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#1
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When using balanced antennas such as loops, dipoles, etc. a voltage
balun can be used, however, great detail should be paid to the symmetry of the antenna and even one leg of a dipole being nearer a metal building, trees, etc. can effect that symmetry. When using unbalanced antennas end fed, long wire, monopole, etc. a unun is better used and will even eliminate most common mode currents. I think most here really want the Unun ... Regards, JS |
#2
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On Sun, 24 Dec 2006 08:30:37 -0800, John Smith
wrote: When using balanced antennas such as loops, dipoles, etc. a voltage balun can be used, however, great detail should be paid to the symmetry of the antenna and even one leg of a dipole being nearer a metal building, trees, etc. can effect that symmetry. When using unbalanced antennas end fed, long wire, monopole, etc. a unun is better used and will even eliminate most common mode currents. I think most here really want the Unun ... Regards, JS Autotransformer |
#3
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David wrote:
On Sun, 24 Dec 2006 08:30:37 -0800, John Smith wrote: When using balanced antennas such as loops, dipoles, etc. a voltage balun can be used, however, great detail should be paid to the symmetry of the antenna and even one leg of a dipole being nearer a metal building, trees, etc. can effect that symmetry. When using unbalanced antennas end fed, long wire, monopole, etc. a unun is better used and will even eliminate most common mode currents. I think most here really want the Unun ... Regards, JS Autotransformer No. Quite a bit of difference between a true autotransformer and a current balun/unun. The obvious physical difference is one (autotransformer) has a single layer winding, the other a bifilar, trifilar, or quadfilar winding. JS |
#4
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JS - Yes and a UnUn Good Night ~ RHF
Merry Christ John Boy {The Waltons} |
#5
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RHF wrote:
JS - Yes and a UnUn Good Night ~ RHF Merry Christ John Boy {The Waltons} . . . . On Dec 24, 8:30 am, John Smith wrote: When using balanced antennas such as loops, dipoles, etc. a voltage balun can be used, however, great detail should be paid to the symmetry of the antenna and even one leg of a dipole being nearer a metal building, trees, etc. can effect that symmetry. When using unbalanced antennas end fed, long wire, monopole, etc. a unun is better used and will even eliminate most common mode currents. I think most here really want the Unun ... Regards, JS MERRY XMAS RHF!!! hearty wave Warmest regards, JS |
#6
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![]() John Smith wrote: When using balanced antennas such as loops, dipoles, etc. a voltage balun can be used, however, great detail should be paid to the symmetry of the antenna and even one leg of a dipole being nearer a metal building, trees, etc. can effect that symmetry. When using unbalanced antennas end fed, long wire, monopole, etc. a unun is better used and will even eliminate most common mode currents. I think most here really want the Unun ... Regards, JS I like ununs on my hamburger. |
#7
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In article ,
John Smith wrote: When using balanced antennas such as loops, dipoles, etc. a voltage balun can be used, however, great detail should be paid to the symmetry of the antenna and even one leg of a dipole being nearer a metal building, trees, etc. can effect that symmetry. You are better off with a current BALUN type. They have a wider, flatter response and are usually more efficient. When using unbalanced antennas end fed, long wire, monopole, etc. a unun is better used and will even eliminate most common mode currents. Well, I think you mean noise currents. The signals the single element antenna picks up are also common mode. Here the voltage type UNUN has the advantage of DC isolation between the receiver and antenna where it can direct static voltage potential to ground. With a receiver plugged into the mains AC supply noise from that system can conduct on the outside of the coax or the coax itself can pick it up if it goes by a noise source. Once it reached the antenna connection it can couple to the antenna. The two circuits of the voltage transformer can be independently grounded so that the antenna RF ground is not the same as the coax ground where the mains noise is going. Single wire element antennas (random wire, long wire) are a Marconi type where the other half of the antenna is ground. If you only have one ground then RF ground for the antenna is also a noise current ground where they can mix. The mode these antennas pick up signals is common mode so the antenna needs to be in a RF quiet environment or you are wasting your time. This usually means you need to be living in a semi-rural to rural area or you cannot get the antenna far enough away from your house or your neighbors. I live in an urban environment and a Marconi antenna picks up way too much noise to work well. -- Telamon Ventura, California |
#8
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Telamon wrote:
... Well, I think you mean noise currents. The signals the single element antenna picks up are also common mode. Here the voltage type UNUN has the advantage of DC isolation between the ... Balun = "BALanced-to-UNbalanced" Unun = "UNbalanced-to-UNbalanced" What type of antenna you are feed AND what type of feed your rcvr/xmitter expects SOLELY determines if you should use a balun or a unun ... Regards, JS |
#9
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On Mon, 25 Dec 2006 23:48:08 -0800, John Smith
wrote: Telamon wrote: ... Well, I think you mean noise currents. The signals the single element antenna picks up are also common mode. Here the voltage type UNUN has the advantage of DC isolation between the ... Balun = "BALanced-to-UNbalanced" Unun = "UNbalanced-to-UNbalanced" What type of antenna you are feed AND what type of feed your rcvr/xmitter expects SOLELY determines if you should use a balun or a unun ... Regards, JS Semantics. |
#10
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David wrote:
... Semantics. Naaa. You can call the damn things anything you wish. It is only if you expect to be able to achieve maximum performance that you need to know the correct terms, use the correct devices, etc. JS |
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