Doublet with ladder line vs coax w.r.t. noise
$begingroup$
I live in the city, with 50’x 100’ lots. I use an 80 meter doublet at 30 feet, fed with ladder line to a tuner. My noise floor ranges from S5 to S9 depending on the time.
Would a coax feed reduce the noise level, while eliminating my ability to tune all the HF bands? Or is this just the nature of city living and the HF bands? I tried a loop antenna and it actually has more noise! I miss the suburbs for my ham radio hobby!
dipole feed-line noise
edited 11 hours ago
Marcus Müller
7,7031031
asked 15 hours ago
SteveSteve
111
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$endgroup$
add a comment |
$begingroup$
I live in the city, with 50’x 100’ lots. I use an 80 meter doublet at 30 feet, fed with ladder line to a tuner. My noise floor ranges from S5 to S9 depending on the time.
Would a coax feed reduce the noise level, while eliminating my ability to tune all the HF bands? Or is this just the nature of city living and the HF bands? I tried a loop antenna and it actually has more noise! I miss the suburbs for my ham radio hobby!
dipole feed-line noise
edited 11 hours ago
Marcus Müller
7,7031031
asked 15 hours ago
SteveSteve
111
New contributor
Steve is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
$endgroup$
$begingroup$
The answer might depend on the noise generator and its location. Please describe the noise; is it atmospheric static or is it produced by devices like TVs, wall-warts and modems?
$endgroup$
– Brian K1LI
15 hours ago
add a comment |
$begingroup$
I live in the city, with 50’x 100’ lots. I use an 80 meter doublet at 30 feet, fed with ladder line to a tuner. My noise floor ranges from S5 to S9 depending on the time.
Would a coax feed reduce the noise level, while eliminating my ability to tune all the HF bands? Or is this just the nature of city living and the HF bands? I tried a loop antenna and it actually has more noise! I miss the suburbs for my ham radio hobby!
dipole feed-line noise
edited 11 hours ago
Marcus Müller
7,7031031
asked 15 hours ago
SteveSteve
111
New contributor
Steve is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
$endgroup$
I live in the city, with 50’x 100’ lots. I use an 80 meter doublet at 30 feet, fed with ladder line to a tuner. My noise floor ranges from S5 to S9 depending on the time.
Would a coax feed reduce the noise level, while eliminating my ability to tune all the HF bands? Or is this just the nature of city living and the HF bands? I tried a loop antenna and it actually has more noise! I miss the suburbs for my ham radio hobby!
dipole feed-line noise
dipole feed-line noise
edited 11 hours ago
Marcus Müller
7,7031031
asked 15 hours ago
SteveSteve
111
New contributor
Steve is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
edited 11 hours ago
Marcus Müller
7,7031031
asked 15 hours ago
SteveSteve
111
New contributor
Steve is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
edited 11 hours ago
Marcus Müller
7,7031031
edited 11 hours ago
Marcus Müller
7,7031031
edited 11 hours ago
Marcus Müller
7,7031031
7,7031031
asked 15 hours ago
SteveSteve
111
New contributor
Steve is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
asked 15 hours ago
SteveSteve
111
asked 15 hours ago
SteveSteve
111
111
New contributor
Steve is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
New contributor
Steve is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
Steve is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
$begingroup$
The answer might depend on the noise generator and its location. Please describe the noise; is it atmospheric static or is it produced by devices like TVs, wall-warts and modems?
$endgroup$
– Brian K1LI
15 hours ago
add a comment |
$begingroup$
The answer might depend on the noise generator and its location. Please describe the noise; is it atmospheric static or is it produced by devices like TVs, wall-warts and modems?
$endgroup$
– Brian K1LI
15 hours ago
$begingroup$
The answer might depend on the noise generator and its location. Please describe the noise; is it atmospheric static or is it produced by devices like TVs, wall-warts and modems?
$endgroup$
– Brian K1LI
15 hours ago
$begingroup$
The answer might depend on the noise generator and its location. Please describe the noise; is it atmospheric static or is it produced by devices like TVs, wall-warts and modems?
