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, [email protected] 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
