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#1
June 3rd 05, 02:58 AM
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Dale:
Yes, someone injected a T-Match in here, but no real interest in a T-Match... Warmest regards, John "Dale Parfitt" wrote in message news:ODOne.7695$vK5.2782@trnddc03... "Dave Platt" wrote in message ... In article tJLne.13595$Vm4.9195@trnddc01, Dale Parfitt wrote: How can a T match have show a bias- it is balanced. Virtually all the serious EME arrays use this matching technique and show the major lobe dead off the front. Are they feeding directly off of the coax, or do they use a halfwave (or other) balun between the coax and the T? Check out any of the antenna handbooks for a Tee match. The driven element is insulated from the boom and split in the middle. Each side of the Tee taps out on the D.E. at a point yielding a 200 Ohm balanced feed. A 4:1 coaxial balun is used to transform the 200 Ohms balanced down to 50 Ohms unbalanced. Dale W4OP |
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#2
June 3rd 05, 01:01 PM
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I should have pointed out, a T-Match requires a dipole, a few seem to
miss I had previously noted this is a monopole in question... a T-Match would unbalance the RF RADIATION PATTERN of a dipole in the same way a gamma does a monopole, there would be no gain from using a T-Match in place of a gamma, EVEN if it could be done here... I suppose you might be able to mount the bottom of T-Match on the mast holding the monopole--but then, that is another experiment for another day... Warmest regards, John "John Smith" wrote in message ... Dale: Yes, someone injected a T-Match in here, but no real interest in a T-Match... Warmest regards, John "Dale Parfitt" wrote in message news:ODOne.7695$vK5.2782@trnddc03... "Dave Platt" wrote in message ... In article tJLne.13595$Vm4.9195@trnddc01, Dale Parfitt wrote: How can a T match have show a bias- it is balanced. Virtually all the serious EME arrays use this matching technique and show the major lobe dead off the front. Are they feeding directly off of the coax, or do they use a halfwave (or other) balun between the coax and the T? Check out any of the antenna handbooks for a Tee match. The driven element is insulated from the boom and split in the middle. Each side of the Tee taps out on the D.E. at a point yielding a 200 Ohm balanced feed. A 4:1 coaxial balun is used to transform the 200 Ohms balanced down to 50 Ohms unbalanced. Dale W4OP |
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#3
June 3rd 05, 01:43 PM
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John Smith wrote:
I should have pointed out, a T-Match requires a dipole, a few seem to miss I had previously noted this is a monopole in question... Is there any difference in a 1/2WL monopole element and a 1/2WL dipole element sans the T-Match? I can't think of any. -- 73, Cecil http://www.qsl.net/w5dxp ----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+ Newsgroups ----= East and West-Coast Server Farms - Total Privacy via Encryption =---- |
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#4
June 3rd 05, 01:50 PM
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Not that I am aware of, only thing is there is no where to "hang" that
T-Match--well, the mast I mentioned... and the fact the monopole is absent the bottom half of a dipole element... this is especially notable if the bottom end of the monopole is sitting on the ground... that tends to remove all confusion... grin Warmest regards, John "Cecil Moore" wrote in message ... John Smith wrote: I should have pointed out, a T-Match requires a dipole, a few seem to miss I had previously noted this is a monopole in question... Is there any difference in a 1/2WL monopole element and a 1/2WL dipole element sans the T-Match? I can't think of any. -- 73, Cecil http://www.qsl.net/w5dxp ----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+ Newsgroups ----= East and West-Coast Server Farms - Total Privacy via Encryption =---- |
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#5
June 3rd 05, 02:02 PM
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.... err, not to be confused with a "dipole beam", which is better