$endgroup$
– Brian K1LI
15 hours ago
add a comment |
2 Answers
2
active
oldest
votes
$begingroup$
No, coax wouldn't be expected to improve the noise, unless your ladder line is running very close (within 1-2 times its conductor spacing) to a specific noise source, in which case you would be better off fixing that by finding a way to provide better spacing. The only thing that will change with coax is that your losses will become quite a bit higher, and more of your transmit power will be spent on heating the coax instead of making radio waves, especially when operating the doublet far away from a match with the coax.
answered 15 hours ago
hobbs - KC2Ghobbs - KC2G
75028
$endgroup$
$begingroup$
Agreed. And, unless specific steps are taken, coax shield can be a very effective "antenna" to pickup noise.
$endgroup$
– Brian K1LI
15 hours ago
add a comment |
$begingroup$
There are a few things to think about.
Coaxial cable will likely not have a positive impact on your RFI.
Unfortunately, urban locations are loaded with RFI. Antenna direction and distance are the primary ways of reducing the received noise. On a small lot, this is not always possible but improvements should at least be evaluated. For example, an electrically shortened antenna may allow the antenna to be located further away from local noise sources and oriented such that its directionality attenuates these noises.
Don't overlook the opportunity to identify and potentially eliminate noise sources. Start with your own house by powering your radio off of a battery and shutting down the house power and other battery powered devices within the house. If the noise level drops, start turning on individual breakers to help identify the sources of your local noise. Go RFI hunting in the neighborhood to identify other noise sources that might be correctable.
If the antenna is not well balanced due to factors such as uneven heights or trees or buildings near the antenna then the feedline can become unbalanced and be a point of ingress for noise. A 1:1 balun at the feedpoint may help mitigate the noise ingress.
Connecting a balanced feedline to an unbalanced tuner can also couple local RFI into the antenna system. The antenna side of an unbalanced tuner should have a 1:1 balun between it and the balanced line. A belts and suspenders approach is to also put a 1:1 balun on the coaxial side of the tuner going to the transceiver.
answered 13 hours ago
Glenn W9IQGlenn W9IQ
16.3k11146
$endgroup$
add a comment |
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2 Answers
2
active
oldest
votes
2 Answers
2
active
oldest
votes
active
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votes
active
oldest
votes
$begingroup$
No, coax wouldn't be expected to improve the noise, unless your ladder line is running very close (within 1-2 times its conductor spacing) to a specific noise source, in which case you would be better off fixing that by finding a way to provide better spacing. The only thing that will change with coax is that your losses will become quite a bit higher, and more of your transmit power will be spent on heating the coax instead of making radio waves, especially when operating the doublet far away from a match with the coax.
answered 15 hours ago
hobbs - KC2Ghobbs - KC2G
75028
$endgroup$
$begingroup$
Agreed. And, unless specific steps are taken, coax shield can be a very effective "antenna" to pickup noise.
$endgroup$
– Brian K1LI
15 hours ago
add a comment |
$begingroup$
No, coax wouldn't be expected to improve the noise, unless your ladder line is running very close (within 1-2 times its conductor spacing) to a specific noise source, in which case you would be better off fixing that by finding a way to provide better spacing. The only thing that will change with coax is that your losses will become quite a bit higher, and more of your transmit power will be spent on heating the coax instead of making radio waves, especially when operating the doublet far away from a match with the coax.
answered 15 hours ago
hobbs - KC2Ghobbs - KC2G
75028
$endgroup$
$begingroup$
Agreed. And, unless specific steps are taken, coax shield can be a very effective "antenna" to pickup noise.
