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Old 10-01-2008, 09:14 PM   #5
N7OQ
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Join Date: Nov 2007
Location: Yuba City, Ca
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Originally Posted by Andy N1ORK View Post
Ok, I know about rf chokes that you can wind near the feed point of an antenna and loading coils and the such. But what is an TRSB?.......OK, skip that. I just looked it up on the B'pole site. It is a Triple Ratio Switch Balun (TRSB) and it's very expensive. Do you think it would help a 20m or 80m 'Hamstick' dipole?
In this case it is a combination of a Balun and a UnUn. If you want to build one here is the site that shows you how. http://www.qsl.net/wb6zqz/trb/ This is the Guy who came up with the design that Buddipole used they just added a switch and a nice case. The Toroid cores are f-125-K 2 each that you can but from these guys http://www.bytemark.com/products/fertabmat.htm along with he wire and fiberglass tape. I have all the parts sitting on my work bench just got to make a PC board and put it all together.

This balun would work well with any shortened dipole because the the feed impendence for a dipole using coils is usually much lower than 50 ohms more like 25 or 12 ohms so it would help get a better match and should increase the band width plus it helps keep the RF from coming back down the shield of the coax. What Buddipole does to get past this problem without a balun is to feed it off center, that is why one coil has mote turns on it than the other one, but it is much better if you can match the natural impedence of the antenna.

So many projects to build and so little time to do it.
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