referred to as a "two element beam" to remove all confusion... grin Warmest regards, John "John Smith" wrote in message ... Not that I am aware of, only thing is there is no where to "hang" that T-Match--well, the mast I mentioned... and the fact the monopole is absent the bottom half of a dipole element... this is especially notable if the bottom end of the monopole is sitting on the ground... that tends to remove all confusion... grin Warmest regards, John "Cecil Moore" wrote in message ... John Smith wrote: I should have pointed out, a T-Match requires a dipole, a few seem to miss I had previously noted this is a monopole in question... Is there any difference in a 1/2WL monopole element and a 1/2WL dipole element sans the T-Match? I can't think of any. -- 73, Cecil http://www.qsl.net/w5dxp ----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+ Newsgroups ----= East and West-Coast Server Farms - Total Privacy via Encryption =---- |
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#6
June 3rd 05, 09:24 PM
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in other words i think he is trying to make a J pole into a coaxial
arrangement where the short part of the J wraps all the way around the pole. personally it sounds like a lot of work to get rid of some small assymetry caused by the gamma rod. the easier solution is a plain vertical with a tuner to make the transmitter happy. "John Smith" wrote in message ... ... err, not to be confused with a "dipole beam", which is better referred to as a "two element beam" to remove all confusion... grin Warmest regards, John "John Smith" wrote in message ... Not that I am aware of, only thing is there is no where to "hang" that T-Match--well, the mast I mentioned... and the fact the monopole is absent the bottom half of a dipole element... this is especially notable if the bottom end of the monopole is sitting on the ground... that tends to remove all confusion... grin Warmest regards, John "Cecil Moore" wrote in message ... John Smith wrote: I should have pointed out, a T-Match requires a dipole, a few seem to miss I had previously noted this is a monopole in question... Is there any difference in a 1/2WL monopole element and a 1/2WL dipole element sans the T-Match? I can't think of any. -- 73, Cecil http://www.qsl.net/w5dxp ----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+ Newsgroups ----= East and West-Coast Server Farms - Total Privacy via Encryption =---- |
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#7
June 3rd 05, 09:52 PM
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why not just a rusty coat hanger and some bailing wire? grin
John "Dave" wrote in message ... in other words i think he is trying to make a J pole into a coaxial arrangement where the short part of the J wraps all the way around the pole. personally it sounds like a lot of work to get rid of some small assymetry caused by the gamma rod. the easier solution is a plain vertical with a tuner to make the transmitter happy. "John Smith" wrote in message ... ... err, not to be confused with a "dipole beam", which is better referred to as a "two element beam" to remove all confusion... grin Warmest regards, John "John Smith" wrote in message ... Not that I am aware of, only thing is there is no where to "hang" that T-Match--well, the mast I mentioned... and the fact the monopole is absent the bottom half of a dipole element... this is especially notable if the bottom end of the monopole is sitting on the ground... that tends to remove all confusion... grin Warmest regards, John "Cecil Moore" wrote in message ... John Smith wrote: I should have pointed out, a T-Match requires a dipole, a few seem to miss I had previously noted this is a monopole in question... Is there any difference in a 1/2WL monopole element and a 1/2WL dipole element sans the T-Match? I can't think of any. -- 73, Cecil http://www.qsl.net/w5dxp ----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+ Newsgroups ----= East and West-Coast Server Farms - Total Privacy via Encryption =---- |
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#8
June 3rd 05, 11:42 PM
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John Smith wrote: I should have pointed out, a T-Match requires a dipole, a few seem to miss I had previously noted this is a monopole in question... a T-Match would unbalance the RF RADIATION PATTERN of a dipole in the same way a gamma does a monopole, there would be no gain from using a T-Match in place of a gamma, EVEN if it could be done here... I suppose you might be able to mount the bottom of T-Match on the mast holding the monopole--but then, that is another experiment for another day... Warmest regards, John I've been thinking about a delta type match as a way to couple to a 1/2 wave radiator. Might be interesting. ac6xg "John Smith" wrote in message ... Dale: Yes, someone injected a T-Match in here, but no real interest in a T-Match... Warmest regards, John "Dale Parfitt" wrote in