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@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
_______________________________________________
UR RST IS ... ... ..9 QSB QSB - hw? BK
_______________________________________________
UR RST IS ... ... ..9 QSB QSB - hw? BK
|