RSOLOMON@systems.TEXTRON.COM wrote:
>
> Since I am taking the 402BA down to rebuild, I might as well replace
> the coax (Preventative measure). The Collins Coaxial balun interests
> me. Not having a CQ library, can anyone provide more info on this.
>
> Thanks, Dick, W1KSZ
> rsolomon@systems.textron.com
>
>
I use the version from Mar '80 HR for a 50ohm 1:1 balun as follows:
RG 8X 50" long
#12 insulated wire 50" long (I use the plastic covered stranded)
The coax and wire are COUNTER wound into a coil of 4.5" dia to make a 3
1/2 turn coil of each piece. This means that the coax is wound
clockwise and the wire counter clockwise with it. The #12 wire attaches
to the shield of the coax at one end and then attaches to the center
conductor of the coax at the other end. I tape the whole thing
together.
Put a coax connector on the same end that the #12 wire attaches to the
shield. The antenna (balanced load) connects at the other end to the
coax shield for one line and the center conductor+#12 wire junction for
the other line. A picture is better. I hope this helps. The artcle
was excellent, I have successfully used these things since 1980 under
high power and SWR conditions.
My power tests and SWR test show it flat to about 35MHz. I check my
recent one with the MFJ analyzer with similar results and I also noted a
self resonant frequency around 47MHz. I use it on dipoles and my Wilson
System 1 through 10 meters.
Good luck.. George W1ZT
--
FAQ on WWW: http://www.contesting.com/towertalkfaq.html
Submissions: towertalk@contesting.com
Administrative requests: towertalk-REQUEST@contesting.com
Problems: owner-towertalk@contesting.com
Search: http://www.contesting.com/km9p/search
|