$endgroup$
– Brian K1LI
15 hours ago
add a comment |
$begingroup$
No, coax wouldn't be expected to improve the noise, unless your ladder line is running very close (within 1-2 times its conductor spacing) to a specific noise source, in which case you would be better off fixing that by finding a way to provide better spacing. The only thing that will change with coax is that your losses will become quite a bit higher, and more of your transmit power will be spent on heating the coax instead of making radio waves, especially when operating the doublet far away from a match with the coax.
answered 15 hours ago
hobbs - KC2Ghobbs - KC2G
75028
$endgroup$
No, coax wouldn't be expected to improve the noise, unless your ladder line is running very close (within 1-2 times its conductor spacing) to a specific noise source, in which case you would be better off fixing that by finding a way to provide better spacing. The only thing that will change with coax is that your losses will become quite a bit higher, and more of your transmit power will be spent on heating the coax instead of making radio waves, especially when operating the doublet far away from a match with the coax.
answered 15 hours ago
hobbs - KC2Ghobbs - KC2G
75028
answered 15 hours ago
hobbs - KC2Ghobbs - KC2G
75028
answered 15 hours ago
hobbs - KC2Ghobbs - KC2G
75028
answered 15 hours ago
hobbs - KC2Ghobbs - KC2G
75028
75028
$begingroup$
Agreed. And, unless specific steps are taken, coax shield can be a very effective "antenna" to pickup noise.
$endgroup$
– Brian K1LI
15 hours ago
add a comment |
$begingroup$
Agreed. And, unless specific steps are taken, coax shield can be a very effective "antenna" to pickup noise.
$endgroup$
– Brian K1LI
15 hours ago
$begingroup$
Agreed. And, unless specific steps are taken, coax shield can be a very effective "antenna" to pickup noise.
$endgroup$
– Brian K1LI
15 hours ago
$begingroup$
Agreed. And, unless specific steps are taken, coax shield can be a very effective "antenna" to pickup noise.
$endgroup$
– Brian K1LI
15 hours ago
add a comment |
$begingroup$
There are a few things to think about.
Coaxial cable will likely not have a positive impact on your RFI.
Unfortunately, urban locations are loaded with RFI. Antenna direction and distance are the primary ways of reducing the received noise. On a small lot, this is not always possible but improvements should at least be evaluated. For example, an electrically shortened antenna may allow the antenna to be located further away from local noise sources and oriented such that its directionality attenuates these noises.
Don't overlook the opportunity to identify and potentially eliminate noise sources. Start with your own house by powering your radio off of a battery and shutting down the house power and other battery powered devices within the house. If the noise level drops, start turning on individual breakers to help identify the sources of your local noise. Go RFI hunting in the neighborhood to identify other noise sources that might be correctable.
If the antenna is not well balanced due to factors such as uneven heights or trees or buildings near the antenna then the feedline can become unbalanced and be a point of ingress for noise. A 1:1 balun at the feedpoint may help mitigate the noise ingress.
Connecting a balanced feedline to an unbalanced tuner can also couple local RFI into the antenna system. The antenna side of an unbalanced tuner should have a 1:1 balun between it and the balanced line. A belts and suspenders approach is to also put a 1:1 balun on the coaxial side of the tuner going to the transceiver.
answered 13 hours ago
Glenn W9IQGlenn W9IQ
16.3k11146
$endgroup$
add a comment |
$begingroup$
There are a few things to think about.
Coaxial cable will likely not have a positive impact on your RFI.
Unfortunately, urban locations are loaded with RFI. Antenna direction and distance are the primary ways of reducing the received noise. On a small lot, this is not always possible but improvements should at least be evaluated. For example, an electrically shortened antenna may allow the antenna to be located further away from local noise sources and oriented such that its directionality attenuates these noises.
Don't overlook the opportunity to identify and potentially eliminate noise sources. Start with your own house by powering your radio off of a battery and shutting down the house power and other battery powered devices within the house. If the noise level drops, start turning on individual breakers to help identify the sources of your local noise. Go RFI hunting in the neighborhood to identify other noise sources that might be correctable.
If the antenna is not well balanced due to factors such as uneven heights or trees or buildings near the antenna then the feedline can become unbalanced and be a point of ingress for noise. A 1:1 balun at the feedpoint may help mitigate the noise ingress.
