17.95 + 3.99 in shipping. Looks like it will be a very nice reference
> Brett, I would recommend the Book "Understanding, Building and Using Baluns
> and Ununs by the late Jerry Sevick, avaliable from CQ
>
http://store.cq-amateur-radio.com/Categories.bok?category=Books%3AAntennas&searchpath=1547318&start=10&total=17> With this book, a BS in Physics, 54 years as a ham and 30 years as an EE I
> finally understood enough to make a balun or an unun. I don't understand
> them well enough to answer your questions correctly. I read all the stuff I
> could find on the internet and 50 years of ham magazines before I bought the
> book and was still too confused to pick a core and build the unun that I
> needed. If you just want a 4:1 balun and don't want a study course, I would
> recommend that you buy one. If you really need one that works 160 to 10 buy
> an expensive one from a good source, the ones that I tested did not have the
> advertised bandwidth. I did not test the Elecraft balun, but what I have
> seen of Elecraft engineering would give me confidence to try one.
>
> Willis 'Cookie' Cooke
> K5EWJ
>
> ________________________________
> From: Brett Howard <
[hidden email]>
> To: elecraft <
[hidden email]>
> Sent: Fri, July 23, 2010 3:53:42 AM
> Subject: [Elecraft] Balun Questions
>
> I'll preface this by explaining that I'm a digital guy and I've lately
> decided I want to get a little better understanding of magnetics and
> RF... Thus why I'm taking on making my own W3NQN band pass filters and
> I've also been interested in building a Balun...
>
> So I've looked at a few sites describing how to make a 4:1 balun... One
> such solution is to take 2 100 ohm 1:1 baluns and connect them in
> parallel on the input side and in series on the output side...
>
> I looked at the Elecraft BL1 manual but I didn't see what material the
> core was... However in another article I saw someone post the recommend
> getting a FT140-61 and winding 7 to 8 turns on each side to make the two
> 100 ohm feedlines.
>
> So I ran the numbers and 8 turns on a FT140-61 gives you about 100 ohms
> on 160 meters. Thus two 100 ohm points in parallel gives you 50 ohms in
> and 200 ohms out. 4:1... Great.
>
> However at say 40 meters... Each feedline is 430 ohms. Thus you've got
> a 215ohm input and a 860 ohm output. This just seems like it would make
> a mess. Why does it still work?
>
> Finally I'll explain my final goal... I've looked at several ways to
> make a 4:1 which involves using two 1:1's. Then there are methods to
> take 2 4:1's to make a 6:1 (the feedlines are 125ohm windings to pull
> this off). My final goal is to try to make a 6:1 and use it to use
> ladder line once I get through the wall with coax. I always just
> figured that a 6:1 would be better as it would have a 50 ohm in and a
> true 300 ohm out.
>
> However once you get away from the design frequency the feed impedances
> go to pot... So is there really much difference in the 6:1 and the 4:1?
> I've read of many people doing what I'm talking about with a 4:1 and
> just figured that a 6:1 should provide a better match... Am I thinking
> right or is the match so terrible anyway that it doesn't so much
> matter?
>
> Is it just that the thing balances the currents on the outputs and I'm
> just over thinking the matching ability?
>
> Appreciated gentlemen.
>
> ~Brett (N7MG)
>
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