message news:ODOne.7695$vK5.2782@trnddc03... "Dave Platt" wrote in message ... In article tJLne.13595$Vm4.9195@trnddc01, Dale Parfitt wrote: How can a T match have show a bias- it is balanced. Virtually all the serious EME arrays use this matching technique and show the major lobe dead off the front. Are they feeding directly off of the coax, or do they use a halfwave (or other) balun between the coax and the T? Check out any of the antenna handbooks for a Tee match. The driven element is insulated from the boom and split in the middle. Each side of the Tee taps out on the D.E. at a point yielding a 200 Ohm balanced feed. A 4:1 coaxial balun is used to transform the 200 Ohms balanced down to 50 Ohms unbalanced. Dale W4OP |
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#9
June 4th 05, 01:20 AM
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might just work, if the total element length is 1 wave! and in a dipole
configuration... Warmest regards, John "Jim Kelley" wrote in message ... John Smith wrote: I should have pointed out, a T-Match requires a dipole, a few seem to miss I had previously noted this is a monopole in question... a T-Match would unbalance the RF RADIATION PATTERN of a dipole in the same way a gamma does a monopole, there would be no gain from using a T-Match in place of a gamma, EVEN if it could be done here... I suppose you might be able to mount the bottom of T-Match on the mast holding the monopole--but then, that is another experiment for another day... Warmest regards, John I've been thinking about a delta type match as a way to couple to a 1/2 wave radiator. Might be interesting. ac6xg "John Smith" wrote in message ... Dale: Yes, someone injected a T-Match in here, but no real interest in a T-Match... Warmest regards, John "Dale Parfitt" wrote in message news:ODOne.7695$vK5.2782@trnddc03... "Dave Platt" wrote in message ... In article tJLne.13595$Vm4.9195@trnddc01, Dale Parfitt wrote: How can a T match have show a bias- it is balanced. Virtually all the serious EME arrays use this matching technique and show the major lobe dead off the front. Are they feeding directly off of the coax, or do they use a halfwave (or other) balun between the coax and the T? Check out any of the antenna handbooks for a Tee match. The driven element is insulated from the boom and split in the middle. Each side of the Tee taps out on the D.E. at a point yielding a 200 Ohm balanced feed. A 4:1 coaxial balun is used to transform the 200 Ohms balanced down to 50 Ohms unbalanced. Dale W4OP |
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#10
June 4th 05, 01:22 AM
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.... however, would still distort radiation pattern due to the match on
one side... perfect symmetry prompted me to begin this line of thought and tweaking the equations... Warmest regards, John "John Smith" wrote in message ... might just work, if the total element length is 1 wave! and in a dipole configuration... Warmest regards, John "Jim Kelley" wrote in message ... John Smith wrote: I should have pointed out, a T-Match requires a dipole, a few seem to miss I had previously noted this is a monopole in question... a T-Match would unbalance the RF RADIATION PATTERN of a dipole in the same way a gamma does a monopole, there would be no gain from using a T-Match in place of a gamma, EVEN if it could be done here... I suppose you might be able to mount the bottom of T-Match on the mast holding the monopole--but then, that is another experiment for another day... Warmest regards, John I've been thinking about a delta type match as a way to couple to a 1/2 wave radiator. Might be interesting. ac6xg "John Smith" wrote in message ... Dale: Yes, someone injected a T-Match in here, but no real interest in a T-Match... Warmest regards, John "Dale Parfitt" wrote in message news:ODOne.7695$vK5.2782@trnddc03... "Dave Platt" wrote in message ... In article tJLne.13595$Vm4.9195@trnddc01, Dale Parfitt wrote: How can a T match have show a bias- it is balanced. Virtually all the serious EME arrays use this matching technique and show the major lobe dead off the front. Are they feeding directly off of the coax, or do they use a halfwave (or other) balun between the coax and the T? Check out any of the antenna handbooks for a Tee match. The driven element is insulated from the boom and split in the middle. Each side of the Tee taps out on the D.E. at a point yielding a 200 Ohm balanced feed. A 4:1 coaxial balun is used to transform the 200 Ohms balanced down to 50 Ohms unbalanced. Dale W4OP |
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