Topband: Wideband Balun...?

[PaulKB8N at aol.com]

The Heathkit Balun is not robust at all, the coils are close-spaced and  
made with #18 or #20 wire.  I had one as a young ham in the 60s and was  quite 
disappointed with the physical construction.  I'd not recommend going  to 
the bother of hunting one down. Over the years, I've designed  a lot of 4:1 
and 6:1 air core baluns.  No matter how I've tried, I've never  been able to 
produce one that will provide the kind of BW that a  torroid-based one will, 
nor do I see any benefit in trying.
 
Paul, K5AF
 
 
In a message dated 8/28/2012 3:12:47 P.M. Central Daylight Time,  
richard at karlquist.com writes:

Eddy  Swynar wrote:

>
> Is there really & truly such a thing as  an air core 4:1 balun that will
> cover the entire spectrum from 1.8- to  29.7-MHz...? I've looked & I've
> repeatedly searched on the  internet, but can not quite come up with such

Basically, you are  describing the old Heathkit balun.
It has two bifilar air core coils and is  designed
to convert 75 ohms to 300 ohms.  Covers 80 through 10  meters.  (Not
160 meters).  You could probably start with two of  these and combine
the coils to get down to  160.

See:

http://tubularelectronics.com/Heath_Manual_Collection/Heath_Manuals_B-D/B-1/
B-1.pdf

I  actually have one of these rare baluns, but I've never used it  for
anything.  It might be fun to hook it up to my Agilent 4  port
network analyzer and characterize it in even and odd  modes.

Rick  N6RK


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