Connecting a balanced feedline to an unbalanced tuner can also couple local RFI into the antenna system. The antenna side of an unbalanced tuner should have a 1:1 balun between it and the balanced line. A belts and suspenders approach is to also put a 1:1 balun on the coaxial side of the tuner going to the transceiver.
answered 13 hours ago
Glenn W9IQGlenn W9IQ
16.3k11146
$endgroup$
add a comment |
$begingroup$
There are a few things to think about.
Coaxial cable will likely not have a positive impact on your RFI.
Unfortunately, urban locations are loaded with RFI. Antenna direction and distance are the primary ways of reducing the received noise. On a small lot, this is not always possible but improvements should at least be evaluated. For example, an electrically shortened antenna may allow the antenna to be located further away from local noise sources and oriented such that its directionality attenuates these noises.
Don't overlook the opportunity to identify and potentially eliminate noise sources. Start with your own house by powering your radio off of a battery and shutting down the house power and other battery powered devices within the house. If the noise level drops, start turning on individual breakers to help identify the sources of your local noise. Go RFI hunting in the neighborhood to identify other noise sources that might be correctable.
If the antenna is not well balanced due to factors such as uneven heights or trees or buildings near the antenna then the feedline can become unbalanced and be a point of ingress for noise. A 1:1 balun at the feedpoint may help mitigate the noise ingress.
Connecting a balanced feedline to an unbalanced tuner can also couple local RFI into the antenna system. The antenna side of an unbalanced tuner should have a 1:1 balun between it and the balanced line. A belts and suspenders approach is to also put a 1:1 balun on the coaxial side of the tuner going to the transceiver.
answered 13 hours ago
Glenn W9IQGlenn W9IQ
16.3k11146
$endgroup$
There are a few things to think about.
Coaxial cable will likely not have a positive impact on your RFI.
Unfortunately, urban locations are loaded with RFI. Antenna direction and distance are the primary ways of reducing the received noise. On a small lot, this is not always possible but improvements should at least be evaluated. For example, an electrically shortened antenna may allow the antenna to be located further away from local noise sources and oriented such that its directionality attenuates these noises.
Don't overlook the opportunity to identify and potentially eliminate noise sources. Start with your own house by powering your radio off of a battery and shutting down the house power and other battery powered devices within the house. If the noise level drops, start turning on individual breakers to help identify the sources of your local noise. Go RFI hunting in the neighborhood to identify other noise sources that might be correctable.
If the antenna is not well balanced due to factors such as uneven heights or trees or buildings near the antenna then the feedline can become unbalanced and be a point of ingress for noise. A 1:1 balun at the feedpoint may help mitigate the noise ingress.
Connecting a balanced feedline to an unbalanced tuner can also couple local RFI into the antenna system. The antenna side of an unbalanced tuner should have a 1:1 balun between it and the balanced line. A belts and suspenders approach is to also put a 1:1 balun on the coaxial side of the tuner going to the transceiver.
answered 13 hours ago
Glenn W9IQGlenn W9IQ
16.3k11146
edited 11 hours ago
answered 13 hours ago
Glenn W9IQGlenn W9IQ
16.3k11146
answered 13 hours ago
Glenn W9IQGlenn W9IQ
16.3k11146
answered 13 hours ago
Glenn W9IQGlenn W9IQ
16.3k11146
16.3k11146
add a comment |
add a comment |
Steve is a new contributor. Be nice, and check out our Code of Conduct.
Steve is a new contributor. Be nice, and check out our Code of Conduct.
Steve is a new contributor. Be nice, and check out our Code of Conduct.
Steve is a new contributor. Be nice, and check out our Code of Conduct.
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$begingroup$
The answer might depend on the noise generator and its location. Please describe the noise; is it atmospheric static or is it produced by devices like TVs, wall-warts and modems?
$endgroup$
– Brian K1LI
15 hours ago