi)
Noise..... whatever is "picked-up" by the antenna.
Now, we can do a couple things.
1- Decrease the beamwidth. (more gain)
We can do this in the azimuth as well as the elevation plane.
(The last one is often forgotten by many many manufacturers and antenna enthousiast
But of vital importance. There can be a dramatical drop of several S-units when it comes down to it.)
2- Make a closed loop configuration e.g. quad/deltaloop/F-yagi/FMR yagi etc.
This will reduce the so called p-static, please google p-statice for futher information.
3- The antenna its impedance. By lowering the impedance the antenna becomes more critical for rain/snow/ etc...a high impedance antenna (50 ohms for example) will have less issues. The additional bennefit is that the a higher impedance antenna becomes less "irritated" by near by obstacles.
Of course there is more, The point im trying to make...there are more ways to reduce noise.
And thats just about the most important thing there is...(with a DXing point of view):
It is not the forward gain from a antenna on 11 meters which makes the difference...
It is the abbility to put the signal under the rigth angle and illuminate those who you do not want to hear that makes a qso.
Kind regards,
Henry 19sd348
HPSD Antenna systems
All about antennas
